Vivint S-4 13 Jun 19 Registration of securities issued in business combination transactions Financial data

Document and Entity Information

Document and Entity Information	3 Months Ended
	Mar. 31, 2019
Document And Entity Information [Abstract]
Document Type	S-4
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Entity Registrant Name	APX Group Holdings, Inc.
Entity Central Index Key	0001584423
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 3,691	$ 12,773	$ 3,872
Accounts and notes receivable, net	55,348	48,724	40,721
Inventories	94,275	50,552	115,222
Prepaid expenses and other current assets	15,128	11,449	16,150
Total current assets	168,442	123,498	175,965
Property, plant and equipment, net	64,614	73,401	78,081
Capitalized contract costs, net	1,092,865	1,115,775	0
Subscriber acquisition costs, net		0	1,308,558
Deferred financing costs, net	1,797	2,058	3,099
Intangible assets, net	235,583	255,085	377,451
Goodwill	835,404	834,855	836,970
Operating lease right-of-use assets	72,891	0
Long-term notes receivables and other assets, net	121,796	119,819	88,723
Total assets	2,593,392	2,524,491	2,868,847
Current Liabilities:
Accounts payable	115,242	66,646	107,347
Accrued payroll and commissions	37,281	65,479	57,752
Accrued expenses and other current liabilities	158,997	136,715	74,321
Deferred revenue	194,326	186,953	88,337
Current portion of operating lease liabilities	11,749	0
Current portion of finance lease liabilities	7,114	7,743
Current portion of capital lease obligations		7,743	10,614
Total current liabilities	524,709	463,536	338,371
Notes payable, net	2,956,702	2,961,947	2,760,297
Notes payable, net - related party	79,288	75,148	0
Revolving credit facility	40,000	0	60,000
Finance lease liabilities, net of current portion	3,952	5,571
Capital lease obligations, net of current portion		5,571	11,089
Deferred revenue, net of current portion	326,631	323,585	264,555
Operating lease liabilities	71,964	0
Other long-term obligations	73,390	90,209	79,020
Deferred income tax liabilities	1,120	1,096	9,041
Total liabilities	4,077,756	3,921,092	3,522,373
Commitments and contingencies
Stockholders’ deficit:
Common stock, $0.01 par value, 100 shares authorized; 100 shares issued and outstanding	0	0
Additional paid-in capital	737,072	736,333	732,346
Accumulated deficit	(2,193,169)	(2,104,097)	(1,358,571)
Accumulated other comprehensive loss	(28,267)	(28,837)	(27,301)
Total stockholders’ deficit	(1,484,364)	(1,396,601)	(653,526)
Total liabilities and stockholders’ deficit	$ 2,593,392	$ 2,524,491	$ 2,868,847

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, authorized (in shares)	100	100	100
Common stock, issued (in shares)	100	100	100
Common stock, outstanding (in shares)	100	100	100

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Revenues:	$ 276,249	$ 246,597	$ 1,050,441	$ 881,983	$ 757,907
Costs and expenses:
Operating expenses (exclusive of depreciation and amortization shown separately below)	83,076	83,760	355,813	321,476	264,865
Selling expenses (exclusive of amortization of deferred commissions, respectively, which are included in depreciation and amortization shown separately below)	43,591	59,243	213,386	198,348	131,421
General and administrative expenses	46,339	50,967	204,536	188,397	143,168
Depreciation and amortization	131,221	124,258	514,082	329,255	288,542
Restructuring and asset impairment charges			4,683	0	1,013
Total costs and expenses	304,227	318,228	1,292,500	1,037,476	829,009
Loss from operations	(27,978)	(71,631)	(242,059)	(155,493)	(71,102)
Other expenses (income):
Interest expense	63,748	58,790	245,214	225,772	197,965
Interest income	(23)	(31)	(425)	(130)	(432)
Other (income) loss, net	(2,246)	(45,240)	(17,323)	27,986	7,255
Loss before income taxes	(89,457)	(85,150)	(469,525)	(409,121)	(275,890)
Income tax (benefit) expense	(301)	(433)	(1,611)	1,078	67
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Recurring and other revenue
Revenues:
Revenues:	$ 276,249	$ 246,597	1,050,441	843,420	724,478
Service and other sales revenue
Revenues:
Revenues:			0	26,988	22,855
Activation fees
Revenues:
Revenues:			$ 0	$ 11,575	$ 10,574

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Amortization of deferred commissions	$ 44,012	$ 38,303	$ 165,797	$ 84,152	$ 64,007

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (89,156)	$ (84,717)	$ (467,914)	$ (410,199)	$ (275,957)
Other comprehensive income (loss), net of tax effects:
Foreign currency translation adjustment	570	(659)	(2,218)	3,155	2,482
Unrealized (loss) gain on marketable securities			0	(1,693)	1,011
Total other comprehensive income (loss)	570	(659)	(2,218)	1,462	3,493
Comprehensive loss	$ (88,586)	$ (85,376)	$ (470,132)	$ (408,737)	$ (272,464)

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Accumulated deficit	Accumulated deficitPreviously Reported [Member]	Accumulated other comprehensive loss	Accumulated other comprehensive lossPreviously Reported [Member]
Stockholders' equity, beginning balance at Dec. 31, 2015	$ (76,993)	$ 0	$ 627,645	$ (672,382)		$ (32,256)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Loss	(275,957)			(275,957)
Foreign currency translation adjustment	2,482					2,482
Unrealized (loss) gain on marketable securities	1,011					1,011
Stock-based compensation	3,868		3,868
Capital contribution	100,407		100,407
Stockholders' equity, ending balance at Dec. 31, 2016	(245,182)	0	731,920	(948,339)		(28,763)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Loss	(410,199)			(410,199)
Foreign currency translation adjustment	3,155					3,155
Unrealized (loss) gain on marketable securities	(1,693)					(1,693)
Stock-based compensation	1,544		1,577	(33)
Return of capital to Vivint Smart Home, Inc.	(1,151)		(1,151)
Stockholders' equity, ending balance at Dec. 31, 2017	(653,526)	0	732,346	(1,358,571)		(27,301)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Loss	(84,717)
Foreign currency translation adjustment	(659)
Stock-based compensation	205		205
Return of capital to Vivint Smart Home, Inc.	(966)		(966)
Stockholders' equity, ending balance at Mar. 31, 2018	(1,022,235)	0	731,585	(1,726,540)		(27,280)
Stockholders' equity, beginning balance at Dec. 31, 2017	(653,526)	0	732,346	(1,358,571)		(27,301)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Loss	(467,914)			(467,914)
Foreign currency translation adjustment	(2,218)					(2,218)
Unrealized (loss) gain on marketable securities	0
Stock-based compensation	2,416		2,416
Capital contribution	4,700		4,700
Return of capital to Vivint Smart Home, Inc.	(3,129)		(3,129)
Stockholders' equity, ending balance at Dec. 31, 2018	(1,396,601)	0	736,333	(2,104,097)	$ (2,104,095)	(28,837)	$ (28,839)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Loss	(89,156)
Foreign currency translation adjustment	570
Stock-based compensation	857		857
Return of capital to Vivint Smart Home, Inc.	(118)		(118)
Stockholders' equity, ending balance at Mar. 31, 2019	$ (1,484,364)	$ 0	$ 737,072	$ (2,193,169)		$ (28,267)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss from operations	$ (89,156)	$ (84,717)	$ (467,914)	$ (410,199)	$ (275,957)
Adjustments to reconcile net loss to net cash used in operating activities of operations:
Amortization of capitalized contract costs	105,031	95,363	398,174	0	0
Amortization of subscriber acquisition costs			0	206,153	154,877
Amortization of customer relationships	18,632	21,084	84,174	94,863	108,178
Gain on fair value changes of equity securities	(2,212)	(332)	(477)	0	0
Depreciation and amortization of property, plant and equipment and other intangible assets	7,558	7,811	31,734	28,239	25,488
Amortization of deferred financing costs and bond premiums and discounts	1,180	1,343	5,152	6,586	10,447
Loss (gain) on sale or disposal of assets	232	(50,459)	(49,762)	458	(33)
Loss on early extinguishment of debt			14,571	23,062	10,085
Stock-based compensation	857	204	2,505	1,595	3,868
Provision for doubtful accounts	5,918	3,968	19,405	22,465	19,624
Deferred income taxes			(2,149)	929	(478)
Restructuring and asset impairment charges			0	0	7,126
Changes in operating assets and liabilities, net of acquisitions:
Accounts and notes receivable, net	(10,424)	(6,124)	(34,008)	(49,590)	(24,338)
Inventories	(43,668)	5,914	64,442	(75,580)	(11,827)
Prepaid expenses and other current assets	(3,678)	(1,010)	4,695	(5,975)	(5,165)
Capitalized contract costs, net	80,614	84,986	499,252	0	0
Subscriber acquisition costs, net			0	(457,679)	(419,509)
Long-term notes receivables, other assets, net and right-of-use assets	2,756	(6,135)	(29,118)	(74,801)	368
Accounts payable	42,864	(25,551)	(27,045)	70,525	(2,978)
Accrued payroll and commissions, accrued expenses, other current and long-term liabilities, and current and long-term operating lease liabilities	(8,113)	30,252	91,469	62,208	12,702
Restructuring liability			0	(91)	(2,797)
Deferred revenue	9,820	33,793	172,905	247,500	24,613
Net cash used in operating activities	(43,017)	(59,582)	(220,499)	(309,332)	(365,706)
Cash flows from investing activities:
Subscriber acquisition costs – company owned equipment			0	0	(5,243)
Capital expenditures	(1,391)	(6,407)	(19,412)	(20,391)	(11,642)
Proceeds from the sale of intangible assets	0	53,693	53,693	0	0
Proceeds from the sale of capital assets			127	776	3,123
(Payments) proceeds from the sale of capital assets	(51)	149
Acquisition of intangible assets	(369)	(849)	(1,486)	(1,745)	(1,385)
Acquisition of other assets			0	(301)	0
Net cash (used in) provided by investing activities	(1,811)	46,586	32,922	(21,661)	(15,147)
Cash flows from financing activities:
Proceeds from notes payable			759,000	724,750	604,000
Proceeds from notes payable - related party			51,000	0	0
Repayments of notes payable	(2,025)	0	(522,191)	(450,000)	(235,535)
Borrowings from revolving credit facility	40,000	57,000	201,000	196,895	57,000
Repayments on revolving line of credit	0	(40,000)	(261,000)	(136,895)	(77,000)
Repayments of capital lease obligations		(3,418)	(12,354)	(10,007)	(8,315)
Repayments of finance lease obligations	(2,136)
Payments of other long-term obligations			0	(2,983)	0
Financing costs			(11,317)	(18,277)	(9,036)
Deferred financing costs			(9,302)	(11,119)	(9,241)
Return of capital	(118)	(966)	(3,129)	(1,151)	0
Proceeds from capital contributions			4,700	0	100,407
Net cash provided by financing activities	35,721	12,616	196,407	291,213	422,280
Cash and cash equivalents:
Beginning of period	12,773	3,872	3,872	43,520	2,559
End of period	3,691	3,473	12,773	3,872	43,520
Supplemental cash flow disclosures:
Income tax paid			330	219	435
Interest paid			239,441	207,433	189,170
Supplemental non-cash investing and financing activities:
Capital lease additions			4,569	14,633	8,411
Intangible asset acquisitions included within accounts payable, accrued expenses and other current liabilities and other long-term obligations			974	557	31,283
Capital expenditures included within accounts payable and accrued expenses and other current liabilities	2,213	572	128	2,531	2,345
Change in fair value of equity securities			0	1,314	1,011
Property acquired under build-to-suit agreements included within other long-term obligations			0	2,300	4,619
Finance lease additions	93	3,524
Intangible assets acquisitions included within accounts payable	374	403
Effect of exchange rate changes on cash	25	(19)	71	132	(466)
Net decrease in cash and cash equivalents	(9,082)	(399)	8,901	(39,648)	40,961
Proceeds from capital contribution	$ 0	$ 0	$ 4,700	$ 0	$ 100,407

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Unaudited Interim Financial Statements The accompanying interim unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q have been prepared by APX Group Holdings, Inc. and subsidiaries (the “Company”) without audit. The accompanying consolidated financial statements include the accounts of APX Group Holdings, Inc. and its subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to such rules and regulations. The information as of December 31, 2018 included in the unaudited condensed consolidated balance sheets was derived from the Company’s audited consolidated financial statements. The unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q were prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments (all of which are considered of a normal recurring nature) considered necessary to present fairly the Company’s financial position, results of operations and cash flows for the periods and dates presented. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 . These unaudited condensed consolidated financial statements and notes should be read in conjunction with the Company’s audited consolidated financial statements and related notes as set forth in the Company’s Annual Report on Form 10-K/A for the fiscal year ended December 31, 2018 , as filed with the Securities and Exchange Commission (“SEC”) on March 8, 2019, which is available on the SEC’s website at www.sec.gov. Basis of Presentation The unaudited condensed consolidated financial statements of the Company are presented for APX Group Holdings, Inc. (“Holdings") and its wholly-owned subsidiaries. The Company has prepared the accompanying unaudited condensed consolidated financial statements pursuant to GAAP. Preparing financial statements requires the Company to make estimates and assumptions that affect the amounts that are reported in the consolidated financial statements and accompanying disclosures. Although these estimates are based on the Company’s best knowledge of current events and actions that the Company may undertake in the future, actual results may be different from the Company’s estimates. The results of operations presented herein are not necessarily indicative of the Company’s results for any future period. Vivint Flex Pay The Vivint Flex Pay plan (“Vivint Flex Pay”) became the Company's primary sales model beginning in March 2017. Under Vivint Flex Pay, customers pay separately for the products (including control panel, security peripheral equipment, smart home equipment, and related installation) (“Products”) and Vivint's smart home and security services (“Services”). The customer has the following three options to pay for the Products: (1) qualified customers in the United States may finance the purchase of Products through a third-party financing provider (“Consumer Financing Program”), (2) customers not eligible for the Consumer Financing Program, but who qualify under the Company's underwriting criteria, may enter into a retail installment contract (“RIC”) directly with Vivint, or (3) customers may purchase the Products at the outset of the service contract by check, automatic clearing house payments (“ACH”), credit or debit card. Although customers pay separately for Products and Services under the Vivint Flex Pay plan, the Company has determined that the sale of Products and Services are one single performance obligation. As a result, all forms of transactions under Vivint Flex Pay create deferred revenue for the gross amount of Products sold. Gross deferred revenues are reduced by imputed interest on the RICs and the present value of expected payments due to the third-party financing provider under the Consumer Financing Program. Under the Consumer Financing Program, qualified customers are eligible for installment loans provided by a third-party financing provider of up to $4,000 for either 42 or 60 months. For a certain third-party provider, the Company pays a monthly fee based on the average daily outstanding balance of the installment loans. Additionally, the Company shares liability for credit losses depending on the credit quality of the customer. Because of the nature of these provisions with this third-party provider, the Company records a derivative liability at its fair value when the third-party financing provider originates installment loans to customers, which reduces the amount of estimated revenue recognized on the provision of the services. The derivative liability is reduced as payments are made by the Company to the third-party financing provider. Subsequent changes to the fair value of the derivative liability are realized through other income, net in the Condensed Consolidated Statement of Operations. (See Note 8 ). For a separate third-party financing provider , the Company receives net proceeds from installment loans (net of fees and expected losses) for which the Company has no further obligation to the third-party. The Company records these net proceeds to deferred revenue. Retail Installment Contract Receivables For subscribers that enter into a RIC to finance the purchase of Products and related installation, the Company records a receivable for the amount financed. The RIC receivables are recorded at their present value, net of the imputed interest discount. At the time of installation, the Company records a long-term note receivable within long-term notes receivables and other assets, net on the condensed consolidated balance sheets for the present value of the receivables that are expected to be collected beyond 12 months of the reporting date. The unbilled receivable amounts that are expected to be collected within 12 months of the reporting date are included as a short-term notes receivable within accounts and notes receivable, net on the condensed consolidated balance sheets. The billed amounts of notes receivables are included in accounts receivable within accounts and notes receivable, net on the condensed consolidated balance sheets. The Company imputes the interest on the RIC receivable using a risk adjusted market interest rate and records it as an adjustment to deferred revenue and as an adjustment to the face amount of the related receivable. The imputed interest discount considers a number of factors, including collection experience, aging of the remaining RIC receivable portfolios, credit quality of the subscriber base and other qualitative considerations, including macro-economic factors. The imputed interest income is recognized over the term of the RIC contract as recurring and other revenue on the condensed consolidated statement of operations. When the Company determines that there are RIC receivables that have become uncollectible, it records an adjustment to the imputed interest discount and reduces the related note receivable balance. Account balances are written-off if collection efforts are unsuccessful and future collection is unlikely based on the length of time from the day accounts become past due. Accounts Receivable Accounts receivable consists primarily of amounts due from subscribers for recurring monthly monitoring Services and the billed portion of RIC receivables. The accounts receivable are recorded at invoiced amounts and are non-interest bearing and are included within accounts and notes receivable, net on the condensed consolidated balance sheets. Accounts receivable totaled $20.0 million and $16.5 million at March 31, 2019 and December 31, 2018 , respectively net of the allowance for doubtful accounts of $5.8 million and $5.6 million at March 31, 2019 and December 31, 2018 , respectively. The Company estimates this allowance based on historical collection experience and subscriber attrition rates. When the Company determines that there are accounts receivable that are uncollectible, they are charged off against the allowance for doubtful accounts. The provision for doubtful accounts is included in general and administrative expenses in the accompanying unaudited condensed consolidated statements of operations and totaled $5.9 million and $4.0 million for the three months ended March 31, 2019 and 2018 , respectively. The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Three Months Ended March 31, 2019 Twelve Months Ended December 31, 2018 Beginning balance $ 5,594 $ 5,356 Provision for doubtful accounts 5,918 19,405 Write-offs and adjustments (5,704 ) (19,167 ) Balance at end of period $ 5,808 $ 5,594 Revenue Recognition The Company offers its customers smart home services combining Products, including a proprietary control panel, door and window sensors, door locks, security cameras and smoke alarms; installation; and a proprietary back-end cloud platform software and Services. These together create an integrated system that allows the Company’s customers to monitor, control and protect their home (“Smart Home Services”). The Company’s customers are buying this integrated system that provides them with these Smart Home Services. The number and type of Products purchased by a customer depends on their desired functionality. Because the Products and Services included in the customer’s contract are integrated and highly interdependent, and because they must work together to deliver the Smart Home Services, the Company has concluded that installed Products, related installation and Services contracted for by the customer are generally not distinct within the context of the contract and, therefore, constitute a single, combined performance obligation. Revenues for this single, combined performance obligation are recognized on a straight-line basis over the customer’s contract term. The Company has determined that certain contracts that do not require a long-term commitment for monitoring services by the customer contain a material right to renew the contract, because the customer does not have to purchase Products upon renewal. Proceeds allocated to the material right are recognized over the period of benefit, which is generally three years. The majority of the Company’s subscription contracts are between three and five years in length and are non-cancelable. These contracts with customers generally convert into month-to-month agreements at the end of the initial term, and some customer contracts are month-to-month from inception. Payment for recurring monitoring and other Smart Home Services is generally due in advance on a monthly basis. Sales of Products and other one-time fees such as service fees or installation fees are invoiced to the customer at the time of sale. Revenues for wireless internet service provided by Vivint Wireless Inc. (“Wireless Internet” or “Wireless”) and any Products or Services that are considered separate performance obligations are recognized when those Products or Services are delivered. Taxes collected from customers and remitted to governmental authorities are not included in revenue. Payments received or amounts billed in advance of revenue recognition are reported as deferred revenue. Deferred Revenue The Company's deferred revenues primarily consist of amounts for sales (including upfront proceeds) of Smart Home Services. Deferred revenues are recognized over the term of the related performance obligation, which is generally three to five years . Capitalized Contract Costs Capitalized contract costs represent the costs directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related subscriber contracts. These include commissions, other compensation and related costs incurred directly for the origination and installation of new or upgraded customer contracts, as well as the cost of Products installed in the customer home at the commencement or modification of the contract. These costs are deferred and amortized on a straight-line basis over the expected period of benefit that the Company has determined to be five years . Amortization of capitalized contract costs is included in “Depreciation and Amortization” on the consolidated statements of operations. These deferred costs are periodically reviewed for impairment. Contract costs not directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related subscriber contracts are expensed as incurred. These costs include those associated with housing, marketing and recruiting, non-direct lead generation costs, certain portions of sales commissions and residuals, overhead and other costs considered not directly and specifically tied to the origination of a particular subscriber. On the condensed consolidated statement of cash flows, capitalized contract costs are classified as operating activities and reported as “Capitalized contract costs – deferred contract costs” as these assets represent deferred costs associated with subscriber contracts. Cash and Cash Equivalents Cash and cash equivalents consists of highly liquid investments with remaining maturities when purchased of three months or less. Inventories Inventories, which are comprised of smart home and security system Products and parts, are stated at the lower of cost or net realizable value with cost determined under the first-in, first-out (“FIFO”) method. The Company adjusts the inventory balance based on anticipated obsolescence, usage and historical write-offs. Property, Plant and Equipment and Long-lived Assets Property, plant and equipment are stated at cost and depreciated on the straight-line method over the estimated useful lives of the assets or the lease term for assets under finance leases, whichever is shorter. Intangible assets with definite lives are amortized over the remaining estimated economic life of the underlying technology or relationships, which ranges from five to ten years . Definite-lived intangible assets are amortized on the straight-line method over the estimated useful life of the asset or in a pattern in which the economic benefits of the intangible asset are consumed. Amortization expense associated with leased assets is included with depreciation expense. Routine repairs and maintenance are charged to expense as incurred. The Company reviews long-lived assets, including property, plant and equipment, capitalized contract costs, and definite-lived intangibles for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. The Company considers whether or not indicators of impairment exist on a regular basis and as part of each quarterly and annual financial statement close process. Factors the Company considers in determining whether or not indicators of impairment exist include market factors and patterns of customer attrition. If indicators of impairment are identified, the Company estimates the fair value of the assets. An impairment loss is recognized if the carrying amount of a long-lived asset is not recoverable and exceeds its fair value. The Company conducts an indefinite-lived intangible impairment analysis annually as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s indefinite-lived intangibles may be less than the carrying amount. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate indefinite-lived intangible impairment using a qualitative approach. When necessary, the Company’s quantitative impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its indefinite-lived intangibles to the carrying value. If the fair value is greater than the carrying value, the intangibles are not considered to be impaired and no further testing is required. If the fair value is less than the carrying value, an impairment loss in an amount equal to the difference is recorded. During the three months ended March 31, 2019 and 2018 , no impairments to long-lived assets or intangibles were recorded. The Company’s depreciation and amortization included in the consolidated statements of operations consisted of the following (in thousands): Three Months Ended March 31, 2019 2018 Amortization of capitalized contract costs $ 105,028 $ 95,363 Amortization of definite-lived intangibles 20,272 22,720 Depreciation of property, plant and equipment 5,921 6,175 Total depreciation and amortization $ 131,221 $ 124,258 Leases Effective January 1, 2019 the Company accounts for leases under Topic 842 (see Recently Adopted Accounting Standards below). Under Topic 842, the Company determines if an arrangement is a lease at inception. Lease right-of-use (“ROU”) assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the present value of lease payments, the Company uses the implicit rate when available. When implicit rates are not available, the Company uses an incremental borrowing rate based on the information available at commencement date. The lease ROU asset also includes any lease payments made and is reduced by lease incentives. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company does not record lease ROU assets and liabilities for leases with terms of 12 months or less. Leases are classified as either operating or finance at lease inception. Operating lease assets and liabilities and finance lease liabilities are stated separately on the condensed consolidated balance sheets. Finance lease assets are included in property, plant and equipment, net on the condensed consolidated balance sheets. The Company has lease agreements with lease and non-lease components. For facility type leases, the Company separates the lease and non-lease components. Generally, the Company accounts for the lease and non-lease components as a single lease component for all other class of leases. Prior to the adoption of Topic 842, the Company's leases were classified as either operating or capital leases. Capital lease liabilities were stated separately on the condensed consolidated balance sheets and capital lease assets were included in property, plant and equipment, net on the condensed consolidated balance sheets. Operating leases were not recognized in the balance sheet. Capital lease balances are presented on the same lines as finance lease balances for comparative prior periods in the unaudited condensed consolidated financial statements. See Recently Adopted Accounting Standards below and note 12 "Leases" for additional information related to the impact of adopting Topic 842. Long-term Investments The Company’s long-term investments are composed of equity securities in both privately held and public companies. As of March 31, 2019 and December 31, 2018 , the Company's equity investments totaled $6.1 million and $3.9 million , respectively. Management determines the appropriate fair value measurement of its investments at the time of purchase and reevaluates the fair value measurement at each balance sheet date. Equity securities are classified as either short-term or long-term, based on the nature of each security and its availability for use in current operations. The Company’s equity securities are carried at fair value, with gains and losses reported in other income or loss within the statement of operations. The Company's equity investments without readily determinable fair values totaled $0.7 million as of March 31, 2019 and December 31, 2018 , respectively. The Company performs impairment analyses of its investments without readily determinable fair values when events occur or circumstances change that would, more likely than not, reduce the fair value of the investment below its carrying value. When indicators of impairment do not exist, the Company evaluates impairment using a qualitative approach. Additionally, increases or decreases in the carrying amount resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer are adjusted through the statement of operations as needed. As of March 31, 2019 and December 31, 2018 , no indicators of impairment or changes in observable prices existed associated with investments without readily determinable fair values. Deferred Financing Costs Certain costs incurred in connection with obtaining debt financing are deferred and amortized utilizing the straight-line method, which approximates the effective-interest method, over the life of the related financing. Deferred financing costs associated with obtaining APX Group, Inc.’s (“APX”) revolving credit facility are amortized over the amended maturity dates discussed in Note 3 . Deferred financing costs included in the accompanying unaudited condensed consolidated balance sheets within deferred financing costs, net at March 31, 2019 and December 31, 2018 were $1.8 million and $2.1 million , net of accumulated amortization of $9.9 million and $9.6 million , respectively. Deferred financing costs included in the accompanying unaudited condensed consolidated balance sheets within notes payable, net at March 31, 2019 and December 31, 2018 were $30.1 million and $32.4 million , net of accumulated amortization of $56.8 million and $54.6 million , respectively. Amortization expense on deferred financing costs recognized and included in interest expense in the accompanying unaudited condensed consolidated statements of operations, totaled $2.5 million and $2.7 million for the three months ended March 31, 2019 and 2018 , respectively (See Note 3 ). Residual Income Plans The Company has a program that allows certain third-party sales channel partners to receive additional compensation based on the performance of the underlying contracts they create (the “Channel Partner Plan”). The Company also has a residual sales compensation plan (the “Residual Plan”) under which the Company's sales personnel (each, a “Plan Participant”) receive compensation based on the performance of the underlying contracts they create. For both the Channel Partner Plan and Residual Plan, the Company calculates the present value of the expected future residual payments and records a liability for this amount in the period the subscriber account is originated. These costs are recorded to capitalized contract costs. The Company monitors actual payments and customer attrition on a periodic basis and, when necessary, makes adjustments to the liability. The amount included in accrued payroll and commissions $3.1 million and $4.9 million at March 31, 2019 and December 31, 2018 , respectively, and the amount included in other long-term obligations was $16.8 million and $17.6 million at March 31, 2019 and December 31, 2018 , respectively. Stock-Based Compensation The Company measures compensation cost based on the grant-date fair value of the award and recognizes that cost over the requisite service period of the awards (See Note 10 ). Advertising Expense Advertising costs are expensed as incurred. Advertising costs were $12.7 million and $13.7 million for the three months ended March 31, 2019 and 2018 , respectively. Income Taxes The Company accounts for income taxes based on the asset and liability method. Under the asset and liability method, deferred tax assets and deferred tax liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Valuation allowances are established when necessary to reduce deferred tax assets when it is determined that it is more likely than not that some portion, or all, of the deferred tax asset will not be realized. The Company recognizes the effect of an uncertain income tax position on the income tax return at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. The Company’s policy for recording interest and penalties is to record such items as a component of the provision for income taxes. Changes in tax laws and rates could also affect recorded deferred tax assets and liabilities in the future. The Company records the effect of a tax rate or law change on the Company’s deferred tax assets and liabilities in the period of enactment. Future tax rate or law changes could have a material effect on the Company’s results of operations, financial condition, or cash flows. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of receivables and cash. At times during the year, the Company maintains cash balances in excess of insured limits. The Company is not dependent on any single customer or geographic location. The loss of a customer would not adversely impact the Company’s operating results or financial position. Concentrations of Supply Risk As of March 31, 2019 , approximately 82% of the Company’s installed panels were SkyControl panels and 17% were 2GIG Go!Control panels and 1% were other panels. During the three months ended March 31, 2018 the Company transitioned to a new panel supplier. The loss of the Company's panel supplier could potentially impact its operating results or financial position. Fair Value Measurement Fair value is based on the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities subject to on-going fair value measurement are categorized and disclosed into one of three categories depending on observable or unobservable inputs employed in the measurement. These two types of inputs have created the following fair value hierarchy: Level 1: Quoted prices in active markets that are accessible at the measurement date for assets and liabilities. Level 2: Observable prices that are based on inputs not quoted in active markets, but corroborated by market data. Level 3: Unobservable inputs are used when little or no market data is available. This hierarchy requires the Company to minimize the use of unobservable inputs and to use observable market data, if available, when determining fair value. The Company recognizes transfers between levels of the hierarchy based on the fair values of the respective financial measurements at the end of the reporting period in which the transfer occurred. There were no transfers between levels of the fair value hierarchy during the three months ended March 31, 2019 and 2018 . The carrying amounts of the Company’s accounts receivable, accounts payable and accrued and other liabilities approximate their fair values due to their short maturities. Goodwill The Company conducts a goodwill impairment analysis annually in the fourth fiscal quarter, as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s reporting units may be less than their carrying amounts. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate goodwill impairment using a qualitative approach. When necessary, the Company’s quantitative goodwill impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its reporting units to the carrying value of the reporting unit’s net assets, including goodwill. If the fair value of the reporting unit is greater than the carrying value of its net assets, goodwill is not considered to be impaired and no further testing is required. If the fair value of the reporting unit is less than the carrying value of its net assets, the Company would be required to complete the second step of the test by analyzing the fair value of its goodwill. If the carrying value of the goodwill exceeds its fair value, an impairment charge is recorded. The Company’s reporting units are determined based on its current reporting structure, which as of December 31, 2018 and March 31, 2019 consisted of two reporting units. As of March 31, 2019 , there were no changes in facts and circumstances since the most recent annual impairment analysis to indicate impairment existed. Foreign Currency Translation and Other Comprehensive Income The functional currency of Vivint Canada, Inc. is the Canadian dollar. Accordingly, Vivint Canada, Inc. assets and liabilities are translated from their respective functional currencies into U.S. dollars at period-end rates and Vivint Canada, Inc. revenue and expenses are translated at the weighted-average exchange rates for the period. Adjustments resulting from this translation process are classified as other comprehensive income (loss) and shown as a separate component of equity. When intercompany foreign currency transactions between entities included in the consolidated financial statements are of a long term investment nature (i.e., those for which settlement is not planned or anticipated in the foreseeable future) foreign currency translation adjustments resulting from those transactions are included in stockholders’ deficit as accumulated other comprehensive loss or income. When intercompany transactions are deemed to be of a short term nature, translation adjustments are required to be included in the condensed consolidated statement of operations. The Company has determined that settlement of Vivint Canada, Inc. intercompany balances is anticipated and therefore such balances are deemed to be of a short term nature. Translation activity included in the statement of operations in other loss, net related to intercompany balances was as follows: (in thousands) Three Months Ended March 31, 2019 2018 Translation (gain) loss $ (1,701 ) $ 2,075 Letters of Credit As of March 31, 2019 and December 31, 2018 , the Company had $13.9 million and $13.8 million , respectively, of letters of credit issued in the ordinary course of business, all of which are undrawn. Restructuring and Asset Impairment Charges Restructuring and asset impairment charges represent expenses incurred in relation to activities to exit or disposal of portions of the Company's business that do not qualify as discontinued operations. Liabilities associated with restructuring are measured at their fair value when the liability is incurred. Expenses for related termination benefits are recognized at the date the Company notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. Liabilities related to termination of a contract are measured and recognized at fair value when the contract does not have any future economic benefit to the entity and the fair value of the liability is determined based on the present value of the remaining obligation. The Company expenses all other costs related to an exit or disposal activity as incurred (See Note 15 ). Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, “Financial Instruments—Credit Losses (Topic 326)” which modifies the measurement of expected credit losses of certain financial instruments. This update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019 and must be applied using a modified-retrospective approach, with early adoption permitted. The Company is evaluating the adoption of ASU 2016-13 and plans to provide additional information about its expected impact at a future date. Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” to increase transpar

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business APX Group Holdings, Inc. (“Holdings” or “Parent”), and its wholly-owned subsidiaries, (collectively the “Company”), is one of the largest smart home companies in North America. The Company is engaged in the sale, installation, servicing and monitoring of smart home and security systems, primarily in the United States and Canada. Holdings is wholly-owned by Vivint Smart Home, Inc., which is majority owned by 313 Acquisition, LLC. Vivint Smart Home, Inc. and APX Group Holdings, Inc. have no operations.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Presentation The Company has prepared the accompanying consolidated financial statements pursuant to generally accepted accounting principles in the United States (“GAAP”). Preparing financial statements requires the Company to make estimates and assumptions that affect the amounts that are reported in the consolidated financial statements and accompanying disclosures. Although these estimates are based on the Company’s best knowledge of current events and actions that the Company may undertake in the future, actual results may be different from the Company’s estimates. The results of operations presented herein are not necessarily indicative of the Company’s results for any future period. Vivint Flex Pay In January 2017, the Company announced the introduction of the Vivint Flex Pay plan (“Vivint Flex Pay”), which became the Company’s primary sales model beginning in March 2017. Under Vivint Flex Pay, customers pay separately for the products (including control panel, security peripheral equipment, smart home equipment, and related installation) (“Products”) and Vivint’s smart home and security services (“Services”). The customer has the following three options to pay for the Products: (1) qualified customers in the United States may finance the purchase of Products through a third-party financing provider (“Consumer Financing Program”) (2) customers not eligible for the Consumer Financing Program, but who qualify under the Company’s underwriting criteria, may enter into a retail installment contract (“RIC”) directly with Vivint, or (3) customers may purchase the Products at the outset of the service contract by check, automatic clearing house payments (“ACH”), credit or debit card. Although customers pay separately for the Products and Services under the Vivint Flex Pay plan, the Company has determined that the shift in its sales model does not change the Company’s conclusion that the sale of Products and Services are one single performance obligation. As a result, all forms of transactions under Vivint Flex Pay create deferred revenue for the gross amount of Products sold. Gross deferred revenues are reduced by imputed interest on the RICs and the present value of expected payments due to the third-party financing provider under the Consumer Financing Program. Under the Consumer Financing Program, qualified customers are eligible for installment loans provided by a third-party financing provider of up to $4,000 for either 42 or 60 months. The Company pays a monthly fee to the third-party financing provider based on the average daily outstanding balance of the installment loans. Additionally, the Company shares liability for credit losses depending on the credit quality of the customer. Because of the nature of these provisions under the Consumer Financing Program, the Company records a derivative liability at its fair value when the third-party financing provider originates installment loans to customers, which reduces the amount of estimated revenue recognized on the provision of the services. The derivative liability is reduced as payments are made from the Company to the third-party financing provider. Subsequent changes to the fair value of the derivative liability are realized through other loss/(income), net in the Consolidated Statement of Operations. (See Note 9 ). Retail Installment Contract Receivables For customers that enter into a RIC under the Vivint Flex Pay plan, the Company records a receivable for the amount financed. The RIC receivables are recorded at their present value, net of the imputed interest discount. At the time of installation, the Company records a long-term note receivable within long-term notes receivables and other assets, net on the consolidated balance sheets for the present value of the receivables that are expected to be collected beyond 12 months of the reporting date. The unbilled receivable amounts that are expected to be collected within 12 months of the reporting date are included as a short-term notes receivable within accounts and notes receivable, net on the consolidated balance sheets. The billed amounts of notes receivables are included in accounts receivable within accounts and notes receivable, net on the consolidated balance sheets. The Company imputes the interest on the RIC receivable using a risk adjusted market interest rate and records it as an adjustment to deferred revenue and as an adjustment to the face amount of the related receivable. The imputed interest discount considers a number of factors, including collection experience, aging of the remaining RIC receivable portfolios, credit quality of the subscriber base and other qualitative considerations, including macro-economic factors. The imputed interest income is recognized over the term of the RIC contract as recurring and other revenue on the consolidated statement of operations. When the Company determines that there are RIC receivables that have become uncollectible, it records an adjustment to the imputed interest discount and reduces the related note receivable balance. Account balances are written-off if collection efforts are unsuccessful and future collection is unlikely based on the length of time from the day accounts become past due. (See Note 4 ). Revenue Recognition The Company offers its customers smart home services combining Products, including a proprietary control panel, door and window sensors, door locks, security cameras and smoke alarms; installation; and a proprietary back-end cloud platform software and Services. These together create an integrated system that allows the Company’s customers to monitor, control and protect their home (“Smart Home Services”). The Company’s customers are buying this integrated system that provides them with these Smart Home Services. The number and type of Products purchased by a customer depends on their desired functionality. Because the Products and Services included in the customer’s contract are integrated and highly interdependent, and because they must work together to deliver the Smart Home Services, the Company has concluded that installed Products, related installation and Services contracted for by the customer are generally not distinct within the context of the contract and, therefore, constitute a single, combined performance obligation. Revenues for this single, combined performance obligation are recognized on a straight-line basis over the customer’s contract term. The Company has determined that certain contracts that do not require a long-term commitment for monitoring services by the customer contain a material right to renew the contract, because the customer does not have to purchase Products upon renewal. Proceeds allocated to the material right are recognized over the period benefit, which is generally three years. The majority of the Company’s subscription contracts are between three and five years in length and are non-cancelable. These contracts with customers generally convert into month-to-month agreements at the end of the initial term, and some customer contracts are month-to-month from inception. Payment for recurring monitoring and other Smart Home Services is generally due in advance on a monthly basis. Sales of Products and other one-time fees such as service fees or installation fees are invoiced to the customer at the time of sale. Revenues for wireless internet service provided by Vivint Wireless Inc. (“Wireless Internet” or “Wireless”) and any Products or Services that are considered separate performance obligations are recognized when those Products or Services are delivered. Taxes collected from customers and remitted to governmental authorities are not included in revenue. Payments received or amounts billed in advance of revenue recognition are reported as deferred revenue. Deferred Revenue The Company's deferred revenues primarily consist of amounts for sales (including upfront proceeds) of Smart Home Services. Deferred revenues are recognized over the term of the related performance obligation. Accounts Receivable Accounts receivable consists primarily of amounts due from customers for recurring monthly monitoring Services and the billed portion of RIC receivables. The accounts receivable are recorded at invoiced amounts and are non-interest bearing and are included within accounts and notes receivable, net on the consolidated balance sheets. Accounts receivable totaled $16.5 million and $24.3 million and December 31, 2018 and 2017 , respectively net of the allowance for doubtful accounts of $5.6 million and $5.4 million at December 31, 2018 and 2017 , respectively. The Company estimates this allowance based on historical collection experience and subscriber attrition rates. When the Company determines that there are accounts receivable that are uncollectible, they are charged off against the allowance for doubtful accounts. The provision for doubtful accounts is included in general and administrative expenses in the accompanying consolidated statements of operations and totaled $19.4 million and $22.5 million for the years ended December 31, 2018 and 2017 , respectively. The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Year ended December 31, 2018 2017 2016 Beginning balance $ 5,356 $ 4,138 $ 3,541 Provision for doubtful accounts 19,405 22,465 19,624 Write-offs and adjustments (19,167 ) (21,247 ) (19,027 ) Balance at end of period $ 5,594 $ 5,356 $ 4,138 Restructuring and Asset Impairment Charges Restructuring and asset impairment charges represent expenses incurred in relation to activities to exit or dispose of portions of the Company's business that do not qualify as discontinued operations. Liabilities associated with restructuring are measured at their fair value when the liability is incurred. Expenses for related termination benefits are recognized at the date the Company notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. Liabilities related to termination of a contract are measured and recognized at fair value when the contract does not have any future economic benefit to the entity and the fair value of the liability is determined based on the present value of the remaining obligation. The Company expenses all other costs related to an exit or disposal activity as incurred (See Note 10 ). Principles of Consolidation The accompanying consolidated financial statements include the accounts of APX Group Holdings, Inc. and its subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Capitalized Contract Costs Capitalized contract costs represent the costs directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related customer contracts. These include commissions, other compensation and related costs incurred directly for the origination and installation of new or upgraded customer contracts, as well as the cost of Products installed in the customer home at the commencement or modification of the contract. These costs are deferred and amortized on a straight-line basis over the expected period of benefit that the Company has determined to be five years. Amortization of capitalized contract costs is included in “Depreciation and Amortization” on the consolidated statements of operations. These deferred costs are periodically reviewed for impairment. Contract costs not directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related customer contracts are expensed as incurred. These costs include those associated with housing, marketing and recruiting, non-direct lead generation costs, certain portions of sales commissions and residuals, overhead and other costs considered not directly and specifically tied to the origination of a particular subscriber. On the consolidated statement of cash flows, capitalized contract costs are classified as operating activities and reported as “Capitalized contract costs - deferred contract costs” as these assets represent deferred costs associated with customer contracts. Cash and Cash Equivalents Cash and cash equivalents consists of highly liquid investments with remaining maturities when purchased of three months or less. Inventories Inventories, which are comprised of smart home and security system equipment and parts are stated at the lower of cost or market with cost determined under the first-in, first-out (FIFO) method. The Company adjusts the inventory balance based on anticipated obsolescence, usage and historical write-offs. Property, Plant and Equipment and Long-lived Assets Property, plant and equipment are stated at cost and depreciated on the straight-line method over the estimated useful lives of the assets or the lease term for assets under capital leases, whichever is shorter. Intangible assets with definite lives are amortized over the remaining estimated economic life of the underlying technology or relationships, which ranges from 5 to 10 years. Definite-lived intangible assets are amortized on the straight-line method over the estimated useful life of the asset or in a pattern in which the economic benefits of the intangible asset are consumed. Amortization expense associated with leased assets is included with depreciation expense. Routine repairs and maintenance are charged to expense as incurred. The Company reviews long-lived assets, including property, plant and equipment, capitalized contract costs, and definite-lived intangibles for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. The Company considers whether or not indicators of impairment exist on a regular basis and as part of each quarterly and annual financial statement close process. Factors the Company considers in determining whether or not indicators of impairment exist include market factors and patterns of customer attrition. If indicators of impairment are identified, the Company estimates the fair value of the assets. An impairment loss is recognized if the carrying amount of a long-lived asset is not recoverable and exceeds its fair value. The Company conducts an indefinite-lived intangible impairment analysis annually as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s indefinite-lived intangibles may be less than the carrying amount. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate indefinite-lived intangible impairment using a qualitative approach. When necessary, the Company’s quantitative impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its indefinite-lived intangibles to the carrying value. If the fair value is greater than the carrying value, the intangibles are not considered to be impaired and no further testing is required. If the fair value is less than the carrying value, an impairment loss in an amount equal to the difference is recorded. During the years ended December 31, 2018 , 2017 and 2016 , no impairments to long-lived assets or intangibles were recorded. The Company’s depreciation and amortization included in the consolidated statements of operations consisted of the following (in thousands): Year ended December 31, 2018 2017 2016 Amortization of capitalized contract costs $ 398,174 $ — $ — Amortization of subscriber acquisition costs — 206,153 154,877 Amortization of definite-lived intangibles 90,945 101,827 116,865 Depreciation of property, plant and equipment 24,963 21,275 16,800 Total depreciation and amortization $ 514,082 $ 329,255 $ 288,542 Wireless Spectrum Licenses The Company had capitalized as an intangible asset wireless spectrum licenses that were acquired from third parties. The cost basis of the wireless spectrum asset includes the purchase price paid for the licenses at the time of acquisition, plus costs incurred to acquire the licenses. The asset and related liability were recorded at the net present value of future cash outflows using the Company's incremental borrowing rate at the time of acquisition. The Company determined that the wireless spectrum licenses met the definition of indefinite-lived intangible assets because the licenses were able to be renewed periodically for a nominal fee, provided that the Company continued to meet the service and geographic coverage provisions. In January 2018, the Company terminated the wireless spectrum licenses for cash consideration. See Note 8 for further discussion. Long-term Investments The Company’s long-term investments are composed of equity securities in both privately held and public companies. As of December 31, 2018 and 2017 , the Company's equity investments totaled $3.9 million and $3.4 million , respectively. Management determines the appropriate fair value measurement of its investments at the time of purchase and reevaluates the fair value measurement at each balance sheet date. Equity securities, are classified as either short-term or long-term, based on the nature of each security and its availability for use in current operations. The Company’s equity securities are carried at fair value, with gains and losses, reported in other income or loss within the statement of operations The Company's equity investments without readily determinable fair values as of both December 31, 2018 and 2017 totaled $0.7 million . The Company performs impairment analyzes of its cost based investments when events occur or circumstances change that would, more likely than not, reduce the fair value of the investment below its carrying value. When indicators of impairment do not exist, the Company evaluates impairment using a qualitative approach. Additionally, increases or decreases in the carrying amount resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer are adjusted through the statement of operations as needed. As of December 31, 2018 , no indicators of impairment or changes in observable prices existed associated with investments without readily determinable fair values. Deferred Financing Costs Certain costs incurred in connection with obtaining debt financing are deferred and amortized utilizing the straight-line method, which approximates the effective-interest method, over the life of the related financing. Deferred financing costs associated with obtaining APX's revolving credit facility are amortized over the amended maturity dates discussed in Note 5 . If such financing is paid off or replaced prior to maturity with debt instruments that have substantially different terms, the unamortized costs are charged to expense. Deferred financing costs included in the accompanying consolidated balance sheets within deferred financing costs, net at December 31, 2018 and 2017 were $2.1 million and $3.1 million , net of accumulated amortization of $9.6 million and $8.6 million , respectively. Deferred financing costs included in the accompanying consolidated balance sheets within notes payable, net at December 31, 2018 and 2017 were $32.4 million and $35.7 million , net of accumulated amortization of $54.6 million and $45.2 million , respectively. Amortization expense on deferred financing costs recognized and included in interest expense in the accompanying consolidated statements of operations totaled $10.4 million , $11.4 million and $11.6 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Residual Income Plans The Company has a program that allows certain third-party sales channel partners to receive additional compensation based on the performance of the underlying contracts they create (the “Channel Partner Plan”). In addition, in 2018, the Company introduced a new residual sales compensation plan (the “Residual Plan”). Under the Residual Plan, the Company's sales personnel (each, a “Plan Participant”) have the option to convert up to a specified portion of their earnings (as defined in the Residual Plan) into the right to receive monthly residual compensation payable over the life of the subscriber accounts sold by such Plan Participant. For both the Channel Partner Plan and Residual Plan, the Company calculates the present value of the expected future residual payments and records a liability for this amount in the period the subscriber account is originated. These costs are recorded to capitalized contract costs. The Company monitors actual payments and customer attrition on a periodic basis and, when necessary, makes adjustments to the liability. The amount included in accrued payroll and commissions was $4.5 million and $3.3 million as of December 31, 2018 and 2017 , respectively, and the amount included in other long-term obligations was $13.0 million and $18.5 million at December 31, 2018 and 2017 , respectively, representing the present value of the estimated amounts owed to third-party sales channel partners. Stock-Based Compensation The Company measures compensation cost based on the grant-date fair value of the award and recognizes that cost over the requisite service period of the awards (See Note 12 ). Advertising Expense Advertising costs are expensed as incurred. Advertising costs were approximately $47.2 million , $42.5 million and $33.0 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Income Taxes The Company accounts for income taxes based on the asset and liability method. Under the asset and liability method, deferred tax assets and deferred tax liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Valuation allowances are established when necessary to reduce deferred tax assets when it is determined that it is more likely than not that some portion, or all, of the deferred tax asset will not be realized. The Company recognizes the effect of an uncertain income tax position on the income tax return at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. The Company’s policy for recording interest and penalties is to record such items as a component of the provision for income taxes. Changes in tax laws and rates could also affect recorded deferred tax assets and liabilities in the future. The Company records the effect of a tax rate or law change on the Company’s deferred tax assets and liabilities in the period of enactment. Future tax rate or law changes could have a material effect on the Company’s results of operations, financial condition, or cash flows (See Note 11 ). Contracts Sold During the year ended December 31, 2016, the Company sold all of its New Zealand and Puerto Rico subscriber contracts and ceased operations in these geographical regions ("2016 Contract Sales"). As a result, during the year ended December 31, 2016 the Company recorded the impact of these transactions in restructuring and asset impairment (See Note 10 ). Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of receivables and cash. At times during the year, the Company maintains cash balances in excess of insured limits. The Company is not dependent on any single customer or geographic location. The loss of a customer would not adversely impact the Company’s operating results or financial position. Concentrations of Supply Risk As of December 31, 2018 , approximately 80% of the Company’s installed panels were SkyControl panels and 19% were 2GIG Go!Control panels. During the three months ended March 31, 2018 the Company transitioned to a new panel supplier. The loss of the Company's panel supplier could potentially impact its operating results or financial position. Fair Value Measurement Fair value is based on the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities subject to on-going fair value measurement are categorized and disclosed into one of three categories depending on observable or unobservable inputs employed in the measurement. These two types of inputs have created the following fair value hierarchy: Level 1: Quoted prices in active markets that are accessible at the measurement date for assets and liabilities. Level 2: Observable prices that are based on inputs not quoted in active markets, but corroborated by market data. Level 3: Unobservable inputs are used when little or no market data is available. This hierarchy requires the Company to minimize the use of unobservable inputs and to use observable market data, if available, when determining fair value. The Company recognizes transfers between levels of the hierarchy based on the fair values of the respective financial measurements at the end of the reporting period in which the transfer occurred. There were no transfers between levels of the fair value hierarchy during the years ended December 31, 2018 and 2017 . The carrying amounts of the Company’s accounts receivable, accounts payable and accrued and other liabilities approximate their fair values due to their short maturities. Goodwill The Company conducts a goodwill impairment analysis annually in the fourth fiscal quarter, as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s reporting units may be less than their carrying amounts. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate goodwill impairment using a qualitative approach. When necessary, the Company’s quantitative goodwill impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its reporting units to the carrying value of the reporting unit’s net assets, including goodwill. If the fair value of the reporting unit is greater than the carrying value of its net assets, goodwill is not considered to be impaired and no further testing is required. If the fair value of the reporting unit is less than the carrying value of its net assets, the Company would be required to complete the second step of the test by analyzing the fair value of its goodwill. If the carrying value of the goodwill exceeds its fair value, an impairment charge is recorded. The Company’s reporting units are determined based on its current reporting structure, which as of December 31, 2018 consisted of two reporting units. The Company found that no indicators of goodwill impairment existed during the year ended December 31, 2018 , thus a qualitative approach was used and it was determined that no impairment existed for goodwill. During the years ended December 31, 2018 , 2017 and 2016 , no impairments to goodwill were recorded. Foreign Currency Translation and Other Comprehensive Income The functional currencies of Vivint Canada, Inc. and Vivint New Zealand, Ltd. are the Canadian and New Zealand dollars, respectively. Accordingly, assets and liabilities are translated from their respective functional currencies into U.S. dollars at period-end rates and revenue and expenses are translated at the weighted-average exchange rates for the period. Adjustments resulting from this translation process are classified as other comprehensive (loss) income and shown as a separate component of equity. During the year ended December 31, 2016, the Company completed the 2016 Contract Sales which included all contracts in the New Zealand, Ltd. entity. (See Note 10 ) When intercompany foreign currency transactions between entities included in the consolidated financial statements are of a long term investment nature (i.e., those for which settlement is not planned or anticipated in the foreseeable future) foreign currency translation adjustments resulting from those transactions are included in stockholders’ (deficit) equity as accumulated other comprehensive loss or income. When intercompany transactions are deemed to be of a short term nature, translation adjustments are required to be included in the consolidated statement of operations. The Company has determined that settlement of Vivint Canada, Inc. and Vivint New Zealand, Ltd. intercompany balances are anticipated and therefore such balances are deemed to be of a short-term nature. Translation activity included in the statements of operations in other loss, net related to intercompany balances was a loss of $7.1 million for the year ended December 31, 2018 , a gain of $4.9 million for the year ended December 31, 2017 , and a gain of $2.1 million for the year ended December 31, 2016 . Letters of Credit As of December 31, 2018 and 2017 , the Company had $13.8 million and $9.5 million , respectively, of letters of credit issued in the ordinary course of business, all of which are undrawn. Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, “Financial Instruments—Credit Losses (Topic 326),” which modifies the measurement of expected credit losses of certain financial instruments. This update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019 and must be applied using a modified-retrospective approach, with early adoption permitted. The Company is evaluating the adoption of ASU 2016-13 and plans to provide additional information about its expected impact at a future date. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” to increase transparency and comparability among organizations as it relates to lease assets and lease liabilities. The update requires that lease assets and lease liabilities be recognized on the balance sheet, and that key information about leasing arrangements be disclosed. Prior to this update, GAAP did not require operating leases to be recognized as lease assets and lease liabilities on the balance sheet. This update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, with early adoption permitted. In July 2018, the FASB issued ASU 2018-11 which provides companies the option to adopt using a modified retrospective approach or a prospective adoption approach. The Company is continuing its evaluation of the impact of ASU 2016-02 on its accounting policies. The Company’s current operating lease portfolio is primarily comprised of network, real estate, and equipment leases. Upon adoption of this standard, the Company expects to record a right of use asset and liability related to all operating lease arrangements. The Company has assigned internal resources to perform the evaluation. Furthermore, the Company has made and will continue to make investments in systems to enable timely and accurate reporting under the new standard. The Company expects the standard will have a material impact on the Company’s consolidated balance sheets but will not have a material impact on the consolidated statements of operations. The most significant impact will be the recognition of right of use assets and lease liabilities for operating leases. In connection with the adoption of the new lease accounting standard, the Company has completed scoping reviews and continues to make progress implementing new processes, systems, accounting policies and internal controls relevant to the standard. The Company will adopt this standard on January 1, 2019 using the prospective adoption approach and has elected to use the practical expedients allowed under the standard. Recently Adopted Accounting Standards ASU 2016-01 In January 2016, the FASB issued ASU 2016-01, "Financial Instruments-Overall (Subtopic 825-10)," which enhances the reporting model for financial instruments by addressing certain aspects of the recognition, measurement, presentation and disclosure of financial instruments. Key provisions require equity investments (except those accounted for under the equity method of accounting) to be measured at fair value with changes in fair value recognized in net inco

Revenue and Capitalized Contrac

Revenue and Capitalized Contract Costs	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue and Capitalized Contract Costs	Revenue and Capitalized Contract Costs Customers are typically invoiced for Smart Home Services in advance or at the time the Company delivers the related Smart Home Services. The majority of customers pay at the time of invoice via credit card, debit card or ACH. Deferred revenue relates to the advance consideration received from customers, which precedes the Company’s satisfaction of the associated performance obligation. The Company’s deferred revenues primarily result from customer payments received in advance for recurring monthly monitoring and other Smart Home Services, or other one-time fees, because these performance obligations are satisfied over time. During the three months ended March 31, 2019 and 2018 , the Company recognized revenues of $86.4 million and $59.8 million , respectively, that were included in the deferred revenue balance as of December 31, 2018 and 2017 , respectively. Transaction Price Allocated to the Remaining Performance Obligations As of March 31, 2019 , approximately $2.2 billion of revenue is expected to be recognized from remaining performance obligations for subscription contracts. The Company expects to recognize approximately 63% of the revenue related to these remaining performance obligations over the next 24 months, with the remaining balance recognized over an additional 36 months. Timing of Revenue Recognition The Company considers Products, related installation, and its proprietary back-end cloud platform software and services an integrated system that allows the Company’s customers to monitor, control and protect their homes. These Smart Home Services are accounted for as a single performance obligation that is recognized over the customer’s contract term, which is generally three to five years . Capitalized Contract Costs Capitalized contract costs generally include commissions, other compensation and related costs paid directly for the generation and installation of new or modified customer contracts, as well as the cost of Products installed in the customer home at the commencement or modification of the contract. The Company defers and amortizes these costs for new or modified subscriber contracts on a straight-line basis over the expected period of benefit of five years .	Revenue and Capitalized Contract Costs Subscribers are typically invoiced for Smart Home Services monthly in advance or at the time the Company delivers the related Smart Home Services. The majority of subscribers pay at the time of invoice via credit card, debit card or ACH. The Company does not generally record any contract assets. The Company records deferred revenues when cash payments (or other consideration) are received or due in advance of performance of the Company's obligations, including amounts which are refundable. The increase in the deferred revenue balance during the year ended December 31, 2018 was primarily driven by cash payments received or due in advance of satisfying the Company's performance obligations, offset by $144.1 million of revenues recognized that were included in the deferred revenue balance as of December 31, 2017 . Transaction Price Allocated to the Remaining Performance Obligations As of December 31, 2018 , approximately $2.2 billion of revenue is expected to be recognized from remaining performance obligations for existing subscription contracts over the remaining contract term and excludes the effect of any cancellations. The Company expects to recognize approximately 62.5% of the revenue related to these remaining performance obligations over the next 24 months, with the remaining balance recognized over an additional 36 months. Financial Statement Impact of Adopting Topic 606 The Company adopted Topic 606 using the modified retrospective method. The cumulative effect of applying the new standard to all contracts with subscribers that were not completed as of January 1, 2018 was recorded as an adjustment to accumulated deficit as of the adoption date. As a result of applying the modified retrospective method to adopt the new revenue guidance, the following cumulative catch-up adjustments were made to select consolidated balance sheet line items as of January 1, 2018 (in thousands): Consolidated Balance Sheets As Reported Adjustments Adjusted December 31, 2017 January 1, 2018 Assets Capitalized contract costs, net $ — $ 1,020,408 $ 1,020,408 Subscriber acquisition costs, net 1,308,558 (1,308,558 ) — Long-term notes receivables and other assets, net 88,723 2,713 91,436 Liabilities and Stockholders' Deficit Accrued expenses and other current liabilities 74,321 10,329 84,650 Deferred revenue 88,337 39,868 128,205 Deferred revenue, net of current portion 264,555 (53,062 ) 211,493 Deferred income tax liabilities 9,041 (5,641 ) 3,400 Accumulated deficit (1,358,571 ) (276,931 ) (1,635,502 ) The following tables compare the select reported consolidated balance sheets, statements of operations and cash flows line items to the amounts had the previous guidance been in effect (in thousands): Consolidated Balance Sheets December 31, 2018 As Reported Balances Without Adoption of Topic 606 Effect of Change Higher/(Lower) Assets Capitalized contract costs, net $ 1,115,775 $ — $ 1,115,775 Subscriber acquisition costs, net — 1,518,188 (1,518,188 ) Liabilities and Stockholders' Deficit Accrued expenses and other current liabilities 136,715 126,900 9,815 Deferred revenue 186,953 126,582 60,371 Deferred revenue, net of current portion 323,585 440,474 (116,889 ) Deferred income tax liabilities 1,096 8,682 (7,586 ) Accumulated deficit (2,104,097 ) (1,754,426 ) (349,671 ) Accumulated other comprehensive loss (28,837 ) (30,384 ) 1,547 Consolidated Statements of Operations and Comprehensive Loss Year ended December 31, 2018 As Reported Balances Without Adoption of Topic 606 Effect of Change Higher/(Lower) Revenues: Recurring and other revenue $ 1,050,441 $ 950,661 $ 99,780 Service and other sales revenue — 46,177 (46,177 ) Activation fees — 9,705 (9,705 ) Total revenues 1,050,441 1,006,543 43,898 Costs and expenses: Operating expenses 355,813 385,672 (29,859 ) Depreciation and amortization 514,082 367,879 146,203 Loss from operations (242,059 ) (169,613 ) (72,446 ) Income tax (benefit) expense (1,611 ) 806 (2,417 ) Net loss (467,914 ) (397,885 ) (70,029 ) Other comprehensive loss, net of tax effects: Foreign currency translation adjustment (2,218 ) (3,765 ) 1,547 Total other comprehensive (loss) income (2,218 ) (3,765 ) 1,547 Comprehensive loss (470,132 ) (401,650 ) (68,482 ) Consolidated Statements of Cashflows Year ended December 31, 2018 As Reported Balances Without Adoption of Topic 606 Effect of Change Cash flows from operating activities: Net loss $ (467,914 ) $ (397,885 ) $ (70,029 ) Adjustments to reconcile net loss to net cash used in operating activities: Amortization of capitalized contract costs 398,174 — 398,174 Amortization of subscriber acquisition costs — 251,971 (251,971 ) Changes in operating assets and liabilities: Capitalized contract costs – deferred contract costs (499,252 ) — (499,252 ) Subscriber acquisition costs – deferred contract costs — (469,393 ) 469,393 Accrued expenses and other current liabilities 91,469 93,886 (2,417 ) Deferred revenue 172,905 216,803 (43,898 ) Net cash used in operating activities (220,499 ) (220,499 ) — Timing of Revenue Recognition The Company previously recognized certain service and other sales revenue when the Services were provided or when title to Products sold transferred to the subscriber. Revenue from the sale of Products that were not part of the service offering (i.e., those Products sold subsequent to the date of the initial installation) were also generally recognized upon delivery of Products. Under the new standard, the Company considers Products, related installation, and its proprietary back-end cloud platform software and services an integrated system that allows the Company’s subscribers to monitor, control and protect their homes. These Smart Home Services are accounted for as a single performance obligation that is recognized over the subscriber’s contract term. Accordingly, the Company now defers a larger portion of certain Smart Home Services revenue, as prior to the adoption of Topic 606 certain of this revenue was recognized at the time services were provided or upon delivery. The Company previously amortized deferred revenues related to sales of Products and activation fees on subscriber contracts over the expected life of the customer, which was 15 years using a 240% declining balance method. Under the new standard, revenues related to sales of Products and activation fees are included in the transaction price allocated to the single Smart Home Service performance obligation and recognized straight-line over the subscriber’s contract term, which is generally three to five years. Capitalized Contract Costs Capitalized contract costs generally include commissions, other compensation and related costs incurred directly for the generation and installation of new or modified subscriber contracts, as well as the cost of Products installed in the subscriber's home at the commencement or modification of the contract. The Company previously deferred and amortized these costs for new subscriber contracts in the same manner as deferred revenue and generally expensed all costs associated with modified subscriber contracts. Under the new standard, the Company defers and amortizes these costs for new or modified subscriber contracts on a straight-line basis over the expected period of benefit of five years.

Long-Term Debt

Long-Term Debt	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt The Company’s debt at March 31, 2019 and December 31, 2018 consisted of the following (in thousands): March 31, 2019 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount Senior Secured Revolving Credit Facilities $ 40,000 $ — $ — $ 40,000 8.75% Senior Notes due 2020 679,299 1,958 (4,678 ) 676,579 8.875% Senior Secured Notes Due 2022 270,000 (2,006 ) (564 ) 267,430 7.875% Senior Secured Notes Due 2022 900,000 19,028 (11,983 ) 907,045 7.625% Senior Notes Due 2023 400,000 — (3,712 ) 396,288 Senior Secured Term Loan - noncurrent 797,850 — (9,202 ) 788,648 Total Long-Term Debt 3,087,149 18,980 (30,139 ) 3,075,990 Senior Secured Term Loan - current 8,100 — — 8,100 Total Debt $ 3,095,249 $ 18,980 $ (30,139 ) $ 3,084,090 December 31, 2018 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount 8.75% Senior Notes due 2020 $ 679,299 $ 2,230 $ (5,380 ) $ 676,149 8.875% Senior Secured Notes due 2022 270,000 (2,122 ) (602 ) 267,276 7.875% Senior Secured Notes due 2022 900,000 20,178 (12,799 ) 907,379 7.625% Senior Notes Due 2023 400,000 — (3,922 ) 396,078 Senior Secured Term Loan - noncurrent 799,875 — (9,662 ) 790,213 Total Long-Term Debt 3,049,174 20,286 (32,365 ) 3,037,095 Senior Secured Term Loan - current 8,100 — — 8,100 Total Debt $ 3,057,274 $ 20,286 $ (32,365 ) $ 3,045,195 (1) Unamortized deferred financing costs related to the revolving credit facilities included in deferred financing costs, net on the condensed consolidated balance sheets at March 31, 2019 and December 31, 2018 were $1.8 million and $2.1 million , respectively. Notes Payable 2020 Notes As of March 31, 2019 , APX had $679.3 million outstanding aggregate principal amount of 8.75% senior notes due 2020 (the “2020 notes”) with a maturity date of December 1, 2020. 2022 Private Placement Notes As of March 31, 2019 , APX had $270.0 million outstanding aggregate principal amount of 8.875% senior secured notes due 2022 (the “2022 private placement notes”). The 2022 private placement notes will mature on December 1, 2022, unless on September 1, 2020 (the 91st day prior to the maturity of the 2020 notes) more than an aggregate principal amount of $190.0 million of such 2020 notes remain outstanding or have not been refinanced as permitted under the note purchase agreement for the 2022 private placement notes, in which case the 2022 private placement notes will mature on September 1, 2020. The 2022 private placement notes are secured, on a pari passu basis, by the collateral securing obligations under the 2022 private placement notes, the 2022 notes (as defined below), and the 2023 notes (as defined below), and the revolving credit facilities and the Term Loan (as defined below), in each case, subject to certain exceptions and permitted liens. 2022 Notes As of March 31, 2019 , APX had $900.0 million outstanding aggregate principal amount of 7.875% senior secured notes due 2022 (the “2022 notes”). The 2022 notes will mature on December 1, 2022, or on such earlier date when any outstanding pari passu lien indebtedness matures as a result of the operation of any “Springing Maturity” provision set forth in the agreements governing such pari passu lien indebtedness. The 2022 notes are secured, on a pari passu basis, by the collateral securing obligations under the 2022 private placement notes, the revolving credit facilities and the Term Loan, in all cases, subject to certain exceptions and permitted liens. 2023 Notes As of March 31, 2019 , APX had $400.0 million outstanding aggregate principal amount of the 7.625% senior notes due 2023 (the “2023 notes” and, together with the 2020 notes, the 2022 notes and the 2022 private placement notes, the “Notes”) with a maturity date of September 1, 2023. Interest accrues at the rate of 8.75% per annum for the 2020 notes, 8.875% per annum for the 2022 private placement notes, 7.875% per annum for the 2022 notes and 7.625% per annum for the 2023 notes. Interest on the 2020 notes, 2022 private placement notes and 2022 notes is payable semiannually in arrears on each June 1 and December 1. Interest on the 2023 notes is payable semiannually in arrears on each March 1 and September 1. APX may redeem the Notes at the prices and on the terms specified in the applicable indenture, or the note purchase agreement. Term Loan In September 2018, APX entered into a credit agreement (the “September 2018 issuance”) for total term loans of $810.0 million (the “Term Loan”). The Company is required to make quarterly amortization payments under the Term Loan in an amount equal to 0.25% of the aggregate principal amount of Term Loan outstanding on the closing date thereof. The remaining principal amount outstanding under the Term Loan will be due and payable in full on March 31, 2024, or earlier if certain springing maturity conditions apply. The net proceeds from the Term Loan were used in-part to redeem in full the entire $269.5 million outstanding aggregate principal amount of the 2019 notes and pay the related accrued interest and redemption premium, to repurchase approximately $250.7 million aggregate principal amount of the outstanding 2020 notes, to repay the outstanding borrowings under the revolving credit facility and to pay fees and expenses related to the Term Loan and the transactions described above. Borrowings under the Term Loan bear interest at a rate per annum equal to an applicable margin plus, at the Company's option, either (1) the base rate determined by reference to the highest of (a) the federal funds rate plus 0.50% , (b) the prime rate of Bank of America, N.A. and (c) the LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month, plus 1.00% or (2) the LIBOR rate determined by reference to the London interbank offered rate for dollars for the interest period relevant to such borrowing. The applicable margin for base rate-based borrowings is 4.0% per annum and the applicable margin for LIBOR rate-based borrowings is 5.0% per annum. APX may prepay the Term Loan at the prices and on the terms specified in the credit agreement covering the Term Loan. Other expense and loss on extinguishment Deferred financing costs Deferred financing costs are amortized to interest expense over the life of the issued debt. The following table presents deferred financing activity for the three months ended March 31, 2019 and year ended December 31, 2018 (in thousands): Unamortized Deferred Financing Costs Balance December 31, 2018 Additions Early Extinguishment Amortized Balance March 31, 2019 Revolving Credit Facility $ 2,058 $ — $ — $ (261 ) $ 1,797 2020 Notes 5,380 — — (702 ) 4,678 2022 Private Placement Notes 602 — — (38 ) 564 2022 Notes 12,799 — — (816 ) 11,983 2023 Notes 3,922 — — (210 ) 3,712 Term Loan 9,662 — (460 ) 9,202 Total Deferred Financing Costs $ 34,423 $ — $ — $ (2,487 ) $ 31,936 Unamortized Deferred Financing Costs Balance December 31, 2017 Additions Early Extinguishment Amortized Balance December 31, 2018 Revolving Credit Facility $ 3,099 $ — $ — $ (1,041 ) $ 2,058 2019 Notes 2,877 — (1,877 ) (1,000 ) — 2020 Notes 11,209 — (2,330 ) (3,499 ) 5,380 2022 Private Placement Notes 752 — — (150 ) 602 2022 Notes 16,067 — — (3,268 ) 12,799 2023 Notes 4,762 — — (840 ) 3,922 Term Loan — 10,275 — (613 ) 9,662 Total Deferred Financing Costs $ 38,766 $ 10,275 $ (4,207 ) $ (10,411 ) $ 34,423 Revolving Credit Facility On November 16, 2012, APX entered into a $200.0 million senior secured revolving credit facility, with a five year maturity. On March 6, 2015, APX amended and restated the credit agreement governing the revolving credit facility to provide for, among other things, (1) an increase in the aggregate commitments previously available to APX thereunder from $200.0 million to $289.4 million (“Revolving Commitments”) and (2) the extension of the maturity date with respect to certain of the previously available commitments. On August 10, 2017, APX further amended and restated the credit agreement governing the revolving credit facility to provide for, among other things, (1) an increase in the aggregate commitments previously available to the Company from $289.4 million to $324.3 million and (2) the extension of the maturity date with respect to certain of the previously available commitments. Borrowings under the amended and restated revolving credit facility bear interest at a rate per annum equal to an applicable margin plus, at APX’s option, either (1) the base rate determined by reference to the highest of (a) the Federal Funds rate plus 0.50% , (b) the prime rate of Bank of America, N.A. and (c) the LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month, plus 1.00% or (2) the LIBOR rate determined by reference to the London interbank offered rate for dollars for the interest period relevant to such borrowing. The applicable margin for base rate-based borrowings (1)(a) under the Series A Revolving Commitments of approximately $267.0 million is and, when in effect, the Series D Revolving Commitments of approximately $15.4 million was 2.0% per annum and (b) under the Series B Revolving Commitments of approximately $21.2 million was 3.0% and (2)(a) the applicable margin for LIBOR rate-based borrowings (a) under the Series A Revolving Commitments is, and, when in effect, the Series D Revolving Commitments is currently 3.0% per annum and (b) under the Series B Revolving Commitments is currently 4.0% . The applicable margin for borrowings under the revolving credit facility is subject to one step-down of 25 basis points based on APX meeting a consolidated first lien net leverage ratio test at the end of each fiscal quarter. Outstanding borrowings under the amended and restated revolving credit facility are allocated on a pro-rata basis between each Series based on the total Revolving Commitments. In addition to paying interest on outstanding principal under the revolving credit facility, APX is required to pay a quarterly commitment fee (which will be subject to one interest rate step-down of 12.5 basis points, based on APX meeting a consolidated first lien net leverage ratio test) to the lenders under the revolving credit facility in respect of the unutilized commitments thereunder. APX also pays customary letter of credit and agency fees. APX is not required to make any scheduled amortization payments under the revolving credit facility. The Series D Revolving Commitments of $15.4 million expired effective April 1, 2019 and the principal amount outstanding under the revolving credit facility will be due and payable in full with respect to the extended commitments under the Series A Revolving Credit Facility and Series B Revolving Credit Facility on March 31, 2021 . As of March 31, 2019 there was $40.0 million outstanding borrowings under the revolving credit facility. As of December 31, 2018 , there were no outstanding borrowings under the revolving credit facility. As of March 31, 2019 the Company had $249.7 million of availability under the revolving credit facility (including the Series D Revolving Commitments scheduled to terminate effective April 1, 2019 and after giving effect to $13.9 million of letters of credit outstanding and $40.0 million of borrowings). Guarantees All of the obligations under the credit agreement governing the revolving credit facility, the credit agreement governing the Term Loan and the debt agreements governing the Notes are guaranteed by APX Group Holdings, Inc. and each of APX Group, Inc.'s existing and future material wholly-owned U.S. restricted subsidiaries. However, such subsidiaries shall only be required to guarantee the obligations under the debt agreements governing the Notes for so long as such entities guarantee the obligations under the revolving credit facility, the credit agreement governing the Term Loan or the Company's other indebtedness.	Long-Term Debt Notes Payable 2019 Notes On November 16, 2012, APX issued $925.0 million aggregate principal amount of 6.375% senior secured notes due 2019 (the “2019 notes”) with a maturity date of December 1, 2019 which were secured on a first-priority lien basis by substantially all of the tangible and intangible assets whether now owned or hereafter acquired by the Company, subject to permitted liens and exceptions. The Company repurchased $205.5 million , $300.0 million and $150.0 million aggregate principal amount of the outstanding 2019 notes in May 2016, February 2017, and August 2017, respectively. In September 2018, the Company redeemed in full the entire remaining $269.5 million outstanding aggregate principal amount of the 2019 notes. 2020 Notes On November 16, 2012 , APX issued $380.0 million aggregate principal amount of 8.75% senior notes due 2020 (the “2020 notes”) with a maturity date of December 1, 2020. During 2013, APX completed two offerings of additional 2020 notes under the indenture dated November 16, 2012 . On May 31, 2013 , APX issued $200.0 million of 2020 notes at a price of 101.75% and on December 13, 2013 , APX issued an additional $250.0 million of 2020 notes at a price of 101.50% . During 2014 , APX issued an additional $100.0 million of 2020 notes at a price of 102.00% . In September 2018 , the Company repurchased $250.7 million outstanding aggregate principal amount of the 2020 notes. 2022 Private Placement Notes In October 2015, APX issued $300.0 million aggregate principal amount of 8.875% senior secured notes due 2022 (the “2022 private placement notes”), pursuant to a note purchase agreement dated as of October 19, 2015 in a private placement exempt from registration under the Securities Act. The 2022 private placement notes will mature on December 1, 2022, unless on September 1, 2020 (the 91st day prior to the maturity of the 2020 notes) more than an aggregate principal amount of $190.0 million of such 2020 notes remain outstanding or have not been refinanced as permitted under the note purchase agreement for the 2022 private placement notes, in which case the 2022 private placement notes will mature on September 1, 2020. The 2022 private placement notes are secured, on a pari passu basis, by the collateral securing obligations under the 2019 notes, the 2022 private placement notes, the 2022 notes (as defined below), and the 2023 notes (as defined below), and the revolving credit facilities and the Term Loan (as defined below), in each case, subject to certain exceptions and permitted liens. In May 2016, the Company repurchased $29.5 million outstanding aggregate principal amount of the 2022 private placement notes. 2022 Notes In May 2016, APX issued $500.0 million aggregate principal amount of 7.875% senior secured notes due 2022 (the “2022 notes”), pursuant to an indenture dated as of May 26, 2016 among APX, the guarantors party thereto and Wilmington Trust, National Association, as trustee and collateral agent. The 2022 notes will mature on December 1, 2022, or on such earlier date when any outstanding pari passu lien indebtedness matures as a result of the operation of any “Springing Maturity” provision set forth in the agreements governing such pari passu lien indebtedness. The 2022 notes are secured, on a pari passu basis, by the collateral securing obligations under the 2019 notes and 2022 private placement notes, the revolving credit facilities and the Term Loan, in all cases, subject to certain exceptions and permitted liens. APX used a portion of the net proceeds from the issuance of the 2022 notes to repurchase approximately $235 million aggregate principal amount of the outstanding 2019 notes and 2022 private placement notes in privately negotiated transactions and repaid borrowings under the existing revolving credit facility. In August 2016, APX issued an additional $100.0 million aggregate principal amount of the 2022 notes at a price of 104.00% . In February 2017, APX issued an additional $300.0 million aggregate principal amount of the 2022 notes at a price of 108.25% (“February 2017 issuance”). A portion of the net proceeds from the offering of these 2022 notes were used to redeem $300.0 million aggregate principal amount of the existing 2019 notes and pay the related accrued interest and redemption premium, and to pay all fees and expenses related thereto and any remaining proceeds will be used for general corporate purposes. 2023 Notes In August 2017, APX issued $400.0 million aggregate principal amount of the 7.625% senior notes due 2023 (the “2023 notes” and, together with the 2019 notes, the 2020 notes and the 2022 private placement notes, the “Notes”) (“August 2017 issuance”). The proceeds from the outstanding 2023 notes offering were used to redeem $150.0 million aggregate principal amount of the outstanding 2019 notes and pay the related accrued interest and redemption premium, and to pay all fees and expenses related thereto. Any remaining net proceeds have been or will be used for general corporate purposes, which may include the repayment of outstanding borrowings under the revolving credit facility. All of the obligations under the credit agreement governing the revolving credit facility, the credit agreement governing the Term Loan (defined below) and the debt agreements governing the Existing Notes are guaranteed by APX Group Holdings, Inc. and each of APX Group, Inc.'s existing and future material wholly-owned U.S. restricted subsidiaries. However, such subsidiaries shall only be required to guarantee the obligations under the debt agreements governing the Existing Notes for so long as such entities guarantee the obligations under the revolving credit facility, the credit agreement governing the Term Loan or the Company's other indebtedness. Interest accrues at the rate of 8.75% per annum for the 2020 notes, 8.875% per annum for the 2022 private placement notes, 7.875% per annum for the 2022 notes and 7.625% per annum for the 2023 notes. Interest on the 2020 notes, 2022 private placement notes and 2022 notes is payable semiannually in arrears on each June 1 and December 1. Interest on the 2023 notes is payable semiannually in arrears on each March 1 and September 1. APX may redeem the Existing Notes at the prices and on the terms specified in the applicable indenture, note purchase agreement or credit agreement. Term Loan In September 2018 , APX entered into a credit agreement (the “September 2018 issuance”) for total term loans of $810.0 million (the “Term Loan”). The Company is required to make quarterly amortization payments under the Term Loan in an amount equal to 0.25% of the aggregate principal amount of Term Loan outstanding on the closing date thereof. The remaining principal amount outstanding under the Term Loan will be due and payable in full on March 31, 2024 , or earlier if certain springing maturity conditions apply. The net proceeds from the Term Loan were used in-part to redeem in full the entire $269.5 million outstanding aggregate principal amount of the 2019 Notes and pay the related accrued interest and redemption premium, to repurchase approximately $250.7 million aggregate principal amount of the outstanding 2020 Notes, to repay the outstanding borrowings under the revolving credit facility and to pay fees and expenses related to the Term Loan and the transactions described above. Borrowings under the Term Loan bear interest at a rate per annum equal to an applicable margin plus, at the Company's option, either (1) the base rate determined by reference to the highest of (a) the federal funds rate plus 0.50% , (b) the prime rate of Bank of America, N.A. and (c) the LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month, plus 1.00% or (2) the LIBOR rate determined by reference to the London interbank offered rate for dollars for the interest period relevant to such borrowing. The applicable margin for base rate-based borrowings is 4.0% per annum and the applicable margin for LIBOR rate-based borrowings is 5.0% per annum. APX may prepay the Term Loan at the prices and on the terms specified in the credit agreement covering the Term Loan. Debt Modifications and Extinguishments In accordance with ASC 470-50 Debt – Modifications and Extinguishments, the Company performed analyses for the September 2018, August 2017 and February 2017 issuances to determine if the notes repurchased with the proceeds from those issuances were substantially different than the notes issued to determine the appropriate accounting treatment of associated issuance fees. As a result of these analyses, the Company recorded the following amounts of other expense and loss on extinguishment and deferred financing costs during the years ended December 31, 2018 , 2017 and 2016 (in thousands): Other expense and loss on extinguishment Deferred financing costs Issuance Original premium extinguished Previously deferred financing costs extinguished New financing costs Total other expense and loss on extinguishment Previously deferred financing rolled over New deferred financing costs Total deferred financing costs For the year ended December 31, 2018 September 2018 issuance $ (953 ) $ 4,207 $ 11,317 $ 14,571 $ — $ 10,275 $ 10,275 For the year ended December 31, 2017 August 2017 issuance $ — $ 1,408 $ 8,881 $ 10,289 $ 473 $ 4,569 $ 5,042 February 2017 issuance — 3,259 9,491 12,750 1,476 6,076 7,552 Total $ — $ 4,667 $ 18,372 $ 23,039 $ 1,949 $ 10,645 $ 12,594 For the year ended December 31, 2016 May 2016 issuance $ 355 $ 695 $ 9,036 $ 10,086 $ 3,423 $ 6,628 $ 10,051 Deferred financing costs are amortized to interest expense over the life of the issued debt. The following table presents deferred financing activity for the year ended December 31, 2018 and 2017 (in thousands): Unamortized Deferred Financing Costs Balance 12/31/2017 Additions Refinances Early Extinguishment Amortized Balance 12/31/2018 Revolving Credit Facility $ 3,099 $ — $ — $ — $ (1,041 ) $ 2,058 2019 Notes 2,877 — — (1,877 ) (1,000 ) — 2020 Notes 11,209 — — (2,330 ) (3,499 ) 5,380 2022 Private Placement Notes 752 — — — (150 ) 602 2022 Notes 16,067 — — — (3,268 ) 12,799 2023 Notes 4,762 — — — (840 ) 3,922 Term Loan — 10,275 — — (613 ) 9,662 Total Deferred Financing Costs $ 38,766 $ 10,275 $ — $ (4,207 ) $ (10,411 ) $ 34,423 Unamortized Deferred Financing Costs Balance 12/31/2016 Additions Refinances Early Extinguishment Amortized Balance 12/31/2017 Revolving Credit Facility $ 4,420 $ 399 $ — $ — $ (1,720 ) $ 3,099 2019 Notes 11,693 — (1,949 ) (4,667 ) (2,200 ) 2,877 2020 Notes 15,053 — — — (3,844 ) 11,209 2022 Private Placement Notes 903 — — — (151 ) 752 2022 Notes 11,714 6,076 1,476 — (3,199 ) 16,067 2023 Notes — 4,569 473 — (280 ) 4,762 Total Deferred Financing Costs $ 43,783 $ 11,044 $ — $ (4,667 ) $ (11,394 ) $ 38,766 Revolving Credit Facility On November 16, 2012, APX entered into a $200.0 million senior secured revolving credit facility, with a five year maturity. On March 6, 2015, APX amended and restated the credit agreement governing the revolving credit facility to provide for, among other things, (1) an increase in the aggregate commitments previously available to APX thereunder from $200.0 million to $289.4 million (“Revolving Commitments”) and (2) the extension of the maturity date with respect to certain of the previously available commitments. On August 10, 2017, APX further amended and restated the credit agreement governing the revolving credit facility to provide for, among other things, (1) an increase in the aggregate commitments previously available to the Company from $289.4 million to $324.3 million and (2) the extension of the maturity date with respect to certain of the previously available commitments. Borrowings under the amended and restated revolving credit facility bear interest at a rate per annum equal to an applicable margin plus, at APX’s option, either (1) the base rate determined by reference to the highest of (a) the Federal Funds rate plus 0.50% , (b) the prime rate of Bank of America, N.A. and (c) the LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month, plus 1.00% or (2) the LIBOR rate determined by reference to the London interbank offered rate for dollars for the interest period relevant to such borrowing. The applicable margin for base rate-based borrowings (1)(a) under the Series A Revolving Commitments of approximately $267.0 million and Series D Revolving Commitments of approximately $15.4 million is currently 2.0% per annum and (b) under the Series B Revolving Commitments of approximately $21.2 million is currently 3.0% and (2)(a) the applicable margin for LIBOR rate-based borrowings (a) under the Series A Revolving Commitments, Series C Revolving Commitments, and Series D Revolving Commitments is currently 3.0% per annum and (b) under the Series B Revolving Commitments is currently 4.0% . The applicable margin for borrowings under the revolving credit facility is subject to one step-down of 25 basis points based on APX meeting a consolidated first lien net leverage ratio test at the end of each fiscal quarter. In November 2017, previous commitments of $20.8 million under the Series C Revolving Commitments had expired. Outstanding borrowings under the amended and restated revolving credit facility are allocated on a pro-rata basis between each Series based on the total Revolving Commitments. In addition to paying interest on outstanding principal under the revolving credit facility, APX is required to pay a quarterly commitment fee (which will be subject to one interest rate step-down of 12.5 basis points, based on APX meeting a consolidated first lien net leverage ratio test) to the lenders under the revolving credit facility in respect of the unutilized commitments thereunder. APX also pays customary letter of credit and agency fees. APX is not required to make any scheduled amortization payments under the revolving credit facility. The principal amount outstanding under the revolving credit facility will be due and payable in full on March 31, 2021. As of December 31, 2018 there was no outstanding borrowings under the revolving credit facility. As of December 31, 2017 , there was $3.0 million outstanding borrowings under the revolving credit facility. As of December 31, 2018 , the Company had $289.8 million of availability under the revolving credit facility (after giving effect to $13.8 million of outstanding letters of credit and no borrowings). The Company’s debt at December 31, 2018 and 2017 consisted of the following (in thousands): December 31, 2018 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount 8.75% Senior Notes due 2020 $ 679,299 $ 2,230 $ (5,380 ) $ 676,149 8.875% Senior Secured Notes Due 2022 270,000 (2,122 ) (602 ) 267,276 7.875% Senior Secured Notes Due 2022 900,000 20,178 (12,799 ) 907,379 7.625% Senior Notes Due 2023 400,000 — (3,922 ) 396,078 Term Loan - noncurrent 799,875 — (9,662 ) 790,213 Total Long-Term Debt 3,049,174 20,286 (32,365 ) 3,037,095 Term Loan - current 8,100 — — 8,100 Total Debt $ 3,057,274 $ 20,286 $ (32,365 ) $ 3,045,195 December 31, 2017 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount Series D Revolving Credit Facility due 2019 $ 3,000 $ — $ — $ 3,000 Series A, B Revolving Credit Facilities due 2021 57,000 — — 57,000 6.375% Senior Secured Notes due 2019 269,465 — (2,877 ) 266,588 8.75% Senior Notes due 2020 930,000 4,465 (11,209 ) 923,256 8.875% Senior Secured Notes Due 2022 270,000 (2,559 ) (752 ) 266,689 7.875% Senior Secured Notes Due 2022 900,000 24,593 (16,067 ) 908,526 7.625% Senior Notes Due 2023 400,000 — (4,762 ) 395,238 Total Debt $ 2,829,465 $ 26,499 $ (35,667 ) $ 2,820,297 (1) Unamortized deferred financing costs related to the revolving credit facilities included in deferred financing costs, net on the consolidated balance sheets at December 31, 2018 and 2017 was $2.1 million and $3.1 million , respectively.

Retail Installment Contract Rec

Retail Installment Contract Receivables	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Retail Installment Contract Receivables	Retail Installment Contract Receivables Certain subscribers have the option to purchase Products under a RIC, payable over either 42 or 60 months. Short-term RIC receivables are recorded in accounts and notes receivable, net and long-term RIC receivables are recorded in long-term notes receivables and other assets, net in the condensed consolidated unaudited balance sheets. The following table summarizes the RIC receivables (in thousands): March 31, 2019 December 31, 2018 RIC receivables, gross $ 173,254 $ 175,250 Deferred interest (29,612 ) (34,163 ) RIC receivables, net of deferred interest $ 143,642 $ 141,087 Classified on the condensed consolidated unaudited balance sheets as: Accounts and notes receivable, net $ 35,370 $ 32,185 Long-term notes receivables and other assets, net 108,272 108,902 RIC receivables, net $ 143,642 $ 141,087 Activity in the deferred interest for the RIC receivables was as follows (in thousands): Three months ended March 31, 2019 Twelve months ended December 31, 2018 Deferred interest, beginning of period $ 34,163 $ 36,048 Write-offs, net of recoveries (6,923 ) (26,360 ) Change in deferred interest on short-term and long-term RIC receivables 2,372 24,475 Deferred interest, end of period $ 29,612 $ 34,163 The amount of RIC imputed interest income recognized in recurring and other revenue was $3.5 million and $3.3 million during the three months ended March 31, 2019 and 2018 , respectively.	Retail Installment Contract Receivables Certain subscribers have the option to purchase Products under a RIC, payable over either 42 or 60 months. Short-term RIC receivables are recorded in accounts and notes receivable, net and long-term RIC receivables are recorded in long-term notes receivables and other assets, net in the consolidated balance sheets. The following table summarizes the installment receivables (in thousands): December 31, 2018 December 31, 2017 RIC receivables, gross $ 175,250 $ 131,024 Deferred interest (34,163 ) (36,048 ) RIC receivables, net of deferred interest $ 141,087 $ 94,976 Classified on the consolidated balance sheets as: Accounts and notes receivable, net $ 32,185 $ 16,469 Long-term notes receivables and other assets, net 108,902 78,507 RIC receivables, net $ 141,087 $ 94,976 Activity in the deferred interest for the RIC receivables was as follows (in thousands): For the Years Ended December 31, 2018 December 31, 2017 Deferred interest, beginning of period $ 36,048 $ — Write-offs, net of recoveries (26,360 ) (6,055 ) Change in deferred interest on short-term and long-term RIC receivables 24,475 42,103 Deferred interest, end of period $ 34,163 $ 36,048 During year ended December 31, 2018 and 2017 , the amount of RIC imputed interest income recognized in recurring and other revenue was $14.9 million and $7.3 million , respectively.

Balance Sheet Components

Balance Sheet Components	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components The following table presents material balance sheet component balances (in thousands): March 31, 2019 December 31, 2018 Prepaid expenses and other current assets Prepaid expenses $ 12,984 $ 7,183 Deposits 1,353 904 Other 791 3,362 Total prepaid expenses and other current assets $ 15,128 $ 11,449 Capitalized contract costs Capitalized contract costs $ 2,445,784 $ 2,361,795 Accumulated amortization (1,352,919 ) (1,246,020 ) Capitalized contract costs, net $ 1,092,865 $ 1,115,775 Long-term notes receivables and other assets RIC receivables, gross $ 137,884 $ 143,065 RIC deferred interest (29,612 ) (34,164 ) Security deposits 7,126 6,586 Investments 6,099 3,865 Other 299 467 Total long-term notes receivables and other assets, net $ 121,796 $ 119,819 Accrued payroll and commissions Accrued commissions $ 11,432 $ 28,726 Accrued payroll 25,849 36,753 Total accrued payroll and commissions $ 37,281 $ 65,479 Accrued expenses and other current liabilities Accrued interest payable $ 55,157 $ 28,885 Current portion of derivative liability 70,137 67,710 Service warranty accrual 8,825 8,813 Current portion of notes payable 8,100 8,100 Loss contingencies 2,131 3,131 Other 14,647 20,076 Total accrued expenses and other current liabilities $ 158,997 $ 136,715	Balance Sheet Components The following table presents material balance sheet component balances as of December 31, 2018 and December 31, 2017 (in thousands): December 31, 2018 2017 Prepaid expenses and other current assets Prepaid expenses $ 7,183 $ 8,000 Deposits 904 1,596 Other 3,362 6,554 Total prepaid expenses and other current assets $ 11,449 $ 16,150 Capitalized contract costs Capitalized contract costs $ 2,361,795 $ — Accumulated amortization (1,246,020 ) — Capitalized contract costs, net $ 1,115,775 $ — Subscriber acquisition costs Subscriber acquisition costs $ — $ 1,837,388 Accumulated amortization — (528,830 ) Subscriber acquisition costs, net $ — $ 1,308,558 Long-term notes receivables and other assets RIC receivables, gross $ 143,065 $ 114,556 RIC deferred interest (34,164 ) (36,049 ) Security deposits 6,586 6,427 Investments 3,865 3,429 Other 467 360 Total long-term notes receivables and other assets, net $ 119,819 $ 88,723 Accrued payroll and commissions Accrued payroll $ 36,753 $ 30,267 Accrued commissions 28,726 27,485 Total accrued payroll and commissions $ 65,479 $ 57,752 Accrued expenses and other current liabilities Accrued interest payable $ 28,885 $ 28,737 Current portion of derivative liability 67,710 25,473 Service warranty accrual 8,813 — Current portion of notes payable 8,100 — Blackstone monitoring fee, a related party 4,793 933 Accrued taxes 5,351 4,585 Spectrum license obligation — 3,861 Accrued payroll taxes and withholdings 5,097 3,185 Loss contingencies 3,131 2,156 Other 4,835 5,391 Total accrued expenses and other current liabilities $ 136,715 $ 74,321

Property Plant and Equipment

Property Plant and Equipment	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property Plant and Equipment	Property Plant and Equipment Property, plant and equipment consisted of the following (in thousands): March 31, 2019 December 31, 2018 Estimated Useful Lives Vehicles $ 44,594 $ 45,050 3 - 5 years Computer equipment and software 55,459 53,891 3 - 5 years Leasehold improvements 27,609 26,401 2 - 15 years Office furniture, fixtures and equipment 19,918 19,532 7 years Build-to-suit lease building — 8,247 10.5 years Construction in process 4,205 2,975 Property, plant and equipment, gross 151,785 156,096 Accumulated depreciation and amortization (87,171 ) (82,695 ) Property, plant and equipment, net $ 64,614 $ 73,401 Property, plant and equipment, net includes approximately $22.2 million and $26.2 million of assets under finance or capital lease obligations at March 31, 2019 and December 31, 2018 , respectively, net of accumulated amortization of $23.2 million and $22.2 million , respectively. Depreciation and amortization expense on all property, plant and equipment was $5.9 million and $6.2 million for the three months ended March 31, 2019 and 2018 , respectively. Amortization expense relates to assets under finance or capital leases and is included in depreciation and amortization expense. As a result of implementing ASU 2016-02, effective January 1, 2019 the Company's build-to-suit leasing arrangement was considered a sale-leaseback and is classified as an operating lease. This resulted in a reduction to property, plant and equipment, net of $6.1 million and a reduction of $6.6 million related the financing lease obligation within accrued expenses and other current liabilities and other long-term obligations. See Note 12 "Leases" for additional information related to the impact of adopting ASU 2016-02.	Property Plant and Equipment Property, plant and equipment consisted of the following (in thousands): December 31, Estimated Useful Lives 2018 2017 Vehicles $ 45,050 $ 42,008 3-5 years Computer equipment and software 53,891 46,651 3-5 years Leasehold improvements 26,401 20,783 2-15 years Office furniture, fixtures and equipment 19,532 17,202 7 years Build-to-suit lease building 8,247 8,268 10.5 years Construction in process 2,975 4,299 Property, plant and equipment, gross 156,096 139,211 Accumulated depreciation and amortization (82,695 ) (61,130 ) Property, plant and equipment, net $ 73,401 $ 78,081 Property plant and equipment includes approximately $23.7 million and $26.2 million of assets under capital lease obligations, net of accumulated amortization of $22.2 million and $16.6 million at December 31, 2018 and 2017 , respectively. Depreciation and amortization expense on all property plant and equipment was $25.0 million , $21.275 million and $16.8 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Amortization expense relates to assets under capital leases as included in depreciation and amortization expense. In June 2016, the Company entered into a non-cancellable lease to occupy a new building constructed in Logan, UT as a location to further sales recruitment and training, as well as conduct research and development (the "Logan Facility"). Because of its involvement in certain aspects of the construction of the Logan Facility, per the terms of the lease, the Company was deemed the owner of the building for accounting purposes during the construction period. Accordingly, the Company recorded a build-to-suit lease asset and a corresponding build-to-suit lease liability during the construction period. In April 2017, construction on the Logan Facility was completed and the Company commenced occupancy. In accordance with ASC 840-40 Sale-Leaseback Transactions, the building did not qualify for sale-leaseback treatment. As such, the Company retains the building asset and corresponding lease obligation on the balance sheet.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill As of March 31, 2019 and December 31, 2018 , the Company had a goodwill balance of $835.4 million and $834.9 million , respectively. The change in the carrying amount of goodwill during the three months ended March 31, 2019 was the result of foreign currency translation adjustments. Intangible assets, net The following table presents intangible asset balances (in thousands): March 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Estimated Definite-lived intangible assets: Customer contracts $ 965,670 $ (737,443 ) $ 228,227 $ 964,100 $ (717,648 ) $ 246,452 10 years 2GIG 2.0 technology 17,000 (15,603 ) 1,397 17,000 (15,292 ) 1,708 8 years Other technology 2,917 (1,771 ) 1,146 2,917 (1,667 ) 1,250 5 - 7 years Space Monkey technology 7,100 (6,019 ) 1,081 7,100 (5,756 ) 1,344 6 years Patents 12,245 (9,136 ) 3,109 12,123 (8,415 ) 3,708 5 years Total definite-lived intangible assets: $ 1,004,932 $ (769,972 ) $ 234,960 $ 1,003,240 $ (748,778 ) $ 254,462 Indefinite-lived intangible assets: IP addresses 564 — 564 564 — 564 Domain names 59 — 59 59 — 59 Total Indefinite-lived intangible assets 623 — 623 623 — 623 Total intangible assets, net $ 1,005,555 $ (769,972 ) $ 235,583 $ 1,003,863 $ (748,778 ) $ 255,085 During the year ended December 31, 2016, Vivint Wireless entered into leasing agreements with Nextlink Wireless, LLC (“Nextlink”) for designated radio frequency spectrum in 40 mid-sized metropolitan markets. The lease term was for seven years, with an option to become the licensor of record with the Federal Communications Commission (“FCC”) with respect to the applicable spectrum licenses at the end of this term for a nominal fee. The Company acquired $31.3 million of spectrum licenses, measured using the present value of the lease payments, and recorded an intangible asset and a corresponding liability within other long-term obligations. While licenses are issued for only a fixed time, such licenses are subject to renewal by the FCC. On January 10, 2018, Vivint Wireless and Verizon consummated the transactions contemplated by a termination agreement to which the parties agreed, among other things, to terminate the spectrum leases between Vivint Wireless and Nextlink, a subsidiary of Verizon, in exchange for a cash payment by Verizon to Vivint Wireless. The calculation of the gain recorded for the three months ended March 31, 2018 included cash proceeds of $55.0 million , extinguishment of the spectrum license liability of $27.9 million , offset by the write-off of the spectrum license asset in the amount of $31.3 million and regulatory costs associated with the sale of $1.2 million for a total net gain on sale of $50.4 million which is included in other income, net in the condensed consolidated statement of operations. Amortization expense related to intangible assets was approximately $20.3 million and $22.7 million for the three months ended March 31, 2019 and 2018 , respectively. As of March 31, 2019 , the remaining weighted-average amortization period for definite-lived intangible assets was 4.0 years . Estimated future amortization expense of intangible assets, excluding approximately $0.3 million in patents currently in process, is as follows as of March 31, 2019 (in thousands): 2019 - Remaining Period $ 59,216 2020 67,990 2021 58,709 2022 48,759 2023 28 Thereafter — Total estimated amortization expense $ 234,702	Goodwill and Intangible Assets Goodwill The changes in the carrying amount of goodwill for the years ended December 31, 2018 and 2017 , were as follows (in thousands): Balance as of January 1, 2017 $ 835,233 Effect of Foreign Currency Translation 1,737 Balance as of December 31, 2017 836,970 Effect of Foreign Currency Translation (2,115 ) Balance as of December 31, 2018 $ 834,855 Intangible assets, net The following table presents intangible asset balances as of December 31, 2018 and 2017 (in thousands): December 31, 2018 December 31, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Estimated Definite-lived intangible assets: Customer contracts $ 964,100 $ (717,648 ) $ 246,452 $ 970,147 $ (637,780 ) $ 332,367 10 years 2GIG 2.0 technology 17,000 (15,292 ) 1,708 17,000 (13,274 ) 3,726 8 years Other technology 2,917 (1,667 ) 1,250 2,917 (1,250 ) 1,667 5 - 7 years Space Monkey technology 7,100 (5,756 ) 1,344 7,100 (4,066 ) 3,034 6 years Patents 12,123 (8,415 ) 3,708 10,616 (5,835 ) 4,781 5 years Total definite-lived intangible assets: 1,003,240 (748,778 ) 254,462 1,007,780 (662,205 ) 345,575 Indefinite-lived intangible assets: Spectrum licenses — — — 31,253 — 31,253 IP addresses 564 — 564 564 — 564 Domain names 59 — 59 59 — 59 Total Indefinite-lived intangible assets 623 — 623 31,876 — 31,876 Total intangible assets, net $ 1,003,863 $ (748,778 ) $ 255,085 $ 1,039,656 $ (662,205 ) $ 377,451 During the year ended December 31, 2016, Vivint Wireless entered into leasing agreements with Nextlink Wireless, LLC (“Nextlink”) for designated radio frequency spectrum in 40 mid-sized metropolitan markets. The lease term was for seven years, with an option to become the licensor of record with the Federal Communications Commission ("FCC") with respect to the applicable spectrum licenses at the end of this initial term for a nominal fee. The Company acquired $31.3 million of spectrum licenses, measured using the present value of the lease payments, and recorded an intangible asset and a corresponding liability within other long-term obligations. While licenses are issued for only a fixed time, such licenses are subject to renewal by the FCC. On January 10, 2018, Vivint Wireless and Verizon consummated the transactions contemplated by a termination agreement to which the parties agreed, among other things, to terminate the spectrum leases between Vivint Wireless and Nextlink, a subsidiary of Verizon, in exchange for a cash payment by Verizon to Vivint Wireless. The calculation of the gain recorded included cash proceeds of $55.0 million , extinguishment of the spectrum license liability of $27.9 million , offset by the write-off of the spectrum license asset in the amount of $31.3 million and regulatory costs associated with the sale of $1.3 million for a total net gain on sale of $50.4 million which is included in other income, net in the consolidated statement of operations. During the year ended December 31, 2018 and 2017 , the Company added $1.7 million and $2.0 million of intangibles related to patents, respectively. Amortization expense related to intangible assets was approximately $90.9 million , $101.8 million and $116.9 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. As of December 31, 2018 , the remaining weighted-average amortization period for definite-lived intangible assets was 3.9 years. Estimated future amortization expense of intangible assets, excluding approximately $0.3 million in patents currently in process, is as follows as of December 31, 2018 (in thousands): 2019 $ 79,062 2020 67,807 2021 58,578 2022 48,674 2023 47 Thereafter 11 Total estimated amortization expense $ 254,179

Financial Instruments

Financial Instruments	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Financial Instruments	Financial Instruments Cash, Cash Equivalents and Equity Securities Cash equivalents and equity securities with readily available determinable fair values (“Corporate Securities”) are classified as level 1 assets, as they have readily available market prices in an active market. As of March 31, 2019 and December 31, 2018 , the Company held an immaterial amount of money market funds. As of March 31, 2019 and December 31, 2018 , the company held $5.4 million and $3.2 million , respectively, of Corporate Securities classified as level 1 investments. The following tables set forth the Company’s cash and cash equivalents and Corporate Securities’ adjusted cost, gross unrealized gains, gross unrealized losses, gross realized gains, gross realized losses and fair value by significant investment category recorded as cash and cash equivalents or long-term notes receivables and other assets, net as of March 31, 2019 and December 31, 2018 (in thousands): March 31, 2019 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 3,599 $ — $ — $ 3,599 $ 3,599 $ — Level 1: Money market funds 92 — — 92 92 — Corporate securities 3,181 2,212 — 5,393 — 5,393 Subtotal 3,273 2,212 — 5,485 92 5,393 Total $ 6,872 $ 2,212 $ — $ 9,084 $ 3,691 $ 5,393 December 31, 2018 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 6,681 $ — $ — $ 6,681 $ 6,681 $ — Level 1: Money market funds 6,092 — — 6,092 6,092 — Corporate securities 3,485 — (304 ) 3,181 — 3,181 Subtotal 9,577 — (304 ) 9,273 6,092 3,181 Total $ 16,258 $ — $ (304 ) $ 15,954 $ 12,773 $ 3,181 The Corporate Securities represents the Company's investment of $3.0 million in publicly traded common stock of a non-affiliated company (“investee”). During the three months ended March 31, 2019 and 2018 , the Company recorded an unrealized gain s of $2.2 million and $0.3 million , respectively, associated with the change in fair value of the investee's stock. The carrying amounts of the Company’s accounts and notes receivable, accounts payable and accrued and other liabilities approximate their fair values. Long-Term Debt Components of long-term debt including the associated interest rates and related fair values are as follows (in thousands, except interest rates): March 31, 2019 December 31, 2018 Stated Interest Rate Issuance Face Value Estimated Fair Value Face Value Estimated Fair Value 2020 Notes 679,299 669,110 679,299 643,568 8.75 % 2022 Private Placement Notes 270,000 271,323 270,000 257,073 8.875 % 2022 Notes 900,000 904,410 900,000 855,000 7.875 % 2023 Notes 400,000 342,120 400,000 326,000 7.625 % Term Loan 805,950 805,950 807,975 807,975 N/A Total $ 3,055,249 $ 2,992,913 $ 3,057,274 $ 2,889,616 The fair values of the 2020 notes, the 2022 private placement notes, the 2022 notes, the 2023 notes, all of which are fixed-rate debt considered Level 2 measurements as the values were determined using observable market inputs, such as current interest rates, prices observable from less active markets, as well as prices observable from comparable securities. The Term Loan is floating-rate debt and approximates the carrying value as interest accrues at floating rates based on market rates. Derivative Financial Instruments Under the Consumer Financing Program, the Company pays a monthly fee to a third-party financing provider based on the average daily outstanding balance of the installment loans and shares the liability for credit losses, depending on the credit quality of the customer. Because of the nature of certain provisions under the Consumer Financing Program, the Company records a derivative liability that is not designated as a hedging instrument and is adjusted to fair value, measured using the present value of the estimated future payments. Changes to the fair value are recorded through other income, net in the Consolidated Statement of Operations. The following represent the contractual obligations with the third-party financing provider under the Consumer Financing Program that are components of the derivative: • The Company pays a monthly fee based on the average daily outstanding balance of the installment loans • The Company shares the liability for credit losses depending on the credit quality of the customer • The Company pays transactional fees associated with customer payment processing The derivative is classified as a Level 3 instrument. The derivative positions are valued using a discounted cash flow model, with inputs consisting of available market data, such as market yield discount rates, as well as unobservable internally derived assumptions, such as collateral prepayment rates, collateral default rates and loss severity rates. These derivatives are priced quarterly using a credit valuation adjustment methodology. In summary, the fair value represents an estimate of the present value of the cash flows the Company will be obligated to pay to the third-party financing provider for each component of the derivative. The following table summarizes the fair value and the notional amount of the Company’s outstanding derivative instrument as of March 31, 2019 and December 31, 2018 (in thousands): March 31, 2019 December 31, 2018 Consumer Financing Program Contractual Obligations: Fair value $ 120,671 $ 117,620 Notional amount 385,955 368,708 Classified on the condensed consolidated unaudited balance sheets as: Accrued expenses and other current liabilities 70,137 67,710 Other long-term obligations 50,534 49,910 Total Consumer Financing Program Contractual Obligation $ 120,671 $ 117,620 Changes in Level 3 Fair Value Measurements The following table summarizes the change in the fair value of the Level 3 outstanding derivative liability instrument for the three months ended March 31, 2019 and the twelve months ended December 31, 2018 (in thousands): Three months ended March 31, 2019 Twelve months ended December 31, 2018 Balance, beginning of period $ 117,620 $ 46,496 Additions 16,480 93,095 Settlements (14,856 ) (34,587 ) Losses included in earnings 1,427 12,616 Balance, end of period $ 120,671 $ 117,620	Financial Instruments Cash, Cash Equivalents and Equity Securities Cash equivalents and equity securities with readily available determinable fair values (“Corporate Securities”) are classified as level 1 assets, as they have readily available market prices in an active market. The following tables set forth the Company’s cash and cash equivalents and Corporate Securities’ adjusted cost, gross unrealized gains, gross unrealized losses, gross realized gains, gross realized losses and fair value by significant investment category recorded as cash and cash equivalents or long-term notes receivables and other assets, net as of December 31, 2018 and 2017 (in thousands): December 31, 2018 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 6,681 $ — $ — $ 6,681 $ 6,681 $ — Level 1: Money market funds 6,092 — — 6,092 6,092 — Corporate securities 3,485 — (304 ) 3,181 — 3,181 Subtotal 9,577 — (304 ) 9,273 6,092 3,181 Total $ 16,258 $ — $ (304 ) $ 15,954 $ 12,773 $ 3,181 December 31, 2017 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 3,866 $ — $ — $ 3,866 $ 3,866 Level 1: Money market funds 6 — — 6 6 — Corporate securities 4,018 — (1,315 ) 2,703 — 2,703 Subtotal 4,024 — (1,315 ) 2,709 6 2,703 Total $ 7,890 $ — $ (1,315 ) $ 6,575 $ 3,872 $ 2,703 The Corporate Securities represents the Company's investment of $3.0 million in publicly traded common stock of a nonaffiliated company (“investee”). During the years ended December 31, 2018 , 2017 and 2016 the Company recorded an unrealized loss of $0.3 million , an unrealized loss of $1.3 million and an unrealized gain of $1.0 million , respectively associated with the change in fair value of the investee's stock. As of December 31, 2018 the Company had no accumulated other comprehensive income associated with unrealized gains and losses for the change in fair value of the investment as a result of the adoption of ASU 2016-01. The balance of accumulated other comprehensive income associated with unrealized gains and losses for the change in fair value totaled net losses of $0.3 million at December 31, 2017 . The carrying amounts of the Company’s accounts and notes receivable, accounts payable and accrued and other liabilities approximate their fair values. Components of the Company's debt including the associated interest rates and related fair values (in thousands, except interest rates) are as follows: Issuance December 31, 2018 December 31, 2017 Stated Interest Rate Face Value Estimated Fair Value Face Value Estimated Fair Value 2019 Notes $ — $ — $ 269,465 $ 273,507 6.375 % 2020 Notes 679,299 643,568 930,000 952,134 8.75 % 2022 Notes Private Placement Notes 270,000 257,073 270,000 276,486 8.875 % 2022 Notes 900,000 855,000 900,000 966,420 7.875 % 2023 Notes 400,000 326,000 400,000 425,000 7.625 % Term Loan 807,975 807,975 — — N/A Total $ 3,057,274 $ 2,889,616 $ 2,769,465 $ 2,893,547 The fair value of the 2019 notes, 2020 notes, 2022 private placement notes, 2022 notes and the 2023 notes are fixed-rate debt and are considered Level 2 measurements as the value was determined using observable market inputs, such as current interest rates as well as prices observable from less active markets. The Term Loan is floating-rate debt and approximates the carrying value as interest accrues at floating rates based on market rates. Derivative Financial Instruments Under the Consumer Financing Program, the Company pays a monthly fee to a third-party financing provider based on the average daily outstanding balance of the installment loans and shares the liability for credit losses, depending on the credit quality of the customer. Because of the nature of certain provisions under the Consumer Financing Program, the Company records a derivative liability that is not designated as a hedging instrument and is adjusted to fair value, measured using the present value of the estimated future payments. Changes to the fair value are recorded through other (income) loss, net in the Consolidated Statement of Operations. The following represent the contractual obligations with the third-party financing provider under the Consumer Financing Program that are components of the derivative: • The Company pays a monthly fee based on the average daily outstanding balance of the installment loans • The Company shares the liability for credit losses depending on the credit quality of the customer • The Company pays transactional fees associated with customer payment processing The derivative is classified as a Level 3 instrument. The derivative positions are valued using a discounted cash flow model, with inputs consisting of available market data, such as market yield discount rates, as well as unobservable internally derived assumptions, such as collateral prepayment rates, collateral default rates and loss severity rates. These derivatives are priced quarterly using a credit valuation adjustment methodology. In summary, the fair value represents an estimate of the present value of the cash flows the Company will be obligated to pay to the third-party financing provider for each component of the derivative. The following table summarizes the fair value and the notional amount of the Company’s outstanding derivative instrument as of December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Consumer Financing Program Contractual Obligations: Fair value $ 117,620 $ 46,496 Notional amount 368,708 163,032 Classified on the consolidated balance sheets as: Accrued expenses and other current liabilities 67,710 25,473 Other long-term obligations 49,910 21,023 Total Consumer Financing Program Contractual Obligation $ 117,620 $ 46,496 Changes in Level 3 Fair Value Measurements The following table summarizes the change in the fair value of the Level 3 outstanding derivative instrument for the years ended December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Balance, beginning of period $ 46,496 $ — Additions 93,095 44,913 Settlements (34,587 ) (7,972 ) Losses included in earnings 12,616 9,555 Balance, end of period $ 117,620 $ 46,496

Income Taxes

Income Taxes	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes In order to determine the quarterly provision for income taxes, the Company uses an estimated annual effective tax rate, which is based on expected annual income and statutory tax rates in the various jurisdictions in which the Company operates. Certain significant or unusual items are separately recognized in the quarter during which they occur and can be a source of variability in the effective tax rates from quarter to quarter. The Company’s effective income tax benefit rate for the three months ended March 31, 2019 and 2018 was approximately 0.34% and 0.51% , respectively. Income tax expense for the three months ended March 31, 2019 was affected by year to date projected loss in Canada and estimated minimum state taxes in the US. Both the 2019 and 2018 effective tax rates differ from the statutory rate primarily due to the combination of not benefiting from expected pre-tax US losses, a result of changes to the valuation allowance, and recognizing current state income tax expense for minimum state taxes. Significant judgment is required in determining the Company’s provision for income taxes, recording valuation allowances against deferred tax assets, and evaluating the Company’s uncertain tax positions. In evaluating the ability to realize its deferred tax assets, in full or in part, the Company considers all available positive and negative evidence, including past operating results, forecasted future earnings, and prudent and feasible tax planning strategies. Due to historical net losses incurred and the uncertainty of realizing the deferred tax assets, for all the periods presented, the Company has maintained a domestic valuation allowance against the deferred tax assets that remain after offset by domestic deferred tax liabilities, and the company currently anticipates recording a valuation allowance against net foreign deferred tax assets by the end of the current year.	Income Taxes The Company files a consolidated federal income tax return with its wholly-owned subsidiaries. The income tax (benefit) expense consisted of the following (in thousands): Year ended December 31, 2018 2017 2016 Current income tax: Federal $ — $ — $ — State 512 151 545 Foreign (52 ) (24 ) 95 Total 460 127 640 Deferred income tax: Federal — (326 ) — State — (53 ) — Foreign (2,071 ) 1,330 (573 ) Total (2,071 ) 951 (573 ) Income tax (benefit) expense $ (1,611 ) $ 1,078 $ 67 The following reconciles the tax expense computed at the statutory federal rate and the Company’s tax expense (in thousands): Year ended December 31, 2018 2017 2016 Computed expected tax expense $ (98,598 ) $ (139,100 ) $ (93,770 ) State income taxes, net of federal tax effect 404 65 360 Foreign income taxes (690 ) (299 ) (949 ) Other reconciling items — (344 ) 666 Permanent differences 4,406 2,008 1,688 Effect of Federal law change — 166,876 — Change in valuation allowance 92,867 (28,128 ) 92,072 Income tax (benefit) expense $ (1,611 ) $ 1,078 $ 67 The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities were as follows (in thousands) December 31, 2018 2017 Gross deferred tax assets: Net operating loss carryforwards $ 591,244 $ 591,619 Deferred subscriber income 113,103 72,389 Interest expense limitation 56,381 — Accrued expenses and allowances 18,766 17,633 Purchased intangibles and deferred financing costs 17,788 15,191 Inventory reserves 4,688 6,662 Property and equipment — 1,176 Research and development credits 41 41 Valuation allowance (467,705 ) (304,509 ) Total 334,306 400,202 Gross deferred tax liabilities: Deferred capitalized contract costs (332,547 ) (408,610 ) Property and equipment (2,242 ) — Prepaid expenses (613 ) (633 ) Total (335,402 ) (409,243 ) Net deferred tax liabilities $ (1,096 ) $ (9,041 ) The Company had net operating loss carryforwards as follows (in thousands): December 31, 2018 2017 Net operating loss carryforwards: Federal $ 2,405,380 $ 2,355,153 States 1,656,333 1,715,004 Canada 19,753 27,326 Total $ 4,081,466 $ 4,097,483 U.S. federal net operating loss carryforwards will begin to expire in 2026 , if not used. State net operating loss carryforwards expire over different periods and some have already begun to expire. The Company had United States research and development credits of approximately $41,000 at December 31, 2018 , and December 31, 2017 , which begin to expire in 2030 . Canadian net operating loss carryforwards will begin to expire in 2029 . Realization of the Company’s federal and state net operating loss carryforwards and tax credits is dependent on generating sufficient taxable income prior to their expiration. Although a portion of these net operating loss carryforwards are subject to the provisions of Internal Revenue Code Section 382, the Company has not performed a formal study to determine the amount of any limitation. The use of the net operating loss carryforwards may have additional limitations resulting from future ownership changes or other factors under Section 382 of the Internal Revenue Code. In December 2017, the SEC issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”), which provides guidance on accounting for the tax effects of Tax Reform. SAB 118 provides a measurement period that should not extend beyond one year from the enactment date for companies to complete the accounting relating to Tax Reform under ASC Topic 740. In accordance with SAB 118, to the extent that a company’s accounting for certain income tax effects of Tax Reform is incomplete, but it is able to determine a reasonable estimate, the company should report a provisional estimate in its financial statements. Where a reasonable estimate cannot be determined, a company should continue to apply ASC Topic 740 based on the provisions of the tax laws that were in effect immediately before the enactment of Tax Reform. The SAB 118 period has closed and, based on its analysis of Tax Reform, the Company did not change its recorded provisional tax expense of $166.9 million for the year ended December 31, 2017, resulting from the remeasurement of its deferred tax balances due to the reduction in the U.S. corporate income tax rate from 35% to 21% . This expense was offset by a corresponding change in the valuation allowance, resulting in no change in net tax expense or benefit. Additionally, the Company's analysis of the new requirement that certain income (i.e., GILTI) earned by foreign subsidiaries must be included currently in the gross income of the U.S. resulted in an inclusion amount of approximately $7.7 million in 2018. The Company has elected to treat taxes due on future inclusions in U.S. taxable income related to GILTI as a current-period expense when incurred. At December 31, 2018 and 2017 , the Company recorded a valuation allowance against its U.S. federal and state net deferred tax assets as it believes it is more likely than not that these benefits will not be realized. Significant judgment is required in determining the Company’s provision for income taxes, recording valuation allowances against net deferred tax assets and evaluating the Company’s uncertain tax positions. The Company has considered and weighed the available evidence, both positive and negative, to determine whether it is more likely than not that some portion, or all, of the deferred tax assets will not be realized. Based on available information, management does not believe it is more likely than not that all of its deferred tax assets will be utilized. The Company recorded a valuation allowance for U.S. net deferred tax assets of approximately $467.7 million and $304.5 million at December 31, 2018 and 2017 , respectively. As of December 31, 2018 , the Company's income tax returns for the tax years 2014 and later, remain subject to examination by the Internal Revenue Service and various state taxing authorities.

Stock-Based Compensation and Eq

Stock-Based Compensation and Equity	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation and Equity	Stock-Based Compensation and Equity 313 Incentive Units The Company’s indirect parent, 313 Acquisition LLC (“313”), which is majority owned by Blackstone, has authorized the award of profits interests, representing the right to share a portion of the value appreciation on the initial capital contributions to 313 (“Incentive Units”). As of March 31, 2019 , 84,132,816 Incentive Units had been awarded, and were outstanding, to current and former members of senior management and a board member, of which 42,169,456 were outstanding to the Company’s Chief Executive Officer and President. In June 2018, the Incentive Units and SARs (defined below) vesting terms were modified (“Modification”). Prior to the Modification, the Incentive Units were subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date and (2) two-thirds subject to the achievement of certain investment return thresholds by The Blackstone Group, L.P. and its affiliates (“Blackstone”). Pursuant to the Modification the Incentive Units are subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date, (2) one-third subject to the achievement of certain investment return thresholds by Blackstone and (3) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date or June 2018 for those granted prior to the modification. The Company has not recorded any expense related to the performance-based portion of the awards, as the achievement of the vesting condition is not yet deemed probable. The fair value of stock-based awards is measured at the grant date, or the Modification date, and is recognized as expense over the employee’s requisite service period. The grant date fair value was primarily determined using a Monte Carlo simulation valuation approach with the following assumptions: expected volatility varies from 55% to 125% ; expected exercise term between 3.96 and 6.00 years ; and risk-free rates between 0.62% and 2.61% . Vivint Stock Appreciation Rights The Company’s subsidiary, Vivint Group, Inc. (“Vivint Group”), has awarded Stock Appreciation Rights (“SARs”) to various levels of key employees and board members, pursuant to an omnibus incentive plan. The purpose of the SARs is to attract and retain personnel and provide an opportunity to acquire an equity interest of Vivint Group. Prior to the Modification in June 2018, the SARs were subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date and (2) two-thirds subject to the achievement of certain investment return thresholds by Blackstone. Pursuant to the Modification the Incentive Units are subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date, (2) one-third subject to the achievement of certain investment return thresholds by Blackstone and (3) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date or June 2018 for those granted prior to the modification. The Company has not recorded any expense related to the performance-based portion of the awards, as the achievement of the vesting condition is not yet deemed probable. In connection with this plan, 36,576,342 SARs were outstanding as of March 31, 2019 . In addition, 53,621,891 SARs have been set aside for funding incentive compensation pools pursuant to long-term sales and installation employee incentive plans established by the Company. The fair value of the Vivint Group awards is measured at the grant date, or the Modification date, and is recognized as expense over the employee’s requisite service period. The fair value is determined using a Black-Scholes option valuation model with the following assumptions: expected volatility varies from 55% to 125% , expected dividends of 0% ; expected exercise term between 6.00 and 6.47 years ; and risk-free rates between 0.61% and 2.61% . Due to the lack of historical exercise data, the Company used the simplified method in determining the estimated exercise term, for all Vivint Group awards. Restricted Stock Units In March 2019 and June 2018, the Company’s subsidiary, Vivint Group, awarded 236,111 and 360,000 Restricted Stock Units (“RSUs”), respectively, to certain board members, pursuant to an omnibus incentive plan. The purpose of the RSUs is to compensate board members for their board service and align their interests of those of the Company's shareholders. The RSUs are subject to a three year time-based ratable vesting period. Stock-based compensation expense in connection with all stock-based awards is presented as follows (in thousands): Three Months Ended March 31, 2019 2018 Operating expenses $ 43 $ 18 Selling expenses 87 45 General and administrative expenses 727 141 Total stock-based compensation $ 857 $ 204 The increase in total stock-based compensation for the three months ended March 31, 2019 was primarily due to the Modification in June 2018.	Stock-Based Compensation and Equity 313 Incentive Units The Company’s indirect parent, 313 Acquisition LLC (“313”), which is wholly owned by the Investors, has authorized the award of profits interests, representing the right to share a portion of the value appreciation on the initial capital contributions to 313 (“Incentive Units”). As of December 31, 2018 , a total of 85,362,836 Incentive Units had been awarded, and were outstanding, to current and former members of senior management and a board member, of which 42,169,456 were issued to the Company’s Chief Executive Officer and President. In June 2018, the Incentive Units and SARs (defined below) vesting terms were modified ("Modification"). Prior to the Modification, the Incentive Units were subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date and (2) two-thirds subject to the achievement of certain investment return thresholds by The Blackstone Group, L.P. and its affiliates (“Blackstone”). Pursuant to the Modification the Incentive Units are subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date, (2) one-third subject to the achievement of certain investment return thresholds by Blackstone and (3) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date or June 2018 for those granted prior to the modification. The Company has not recorded any expense related to the performance-based portion of the awards, as the achievement of the vesting condition is not yet deemed probable. The fair value of stock-based awards is measured at the grant date, or the Modification date, and is recognized as expense over the employee’s requisite service period. The grant date fair value was determined using a Monte Carlo simulation valuation approach with the following assumptions: expected volatility varies from 55% to 125% ; expected exercise term between 3.96 and 6.00 years; and risk-free rate between 0.61% and 2.61% . A summary of the Incentive Unit activity for the years ended December 31, 2018 and 2017 is presented below: Incentive Units Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Life (Years) Aggregate Intrinsic Value Outstanding, December 31, 2016 85,882,836 $ 1.19 6.81 $ — Forfeited (70,000 ) 1.30 Outstanding, December 31, 2017 85,812,836 1.19 5.81 — Forfeited (450,000 ) 1.93 Outstanding, December 31, 2018 85,362,836 1.18 4.81 — Unvested shares expected to vest after December 31, 2018 59,663,659 1.22 4.93 — Exercisable at December 31, 2018 25,699,177 $ 1.11 4.50 $ — As of December 31, 2018 , there was $10.7 million of unrecognized compensation expense related to outstanding Incentive Units, which will be recognized over a weighted-average period of 4.29 years . As of December 31, 2018 and 2017 , the weighted average grant date fair value per share of the outstanding incentive units was $0.36 and $0.30 , respectively. Stock Appreciation Rights The Company’s subsidiary, Vivint Group, Inc. (“Vivint Group”), has awarded Stock Appreciation Rights (“SARs”) to various levels of key employees and board members, pursuant to an omnibus incentive plan. The purpose of the SARs is to attract and retain personnel and provide an opportunity to acquire an equity interest of Vivint Group. Prior to the Modification in June 2018, the SARs were subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date and (2) two-thirds subject to the achievement of certain investment return thresholds by Blackstone. Pursuant to the Modification the Incentive Units are subject to time-based and performance-based vesting conditions, with (1) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date, (2) one-third subject to the achievement of certain investment return thresholds by Blackstone and (3) one-third subject to ratable time-based vesting over a five year period from the applicable vesting reference date or June 2018 for those granted prior to the modification. The Company has not recorded any expense related to the performance-based portion of the awards, as the achievement of the vesting condition is not yet deemed probable. In connection with this plan, 38,011,879 SARs were outstanding as of December 31, 2018 . In addition, 53,621,891 SARs have been set aside for funding incentive compensation pools pursuant to long-term sales and installation employee incentive plans established by the Company. The fair value of the Vivint Group awards is measured at the grant date, or the Modification date, and is recognized as expense over the employee’s requisite service period. The fair value is determined using a Black-Scholes option valuation model with the following assumptions: expected volatility varies from 55% to 125% , expected dividends of 0% ; expected exercise term between 6.00 and 6.50 years ; and risk-free rates between 0.61% and 2.61% . Due to the lack of historical exercise data, the Company used the simplified method in determining the estimated exercise term, for all Vivint Group awards. A summary of the Vivint Group SAR activity for the years ended December 31, 2018 and 2017 is presented below: Stock Appreciation Rights Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Life (Years) Aggregate Intrinsic Value Outstanding, December 31, 2016 21,993,158 $ 0.96 8.23 $ — Granted 13,250,640 1.74 Forfeited (2,374,864 ) 1.12 Exercised (114,644 ) 0.72 Outstanding, December 31, 2017 32,754,290 1.26 9.21 — Granted 14,630,000 1.79 Forfeited (9,255,137 ) 1.31 Exercised (117,274 ) 0.89 Outstanding, December 31, 2018 38,011,879 1.46 8.07 — Unvested shares expected to vest after December 31, 2018 33,813,668 1.51 8.28 — Exercisable at December 31, 2018 4,198,211 $ 1.02 6.30 $ — As of December 31, 2018 , there was $4.6 million of unrecognized compensation expense related to outstanding Vivint awards, which will be recognized over a weighted-average period of 4.40 years . As of December 31, 2018 and 2017 , the weighted average grant date fair value per share of the outstanding SARs was $0.23 and $0.19 , respectively. The Company’s subsidiary, Vivint Wireless, has also awarded an immaterial amount of Wireless SARs to various employees. There were no Wireless SARs outstanding as of December 31, 2018 and the Company does not intend to issue any additional Wireless SARs. Restricted Stock Units In June 2018, the Company’s subsidiary, Vivint Group, awarded 360,000 Restricted Stock Units (“RSUs”) to certain board members, pursuant to an omnibus incentive plan. The purpose of the RSUs is to compensate board members for their board service and align their interests of those of the Company's shareholders. The RSUs are subject to a three year time-based ratable vesting period. All RSUs are expected to vest after December 31, 2018 and none are exercisable at December 31, 2018 . The fair value of the RSU awards is measured at the grant date, and is recognized as expense over the requisite service period. The fair value was determined using a Black-Scholes valuation model with the following assumptions: expected volatility of 95% , expected dividends of 0% ; expected exercise term of 3 years ; and a risk-free rate of 2.61% . As of December 31, 2018 , there was $0.1 million of unrecognized compensation expense related to outstanding RSUs, which will be recognized over a period of 2.44 years . The grant date fair value per share of the outstanding SARs was $0.48 . Stock-based compensation expense in connection with all stock-based awards for the years ended December 31, 2018 , 2017 and 2016 is allocated as follows (in thousands): Year ended December 31, 2018 2017 2016 Operating expenses $ 129 $ 65 $ 68 Selling expenses 285 217 (127 ) General and administrative expenses 2,091 1,313 3,927 Total stock-based compensation $ 2,505 $ 1,595 $ 3,868 Total stock-based compensation increased in 2018, partially as a result of the Modification. Stock-based compensation expense presented in selling expenses was negative for the year ended December 31, 2016 due to a retrospective adjustment in the grant-date fair value of a series of stock-based awards. Stock-based compensation expense included in general and administrative expenses for the year ended December 31, 2016 included $2.2 million of compensation related to an equity repurchase by 313 from one of the Company's executives. Capital Contribution In April 2016, Parent completed the first installment of an issuance and sale to certain investors of a series of preferred stock and contributed the net proceeds from such issuance of $69.8 million to the Company as an equity contribution. In July 2016, Parent completed the final installment of the issuance and sale to certain investors of such series of preferred stock and, in August 2016, contributed the net proceeds from such issuance of $30.6 million to the Company as an equity contribution. Both issuances were private placements exempt from registration under the Securities Act. During the year ended December 31, 2018 , Parent contributed $4.7 million to the Company as a capital contribution. During the years ended December 31, 2018 and 2017, the Company returned capital to Parent of $3.1 million and $1.2 million , respectively.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Indemnification Subject to certain limitations, the Company is obligated to indemnify its current and former directors, officers and employees with respect to certain litigation matters and investigations that arise in connection with their service to the Company. These obligations arise under the terms of its certificate of incorporation, its bylaws, applicable contracts, and Delaware and California law. The obligation to indemnify generally means that the Company is required to pay or reimburse these individuals’ reasonable legal expenses and possibly damages and other liabilities incurred in connection with these matters. Legal The Company is named from time to time as a party to lawsuits arising in the ordinary course of business related to its sales, marketing, and the provision of its services and equipment claims. Actions filed against the Company include commercial, intellectual property, customer, and labor and employment related claims, including complaints of alleged wrongful termination and potential class action lawsuits regarding alleged violations of federal and state wage and hour and other laws. In general, litigation can be expensive and disruptive to normal business operations. Moreover, the results of legal proceedings are difficult to predict and the costs incurred in litigation can be substantial. The Company believes the amounts provided in its financial statements are adequate in light of the probable and estimated liabilities. Factors that the Company considers in the determination of the likelihood of a loss and the estimate of the range of that loss in respect of legal matters include the merits of a particular matter, the nature of the matter, the length of time the matter has been pending, the procedural posture of the matter, how the Company intends to defend the matter, the likelihood of settling the matter and the anticipated range of a possible settlement. Because such matters are subject to many uncertainties, the ultimate outcomes are not predictable and there can be no assurances that the actual amounts required to satisfy alleged liabilities from the matters described above will not exceed the amounts reflected in the Company’s financial statements or that the matters will not have a material adverse effect on the Company’s results of operations, financial condition or cash flows. The Company regularly reviews outstanding legal claims and actions to determine if reserves for expected negative outcomes of such claims and actions are necessary. The Company had reserves for all such matters of approximately $2.1 million and $3.1 million as of March 31, 2019 and December 31, 2018 , respectively. In conjunction with one of the settlements, the Company is obligated to pay certain future royalties, based on sales of future Products. Operating Leases The Company leases office and warehouse space and an aircraft under operating leases with related and unrelated parties expiring in various years through 2028 . The leases require the Company to pay additional rent for increases in operating expenses and real estate taxes and contain renewal options. Total rent expense for all operating leases for the three months ended March 31, 2018 was $4.3 million . Capital Leases The Company also enters into certain capital leases with expiration dates through July 2022 . On an ongoing basis, the Company enters into vehicle lease agreements under a Fleet Lease Agreement. The lease agreements are typically 36 month leases for each vehicle and the average remaining life for the fleet is 10 months , as of March 31, 2019 . As of December 31, 2018 , the capital lease obligation balance was $13.3 million . See Note 12 "Leases" for additional information related to the impact of adopting Topic 842.	Commitments and Contingencies Indemnification Subject to certain limitations, the Company is obligated to indemnify its current and former directors, officers and employees with respect to certain litigation matters and investigations that arise in connection with their service to the Company. These obligations arise under the terms of its certificate of incorporation, its bylaws, applicable contracts, and Delaware and California law. The obligation to indemnify generally means that the Company is required to pay or reimburse these individuals’ reasonable legal expenses and possibly damages and other liabilities incurred in connection with these matters. Legal The Company is named from time to time as a party to lawsuits arising in the ordinary course of business related to its sales, marketing, and the provision of its services and equipment claims. Actions filed against the Company include commercial, intellectual property, customer, and labor and employment related claims, including complaints of alleged wrongful termination and potential class action lawsuits regarding alleged violations of federal and state wage and hour and other laws. In general, litigation can be expensive and disruptive to normal business operations. Moreover, the results of legal proceedings are difficult to predict and the costs incurred in litigation can be substantial. The Company believes the amounts provided in its financial statements are adequate in light of the probable and estimated liabilities. Factors that the Company considers in the determination of the likelihood of a loss and the estimate of the range of that loss in respect of legal matters include the merits of a particular matter, the nature of the matter, the length of time the matter has been pending, the procedural posture of the matter, how the Company intends to defend the matter, the likelihood of settling the matter and the anticipated range of a possible settlement. Because such matters are subject to many uncertainties, the ultimate outcomes are not predictable and there can be no assurances that the actual amounts required to satisfy alleged liabilities from the matters described above will not exceed the amounts reflected in the Company’s financial statements or that the matters will not have a material adverse effect on the Company’s results of operations, financial condition or cash flows. The Company regularly reviews outstanding legal claims and actions to determine if reserves for expected negative outcomes of such claims and actions are necessary. The Company had reserves for all such matters of approximately $2.5 million and $2.2 million as of December 31, 2018 and 2017 , respectively. During the year ended December 31, 2017 the Company accrued $10.0 million related to the settlement of litigation with ADT Inc. included in accounts payable on the consolidated balance sheets. The Company paid the full amount in early 2018. Operating Leases The Company leases office and warehouse space, certain equipment, towers, wireless spectrum, software and an aircraft under operating leases with related and unrelated parties expiring in various years through 2028 . The leases require the Company to pay additional rent for increases in operating expenses and real estate taxes and contain renewal options. Total rent expense for all operating leases for the years ended December 31, 2018 , 2017 and 2016 was $16.5 million , $17.0 million and $16.0 million , respectively. Capital Leases The Company also enters into certain capital leases with expiration dates through May 2022 . On an ongoing basis, the Company enters into vehicle lease agreements under a Fleet Lease Agreement. The lease agreements are typically 36 months leases for each vehicle and the average remaining life for the fleet is 19 months as of December 31, 2018 . As of December 31, 2018 and 2017 , the capital lease obligation balance was $13.3 million and $21.7 million , respectively. Spectrum Licenses During the year ended December 31, 2016, Vivint Wireless, Inc. (“Vivint Wireless”), an indirect wholly owned subsidiary of the Company, entered into leasing agreements with Nextlink Wireless, LLC (“Nextlink”) for designated radio frequency spectrum in 40 mid-sized metropolitan markets. In December 2017, Vivint Wireless entered into a Termination Agreement with Verizon Communications Inc. (“Verizon”) pursuant to which the parties agreed, among other things, to terminate certain spectrum leases, including the 40 aforementioned leasing agreements, between Vivint Wireless and Nextlink, a subsidiary of Verizon, in exchange for cash consideration. Subsequent to the year ended December 31, 2018 , the Company consummated the transactions contemplated by the Termination Agreement with Verizon. See Note 18 for further discussion. As of December 31, 2018 , future minimum lease payments were as follows (in thousands): Operating Capital Total 2019 $ 16,709 $ 8,193 $ 24,902 2020 15,478 5,209 20,687 2021 14,926 363 15,289 2022 13,655 7 13,662 2023 13,701 — 13,701 Thereafter 28,824 — 28,824 Amounts representing interest — (459 ) (459 ) Total lease payments $ 103,293 $ 13,313 $ 116,606 In addition to the commitments mentioned above, the Company had other purchase obligations of $59.5 million as of December 31, 2018 that consisted of commitments related to software licenses, marketing activities, and other goods and services.

Leases (Notes)

Leases (Notes)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	Leases The Company has operating leases for corporate offices, warehouse facilities, research and development and other operating facilities, an aircraft, and other operating assets. The Company has finance leases for vehicles, office equipment and other warehouse equipment. The leases have remaining terms of 1 year to 9 years , some of which include options to extend the leases for up to 10 years , and some of which include options to terminate the leases within 1 year . The components of lease expense were as follows (in thousands): Three Months Ended March 31, 2019 Operating lease cost $ 4,298 Finance lease cost: Amortization of right-of-use assets $ 1,376 Interest on lease liabilities 154 Total finance lease cost $ 1,530 Supplemental cash flow information related to leases was as follows (in thousands): Three Months Ended March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ (4,375 ) Operating cash flows from finance leases (154 ) Financing cash flows from finance leases (2,136 ) Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 584 Finance leases 230 Supplemental balance sheet information related to leases was as follows (in thousands, except lease term and discount rate): March 31, 2019 Operating Leases Operating lease right-of-use assets $ 72,891 Current operating lease liabilities $ 11,749 Operating lease liabilities 71,964 Total operating lease liabilities $ 83,713 Finance Leases Property, plant and equipment, gross $ 45,440 Accumulated depreciation (23,205 ) Property, plant and equipment, net $ 22,235 Current finance lease liabilities $ 7,114 Finance lease liabilities 3,952 Total finance lease liabilities $ 11,066 Weighted Average Remaining Lease Term Operating leases 7 years Finance leases 1.5 years Weighted Average Discount Rate Operating leases 7 % Finance leases 4 % Maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the three months ended March 31, 2019) $ 13,163 $ 5,827 2020 16,345 5,167 2021 15,649 384 2022 14,514 38 2023 14,553 — Thereafter 32,404 — Total lease payments 106,628 11,416 Less imputed interest (22,915 ) (350 ) Total $ 83,713 $ 11,066 As of March 31, 2019 , the Company has an additional facility operating lease that has not yet commenced of $0.6 million . The operating lease will commence in fiscal year 2019 with a lease term of 5 years .
Leases	Leases The Company has operating leases for corporate offices, warehouse facilities, research and development and other operating facilities, an aircraft, and other operating assets. The Company has finance leases for vehicles, office equipment and other warehouse equipment. The leases have remaining terms of 1 year to 9 years , some of which include options to extend the leases for up to 10 years , and some of which include options to terminate the leases within 1 year . The components of lease expense were as follows (in thousands): Three Months Ended March 31, 2019 Operating lease cost $ 4,298 Finance lease cost: Amortization of right-of-use assets $ 1,376 Interest on lease liabilities 154 Total finance lease cost $ 1,530 Supplemental cash flow information related to leases was as follows (in thousands): Three Months Ended March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ (4,375 ) Operating cash flows from finance leases (154 ) Financing cash flows from finance leases (2,136 ) Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 584 Finance leases 230 Supplemental balance sheet information related to leases was as follows (in thousands, except lease term and discount rate): March 31, 2019 Operating Leases Operating lease right-of-use assets $ 72,891 Current operating lease liabilities $ 11,749 Operating lease liabilities 71,964 Total operating lease liabilities $ 83,713 Finance Leases Property, plant and equipment, gross $ 45,440 Accumulated depreciation (23,205 ) Property, plant and equipment, net $ 22,235 Current finance lease liabilities $ 7,114 Finance lease liabilities 3,952 Total finance lease liabilities $ 11,066 Weighted Average Remaining Lease Term Operating leases 7 years Finance leases 1.5 years Weighted Average Discount Rate Operating leases 7 % Finance leases 4 % Maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the three months ended March 31, 2019) $ 13,163 $ 5,827 2020 16,345 5,167 2021 15,649 384 2022 14,514 38 2023 14,553 — Thereafter 32,404 — Total lease payments 106,628 11,416 Less imputed interest (22,915 ) (350 ) Total $ 83,713 $ 11,066 As of March 31, 2019 , the Company has an additional facility operating lease that has not yet commenced of $0.6 million . The operating lease will commence in fiscal year 2019 with a lease term of 5 years .

Related Party Transactions

Related Party Transactions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Transactions with Vivint Solar The Company has negotiated and entered into a number of agreements with its sister company, Vivint Solar, Inc. (“Solar”). Some of those agreements related to Solar’s use of certain of the Company’s information technology and infrastructure services; however, Solar stopped using such services in July 2017. In August 2017, the Company entered into a sales dealer agreement with Solar, pursuant to which each company will act as a non-exclusive dealer for the other party to market, promote and sell each other’s products. The agreement has an initial term of two years and replaces substantially all of the activities being undertaken under the parties’ former marketing and customer relations agreement. The Company and Solar also agreed to extend the term of the non-solicitation provisions under an existing non-competition agreement to match the term of the sales dealer agreement. During the three months ended March 31, 2019 and 2018 , the Company charged $2.4 million and $1.0 million , respectively, of net expenses to Solar in connection with these agreements. The balance due from Solar in connection with these agreements and other expenses paid on Solar’s behalf was immaterial at March 31, 2019 and December 31, 2018 , respectively, and is included in prepaid expenses and other current assets in the accompanying condensed consolidated balance sheets. Other Related-party Transactions Prepaid expenses and other current assets at March 31, 2019 and December 31, 2018 included a receivable for $0.2 million and $1.8 million , respectively, from certain members of management in regards to their personal use of the corporate jet. The Company incurred additional expenses of $0.4 million and $0.6 million during the three months ended March 31, 2019 and 2018 , respectively, for other related-party transactions including contributions to the charitable organization Vivint Gives Back, legal fees, and other services. Accrued expenses and other current liabilities at March 31, 2019 and December 31, 2018 , included a net payable associated with these related-party transactions of $0.1 million and $0.2 million , respectively. On November 16, 2012, the Company was acquired by an investor group comprised of certain investment funds affiliated with Blackstone Capital Partners VI L.P., and certain co-investors and management investors through certain mergers and related reorganization transactions (collectively, the “Merger”). In connection with the Merger, the Company engaged Blackstone Management Partners L.L.C. (“BMP”) to provide monitoring, advisory and consulting services on an ongoing basis. In consideration for these services, the Company agreed to pay an annual monitoring fee equal to the greater of (i) a minimum base fee of $2.7 million , subject to adjustments if the Company engages in a business combination or disposition that is deemed significant and (ii) the amount of the monitoring fee paid in respect of the immediately preceding fiscal year, without regard to any post-fiscal year “true-up” adjustments as determined by the agreement. The Company incurred expenses for such services of approximately $1.0 million and $1.2 million during the three months ended March 31, 2019 and 2018 , respectively. Accrued expenses and other current liabilities at March 31, 2019 and December 31, 2018 , included a liability to BMP in regards to the monitoring fee for $1.0 million and $4.8 million , respectively. Under the support and services agreement, the Company also engaged BMP to arrange for Blackstone’s portfolio operations group to provide support services customarily provided by Blackstone’s portfolio operations group to Blackstone’s private equity portfolio companies of a type and amount determined by such portfolio services group to be warranted and appropriate. BMP will invoice the Company for such services based on the time spent by the relevant personnel providing such services during the applicable period but in no event shall the Company be obligated to pay more than $1.5 million during any calendar year. During the three months ended March 31, 2019 and 2018 the Company incurred no costs associated with such services. An affiliate of Blackstone participated as one of the arrangers in the Term Loan in September 2018 and received approximately $0.9 million of total fees associated with this issuance. In September 2018, GSO Capital Partners, an affiliate of Blackstone, participated as a lender in the Term Loan. As of March 31, 2019 and December 31, 2018 , GSO Capital Partners held $79.3 million and $75.1 million , respectively, of outstanding aggregate principal of the Term Loan. In September 2018, Vivint Smart Home, Inc. contributed $4.7 million to the Company as a capital contribution. From time to time, the Company does business with a number of other companies affiliated with Blackstone. Transactions involving related parties cannot be presumed to be carried out at an arm’s-length basis.	Related Party Transactions Transactions with Vivint Solar The Company and Vivint Solar, Inc. (“Solar”) have entered into agreements under which the Company provided certain ongoing administrative services to Solar through September 2017 and the Sales Dealer Agreement (as defined below). During the year ended December 31, 2018 , 2017 and 2016 the Company charged $17.3 million , $2.8 million and $4.6 million , respectively of net expenses to Solar in connection with these agreements. The balance due from Solar in connection with these agreements and other expenses paid on Solar’s behalf was immaterial at both December 31, 2018 and 2017 . Also in connection with Solar’s initial public offering in 2014 , the Company entered into a number of agreements with Solar related to services and other support that it has provided and will provide to Solar including: • A Master Intercompany Framework Agreement which established a framework for the ongoing relationship between the Company and Solar and contains master terms regarding the protection of each other’s confidential information, and master procedural terms, such as notice procedures, restrictions on assignment, interpretive provisions, governing law and dispute resolution; • A Non-Competition Agreement in which the Company and Solar each defined their current areas of business and their competitors, and agreed not to directly or indirectly engage in the other’s business for three years; • A Transition Services Agreement pursuant to which the Company agreed to provide to Solar various enterprise services, including services relating to information technology and infrastructure, human resources and employee benefits, administration services and facilities-related services; • A Product Development and Supply Agreement pursuant to which one of Solar’s wholly owned subsidiaries would, for an initial term of three years, subject to automatic renewal for successive one -year periods unless either party elects otherwise, collaborate with the Company to develop certain monitoring and communications equipment that will be compatible with other equipment used in Solar’s energy systems and will replace equipment Solar currently procures from third parties; • A Marketing and Customer Relations Agreement which governs various cross-marketing initiatives between the Company and Solar, in particularly the provision of sales leads from each company to the other; and • A Trademark License Agreement pursuant to which the licensor, a special purpose subsidiary majority-owned by the Company and minority-owned by Solar, will grant Solar a royalty-free exclusive license to the trademark “VIVINT SOLAR” in the field of selling renewable energy or energy storage products and services. In 2016, the Company and Solar amended the Marketing and Customer Relations Agreement to update certain terms and conditions governing existing cross-marketing initiatives and to implement new cross-marketing initiatives including a pilot program with the purpose of exploring potential opportunities for each company to offer, sell and integrate the other company’s respective products and services with its standard product offering. In 2017, the Company and Solar entered into a Sales Dealer Agreement (the “Sales Dealer Agreement”), pursuant to which each party will act as a non-exclusive dealer for the other party to market, promote and sell each other’s products. The agreement has an initial two -year term, which will be automatically renewed for successive one -year terms unless written notice of termination is provided by one of the parties to the other no less than 90 days prior to the end of the then current term. The products, territories and consideration that is payable by each party to the other will be determined in accordance with the agreement. The Sales Dealer Agreement governs and replaces substantially all of the activities that were previously undertaken under the Marketing and Customer Relations Agreement described above, including the pilot program. The Company and Solar also agreed to extend the term of the non-solicitation provisions under the existing Non-Competition Agreement to match the term of the Sales Dealer Agreement. Other Related-party Transactions The Company incurred additional expenses during the years ended December 31, 2018 , 2017 and 2016 of approximately $2.7 million , $3.5 million , $4.2 million , respectively, for other related-party transactions including contributions to the charitable organization Vivint Gives Back, legal fees, and other services. Accrued expenses and other current liabilities at December 31, 2018 and 2017 included net payables associated with these related-party transactions of $0.2 million and $1.4 million , respectively. On November 16, 2012, the Company was acquired by an investor group comprised of certain investment funds affiliated with Blackstone Capital Partners VI L.P., and certain co-investors and management investors through certain mergers and related reorganization transactions (collectively, the “Merger”). In connection with the Merger, the Company engaged Blackstone Management Partners L.L.C. (“BMP”) to provide monitoring, advisory and consulting services on an ongoing basis. In consideration for these services, the Company agreed to pay an annual monitoring fee equal to the greater of (i) a minimum base fee of $2.7 million subject to adjustments if the Company engages in a business combination or disposition that is deemed significant and (ii) the amount of the monitoring fee paid in respect of the immediately preceding fiscal year, without regard to any post-fiscal year “true-up” adjustments as determined by the agreement. The Company incurred expenses for such services of approximately $4.1 million , $3.5 million and $3.7 million during the years ended December 31, 2018 , 2017 and 2016 , respectively. Accrued expenses and other current liabilities at December 31, 2018 and 2017 included a liability of $4.8 million and $0.9 million , respectively, to BMP in regards to the monitoring fee. Under the support and services agreement, the Company also engaged BMP to arrange for Blackstone’s portfolio operations group to provide support services customarily provided by Blackstone’s portfolio operations group to Blackstone’s private equity portfolio companies of a type and amount determined by such portfolio services group to be warranted and appropriate. BMP will invoice the Company for such services based on the time spent by the relevant personnel providing such services during the applicable period but in no event shall the Company be obligated to pay more than $1.5 million during any calendar year. During the years ended December 31, 2018 , 2017 and 2016 the Company incurred no costs associated with such services. During the year ended December 31, 2018, Blackstone Advisory Partners L.P. (“BAP”), an affiliate of Blackstone, participated as one of the initial purchasers of the Term Loan in September 2018 and received fees at the time of closing of such issuances aggregating approximately $0.9 million . During the year ended December 31, 2017, BAP participated as one of the initial purchasers of the 2022 notes in the February 2017 issuance and the 2023 notes in the August 2017 issuance and received fees at the time of closing of such issuances aggregating approximately $0.6 million . During the year ended December 31, 2016, BAP participated as one of the initial purchasers of the 2022 notes in each of the May 2016 and August 2016 offerings and received fees at the time of closing of such issuances aggregating approximately $0.5 million . In addition, GSO Capital Partners, an affiliate of Blackstone, is a participating lender in the Term Loan and as of December 31, 2018 had received in aggregate interest payments of approximately $0.9 million . As of December 31, 2018 , GSO Capital Partners holds $75.1 million of outstanding aggregate principal of the Term Loan. In September 2018, Vivint Smart Home, Inc. contributed $4.7 million to the Company as a capital contribution. In April 2016, Parent completed the first installment of an issuance and sale to certain investors of a series of preferred stock and contributed the net proceeds from such issuance of $69.8 million to the Company as an equity contribution. In July 2016, Parent completed the final installment of the issuance and sale to certain investors of such series of preferred stock and, in August 2016, contributed the net proceeds from such issuance of $30.6 million to the Company as an equity contribution. Both issuances were private placements exempt from registration under the Securities Act. The company incurred stock-based compensation expense of $2.2 million included in general and administrative expenses for the year ended December 31, 2016 related to an equity repurchase by 313 from one of the Company's executives. Long-term notes receivables and other assets, includes amounts due for non-interest bearing advances made to employees that are expected to be repaid in excess of one year . Amounts due from employees as of both December 31, 2018 and 2017 , amounted to approximately $0.3 million . As of December 31, 2018 and 2017 , this amount was fully reserved. Prepaid expenses and other current assets at December 31, 2018 and 2017 included a receivable for $1.8 million and $0.5 million , respectively, from certain members of management in regards to their personal use of the corporate jet. From time to time, the Company does business with a number of other companies affiliated with Blackstone. Transactions involving related parties cannot be presumed to be carried out at an arm’s-length basis.

Employee Benefit Plan

Employee Benefit Plan	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Postemployment Benefits [Abstract]
Employee Benefit Plan	Employee Benefit Plan The Company offers eligible employees the opportunity to contribute a percentage of their earned income into company-sponsored 401(k) plans. Since January 2018, participants in the 401(k) plans have been eligible for the Company's matching program. Under this matching program, the Company matches an employee’s contributions to the 401(k) savings plan dollar-for-dollar up to 1% of such employee’s eligible earnings and $0.50 for every $1.00 for the next 5% of such employee’s eligible earnings. The maximum match available under the 401(k) plan is 3.5% of the employee’s eligible earnings. For employees who have been employed by the Company for less than two years, matching contributions vest on the second anniversary of their date of hire. The Company's matching contributions to employees who have been employed by the Company for two years or more are fully vested. Matching contributions that were made to the plans during the three months ended March 31, 2019 and 2018 totaled $1.9 million and $1.6 million , respectively.	Employee Benefit Plan The Company offers eligible employees the opportunity to defer a percentage of their earned income into company-sponsored 401(k) plans. The Company offers eligible employees the opportunity to contribute a percentage of their earned income into company-sponsored 401(k) plans. Beginning in January 2018, participants in the 401(k) plans are eligible for the Company's matching program. Under this new matching program, the Company matches an employee’s contributions to the 401(k) savings plan dollar-for-dollar up to 1% of such employee’s eligible earnings and $0.50 for every $1.00 for the next 5% of such employee’s eligible earnings. The maximum match available under the 401(k) plan is 3.5% of the employee’s eligible earnings. For employees who have been employed by the Company for less than two years, matching contributions vest on the second anniversary of their date of hire. The Company's matching contributions to employees who have been employed by the Company for two years or more are fully vested. Matching contributions that were made to the plans during the year ended December 31, 2018 totaled $6.0 million . No matching contributions were made to the plans for the years ended December 31, 2017 and 2016.

Restructuring and Asset Impairm

Restructuring and Asset Impairment Charges	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Asset Impairment Charges	Restructuring and Asset Impairment Charges In July 2018, the Company announced a number of cost reduction initiatives that are expected to reduce certain of the Company’s General and Administrative, Customer Service, and Sales Support fixed costs. The Company completed the majority of these cost reduction initiatives in the second and third quarters of 2018, with the remainder by the end of 2018. In addition to resulting in meaningful cost reductions, the Company’s initiatives are expected to streamline operations, focus engineering and innovation and provide a better focus on driving customer satisfaction. As part of these initiatives, the Company and Best Buy agreed in principle to end the co-branded Best Buy Smart Home by Vivint arrangement, which resulted in the elimination of in-store sales positions. In addition, the Company eliminated other general and administrative positions. The following table presents accrued restructuring activity for the three months ended March 31, 2019 and the twelve months ended December 31, 2018 (in thousands): Contract termination costs Employee severance and termination benefits Total Accrued restructuring balance as of December 31, 2017 $ 558 $ — $ 558 Restructuring expenses — 4,683 4,683 Cash payments (91 ) (4,341 ) (4,432 ) Accrued restructuring balance as of December 31, 2018 467 342 809 Cash payments (23 ) (257 ) (280 ) Accrued restructuring balance as of March 31, 2019 $ 444 $ 85 $ 529 Contract termination costs represent ongoing contractual commitments related to the 2015 restructuring of the Company's Wireless Internet Business. Additional charges may be incurred in the future for facility-related or other restructuring activities as the Company continues to align resources to meet the needs of the business.	Restructuring and Asset Impairment Charges Restructuring During the year ended December 31, 2018, the Company announced a number of cost reduction initiatives that are expected to reduce certain of the Company’s General and Administrative, Customer Service, and Sales Support fixed costs. The Company completed the majority of these cost reduction initiatives in the second and third quarters of 2018, with the remainder by the end of 2018. In addition to resulting in meaningful cost reductions, the Company’s initiatives are expected to streamline operations, focus engineering and innovation and provide a better focus on driving customer satisfaction. As part of these initiatives, the Company and Best Buy agreed in principle to end the co-branded Best Buy Smart Home by Vivint arrangement ("Best Buy Agreement"), which resulted in the elimination of in-store sales positions. In addition, the Company eliminated other general and administrative positions. These actions resulted in one-time cash employee severance and termination benefits expenses of $4.7 million during the year ended December 31, 2018. The Company formally terminated its relationship with Best Buy in December 2018 and agreed to pay a termination fee of $5.5 million . The difference between the termination fee and all previously recorded liabilities relating to the Company's Best Buy Agreement was recorded as a reduction to capitalized contract costs. During the year ended December 31, 2016, the Company sold all of its New Zealand and Puerto Rico contracts and recorded the impact of these transactions in restructuring and asset impairment. The calculation of the net loss recorded related to the 2016 Contract Sales included the expensing of all unamortized deferred subscriber acquisition costs associated with these subscriber accounts in the amount of $7.6 million , the realization of outstanding amounts of accumulated other comprehensive loss associated with the New Zealand foreign currency translation process of $1.1 million upon the substantial sale of the subsidiary, offset by cash proceeds of $6.2 million for a total net loss on the 2016 Contract Sales of $2.6 million . Restructuring and asset impairment charges were as follows (in thousands): Year ended December 31, 2018 2017 2016 Wireless restructuring recoveries: Asset recoveries $ — $ — $ (710 ) Contract termination recoveries — — (751 ) Employee severance and termination benefits recoveries — — (77 ) Total wireless restructuring recoveries — — (1,538 ) Loss on subscriber contract sales — — 2,551 Employee severance and termination benefits charges 4,683 — — Total restructuring and asset impairment charges $ 4,683 $ — $ 1,013 The following table presents accrued restructuring activity for the years ended December 31, 2018 and 2017 . Asset impairments Contract termination costs Employee severance and termination benefits Total Accrued restructuring balance as of December 31, 2015 $ — $ 3,954 $ 321 $ 4,275 Restructuring and impairment recoveries (710 ) (751 ) (77 ) (1,538 ) Cash payments — (2,554 ) (244 ) (2,798 ) Non-cash settlements 710 — — 710 Accrued restructuring balance as of December 31, 2016 — 649 — 649 Cash payments — (91 ) — (91 ) Accrued restructuring balance as of December 31, 2017 — 558 — 558 Restructuring expenses — — 4,683 4,683 Cash payments — (91 ) (4,341 ) (4,432 ) Accrued restructuring balance as of December 31, 2018 $ — $ 467 $ 342 $ 809 Accrued restructuring at December 31, 2018 is included in current liabilities within accrued expenses and other current liabilities of $0.4 million and in long-term liabilities within other long-term obligations of $0.4 million . Contract termination costs represent ongoing contractual commitments related to the 2015 restructuring of the Company's Wireless Internet Business. Additional charges may be incurred in the future for facility-related or other restructuring activities as the Company continues to align resources to meet the needs of the business.

Segment Reporting and Business

Segment Reporting and Business Concentrations	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Reporting and Business Concentrations	Segment Reporting and Business Concentrations For the three months ended March 31, 2019 and 2018 , the Company conducted business through one operating segment, Vivint. The Company primarily operated in two geographic regions: United States and Canada. Revenues disaggregated by geographic region were as follows (in thousands): United States Canada Total Revenue from external customers Three months ended March 31, 2019 $ 258,436 $ 17,813 $ 276,249 Three months ended March 31, 2018 228,542 18,055 246,597	Segment Reporting and Business Concentrations For the years ended December 31, 2018 , 2017 and 2016 , the Company conducted business through one operating segment, Vivint. Historically, the Company primarily operated in three geographic regions: United States, Canada and New Zealand. During the year ended December 31, 2016, the Company completed the 2016 Contract Sales and ceased operations in New Zealand. Historically, the Company's operations in New Zealand were considered immaterial and reported in conjunction with the United States. Revenues by geographic region were as follows (in thousands): United States Canada Total Revenue from external customers Year ended December 31, 2018 $ 977,877 $ 72,564 $ 1,050,441 Year ended December 31, 2017 $ 816,026 $ 65,957 $ 881,983 Year ended December 31, 2016 $ 700,471 $ 57,436 $ 757,907

Guarantor and Non-Guarantor Sup

Guarantor and Non-Guarantor Supplemental Financial Information	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Guarantor And Non Guarantor Supplemental Financial Information [Abstract]
Guarantor and Non-Guarantor Supplemental Financial Information	Guarantor and Non-Guarantor Supplemental Financial Information The Notes were issued by APX and are fully and unconditionally guaranteed, jointly and severally by Holdings and each of APX’s existing and future material wholly-owned U.S. restricted subsidiaries. APX’s existing and future foreign subsidiaries are not expected to guarantee the Notes. Presented below is the condensed consolidating financial information of APX, subsidiaries of APX that are guarantors (the “Guarantor Subsidiaries”), and APX’s subsidiaries that are not guarantors (the “Non-Guarantor Subsidiaries”) as of March 31, 2019 and December 31, 2018 and for the three months ended March 31, 2019 and 2018 . The unaudited condensed consolidating financial information reflects the investments of APX in the Guarantor Subsidiaries and the Non-Guarantor Subsidiaries using the equity method of accounting. Supplemental Condensed Consolidating Balance Sheet March 31, 2019 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 2,919 $ 335,398 $ 119,909 $ (289,784 ) $ 168,442 Property, plant and equipment, net — — 64,188 426 — 64,614 Capitalized contract costs, net — — 1,027,364 65,501 — 1,092,865 Deferred financing costs, net — 1,797 — — — 1,797 Investment in subsidiaries — 1,650,064 — — (1,650,064 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 218,194 17,389 — 235,583 Goodwill — — 809,678 25,726 — 835,404 Operating lease right-of-use assets — — 72,661 230 — 72,891 Long-term notes receivables and other assets — 106 104,486 17,310 (106 ) 121,796 Total Assets $ — $ 1,654,886 $ 2,638,272 $ 246,491 $ (1,946,257 ) $ 2,593,392 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 63,260 $ 558,398 $ 192,835 $ (289,784 ) $ 524,709 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving credit facility, net of current portion — 3,075,990 — — — 3,075,990 Finance lease obligations, net of current portion — — 3,952 — — 3,952 Deferred revenue, net of current portion — — 309,896 16,735 — 326,631 Operating lease liabilities — — 71,878 86 — 71,964 Other long-term obligations — — 73,043 347 — 73,390 Accumulated losses of investee, net 1,484,364 (1,484,364 ) — Deferred income tax liability — — 106 1,120 (106 ) 1,120 Total (deficit) equity (1,484,364 ) (1,484,364 ) 1,620,999 29,065 (165,700 ) (1,484,364 ) Total liabilities and stockholders’ (deficit) equity $ — $ 1,654,886 $ 2,638,272 $ 246,491 $ (1,946,257 ) $ 2,593,392 Supplemental Condensed Consolidating Balance Sheet December 31, 2018 (in thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 12,951 $ 269,770 $ 103,451 $ (262,674 ) $ 123,498 Property, plant and equipment, net — — 72,937 464 — 73,401 Capitalized contract costs, net — — 1,047,532 68,243 — 1,115,775 Deferred financing costs, net — 2,058 — — — 2,058 Investment in subsidiaries — 1,662,367 — — (1,662,367 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 236,677 18,408 — 255,085 Goodwill — — 809,678 25,177 — 834,855 Long-term notes receivables and other assets — 106 102,695 17,124 (106 ) 119,819 Total Assets $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 36,988 $ 507,063 $ 182,159 $ (262,674 ) $ 463,536 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving credit facility, net of current portion — 3,037,095 — — — 3,037,095 Capital lease obligations, net of current portion — — 5,570 1 — 5,571 Deferred revenue, net of current portion — — 306,653 16,932 — 323,585 Accumulated Losses of Investee, net 1,396,601 (1,396,601 ) — Other long-term obligations — — 90,209 — — 90,209 Deferred income tax liability — — 106 1,096 (106 ) 1,096 Total (deficit) equity (1,396,601 ) (1,396,601 ) 1,635,991 26,376 (265,766 ) (1,396,601 ) Total liabilities and stockholders’ (deficit) equity $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491 Supplemental Condensed Consolidating Statements of Operations and Comprehensive Loss For the Three Months Ended March 31, 2019 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 263,539 $ 12,912 $ (202 ) $ 276,249 Costs and expenses — — 291,509 12,920 (202 ) 304,227 Loss from operations — — (27,970 ) (8 ) — (27,978 ) Loss from subsidiaries (89,156 ) (25,981 ) — — 115,137 — Other expense (income), net — 63,175 (52 ) (1,644 ) — 61,479 (Loss) income before income tax expenses (89,156 ) (89,156 ) (27,918 ) 1,636 115,137 (89,457 ) Income tax expense (benefit) — — 182 (483 ) — (301 ) Net (loss) income (89,156 ) (89,156 ) (28,100 ) 2,119 115,137 (89,156 ) Other comprehensive loss, net of tax effects: Net (loss) income (89,156 ) (89,156 ) (28,100 ) 2,119 115,137 (89,156 ) Foreign currency translation adjustment 570 570 — 570 (1,140 ) 570 Total other comprehensive income 570 570 — 570 (1,140 ) 570 Comprehensive (loss) income $ (88,586 ) $ (88,586 ) $ (28,100 ) $ 2,689 $ 113,997 $ (88,586 ) Supplemental Condensed Consolidating Statements of Operations and Comprehensive Loss For the Three Months Ended March 31, 2018 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 233,788 $ 13,465 $ (656 ) $ 246,597 Costs and expenses — — 305,221 13,663 (656 ) 318,228 (Loss) income from operations — — (71,433 ) (198 ) — (71,631 ) Loss from subsidiaries (84,717 ) (26,320 ) — — 111,037 — Other expense (income), net — 58,397 (46,970 ) 2,092 — 13,519 Loss before income tax expenses (84,717 ) (84,717 ) (24,463 ) (2,290 ) 111,037 (85,150 ) Income tax expense (benefit) — — 172 (605 ) — (433 ) Net loss (84,717 ) (84,717 ) (24,635 ) (1,685 ) 111,037 (84,717 ) Other comprehensive loss, net of tax effects: Net loss (84,717 ) (84,717 ) (24,635 ) (1,685 ) 111,037 (84,717 ) Foreign currency translation adjustment (659 ) (659 ) — (659 ) 1,318 (659 ) Total other comprehensive loss (659 ) (659 ) — (659 ) 1,318 (659 ) Comprehensive loss $ (85,376 ) $ (85,376 ) $ (24,635 ) $ (2,344 ) $ 112,355 $ (85,376 ) Supplemental Condensed Consolidating Statements of Cash Flows For the Three Months Ended March 31, 2019 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (43,058 ) $ 41 $ — $ (43,017 ) Cash flows from investing activities: Capital expenditures — — (1,391 ) — — (1,391 ) Proceeds from sale of capital assets — — (51 ) — — (51 ) Investment in subsidiary (118 ) (46,487 ) — — 46,605 — Acquisition of intangible assets — — (369 ) — — (369 ) Net cash used in investing activities (118 ) (46,487 ) (1,811 ) — 46,605 (1,811 ) Cash flows from financing activities: Repayment on notes payable — (2,025 ) — — — (2,025 ) Borrowings from revolving credit facility — 40,000 — — — 40,000 Proceeds from capital contribution — — 46,369 — (46,369 ) — Repayments of finance lease obligations — — (2,064 ) (72 ) — (2,136 ) Return of capital 118 118 (118 ) — (236 ) (118 ) Net cash provided by (used in) financing activities 118 38,093 44,187 (72 ) (46,605 ) 35,721 Effect of exchange rate changes on cash — — — 25 — 25 Net decrease in cash and cash equivalents — (8,394 ) (682 ) (6 ) — (9,082 ) Cash and cash equivalents: Beginning of period — 11,130 682 961 — 12,773 End of period $ — $ 2,736 $ — $ 955 $ — $ 3,691 Supplemental Condensed Consolidating Statements of Cash Flows For the Three Months Ended March 31, 2018 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (59,159 ) $ (423 ) $ — $ (59,582 ) Cash flows from investing activities: Capital expenditures — — (6,407 ) — — (6,407 ) Investment in subsidiary 966 (16,450 ) — — 15,484 — Acquisition of intangible assets — — (849 ) — — (849 ) Proceeds from sale of intangibles — — 53,693 — — 53,693 Proceeds from sale of capital assets — — 149 — — 149 Net cash provided by (used in) investing activities 966 (16,450 ) 46,586 — 15,484 46,586 Cash flows from financing activities: Borrowings from revolving credit facility — 57,000 — — — 57,000 Repayments on revolving credit facility — (40,000 ) — — — (40,000 ) Proceeds from capital contributions — — 17,416 — (17,416 ) — Repayments of capital lease obligations — — (3,305 ) (113 ) — (3,418 ) Return of capital (966 ) (966 ) (966 ) — 1,932 (966 ) Net cash (used in) provided by financing activities (966 ) 16,034 13,145 (113 ) (15,484 ) 12,616 Effect of exchange rate changes on cash — — — (19 ) — (19 ) Net (decrease) increase in cash and cash equivalents — (416 ) 572 (555 ) — (399 ) Cash and cash equivalents: Beginning of period — 3,661 (572 ) 783 — 3,872 End of period $ — $ 3,245 $ — $ 228 $ — $ 3,473	Guarantor and Non-Guarantor Supplemental Financial Information The Notes were issued by APX and are fully and unconditionally guaranteed, jointly and severally by Holdings and each of APX’s existing and future material wholly-owned U.S. restricted subsidiaries. APX’s existing and future foreign subsidiaries are not expected to guarantee the Notes. Presented below is the consolidating financial information of APX, subsidiaries of APX that are guarantors (the “Guarantor Subsidiaries”), and APX’s subsidiaries that are not guarantors (the “Non-Guarantor Subsidiaries”) as of December 31, 2018 and 2017 and for the years ended December 31, 2018 , 2017 and 2016 . The audited consolidating financial information reflects the investments of APX in the Guarantor Subsidiaries and the Non-Guarantor Subsidiaries using the equity method of accounting. Condensed Consolidating Balance Sheet December 31, 2018 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 12,951 $ 269,770 $ 103,451 $ (262,674 ) $ 123,498 Property and equipment, net — — 72,937 464 — 73,401 Capitalized contract costs, net — — 1,047,532 68,243 — 1,115,775 Deferred financing costs, net — 2,058 — — — 2,058 Investment in subsidiaries — 1,662,367 — — (1,662,367 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 236,677 18,408 — 255,085 Goodwill — — 809,678 25,177 — 834,855 Long-term notes receivables and other assets, net — 106 102,695 17,124 (106 ) 119,819 Total Assets $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 36,988 $ 507,063 $ 182,159 $ (262,674 ) $ 463,536 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving line of credit, net of current portion — 3,037,095 — — — 3,037,095 Capital lease obligations, net of current portion — — 5,570 1 — 5,571 Deferred revenue, net of current portion — — 306,653 16,932 — 323,585 Accumulated losses of investee 1,396,601 (1,396,601 ) — Other long-term obligations — — 90,209 — — 90,209 Deferred income tax liability — — 106 1,096 (106 ) 1,096 Total (deficit) equity (1,396,601 ) (1,396,601 ) 1,635,991 26,376 (265,766 ) (1,396,601 ) Total liabilities and stockholders’ (deficit) equity $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491 Condensed Consolidating Balance Sheet December 31, 2017 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 4,150 $ 284,293 $ 49,935 $ (162,413 ) $ 175,965 Property and equipment, net — — 77,345 736 — 78,081 Subscriber acquisition costs, net — — 1,214,678 93,880 — 1,308,558 Deferred financing costs, net — 3,099 — — — 3,099 Investment in subsidiaries — 2,188,221 — — (2,188,221 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 350,710 26,741 — 377,451 Goodwill — — 809,678 27,292 — 836,970 Long-term notes receivables and other assets, net — 106 78,173 10,550 (106 ) 88,723 Total Assets $ — $ 2,195,576 $ 2,821,180 $ 209,134 $ (2,357,043 ) $ 2,868,847 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 28,805 $ 343,398 $ 128,581 $ (162,413 ) $ 338,371 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving line of credit, net of current portion — 2,820,297 — — — 2,820,297 Capital lease obligations, net of current portion — — 10,791 298 — 11,089 Deferred revenue, net of current portion — — 248,643 15,912 — 264,555 Accumulated losses of investee 653,526 (653,526 ) — Other long-term obligations — — 79,020 — — 79,020 Deferred income tax liability — — 106 9,041 (106 ) 9,041 Total (deficit) equity (653,526 ) (653,526 ) 2,139,222 48,999 (1,534,695 ) (653,526 ) Total liabilities and stockholders’ (deficit) equity $ — $ 2,195,576 $ 2,821,180 $ 209,134 $ (2,357,043 ) $ 2,868,847 Condensed Consolidating Statements of Operations and Comprehensive Loss For the Year ended December 31, 2018 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 998,190 $ 54,818 $ (2,567 ) $ 1,050,441 Costs and expenses — — 1,240,570 54,497 (2,567 ) 1,292,500 (Loss) income from operations — — (242,380 ) 321 — (242,059 ) Loss from subsidiaries (467,914 ) (211,665 ) — — 679,579 — Other expense (income), net — 256,249 (35,936 ) 7,153 — 227,466 Loss before income taxes (467,914 ) (467,914 ) (206,444 ) (6,832 ) 679,579 (469,525 ) Income tax expense (benefit) — — 512 (2,123 ) — (1,611 ) Net loss $ (467,914 ) $ (467,914 ) $ (206,956 ) $ (4,709 ) $ 679,579 $ (467,914 ) Other comprehensive loss, net of tax effects: Foreign currency translation adjustment (2,218 ) (2,218 ) — (2,218 ) 4,436 (2,218 ) Total other comprehensive loss, net of tax effects (2,218 ) (2,218 ) — (2,218 ) 4,436 (2,218 ) Comprehensive loss $ (470,132 ) $ (470,132 ) $ (206,956 ) $ (6,927 ) $ 684,015 $ (470,132 ) Condensed Consolidating Statements of Operations and Comprehensive Loss For the Year ended December 31, 2017 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 841,658 $ 43,015 $ (2,690 ) $ 881,983 Costs and expenses — — 997,247 42,919 (2,690 ) 1,037,476 (Loss) income from operations — — (155,589 ) 96 — (155,493 ) Loss from subsidiaries (410,199 ) (165,497 ) — — 575,696 — Other expense (income), net — 244,702 13,545 (4,619 ) — 253,628 (Loss) income before income taxes (410,199 ) (410,199 ) (169,134 ) 4,715 575,696 (409,121 ) Income tax expense (benefit) — — (228 ) 1,306 — 1,078 Net (loss) income $ (410,199 ) $ (410,199 ) $ (168,906 ) $ 3,409 $ 575,696 $ (410,199 ) Other comprehensive income (loss), net of tax effects: Foreign currency translation adjustment 3,155 3,155 — 3,155 (6,310 ) 3,155 Unrealized gain on marketable securities (1,693 ) (1,693 ) (1,693 ) — 3,386 (1,693 ) Total other comprehensive income (loss), net of tax effects 1,462 1,462 (1,693 ) 3,155 (2,924 ) 1,462 Comprehensive (loss) income $ (408,737 ) $ (408,737 ) $ (170,599 ) $ 6,564 $ 572,772 $ (408,737 ) Condensed Consolidating Statements of Operations and Comprehensive Loss For the Year ended December 31, 2016 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 715,072 $ 45,539 $ (2,704 ) $ 757,907 Costs and expenses — — 787,138 44,575 (2,704 ) 829,009 (Loss) income from operations — — (72,066 ) 964 — (71,102 ) Loss from subsidiaries (275,957 ) (69,637 ) — — 345,594 — Other expense (income), net — 206,320 (1,207 ) (325 ) — 204,788 Loss before income taxes (275,957 ) (275,957 ) (70,859 ) 1,289 345,594 (275,890 ) Income tax expense (benefit) — — 545 (478 ) — 67 Net (loss) income $ (275,957 ) $ (275,957 ) $ (71,404 ) $ 1,767 $ 345,594 $ (275,957 ) Other comprehensive income, net of tax effects: Foreign currency translation adjustment 2,482 2,482 — 2,482 (4,964 ) 2,482 Unrealized gain on marketable securities 1,011 1,011 1,011 — (2,022 ) 1,011 Total other comprehensive income, net of tax effects 3,493 3,493 1,011 2,482 (6,986 ) 3,493 Comprehensive loss $ (272,464 ) $ (272,464 ) $ (70,393 ) $ 4,249 $ 338,608 $ (272,464 ) Condensed Consolidating Statements of Cash Flows For the Year ended December 31, 2018 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (220,952 ) $ 453 $ — $ (220,499 ) Cash flows from investing activities: Capital expenditures — — (19,409 ) (3 ) — (19,412 ) Proceeds from sale of intangibles — — 53,693 — — 53,693 Proceeds from sale of capital assets — — 127 — — 127 Investment in subsidiary (1,571 ) (201,292 ) — — 202,863 — Acquisition of intangible assets — — (1,486 ) — — (1,486 ) Net cash (used in) provided by investing activities (1,571 ) (201,292 ) 32,925 (3 ) 202,863 32,922 Cash flows from financing activities: Proceeds from notes payable — 810,000 — — — 810,000 Repayment on notes payable — (522,191 ) — — — (522,191 ) Borrowings from revolving line of credit — 201,000 — — — 201,000 Repayment of revolving line of credit — (261,000 ) — — — (261,000 ) Proceeds from capital contribution 4,700 4,700 204,421 — (209,121 ) 4,700 Repayments of capital lease obligations — — (12,011 ) (343 ) — (12,354 ) Financing costs — (11,317 ) — — — (11,317 ) Deferred financing costs — (9,302 ) — — — (9,302 ) Return of capital (3,129 ) (3,129 ) (3,129 ) — 6,258 (3,129 ) Net cash provided by (used in) financing activities 1,571 208,761 189,281 (343 ) (202,863 ) 196,407 Effect of exchange rate changes on cash — — — 71 — 71 Net increase in cash — 7,469 1,254 178 — 8,901 Cash: Beginning of period — 3,661 (572 ) 783 — 3,872 End of period $ — $ 11,130 $ 682 $ 961 $ — $ 12,773 Condensed Consolidating Statements of Cash Flows For the Year ended December 31, 2017 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (313,290 ) $ 3,958 $ — $ (309,332 ) Cash flows from investing activities: Capital expenditures — — (20,391 ) — — (20,391 ) Proceeds from sale of capital assets — — 776 — — 776 Investment in subsidiary 1,151 (325,222 ) — — 324,071 — Acquisition of intangible assets — — (1,745 ) — — (1,745 ) Other assets — — (301 ) — — (301 ) Net cash provided by (used in) investing activities 1,151 (325,222 ) (21,661 ) — 324,071 (21,661 ) Cash flows from financing activities: Proceeds from notes payable — 724,750 — — — 724,750 Repayment on notes payable — (450,000 ) — — — (450,000 ) Borrowings from revolving line of credit — 196,895 — — — 196,895 Repayment of revolving line of credit — (136,895 ) — — — (136,895 ) Proceeds from capital contribution — — 326,373 — (326,373 ) — Payment of intercompany settlement — — (2,983 ) — — (2,983 ) Intercompany receivable — 3,621 — (3,621 ) — Intercompany payable — — — (3,621 ) 3,621 — Repayments of capital lease obligations — — (9,667 ) (340 ) — (10,007 ) Financing costs — (18,277 ) — — — (18,277 ) Deferred financing costs — (11,119 ) — — — (11,119 ) Return of capital (1,151 ) (1,151 ) (1,151 ) — 2,302 (1,151 ) Net cash (used in) provided by financing activities (1,151 ) 304,203 316,193 (3,961 ) (324,071 ) 291,213 Effect of exchange rate changes on cash — — — 132 — 132 Net increase (decrease) in cash — (21,019 ) (18,758 ) 129 — (39,648 ) Cash: Beginning of period — 24,680 18,186 654 — 43,520 End of period $ — $ 3,661 $ (572 ) $ 783 $ — $ 3,872 Condensed Consolidating Statements of Cash Flows For the Year ended December 31, 2016 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (380,508 ) $ 14,802 $ — $ (365,706 ) Cash flows from investing activities: Subscriber acquisition costs – company owned equipment — — (5,243 ) — — (5,243 ) Capital expenditures — — (11,642 ) — — (11,642 ) Proceeds from sale of capital assets — — 3,080 43 — 3,123 Investment in subsidiary (100,407 ) (408,214 ) — — 508,621 — Acquisition of intangible assets — — (1,385 ) — — (1,385 ) Net cash used in investing activities (100,407 ) (408,214 ) (15,190 ) 43 508,621 (15,147 ) Cash flows from financing activities: Proceeds from notes payable — 604,000 — — — 604,000 Repayment on notes payable — (235,535 ) — — — (235,535 ) Borrowings from revolving line of credit — 57,000 — — — 57,000 Repayment of revolving line of credit — (77,000 ) — — — (77,000 ) Proceeds from capital contribution 100,407 100,407 — — (100,407 ) 100,407 Payment of intercompany settlement — — 3,000 (3,000 ) — — Intercompany receivable — — 12,906 — (12,906 ) — Intercompany payable — — 408,214 (12,906 ) (395,308 ) — Repayments of capital lease obligations — — (8,295 ) (20 ) — (8,315 ) Financing costs — (9,036 ) — — — (9,036 ) Deferred financing costs — (9,241 ) — — — (9,241 ) Net cash provided by (used in) financing activities 100,407 430,595 415,825 (15,926 ) (508,621 ) 422,280 Effect of exchange rate changes on cash — — — (466 ) — (466 ) Net increase (decrease) in cash — 22,381 20,127 (1,547 ) — 40,961 Cash: Beginning of period — 2,299 (1,941 ) 2,201 — 2,559 End of period $ — $ 24,680 $ 18,186 $ 654 $ — $ 43,520

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On May 10, 2019, APX issued $225.0 million aggregate principal amount of 8.5% Senior Secured Notes due 2024 (“2024 notes”) in a private placement. APX used the net proceeds from the 2024 notes offering to redeem $225.0 million aggregate principal amount of its 2020 notes, and to pay the related accrued interest and to pay all fees and expenses related thereto. The indenture governing the 2024 notes contains covenants similar to the 2022 notes. An affiliate of Blackstone acted as one of the initial purchasers in connection with this offering.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements of the Company are presented for APX Group Holdings, Inc. (“Holdings") and its wholly-owned subsidiaries. The Company has prepared the accompanying unaudited condensed consolidated financial statements pursuant to GAAP. Preparing financial statements requires the Company to make estimates and assumptions that affect the amounts that are reported in the consolidated financial statements and accompanying disclosures. Although these estimates are based on the Company’s best knowledge of current events and actions that the Company may undertake in the future, actual results may be different from the Company’s estimates. The results of operations presented herein are not necessarily indicative of the Company’s results for any future period.	Basis of Presentation The Company has prepared the accompanying consolidated financial statements pursuant to generally accepted accounting principles in the United States (“GAAP”). Preparing financial statements requires the Company to make estimates and assumptions that affect the amounts that are reported in the consolidated financial statements and accompanying disclosures. Although these estimates are based on the Company’s best knowledge of current events and actions that the Company may undertake in the future, actual results may be different from the Company’s estimates. The results of operations presented herein are not necessarily indicative of the Company’s results for any future period.
Vivint Flex Pay	Vivint Flex Pay The Vivint Flex Pay plan (“Vivint Flex Pay”) became the Company's primary sales model beginning in March 2017. Under Vivint Flex Pay, customers pay separately for the products (including control panel, security peripheral equipment, smart home equipment, and related installation) (“Products”) and Vivint's smart home and security services (“Services”). The customer has the following three options to pay for the Products: (1) qualified customers in the United States may finance the purchase of Products through a third-party financing provider (“Consumer Financing Program”), (2) customers not eligible for the Consumer Financing Program, but who qualify under the Company's underwriting criteria, may enter into a retail installment contract (“RIC”) directly with Vivint, or (3) customers may purchase the Products at the outset of the service contract by check, automatic clearing house payments (“ACH”), credit or debit card. Although customers pay separately for Products and Services under the Vivint Flex Pay plan, the Company has determined that the sale of Products and Services are one single performance obligation. As a result, all forms of transactions under Vivint Flex Pay create deferred revenue for the gross amount of Products sold. Gross deferred revenues are reduced by imputed interest on the RICs and the present value of expected payments due to the third-party financing provider under the Consumer Financing Program. Under the Consumer Financing Program, qualified customers are eligible for installment loans provided by a third-party financing provider of up to $4,000 for either 42 or 60 months. For a certain third-party provider, the Company pays a monthly fee based on the average daily outstanding balance of the installment loans. Additionally, the Company shares liability for credit losses depending on the credit quality of the customer. Because of the nature of these provisions with this third-party provider, the Company records a derivative liability at its fair value when the third-party financing provider originates installment loans to customers, which reduces the amount of estimated revenue recognized on the provision of the services. The derivative liability is reduced as payments are made by the Company to the third-party financing provider. Subsequent changes to the fair value of the derivative liability are realized through other income, net in the Condensed Consolidated Statement of Operations. (See Note 8 ). For a separate third-party financing provider , the Company receives net proceeds from installment loans (net of fees and expected losses) for which the Company has no further obligation to the third-party. The Company records these net proceeds to deferred revenue.
Retail Installment Contract Receivables	Retail Installment Contract Receivables For subscribers that enter into a RIC to finance the purchase of Products and related installation, the Company records a receivable for the amount financed. The RIC receivables are recorded at their present value, net of the imputed interest discount. At the time of installation, the Company records a long-term note receivable within long-term notes receivables and other assets, net on the condensed consolidated balance sheets for the present value of the receivables that are expected to be collected beyond 12 months of the reporting date. The unbilled receivable amounts that are expected to be collected within 12 months of the reporting date are included as a short-term notes receivable within accounts and notes receivable, net on the condensed consolidated balance sheets. The billed amounts of notes receivables are included in accounts receivable within accounts and notes receivable, net on the condensed consolidated balance sheets. The Company imputes the interest on the RIC receivable using a risk adjusted market interest rate and records it as an adjustment to deferred revenue and as an adjustment to the face amount of the related receivable. The imputed interest discount considers a number of factors, including collection experience, aging of the remaining RIC receivable portfolios, credit quality of the subscriber base and other qualitative considerations, including macro-economic factors. The imputed interest income is recognized over the term of the RIC contract as recurring and other revenue on the condensed consolidated statement of operations. When the Company determines that there are RIC receivables that have become uncollectible, it records an adjustment to the imputed interest discount and reduces the related note receivable balance. Account balances are written-off if collection efforts are unsuccessful and future collection is unlikely based on the length of time from the day accounts become past due.	Retail Installment Contract Receivables For customers that enter into a RIC under the Vivint Flex Pay plan, the Company records a receivable for the amount financed. The RIC receivables are recorded at their present value, net of the imputed interest discount. At the time of installation, the Company records a long-term note receivable within long-term notes receivables and other assets, net on the consolidated balance sheets for the present value of the receivables that are expected to be collected beyond 12 months of the reporting date. The unbilled receivable amounts that are expected to be collected within 12 months of the reporting date are included as a short-term notes receivable within accounts and notes receivable, net on the consolidated balance sheets. The billed amounts of notes receivables are included in accounts receivable within accounts and notes receivable, net on the consolidated balance sheets. The Company imputes the interest on the RIC receivable using a risk adjusted market interest rate and records it as an adjustment to deferred revenue and as an adjustment to the face amount of the related receivable. The imputed interest discount considers a number of factors, including collection experience, aging of the remaining RIC receivable portfolios, credit quality of the subscriber base and other qualitative considerations, including macro-economic factors. The imputed interest income is recognized over the term of the RIC contract as recurring and other revenue on the consolidated statement of operations. When the Company determines that there are RIC receivables that have become uncollectible, it records an adjustment to the imputed interest discount and reduces the related note receivable balance. Account balances are written-off if collection efforts are unsuccessful and future collection is unlikely based on the length of time from the day accounts become past due.
Accounts Receivable	Accounts Receivable Accounts receivable consists primarily of amounts due from subscribers for recurring monthly monitoring Services and the billed portion of RIC receivables. The accounts receivable are recorded at invoiced amounts and are non-interest bearing and are included within accounts and notes receivable, net on the condensed consolidated balance sheets. Accounts receivable totaled $20.0 million and $16.5 million at March 31, 2019 and December 31, 2018 , respectively net of the allowance for doubtful accounts of $5.8 million and $5.6 million at March 31, 2019 and December 31, 2018 , respectively. The Company estimates this allowance based on historical collection experience and subscriber attrition rates. When the Company determines that there are accounts receivable that are uncollectible, they are charged off against the allowance for doubtful accounts. The provision for doubtful accounts is included in general and administrative expenses in the accompanying unaudited condensed consolidated statements of operations and totaled $5.9 million and $4.0 million for the three months ended March 31, 2019 and 2018 , respectively.	Accounts Receivable Accounts receivable consists primarily of amounts due from customers for recurring monthly monitoring Services and the billed portion of RIC receivables. The accounts receivable are recorded at invoiced amounts and are non-interest bearing and are included within accounts and notes receivable, net on the consolidated balance sheets. Accounts receivable totaled $16.5 million and $24.3 million and December 31, 2018 and 2017 , respectively net of the allowance for doubtful accounts of $5.6 million and $5.4 million at December 31, 2018 and 2017 , respectively. The Company estimates this allowance based on historical collection experience and subscriber attrition rates. When the Company determines that there are accounts receivable that are uncollectible, they are charged off against the allowance for doubtful accounts. The provision for doubtful accounts is included in general and administrative expenses in the accompanying consolidated statements of operations and totaled $19.4 million and $22.5 million for the years ended December 31, 2018 and 2017 , respectively.
Revenue Recognition	Revenue Recognition The Company offers its customers smart home services combining Products, including a proprietary control panel, door and window sensors, door locks, security cameras and smoke alarms; installation; and a proprietary back-end cloud platform software and Services. These together create an integrated system that allows the Company’s customers to monitor, control and protect their home (“Smart Home Services”). The Company’s customers are buying this integrated system that provides them with these Smart Home Services. The number and type of Products purchased by a customer depends on their desired functionality. Because the Products and Services included in the customer’s contract are integrated and highly interdependent, and because they must work together to deliver the Smart Home Services, the Company has concluded that installed Products, related installation and Services contracted for by the customer are generally not distinct within the context of the contract and, therefore, constitute a single, combined performance obligation. Revenues for this single, combined performance obligation are recognized on a straight-line basis over the customer’s contract term. The Company has determined that certain contracts that do not require a long-term commitment for monitoring services by the customer contain a material right to renew the contract, because the customer does not have to purchase Products upon renewal. Proceeds allocated to the material right are recognized over the period of benefit, which is generally three years. The majority of the Company’s subscription contracts are between three and five years in length and are non-cancelable. These contracts with customers generally convert into month-to-month agreements at the end of the initial term, and some customer contracts are month-to-month from inception. Payment for recurring monitoring and other Smart Home Services is generally due in advance on a monthly basis. Sales of Products and other one-time fees such as service fees or installation fees are invoiced to the customer at the time of sale. Revenues for wireless internet service provided by Vivint Wireless Inc. (“Wireless Internet” or “Wireless”) and any Products or Services that are considered separate performance obligations are recognized when those Products or Services are delivered. Taxes collected from customers and remitted to governmental authorities are not included in revenue. Payments received or amounts billed in advance of revenue recognition are reported as deferred revenue.
Deferred Revenue	Deferred Revenue The Company's deferred revenues primarily consist of amounts for sales (including upfront proceeds) of Smart Home Services. Deferred revenues are recognized over the term of the related performance obligation, which is generally three to five years .
Capitalized Contract Costs	Capitalized Contract Costs Capitalized contract costs represent the costs directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related subscriber contracts. These include commissions, other compensation and related costs incurred directly for the origination and installation of new or upgraded customer contracts, as well as the cost of Products installed in the customer home at the commencement or modification of the contract. These costs are deferred and amortized on a straight-line basis over the expected period of benefit that the Company has determined to be five years . Amortization of capitalized contract costs is included in “Depreciation and Amortization” on the consolidated statements of operations. These deferred costs are periodically reviewed for impairment. Contract costs not directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related subscriber contracts are expensed as incurred. These costs include those associated with housing, marketing and recruiting, non-direct lead generation costs, certain portions of sales commissions and residuals, overhead and other costs considered not directly and specifically tied to the origination of a particular subscriber. On the condensed consolidated statement of cash flows, capitalized contract costs are classified as operating activities and reported as “Capitalized contract costs – deferred contract costs” as these assets represent deferred costs associated with subscriber contracts.	Capitalized Contract Costs Capitalized contract costs represent the costs directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related customer contracts. These include commissions, other compensation and related costs incurred directly for the origination and installation of new or upgraded customer contracts, as well as the cost of Products installed in the customer home at the commencement or modification of the contract. These costs are deferred and amortized on a straight-line basis over the expected period of benefit that the Company has determined to be five years. Amortization of capitalized contract costs is included in “Depreciation and Amortization” on the consolidated statements of operations. These deferred costs are periodically reviewed for impairment. Contract costs not directly related and incremental to the origination of new contracts, modification of existing contracts or to the fulfillment of the related customer contracts are expensed as incurred. These costs include those associated with housing, marketing and recruiting, non-direct lead generation costs, certain portions of sales commissions and residuals, overhead and other costs considered not directly and specifically tied to the origination of a particular subscriber. On the consolidated statement of cash flows, capitalized contract costs are classified as operating activities and reported as “Capitalized contract costs - deferred contract costs” as these assets represent deferred costs associated with customer contracts.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consists of highly liquid investments with remaining maturities when purchased of three months or less.	Cash and Cash Equivalents Cash and cash equivalents consists of highly liquid investments with remaining maturities when purchased of three months or less.
Inventories	Inventories Inventories, which are comprised of smart home and security system Products and parts, are stated at the lower of cost or net realizable value with cost determined under the first-in, first-out (“FIFO”) method. The Company adjusts the inventory balance based on anticipated obsolescence, usage and historical write-offs.	Inventories Inventories, which are comprised of smart home and security system equipment and parts are stated at the lower of cost or market with cost determined under the first-in, first-out (FIFO) method. The Company adjusts the inventory balance based on anticipated obsolescence, usage and historical write-offs.
Property, Plant and Equipment and Long-lived Assets	Property, Plant and Equipment and Long-lived Assets Property, plant and equipment are stated at cost and depreciated on the straight-line method over the estimated useful lives of the assets or the lease term for assets under finance leases, whichever is shorter. Intangible assets with definite lives are amortized over the remaining estimated economic life of the underlying technology or relationships, which ranges from five to ten years . Definite-lived intangible assets are amortized on the straight-line method over the estimated useful life of the asset or in a pattern in which the economic benefits of the intangible asset are consumed. Amortization expense associated with leased assets is included with depreciation expense. Routine repairs and maintenance are charged to expense as incurred. The Company reviews long-lived assets, including property, plant and equipment, capitalized contract costs, and definite-lived intangibles for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. The Company considers whether or not indicators of impairment exist on a regular basis and as part of each quarterly and annual financial statement close process. Factors the Company considers in determining whether or not indicators of impairment exist include market factors and patterns of customer attrition. If indicators of impairment are identified, the Company estimates the fair value of the assets. An impairment loss is recognized if the carrying amount of a long-lived asset is not recoverable and exceeds its fair value. The Company conducts an indefinite-lived intangible impairment analysis annually as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s indefinite-lived intangibles may be less than the carrying amount. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate indefinite-lived intangible impairment using a qualitative approach. When necessary, the Company’s quantitative impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its indefinite-lived intangibles to the carrying value. If the fair value is greater than the carrying value, the intangibles are not considered to be impaired and no further testing is required. If the fair value is less than the carrying value, an impairment loss in an amount equal to the difference is recorded.	Property, Plant and Equipment and Long-lived Assets Property, plant and equipment are stated at cost and depreciated on the straight-line method over the estimated useful lives of the assets or the lease term for assets under capital leases, whichever is shorter. Intangible assets with definite lives are amortized over the remaining estimated economic life of the underlying technology or relationships, which ranges from 5 to 10 years. Definite-lived intangible assets are amortized on the straight-line method over the estimated useful life of the asset or in a pattern in which the economic benefits of the intangible asset are consumed. Amortization expense associated with leased assets is included with depreciation expense. Routine repairs and maintenance are charged to expense as incurred. The Company reviews long-lived assets, including property, plant and equipment, capitalized contract costs, and definite-lived intangibles for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. The Company considers whether or not indicators of impairment exist on a regular basis and as part of each quarterly and annual financial statement close process. Factors the Company considers in determining whether or not indicators of impairment exist include market factors and patterns of customer attrition. If indicators of impairment are identified, the Company estimates the fair value of the assets. An impairment loss is recognized if the carrying amount of a long-lived asset is not recoverable and exceeds its fair value. The Company conducts an indefinite-lived intangible impairment analysis annually as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s indefinite-lived intangibles may be less than the carrying amount. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate indefinite-lived intangible impairment using a qualitative approach. When necessary, the Company’s quantitative impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its indefinite-lived intangibles to the carrying value. If the fair value is greater than the carrying value, the intangibles are not considered to be impaired and no further testing is required. If the fair value is less than the carrying value, an impairment loss in an amount equal to the difference is recorded.
Leases	Leases Effective January 1, 2019 the Company accounts for leases under Topic 842 (see Recently Adopted Accounting Standards below). Under Topic 842, the Company determines if an arrangement is a lease at inception. Lease right-of-use (“ROU”) assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the present value of lease payments, the Company uses the implicit rate when available. When implicit rates are not available, the Company uses an incremental borrowing rate based on the information available at commencement date. The lease ROU asset also includes any lease payments made and is reduced by lease incentives. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company does not record lease ROU assets and liabilities for leases with terms of 12 months or less. Leases are classified as either operating or finance at lease inception. Operating lease assets and liabilities and finance lease liabilities are stated separately on the condensed consolidated balance sheets. Finance lease assets are included in property, plant and equipment, net on the condensed consolidated balance sheets. The Company has lease agreements with lease and non-lease components. For facility type leases, the Company separates the lease and non-lease components. Generally, the Company accounts for the lease and non-lease components as a single lease component for all other class of leases.
Long-term Investments	Long-term Investments The Company’s long-term investments are composed of equity securities in both privately held and public companies. As of March 31, 2019 and December 31, 2018 , the Company's equity investments totaled $6.1 million and $3.9 million , respectively. Management determines the appropriate fair value measurement of its investments at the time of purchase and reevaluates the fair value measurement at each balance sheet date. Equity securities are classified as either short-term or long-term, based on the nature of each security and its availability for use in current operations. The Company’s equity securities are carried at fair value, with gains and losses reported in other income or loss within the statement of operations. The Company's equity investments without readily determinable fair values totaled $0.7 million as of March 31, 2019 and December 31, 2018 , respectively. The Company performs impairment analyses of its investments without readily determinable fair values when events occur or circumstances change that would, more likely than not, reduce the fair value of the investment below its carrying value. When indicators of impairment do not exist, the Company evaluates impairment using a qualitative approach. Additionally, increases or decreases in the carrying amount resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer are adjusted through the statement of operations as needed. As of March 31, 2019 and December 31, 2018 , no indicators of impairment or changes in observable prices existed associated with investments without readily determinable fair values.
Deferred Financing Costs	Deferred Financing Costs Certain costs incurred in connection with obtaining debt financing are deferred and amortized utilizing the straight-line method, which approximates the effective-interest method, over the life of the related financing. Deferred financing costs associated with obtaining APX Group, Inc.’s (“APX”) revolving credit facility are amortized over the amended maturity dates discussed in Note 3 .	Deferred Financing Costs Certain costs incurred in connection with obtaining debt financing are deferred and amortized utilizing the straight-line method, which approximates the effective-interest method, over the life of the related financing. Deferred financing costs associated with obtaining APX's revolving credit facility are amortized over the amended maturity dates discussed in Note 5 . If such financing is paid off or replaced prior to maturity with debt instruments that have substantially different terms, the unamortized costs are charged to expense. Deferred financing costs included in the accompanying consolidated balance sheets within deferred financing costs, net at December 31, 2018 and 2017 were $2.1 million and $3.1 million , net of accumulated amortization of $9.6 million and $8.6 million , respectively. Deferred financing costs included in the accompanying consolidated balance sheets within notes payable, net at December 31, 2018 and 2017 were $32.4 million and $35.7 million , net of accumulated amortization of $54.6 million and $45.2 million , respectively. Amortization expense on deferred financing costs recognized and included in interest expense in the accompanying consolidated statements of operations totaled $10.4 million , $11.4 million and $11.6 million for the years ended December 31, 2018 , 2017 and 2016 , respectively.
Residual Income Plans	Residual Income Plans The Company has a program that allows certain third-party sales channel partners to receive additional compensation based on the performance of the underlying contracts they create (the “Channel Partner Plan”). The Company also has a residual sales compensation plan (the “Residual Plan”) under which the Company's sales personnel (each, a “Plan Participant”) receive compensation based on the performance of the underlying contracts they create. For both the Channel Partner Plan and Residual Plan, the Company calculates the present value of the expected future residual payments and records a liability for this amount in the period the subscriber account is originated. These costs are recorded to capitalized contract costs. The Company monitors actual payments and customer attrition on a periodic basis and, when necessary, makes adjustments to the liability.	Residual Income Plans The Company has a program that allows certain third-party sales channel partners to receive additional compensation based on the performance of the underlying contracts they create (the “Channel Partner Plan”). In addition, in 2018, the Company introduced a new residual sales compensation plan (the “Residual Plan”). Under the Residual Plan, the Company's sales personnel (each, a “Plan Participant”) have the option to convert up to a specified portion of their earnings (as defined in the Residual Plan) into the right to receive monthly residual compensation payable over the life of the subscriber accounts sold by such Plan Participant. For both the Channel Partner Plan and Residual Plan, the Company calculates the present value of the expected future residual payments and records a liability for this amount in the period the subscriber account is originated. These costs are recorded to capitalized contract costs. The Company monitors actual payments and customer attrition on a periodic basis and, when necessary, makes adjustments to the liability. The amount included in accrued payroll and commissions was $4.5 million and $3.3 million as of December 31, 2018 and 2017 , respectively, and the amount included in other long-term obligations was $13.0 million and $18.5 million at December 31, 2018 and 2017 , respectively, representing the present value of the estimated amounts owed to third-party sales channel partners.
Stock-Based Compensation	Stock-Based Compensation The Company measures compensation cost based on the grant-date fair value of the award and recognizes that cost over the requisite service period of the awards (See Note 10 ).	Stock-Based Compensation The Company measures compensation cost based on the grant-date fair value of the award and recognizes that cost over the requisite service period of the awards (See Note 12 ).
Advertising Expense	Advertising Expense Advertising costs are expensed as incurred.	Advertising Expense Advertising costs are expensed as incurred.
Income Taxes	Income Taxes The Company accounts for income taxes based on the asset and liability method. Under the asset and liability method, deferred tax assets and deferred tax liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Valuation allowances are established when necessary to reduce deferred tax assets when it is determined that it is more likely than not that some portion, or all, of the deferred tax asset will not be realized. The Company recognizes the effect of an uncertain income tax position on the income tax return at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. The Company’s policy for recording interest and penalties is to record such items as a component of the provision for income taxes. Changes in tax laws and rates could also affect recorded deferred tax assets and liabilities in the future. The Company records the effect of a tax rate or law change on the Company’s deferred tax assets and liabilities in the period of enactment. Future tax rate or law changes could have a material effect on the Company’s results of operations, financial condition, or cash flows.	Income Taxes The Company accounts for income taxes based on the asset and liability method. Under the asset and liability method, deferred tax assets and deferred tax liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Valuation allowances are established when necessary to reduce deferred tax assets when it is determined that it is more likely than not that some portion, or all, of the deferred tax asset will not be realized. The Company recognizes the effect of an uncertain income tax position on the income tax return at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. The Company’s policy for recording interest and penalties is to record such items as a component of the provision for income taxes. Changes in tax laws and rates could also affect recorded deferred tax assets and liabilities in the future. The Company records the effect of a tax rate or law change on the Company’s deferred tax assets and liabilities in the period of enactment. Future tax rate or law changes could have a material effect on the Company’s results of operations, financial condition, or cash flows (See Note 11 )
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of receivables and cash. At times during the year, the Company maintains cash balances in excess of insured limits. The Company is not dependent on any single customer or geographic location. The loss of a customer would not adversely impact the Company’s operating results or financial position.	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of receivables and cash. At times during the year, the Company maintains cash balances in excess of insured limits. The Company is not dependent on any single customer or geographic location. The loss of a customer would not adversely impact the Company’s operating results or financial position.
Concentrations of Supply Risk	Concentrations of Supply Risk As of March 31, 2019 , approximately 82% of the Company’s installed panels were SkyControl panels and 17% were 2GIG Go!Control panels and 1% were other panels. During the three months ended March 31, 2018 the Company transitioned to a new panel supplier. The loss of the Company's panel supplier could potentially impact its operating results or financial position.	Concentrations of Supply Risk As of December 31, 2018 , approximately 80% of the Company’s installed panels were SkyControl panels and 19% were 2GIG Go!Control panels. During the three months ended March 31, 2018 the Company transitioned to a new panel supplier. The loss of the Company's panel supplier could potentially impact its operating results or financial position.
Fair Value Measurement	Fair Value Measurement Fair value is based on the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities subject to on-going fair value measurement are categorized and disclosed into one of three categories depending on observable or unobservable inputs employed in the measurement. These two types of inputs have created the following fair value hierarchy: Level 1: Quoted prices in active markets that are accessible at the measurement date for assets and liabilities. Level 2: Observable prices that are based on inputs not quoted in active markets, but corroborated by market data. Level 3: Unobservable inputs are used when little or no market data is available. This hierarchy requires the Company to minimize the use of unobservable inputs and to use observable market data, if available, when determining fair value. The Company recognizes transfers between levels of the hierarchy based on the fair values of the respective financial measurements at the end of the reporting period in which the transfer occurred. There were no transfers between levels of the fair value hierarchy during the three months ended March 31, 2019 and 2018 . The carrying amounts of the Company’s accounts receivable, accounts payable and accrued and other liabilities approximate their fair values due to their short maturities.	Fair Value Measurement Fair value is based on the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities subject to on-going fair value measurement are categorized and disclosed into one of three categories depending on observable or unobservable inputs employed in the measurement. These two types of inputs have created the following fair value hierarchy: Level 1: Quoted prices in active markets that are accessible at the measurement date for assets and liabilities. Level 2: Observable prices that are based on inputs not quoted in active markets, but corroborated by market data. Level 3: Unobservable inputs are used when little or no market data is available. This hierarchy requires the Company to minimize the use of unobservable inputs and to use observable market data, if available, when determining fair value. The Company recognizes transfers between levels of the hierarchy based on the fair values of the respective financial measurements at the end of the reporting period in which the transfer occurred. There were no transfers between levels of the fair value hierarchy during the years ended December 31, 2018 and 2017 . The carrying amounts of the Company’s accounts receivable, accounts payable and accrued and other liabilities approximate their fair values due to their short maturities.
Goodwill	Goodwill The Company conducts a goodwill impairment analysis annually in the fourth fiscal quarter, as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s reporting units may be less than their carrying amounts. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate goodwill impairment using a qualitative approach. When necessary, the Company’s quantitative goodwill impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its reporting units to the carrying value of the reporting unit’s net assets, including goodwill. If the fair value of the reporting unit is greater than the carrying value of its net assets, goodwill is not considered to be impaired and no further testing is required. If the fair value of the reporting unit is less than the carrying value of its net assets, the Company would be required to complete the second step of the test by analyzing the fair value of its goodwill. If the carrying value of the goodwill exceeds its fair value, an impairment charge is recorded. The Company’s reporting units are determined based on its current reporting structure, which as of December 31, 2018 and March 31, 2019 consisted of two reporting units. As of March 31, 2019 , there were no changes in facts and circumstances since the most recent annual impairment analysis to indicate impairment existed.	Goodwill The Company conducts a goodwill impairment analysis annually in the fourth fiscal quarter, as of October 1, and as necessary if changes in facts and circumstances indicate that the fair value of the Company’s reporting units may be less than their carrying amounts. When indicators of impairment do not exist and certain accounting criteria are met, the Company is able to evaluate goodwill impairment using a qualitative approach. When necessary, the Company’s quantitative goodwill impairment test consists of two steps. The first step requires that the Company compare the estimated fair value of its reporting units to the carrying value of the reporting unit’s net assets, including goodwill. If the fair value of the reporting unit is greater than the carrying value of its net assets, goodwill is not considered to be impaired and no further testing is required. If the fair value of the reporting unit is less than the carrying value of its net assets, the Company would be required to complete the second step of the test by analyzing the fair value of its goodwill. If the carrying value of the goodwill exceeds its fair value, an impairment charge is recorded. The Company’s reporting units are determined based on its current reporting structure, which as of December 31, 2018 consisted of two reporting units. The Company found that no indicators of goodwill impairment existed during the year ended December 31, 2018 , thus a qualitative approach was used and it was determined that no impairment existed for goodwill.
Foreign Currency Translation and Other Comprehensive Income	Foreign Currency Translation and Other Comprehensive Income The functional currency of Vivint Canada, Inc. is the Canadian dollar. Accordingly, Vivint Canada, Inc. assets and liabilities are translated from their respective functional currencies into U.S. dollars at period-end rates and Vivint Canada, Inc. revenue and expenses are translated at the weighted-average exchange rates for the period. Adjustments resulting from this translation process are classified as other comprehensive income (loss) and shown as a separate component of equity. When intercompany foreign currency transactions between entities included in the consolidated financial statements are of a long term investment nature (i.e., those for which settlement is not planned or anticipated in the foreseeable future) foreign currency translation adjustments resulting from those transactions are included in stockholders’ deficit as accumulated other comprehensive loss or income. When intercompany transactions are deemed to be of a short term nature, translation adjustments are required to be included in the condensed consolidated statement of operations. The Company has determined that settlement of Vivint Canada, Inc. intercompany balances is anticipated and therefore such balances are deemed to be of a short term nature.	Foreign Currency Translation and Other Comprehensive Income The functional currencies of Vivint Canada, Inc. and Vivint New Zealand, Ltd. are the Canadian and New Zealand dollars, respectively. Accordingly, assets and liabilities are translated from their respective functional currencies into U.S. dollars at period-end rates and revenue and expenses are translated at the weighted-average exchange rates for the period. Adjustments resulting from this translation process are classified as other comprehensive (loss) income and shown as a separate component of equity. During the year ended December 31, 2016, the Company completed the 2016 Contract Sales which included all contracts in the New Zealand, Ltd. entity. (See Note 10 ) When intercompany foreign currency transactions between entities included in the consolidated financial statements are of a long term investment nature (i.e., those for which settlement is not planned or anticipated in the foreseeable future) foreign currency translation adjustments resulting from those transactions are included in stockholders’ (deficit) equity as accumulated other comprehensive loss or income. When intercompany transactions are deemed to be of a short term nature, translation adjustments are required to be included in the consolidated statement of operations. The Company has determined that settlement of Vivint Canada, Inc. and Vivint New Zealand, Ltd. intercompany balances are anticipated and therefore such balances are deemed to be of a short-term nature. Translation activity included in the statements of operations in other loss, net related to intercompany balances was a loss of $7.1 million for the year ended December 31, 2018 , a gain of $4.9 million for the year ended December 31, 2017 , and a gain of $2.1 million for the year ended December 31, 2016 .
Letters of Credit	Letters of Credit As of March 31, 2019 and December 31, 2018 , the Company had $13.9 million and $13.8 million , respectively, of letters of credit issued in the ordinary course of business, all of which are undrawn.	Letters of Credit As of December 31, 2018 and 2017 , the Company had $13.8 million and $9.5 million , respectively, of letters of credit issued in the ordinary course of business, all of which are undrawn.
Restructuring and Asset Impairment Charges	Restructuring and Asset Impairment Charges Restructuring and asset impairment charges represent expenses incurred in relation to activities to exit or disposal of portions of the Company's business that do not qualify as discontinued operations. Liabilities associated with restructuring are measured at their fair value when the liability is incurred. Expenses for related termination benefits are recognized at the date the Company notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. Liabilities related to termination of a contract are measured and recognized at fair value when the contract does not have any future economic benefit to the entity and the fair value of the liability is determined based on the present value of the remaining obligation. The Company expenses all other costs related to an exit or disposal activity as incurred (See Note 15 ).	Restructuring and Asset Impairment Charges Restructuring and asset impairment charges represent expenses incurred in relation to activities to exit or dispose of portions of the Company's business that do not qualify as discontinued operations. Liabilities associated with restructuring are measured at their fair value when the liability is incurred. Expenses for related termination benefits are recognized at the date the Company notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. Liabilities related to termination of a contract are measured and recognized at fair value when the contract does not have any future economic benefit to the entity and the fair value of the liability is determined based on the present value of the remaining obligation. The Company expenses all other costs related to an exit or disposal activity as incurred (See Note 10 ).
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, “Financial Instruments—Credit Losses (Topic 326)” which modifies the measurement of expected credit losses of certain financial instruments. This update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019 and must be applied using a modified-retrospective approach, with early adoption permitted. The Company is evaluating the adoption of ASU 2016-13 and plans to provide additional information about its expected impact at a future date. Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” to increase transparency and comparability among organizations as it relates to lease assets and lease liabilities. The update requires that lease assets and lease liabilities be recognized on the balance sheet, and that key information about leasing arrangements be disclosed. Prior to this update, GAAP did not require operating leases to be recognized as lease assets and lease liabilities on the balance sheet. The Company adopted ASU 2016-02 as of January 1, 2019, utilizing the modified retrospective approach and using certain practical expedients. The adoption of the standard resulted in recording ROU assets of $75.5 million and lease liabilities of $85.9 million as of January 1, 2019. The ROU assets are lower than the lease liabilities as existing deferred rent and lease incentive liabilities were recorded against the ROU assets at adoption in accordance with the standard. The standard did not materially affect the Company's condensed consolidated statements of operations or its condensed consolidated statements of cash flows. The standard also resulted in a reassessment that a sale would have occurred at January 1, 2019 for the Company's build-to-suit building. As a result, the Company classifies the leasing arrangement as an operating lease. The recognition of the sale-leaseback transaction resulted in an immaterial amount recorded to opening equity. See Note 6 for additional information on the sale-leaseback transaction. See Note 12 "Leases" for additional information related to the impact of adopting this standard.	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, “Financial Instruments—Credit Losses (Topic 326),” which modifies the measurement of expected credit losses of certain financial instruments. This update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019 and must be applied using a modified-retrospective approach, with early adoption permitted. The Company is evaluating the adoption of ASU 2016-13 and plans to provide additional information about its expected impact at a future date. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” to increase transparency and comparability among organizations as it relates to lease assets and lease liabilities. The update requires that lease assets and lease liabilities be recognized on the balance sheet, and that key information about leasing arrangements be disclosed. Prior to this update, GAAP did not require operating leases to be recognized as lease assets and lease liabilities on the balance sheet. This update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, with early adoption permitted. In July 2018, the FASB issued ASU 2018-11 which provides companies the option to adopt using a modified retrospective approach or a prospective adoption approach. The Company is continuing its evaluation of the impact of ASU 2016-02 on its accounting policies. The Company’s current operating lease portfolio is primarily comprised of network, real estate, and equipment leases. Upon adoption of this standard, the Company expects to record a right of use asset and liability related to all operating lease arrangements. The Company has assigned internal resources to perform the evaluation. Furthermore, the Company has made and will continue to make investments in systems to enable timely and accurate reporting under the new standard. The Company expects the standard will have a material impact on the Company’s consolidated balance sheets but will not have a material impact on the consolidated statements of operations. The most significant impact will be the recognition of right of use assets and lease liabilities for operating leases. In connection with the adoption of the new lease accounting standard, the Company has completed scoping reviews and continues to make progress implementing new processes, systems, accounting policies and internal controls relevant to the standard. The Company will adopt this standard on January 1, 2019 using the prospective adoption approach and has elected to use the practical expedients allowed under the standard. Recently Adopted Accounting Standards ASU 2016-01 In January 2016, the FASB issued ASU 2016-01, "Financial Instruments-Overall (Subtopic 825-10)," which enhances the reporting model for financial instruments by addressing certain aspects of the recognition, measurement, presentation and disclosure of financial instruments. Key provisions require equity investments (except those accounted for under the equity method of accounting) to be measured at fair value with changes in fair value recognized in net income (loss). In addition, the exit price notion must be used when measuring the fair value of financial instruments for disclosure purposes. The Company adopted ASU 2016-01 on January 1, 2018, with a cumulative-effect adjustment to increase accumulated deficit by $0.7 million for the net unrealized losses within accumulated other comprehensive income related to equity investments. During the year ended December 31, 2018, the Company recorded a net loss of $0.3 million , respectively, to other income associated with the change in fair value of equity investments. ASU 2014-09 In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605).” Under Topic 606, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. In addition, Topic 606 requires enhanced disclosures, including disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. Topic 606 also includes Subtopic 340-40, Other Assets and Deferred Costs - Contracts with Customers, which requires the deferral of incremental costs of obtaining a contract with a customer. Collectively, the Company refers to Topic 606 and Subtopic 340-40 as the “new standard”. The Company adopted the new standard as of January 1, 2018, utilizing the modified retrospective method of transition (the cumulative catch-up transition method). Adoption of the new standard resulted in changes to the accounting policies for revenue recognition, deferred revenue, and capitalized contract costs (formerly subscriber acquisition costs). The cumulative effect of applying the new standard to all contracts with customers that were not completed as of January 1, 2018 was recorded as an adjustment to accumulated deficit as of the adoption date. The comparative information has not been adjusted and continues to be reported under Topic 605. See Note 3 "Revenue and Capitalized Contract Costs" for additional information related to the impact of adopting this standard and a discussion of the Company's updated policies related to revenue recognition and accounting for costs to obtain and fulfill a customer contract.
Revenue		Revenue Recognition The Company offers its customers smart home services combining Products, including a proprietary control panel, door and window sensors, door locks, security cameras and smoke alarms; installation; and a proprietary back-end cloud platform software and Services. These together create an integrated system that allows the Company’s customers to monitor, control and protect their home (“Smart Home Services”). The Company’s customers are buying this integrated system that provides them with these Smart Home Services. The number and type of Products purchased by a customer depends on their desired functionality. Because the Products and Services included in the customer’s contract are integrated and highly interdependent, and because they must work together to deliver the Smart Home Services, the Company has concluded that installed Products, related installation and Services contracted for by the customer are generally not distinct within the context of the contract and, therefore, constitute a single, combined performance obligation. Revenues for this single, combined performance obligation are recognized on a straight-line basis over the customer’s contract term. The Company has determined that certain contracts that do not require a long-term commitment for monitoring services by the customer contain a material right to renew the contract, because the customer does not have to purchase Products upon renewal. Proceeds allocated to the material right are recognized over the period benefit, which is generally three years. The majority of the Company’s subscription contracts are between three and five years in length and are non-cancelable. These contracts with customers generally convert into month-to-month agreements at the end of the initial term, and some customer contracts are month-to-month from inception. Payment for recurring monitoring and other Smart Home Services is generally due in advance on a monthly basis. Sales of Products and other one-time fees such as service fees or installation fees are invoiced to the customer at the time of sale. Revenues for wireless internet service provided by Vivint Wireless Inc. (“Wireless Internet” or “Wireless”) and any Products or Services that are considered separate performance obligations are recognized when those Products or Services are delivered. Taxes collected from customers and remitted to governmental authorities are not included in revenue. Payments received or amounts billed in advance of revenue recognition are reported as deferred revenue. Deferred Revenue The Company's deferred revenues primarily consist of amounts for sales (including upfront proceeds) of Smart Home Services. Deferred revenues are recognized over the term of the related performance obligation. Vivint Flex Pay In January 2017, the Company announced the introduction of the Vivint Flex Pay plan (“Vivint Flex Pay”), which became the Company’s primary sales model beginning in March 2017. Under Vivint Flex Pay, customers pay separately for the products (including control panel, security peripheral equipment, smart home equipment, and related installation) (“Products”) and Vivint’s smart home and security services (“Services”). The customer has the following three options to pay for the Products: (1) qualified customers in the United States may finance the purchase of Products through a third-party financing provider (“Consumer Financing Program”) (2) customers not eligible for the Consumer Financing Program, but who qualify under the Company’s underwriting criteria, may enter into a retail installment contract (“RIC”) directly with Vivint, or (3) customers may purchase the Products at the outset of the service contract by check, automatic clearing house payments (“ACH”), credit or debit card. Although customers pay separately for the Products and Services under the Vivint Flex Pay plan, the Company has determined that the shift in its sales model does not change the Company’s conclusion that the sale of Products and Services are one single performance obligation. As a result, all forms of transactions under Vivint Flex Pay create deferred revenue for the gross amount of Products sold. Gross deferred revenues are reduced by imputed interest on the RICs and the present value of expected payments due to the third-party financing provider under the Consumer Financing Program. Under the Consumer Financing Program, qualified customers are eligible for installment loans provided by a third-party financing provider of up to $4,000 for either 42 or 60 months. The Company pays a monthly fee to the third-party financing provider based on the average daily outstanding balance of the installment loans. Additionally, the Company shares liability for credit losses depending on the credit quality of the customer. Because of the nature of these provisions under the Consumer Financing Program, the Company records a derivative liability at its fair value when the third-party financing provider originates installment loans to customers, which reduces the amount of estimated revenue recognized on the provision of the services. The derivative liability is reduced as payments are made from the Company to the third-party financing provider. Subsequent changes to the fair value of the derivative liability are realized through other loss/(income), net in the Consolidated Statement of Operations.
Principles of Consolidation		Principles of Consolidation The accompanying consolidated financial statements include the accounts of APX Group Holdings, Inc. and its subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.
Wireless Spectrum Licenses		Wireless Spectrum Licenses The Company had capitalized as an intangible asset wireless spectrum licenses that were acquired from third parties. The cost basis of the wireless spectrum asset includes the purchase price paid for the licenses at the time of acquisition, plus costs incurred to acquire the licenses. The asset and related liability were recorded at the net present value of future cash outflows using the Company's incremental borrowing rate at the time of acquisition. The Company determined that the wireless spectrum licenses met the definition of indefinite-lived intangible assets because the licenses were able to be renewed periodically for a nominal fee, provided that the Company continued to meet the service and geographic coverage provisions. In January 2018, the Company terminated the wireless spectrum licenses for cash consideration.
Long-term Investments		Long-term Investments The Company’s long-term investments are composed of equity securities in both privately held and public companies. As of December 31, 2018 and 2017 , the Company's equity investments totaled $3.9 million and $3.4 million , respectively. Management determines the appropriate fair value measurement of its investments at the time of purchase and reevaluates the fair value measurement at each balance sheet date. Equity securities, are classified as either short-term or long-term, based on the nature of each security and its availability for use in current operations. The Company’s equity securities are carried at fair value, with gains and losses, reported in other income or loss within the statement of operations The Company's equity investments without readily determinable fair values as of both December 31, 2018 and 2017 totaled $0.7 million . The Company performs impairment analyzes of its cost based investments when events occur or circumstances change that would, more likely than not, reduce the fair value of the investment below its carrying value. When indicators of impairment do not exist, the Company evaluates impairment using a qualitative approach. Additionally, increases or decreases in the carrying amount resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer are adjusted through the statement of operations as needed. As of December 31, 2018 , no indicators of impairment or changes in observable prices existed associated with investments without readily determinable fair values.
Contracts Sold		Contracts Sold During the year ended December 31, 2016, the Company sold all of its New Zealand and Puerto Rico subscriber contracts and ceased operations in these geographical regions ("2016 Contract Sales"). As a result, during the year ended December 31, 2016 the Company recorded the impact of these transactions in restructuring and asset impairment (See Note 10 ).

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Changes in Company's Allowance for Accounts Receivable	The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Three Months Ended March 31, 2019 Twelve Months Ended December 31, 2018 Beginning balance $ 5,594 $ 5,356 Provision for doubtful accounts 5,918 19,405 Write-offs and adjustments (5,704 ) (19,167 ) Balance at end of period $ 5,808 $ 5,594 The following table summarizes the RIC receivables (in thousands): March 31, 2019 December 31, 2018 RIC receivables, gross $ 173,254 $ 175,250 Deferred interest (29,612 ) (34,163 ) RIC receivables, net of deferred interest $ 143,642 $ 141,087 Classified on the condensed consolidated unaudited balance sheets as: Accounts and notes receivable, net $ 35,370 $ 32,185 Long-term notes receivables and other assets, net 108,272 108,902 RIC receivables, net $ 143,642 $ 141,087	The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Year ended December 31, 2018 2017 2016 Beginning balance $ 5,356 $ 4,138 $ 3,541 Provision for doubtful accounts 19,405 22,465 19,624 Write-offs and adjustments (19,167 ) (21,247 ) (19,027 ) Balance at end of period $ 5,594 $ 5,356 $ 4,138 The following table summarizes the installment receivables (in thousands): December 31, 2018 December 31, 2017 RIC receivables, gross $ 175,250 $ 131,024 Deferred interest (34,163 ) (36,048 ) RIC receivables, net of deferred interest $ 141,087 $ 94,976 Classified on the consolidated balance sheets as: Accounts and notes receivable, net $ 32,185 $ 16,469 Long-term notes receivables and other assets, net 108,902 78,507 RIC receivables, net $ 141,087 $ 94,976
Schedule Of Depreciation And Amortization Expense	The Company’s depreciation and amortization included in the consolidated statements of operations consisted of the following (in thousands): Three Months Ended March 31, 2019 2018 Amortization of capitalized contract costs $ 105,028 $ 95,363 Amortization of definite-lived intangibles 20,272 22,720 Depreciation of property, plant and equipment 5,921 6,175 Total depreciation and amortization $ 131,221 $ 124,258	The Company’s depreciation and amortization included in the consolidated statements of operations consisted of the following (in thousands): Year ended December 31, 2018 2017 2016 Amortization of capitalized contract costs $ 398,174 $ — $ — Amortization of subscriber acquisition costs — 206,153 154,877 Amortization of definite-lived intangibles 90,945 101,827 116,865 Depreciation of property, plant and equipment 24,963 21,275 16,800 Total depreciation and amortization $ 514,082 $ 329,255 $ 288,542
Schedule Of Foreign Translation Activity	Translation activity included in the statement of operations in other loss, net related to intercompany balances was as follows: (in thousands) Three Months Ended March 31, 2019 2018 Translation (gain) loss $ (1,701 ) $ 2,075

Retail Installment Contract R_2

Retail Installment Contract Receivables (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Schedule of Installment Receivables	The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Three Months Ended March 31, 2019 Twelve Months Ended December 31, 2018 Beginning balance $ 5,594 $ 5,356 Provision for doubtful accounts 5,918 19,405 Write-offs and adjustments (5,704 ) (19,167 ) Balance at end of period $ 5,808 $ 5,594 The following table summarizes the RIC receivables (in thousands): March 31, 2019 December 31, 2018 RIC receivables, gross $ 173,254 $ 175,250 Deferred interest (29,612 ) (34,163 ) RIC receivables, net of deferred interest $ 143,642 $ 141,087 Classified on the condensed consolidated unaudited balance sheets as: Accounts and notes receivable, net $ 35,370 $ 32,185 Long-term notes receivables and other assets, net 108,272 108,902 RIC receivables, net $ 143,642 $ 141,087	The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Year ended December 31, 2018 2017 2016 Beginning balance $ 5,356 $ 4,138 $ 3,541 Provision for doubtful accounts 19,405 22,465 19,624 Write-offs and adjustments (19,167 ) (21,247 ) (19,027 ) Balance at end of period $ 5,594 $ 5,356 $ 4,138 The following table summarizes the installment receivables (in thousands): December 31, 2018 December 31, 2017 RIC receivables, gross $ 175,250 $ 131,024 Deferred interest (34,163 ) (36,048 ) RIC receivables, net of deferred interest $ 141,087 $ 94,976 Classified on the consolidated balance sheets as: Accounts and notes receivable, net $ 32,185 $ 16,469 Long-term notes receivables and other assets, net 108,902 78,507 RIC receivables, net $ 141,087 $ 94,976
Allowance for Credit Losses on Financing Receivables	Activity in the deferred interest for the RIC receivables was as follows (in thousands): Three months ended March 31, 2019 Twelve months ended December 31, 2018 Deferred interest, beginning of period $ 34,163 $ 36,048 Write-offs, net of recoveries (6,923 ) (26,360 ) Change in deferred interest on short-term and long-term RIC receivables 2,372 24,475 Deferred interest, end of period $ 29,612 $ 34,163	Activity in the deferred interest for the RIC receivables was as follows (in thousands): For the Years Ended December 31, 2018 December 31, 2017 Deferred interest, beginning of period $ 36,048 $ — Write-offs, net of recoveries (26,360 ) (6,055 ) Change in deferred interest on short-term and long-term RIC receivables 24,475 42,103 Deferred interest, end of period $ 34,163 $ 36,048

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Company's Balance Sheet Components	The following table presents material balance sheet component balances (in thousands): March 31, 2019 December 31, 2018 Prepaid expenses and other current assets Prepaid expenses $ 12,984 $ 7,183 Deposits 1,353 904 Other 791 3,362 Total prepaid expenses and other current assets $ 15,128 $ 11,449 Capitalized contract costs Capitalized contract costs $ 2,445,784 $ 2,361,795 Accumulated amortization (1,352,919 ) (1,246,020 ) Capitalized contract costs, net $ 1,092,865 $ 1,115,775 Long-term notes receivables and other assets RIC receivables, gross $ 137,884 $ 143,065 RIC deferred interest (29,612 ) (34,164 ) Security deposits 7,126 6,586 Investments 6,099 3,865 Other 299 467 Total long-term notes receivables and other assets, net $ 121,796 $ 119,819 Accrued payroll and commissions Accrued commissions $ 11,432 $ 28,726 Accrued payroll 25,849 36,753 Total accrued payroll and commissions $ 37,281 $ 65,479 Accrued expenses and other current liabilities Accrued interest payable $ 55,157 $ 28,885 Current portion of derivative liability 70,137 67,710 Service warranty accrual 8,825 8,813 Current portion of notes payable 8,100 8,100 Loss contingencies 2,131 3,131 Other 14,647 20,076 Total accrued expenses and other current liabilities $ 158,997 $ 136,715	The following table presents material balance sheet component balances as of December 31, 2018 and December 31, 2017 (in thousands): December 31, 2018 2017 Prepaid expenses and other current assets Prepaid expenses $ 7,183 $ 8,000 Deposits 904 1,596 Other 3,362 6,554 Total prepaid expenses and other current assets $ 11,449 $ 16,150 Capitalized contract costs Capitalized contract costs $ 2,361,795 $ — Accumulated amortization (1,246,020 ) — Capitalized contract costs, net $ 1,115,775 $ — Subscriber acquisition costs Subscriber acquisition costs $ — $ 1,837,388 Accumulated amortization — (528,830 ) Subscriber acquisition costs, net $ — $ 1,308,558 Long-term notes receivables and other assets RIC receivables, gross $ 143,065 $ 114,556 RIC deferred interest (34,164 ) (36,049 ) Security deposits 6,586 6,427 Investments 3,865 3,429 Other 467 360 Total long-term notes receivables and other assets, net $ 119,819 $ 88,723 Accrued payroll and commissions Accrued payroll $ 36,753 $ 30,267 Accrued commissions 28,726 27,485 Total accrued payroll and commissions $ 65,479 $ 57,752 Accrued expenses and other current liabilities Accrued interest payable $ 28,885 $ 28,737 Current portion of derivative liability 67,710 25,473 Service warranty accrual 8,813 — Current portion of notes payable 8,100 — Blackstone monitoring fee, a related party 4,793 933 Accrued taxes 5,351 4,585 Spectrum license obligation — 3,861 Accrued payroll taxes and withholdings 5,097 3,185 Loss contingencies 3,131 2,156 Other 4,835 5,391 Total accrued expenses and other current liabilities $ 136,715 $ 74,321

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Components of Property Plant and Equipment	Property, plant and equipment consisted of the following (in thousands): March 31, 2019 December 31, 2018 Estimated Useful Lives Vehicles $ 44,594 $ 45,050 3 - 5 years Computer equipment and software 55,459 53,891 3 - 5 years Leasehold improvements 27,609 26,401 2 - 15 years Office furniture, fixtures and equipment 19,918 19,532 7 years Build-to-suit lease building — 8,247 10.5 years Construction in process 4,205 2,975 Property, plant and equipment, gross 151,785 156,096 Accumulated depreciation and amortization (87,171 ) (82,695 ) Property, plant and equipment, net $ 64,614 $ 73,401	Property, plant and equipment consisted of the following (in thousands): December 31, Estimated Useful Lives 2018 2017 Vehicles $ 45,050 $ 42,008 3-5 years Computer equipment and software 53,891 46,651 3-5 years Leasehold improvements 26,401 20,783 2-15 years Office furniture, fixtures and equipment 19,532 17,202 7 years Build-to-suit lease building 8,247 8,268 10.5 years Construction in process 2,975 4,299 Property, plant and equipment, gross 156,096 139,211 Accumulated depreciation and amortization (82,695 ) (61,130 ) Property, plant and equipment, net $ 73,401 $ 78,081

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Indefinite-Lived Intangible Assets	The following table presents intangible asset balances (in thousands): March 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Estimated Definite-lived intangible assets: Customer contracts $ 965,670 $ (737,443 ) $ 228,227 $ 964,100 $ (717,648 ) $ 246,452 10 years 2GIG 2.0 technology 17,000 (15,603 ) 1,397 17,000 (15,292 ) 1,708 8 years Other technology 2,917 (1,771 ) 1,146 2,917 (1,667 ) 1,250 5 - 7 years Space Monkey technology 7,100 (6,019 ) 1,081 7,100 (5,756 ) 1,344 6 years Patents 12,245 (9,136 ) 3,109 12,123 (8,415 ) 3,708 5 years Total definite-lived intangible assets: $ 1,004,932 $ (769,972 ) $ 234,960 $ 1,003,240 $ (748,778 ) $ 254,462 Indefinite-lived intangible assets: IP addresses 564 — 564 564 — 564 Domain names 59 — 59 59 — 59 Total Indefinite-lived intangible assets 623 — 623 623 — 623 Total intangible assets, net $ 1,005,555 $ (769,972 ) $ 235,583 $ 1,003,863 $ (748,778 ) $ 255,085
Schedule of Definite-Lived Intangible Assets	The following table presents intangible asset balances (in thousands): March 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Estimated Definite-lived intangible assets: Customer contracts $ 965,670 $ (737,443 ) $ 228,227 $ 964,100 $ (717,648 ) $ 246,452 10 years 2GIG 2.0 technology 17,000 (15,603 ) 1,397 17,000 (15,292 ) 1,708 8 years Other technology 2,917 (1,771 ) 1,146 2,917 (1,667 ) 1,250 5 - 7 years Space Monkey technology 7,100 (6,019 ) 1,081 7,100 (5,756 ) 1,344 6 years Patents 12,245 (9,136 ) 3,109 12,123 (8,415 ) 3,708 5 years Total definite-lived intangible assets: $ 1,004,932 $ (769,972 ) $ 234,960 $ 1,003,240 $ (748,778 ) $ 254,462 Indefinite-lived intangible assets: IP addresses 564 — 564 564 — 564 Domain names 59 — 59 59 — 59 Total Indefinite-lived intangible assets 623 — 623 623 — 623 Total intangible assets, net $ 1,005,555 $ (769,972 ) $ 235,583 $ 1,003,863 $ (748,778 ) $ 255,085	The following table presents intangible asset balances as of December 31, 2018 and 2017 (in thousands): December 31, 2018 December 31, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Estimated Definite-lived intangible assets: Customer contracts $ 964,100 $ (717,648 ) $ 246,452 $ 970,147 $ (637,780 ) $ 332,367 10 years 2GIG 2.0 technology 17,000 (15,292 ) 1,708 17,000 (13,274 ) 3,726 8 years Other technology 2,917 (1,667 ) 1,250 2,917 (1,250 ) 1,667 5 - 7 years Space Monkey technology 7,100 (5,756 ) 1,344 7,100 (4,066 ) 3,034 6 years Patents 12,123 (8,415 ) 3,708 10,616 (5,835 ) 4,781 5 years Total definite-lived intangible assets: 1,003,240 (748,778 ) 254,462 1,007,780 (662,205 ) 345,575 Indefinite-lived intangible assets: Spectrum licenses — — — 31,253 — 31,253 IP addresses 564 — 564 564 — 564 Domain names 59 — 59 59 — 59 Total Indefinite-lived intangible assets 623 — 623 31,876 — 31,876 Total intangible assets, net $ 1,003,863 $ (748,778 ) $ 255,085 $ 1,039,656 $ (662,205 ) $ 377,451
Schedule of Estimated Future Amortization Expense of Intangible Assets Excluding Patents Currently in Process	Estimated future amortization expense of intangible assets, excluding approximately $0.3 million in patents currently in process, is as follows as of March 31, 2019 (in thousands): 2019 - Remaining Period $ 59,216 2020 67,990 2021 58,709 2022 48,759 2023 28 Thereafter — Total estimated amortization expense $ 234,702	Estimated future amortization expense of intangible assets, excluding approximately $0.3 million in patents currently in process, is as follows as of December 31, 2018 (in thousands): 2019 $ 79,062 2020 67,807 2021 58,578 2022 48,674 2023 47 Thereafter 11 Total estimated amortization expense $ 254,179
Changes in Carrying Amount of Goodwill		The changes in the carrying amount of goodwill for the years ended December 31, 2018 and 2017 , were as follows (in thousands): Balance as of January 1, 2017 $ 835,233 Effect of Foreign Currency Translation 1,737 Balance as of December 31, 2017 836,970 Effect of Foreign Currency Translation (2,115 ) Balance as of December 31, 2018 $ 834,855

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Financial Instruments at Fair Value Based on Valuation Approach Applied to Each Class of Security	The following tables set forth the Company’s cash and cash equivalents and Corporate Securities’ adjusted cost, gross unrealized gains, gross unrealized losses, gross realized gains, gross realized losses and fair value by significant investment category recorded as cash and cash equivalents or long-term notes receivables and other assets, net as of March 31, 2019 and December 31, 2018 (in thousands): March 31, 2019 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 3,599 $ — $ — $ 3,599 $ 3,599 $ — Level 1: Money market funds 92 — — 92 92 — Corporate securities 3,181 2,212 — 5,393 — 5,393 Subtotal 3,273 2,212 — 5,485 92 5,393 Total $ 6,872 $ 2,212 $ — $ 9,084 $ 3,691 $ 5,393 December 31, 2018 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 6,681 $ — $ — $ 6,681 $ 6,681 $ — Level 1: Money market funds 6,092 — — 6,092 6,092 — Corporate securities 3,485 — (304 ) 3,181 — 3,181 Subtotal 9,577 — (304 ) 9,273 6,092 3,181 Total $ 16,258 $ — $ (304 ) $ 15,954 $ 12,773 $ 3,181	The following tables set forth the Company’s cash and cash equivalents and Corporate Securities’ adjusted cost, gross unrealized gains, gross unrealized losses, gross realized gains, gross realized losses and fair value by significant investment category recorded as cash and cash equivalents or long-term notes receivables and other assets, net as of December 31, 2018 and 2017 (in thousands): December 31, 2018 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 6,681 $ — $ — $ 6,681 $ 6,681 $ — Level 1: Money market funds 6,092 — — 6,092 6,092 — Corporate securities 3,485 — (304 ) 3,181 — 3,181 Subtotal 9,577 — (304 ) 9,273 6,092 3,181 Total $ 16,258 $ — $ (304 ) $ 15,954 $ 12,773 $ 3,181 December 31, 2017 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Long-Term Notes Receivables and Other Assets, net Cash $ 3,866 $ — $ — $ 3,866 $ 3,866 Level 1: Money market funds 6 — — 6 6 — Corporate securities 4,018 — (1,315 ) 2,703 — 2,703 Subtotal 4,024 — (1,315 ) 2,709 6 2,703 Total $ 7,890 $ — $ (1,315 ) $ 6,575 $ 3,872 $ 2,703
Components of Long-Term Debt Including Associated Interest Rates and Related Fair Values	Components of long-term debt including the associated interest rates and related fair values are as follows (in thousands, except interest rates): March 31, 2019 December 31, 2018 Stated Interest Rate Issuance Face Value Estimated Fair Value Face Value Estimated Fair Value 2020 Notes 679,299 669,110 679,299 643,568 8.75 % 2022 Private Placement Notes 270,000 271,323 270,000 257,073 8.875 % 2022 Notes 900,000 904,410 900,000 855,000 7.875 % 2023 Notes 400,000 342,120 400,000 326,000 7.625 % Term Loan 805,950 805,950 807,975 807,975 N/A Total $ 3,055,249 $ 2,992,913 $ 3,057,274 $ 2,889,616	Components of the Company's debt including the associated interest rates and related fair values (in thousands, except interest rates) are as follows: Issuance December 31, 2018 December 31, 2017 Stated Interest Rate Face Value Estimated Fair Value Face Value Estimated Fair Value 2019 Notes $ — $ — $ 269,465 $ 273,507 6.375 % 2020 Notes 679,299 643,568 930,000 952,134 8.75 % 2022 Notes Private Placement Notes 270,000 257,073 270,000 276,486 8.875 % 2022 Notes 900,000 855,000 900,000 966,420 7.875 % 2023 Notes 400,000 326,000 400,000 425,000 7.625 % Term Loan 807,975 807,975 — — N/A Total $ 3,057,274 $ 2,889,616 $ 2,769,465 $ 2,893,547
Schedule of Derivative Liabilities at Fair Value	he following table summarizes the fair value and the notional amount of the Company’s outstanding derivative instrument as of March 31, 2019 and December 31, 2018 (in thousands): March 31, 2019 December 31, 2018 Consumer Financing Program Contractual Obligations: Fair value $ 120,671 $ 117,620 Notional amount 385,955 368,708 Classified on the condensed consolidated unaudited balance sheets as: Accrued expenses and other current liabilities 70,137 67,710 Other long-term obligations 50,534 49,910 Total Consumer Financing Program Contractual Obligation $ 120,671 $ 117,620	The following table summarizes the fair value and the notional amount of the Company’s outstanding derivative instrument as of December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Consumer Financing Program Contractual Obligations: Fair value $ 117,620 $ 46,496 Notional amount 368,708 163,032 Classified on the consolidated balance sheets as: Accrued expenses and other current liabilities 67,710 25,473 Other long-term obligations 49,910 21,023 Total Consumer Financing Program Contractual Obligation $ 117,620 $ 46,496
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation	he following table summarizes the change in the fair value of the Level 3 outstanding derivative liability instrument for the three months ended March 31, 2019 and the twelve months ended December 31, 2018 (in thousands): Three months ended March 31, 2019 Twelve months ended December 31, 2018 Balance, beginning of period $ 117,620 $ 46,496 Additions 16,480 93,095 Settlements (14,856 ) (34,587 ) Losses included in earnings 1,427 12,616 Balance, end of period $ 120,671 $ 117,620	The following table summarizes the change in the fair value of the Level 3 outstanding derivative instrument for the years ended December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Balance, beginning of period $ 46,496 $ — Additions 93,095 44,913 Settlements (34,587 ) (7,972 ) Losses included in earnings 12,616 9,555 Balance, end of period $ 117,620 $ 46,496

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Lease Expense	The components of lease expense were as follows (in thousands): Three Months Ended March 31, 2019 Operating lease cost $ 4,298 Finance lease cost: Amortization of right-of-use assets $ 1,376 Interest on lease liabilities 154 Total finance lease cost $ 1,530 Supplemental cash flow information related to leases was as follows (in thousands): Three Months Ended March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ (4,375 ) Operating cash flows from finance leases (154 ) Financing cash flows from finance leases (2,136 ) Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 584 Finance leases 230
Schedule Of Supplemental Balance Sheet Information Related To Leases	Supplemental balance sheet information related to leases was as follows (in thousands, except lease term and discount rate): March 31, 2019 Operating Leases Operating lease right-of-use assets $ 72,891 Current operating lease liabilities $ 11,749 Operating lease liabilities 71,964 Total operating lease liabilities $ 83,713 Finance Leases Property, plant and equipment, gross $ 45,440 Accumulated depreciation (23,205 ) Property, plant and equipment, net $ 22,235 Current finance lease liabilities $ 7,114 Finance lease liabilities 3,952 Total finance lease liabilities $ 11,066 Weighted Average Remaining Lease Term Operating leases 7 years Finance leases 1.5 years Weighted Average Discount Rate Operating leases 7 % Finance leases 4 %
Schedule Of Maturities Of Financing Leases Liabilities	Maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the three months ended March 31, 2019) $ 13,163 $ 5,827 2020 16,345 5,167 2021 15,649 384 2022 14,514 38 2023 14,553 — Thereafter 32,404 — Total lease payments 106,628 11,416 Less imputed interest (22,915 ) (350 ) Total $ 83,713 $ 11,066
Schedule Of Maturities Of Operating Leases Liabilities	Maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the three months ended March 31, 2019) $ 13,163 $ 5,827 2020 16,345 5,167 2021 15,649 384 2022 14,514 38 2023 14,553 — Thereafter 32,404 — Total lease payments 106,628 11,416 Less imputed interest (22,915 ) (350 ) Total $ 83,713 $ 11,066

Segment Reporting and Busines_2

Segment Reporting and Business Concentrations (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	Revenues disaggregated by geographic region were as follows (in thousands): United States Canada Total Revenue from external customers Three months ended March 31, 2019 $ 258,436 $ 17,813 $ 276,249 Three months ended March 31, 2018 228,542 18,055 246,597	Revenues by geographic region were as follows (in thousands): United States Canada Total Revenue from external customers Year ended December 31, 2018 $ 977,877 $ 72,564 $ 1,050,441 Year ended December 31, 2017 $ 816,026 $ 65,957 $ 881,983 Year ended December 31, 2016 $ 700,471 $ 57,436 $ 757,907

Guarantor and Non-Guarantor S_2

Guarantor and Non-Guarantor Supplemental Financial Information (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Guarantor And Non Guarantor Supplemental Financial Information [Abstract]
Supplemental Condensed Consolidating Balance Sheet	Supplemental Condensed Consolidating Balance Sheet March 31, 2019 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 2,919 $ 335,398 $ 119,909 $ (289,784 ) $ 168,442 Property, plant and equipment, net — — 64,188 426 — 64,614 Capitalized contract costs, net — — 1,027,364 65,501 — 1,092,865 Deferred financing costs, net — 1,797 — — — 1,797 Investment in subsidiaries — 1,650,064 — — (1,650,064 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 218,194 17,389 — 235,583 Goodwill — — 809,678 25,726 — 835,404 Operating lease right-of-use assets — — 72,661 230 — 72,891 Long-term notes receivables and other assets — 106 104,486 17,310 (106 ) 121,796 Total Assets $ — $ 1,654,886 $ 2,638,272 $ 246,491 $ (1,946,257 ) $ 2,593,392 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 63,260 $ 558,398 $ 192,835 $ (289,784 ) $ 524,709 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving credit facility, net of current portion — 3,075,990 — — — 3,075,990 Finance lease obligations, net of current portion — — 3,952 — — 3,952 Deferred revenue, net of current portion — — 309,896 16,735 — 326,631 Operating lease liabilities — — 71,878 86 — 71,964 Other long-term obligations — — 73,043 347 — 73,390 Accumulated losses of investee, net 1,484,364 (1,484,364 ) — Deferred income tax liability — — 106 1,120 (106 ) 1,120 Total (deficit) equity (1,484,364 ) (1,484,364 ) 1,620,999 29,065 (165,700 ) (1,484,364 ) Total liabilities and stockholders’ (deficit) equity $ — $ 1,654,886 $ 2,638,272 $ 246,491 $ (1,946,257 ) $ 2,593,392 Supplemental Condensed Consolidating Balance Sheet December 31, 2018 (in thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 12,951 $ 269,770 $ 103,451 $ (262,674 ) $ 123,498 Property, plant and equipment, net — — 72,937 464 — 73,401 Capitalized contract costs, net — — 1,047,532 68,243 — 1,115,775 Deferred financing costs, net — 2,058 — — — 2,058 Investment in subsidiaries — 1,662,367 — — (1,662,367 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 236,677 18,408 — 255,085 Goodwill — — 809,678 25,177 — 834,855 Long-term notes receivables and other assets — 106 102,695 17,124 (106 ) 119,819 Total Assets $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 36,988 $ 507,063 $ 182,159 $ (262,674 ) $ 463,536 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving credit facility, net of current portion — 3,037,095 — — — 3,037,095 Capital lease obligations, net of current portion — — 5,570 1 — 5,571 Deferred revenue, net of current portion — — 306,653 16,932 — 323,585 Accumulated Losses of Investee, net 1,396,601 (1,396,601 ) — Other long-term obligations — — 90,209 — — 90,209 Deferred income tax liability — — 106 1,096 (106 ) 1,096 Total (deficit) equity (1,396,601 ) (1,396,601 ) 1,635,991 26,376 (265,766 ) (1,396,601 ) Total liabilities and stockholders’ (deficit) equity $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491	Condensed Consolidating Balance Sheet December 31, 2018 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 12,951 $ 269,770 $ 103,451 $ (262,674 ) $ 123,498 Property and equipment, net — — 72,937 464 — 73,401 Capitalized contract costs, net — — 1,047,532 68,243 — 1,115,775 Deferred financing costs, net — 2,058 — — — 2,058 Investment in subsidiaries — 1,662,367 — — (1,662,367 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 236,677 18,408 — 255,085 Goodwill — — 809,678 25,177 — 834,855 Long-term notes receivables and other assets, net — 106 102,695 17,124 (106 ) 119,819 Total Assets $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 36,988 $ 507,063 $ 182,159 $ (262,674 ) $ 463,536 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving line of credit, net of current portion — 3,037,095 — — — 3,037,095 Capital lease obligations, net of current portion — — 5,570 1 — 5,571 Deferred revenue, net of current portion — — 306,653 16,932 — 323,585 Accumulated losses of investee 1,396,601 (1,396,601 ) — Other long-term obligations — — 90,209 — — 90,209 Deferred income tax liability — — 106 1,096 (106 ) 1,096 Total (deficit) equity (1,396,601 ) (1,396,601 ) 1,635,991 26,376 (265,766 ) (1,396,601 ) Total liabilities and stockholders’ (deficit) equity $ — $ 1,677,482 $ 2,545,592 $ 232,867 $ (1,931,450 ) $ 2,524,491 Condensed Consolidating Balance Sheet December 31, 2017 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets Current assets $ — $ 4,150 $ 284,293 $ 49,935 $ (162,413 ) $ 175,965 Property and equipment, net — — 77,345 736 — 78,081 Subscriber acquisition costs, net — — 1,214,678 93,880 — 1,308,558 Deferred financing costs, net — 3,099 — — — 3,099 Investment in subsidiaries — 2,188,221 — — (2,188,221 ) — Intercompany receivable — — 6,303 — (6,303 ) — Intangible assets, net — — 350,710 26,741 — 377,451 Goodwill — — 809,678 27,292 — 836,970 Long-term notes receivables and other assets, net — 106 78,173 10,550 (106 ) 88,723 Total Assets $ — $ 2,195,576 $ 2,821,180 $ 209,134 $ (2,357,043 ) $ 2,868,847 Liabilities and Stockholders’ (Deficit) Equity Current liabilities $ — $ 28,805 $ 343,398 $ 128,581 $ (162,413 ) $ 338,371 Intercompany payable — — — 6,303 (6,303 ) — Notes payable and revolving line of credit, net of current portion — 2,820,297 — — — 2,820,297 Capital lease obligations, net of current portion — — 10,791 298 — 11,089 Deferred revenue, net of current portion — — 248,643 15,912 — 264,555 Accumulated losses of investee 653,526 (653,526 ) — Other long-term obligations — — 79,020 — — 79,020 Deferred income tax liability — — 106 9,041 (106 ) 9,041 Total (deficit) equity (653,526 ) (653,526 ) 2,139,222 48,999 (1,534,695 ) (653,526 ) Total liabilities and stockholders’ (deficit) equity $ — $ 2,195,576 $ 2,821,180 $ 209,134 $ (2,357,043 ) $ 2,868,847
Supplemental Condensed Consolidating Statements of Operations and Comprehensive (Loss) Income	Supplemental Condensed Consolidating Statements of Operations and Comprehensive Loss For the Three Months Ended March 31, 2019 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 263,539 $ 12,912 $ (202 ) $ 276,249 Costs and expenses — — 291,509 12,920 (202 ) 304,227 Loss from operations — — (27,970 ) (8 ) — (27,978 ) Loss from subsidiaries (89,156 ) (25,981 ) — — 115,137 — Other expense (income), net — 63,175 (52 ) (1,644 ) — 61,479 (Loss) income before income tax expenses (89,156 ) (89,156 ) (27,918 ) 1,636 115,137 (89,457 ) Income tax expense (benefit) — — 182 (483 ) — (301 ) Net (loss) income (89,156 ) (89,156 ) (28,100 ) 2,119 115,137 (89,156 ) Other comprehensive loss, net of tax effects: Net (loss) income (89,156 ) (89,156 ) (28,100 ) 2,119 115,137 (89,156 ) Foreign currency translation adjustment 570 570 — 570 (1,140 ) 570 Total other comprehensive income 570 570 — 570 (1,140 ) 570 Comprehensive (loss) income $ (88,586 ) $ (88,586 ) $ (28,100 ) $ 2,689 $ 113,997 $ (88,586 ) Supplemental Condensed Consolidating Statements of Operations and Comprehensive Loss For the Three Months Ended March 31, 2018 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 233,788 $ 13,465 $ (656 ) $ 246,597 Costs and expenses — — 305,221 13,663 (656 ) 318,228 (Loss) income from operations — — (71,433 ) (198 ) — (71,631 ) Loss from subsidiaries (84,717 ) (26,320 ) — — 111,037 — Other expense (income), net — 58,397 (46,970 ) 2,092 — 13,519 Loss before income tax expenses (84,717 ) (84,717 ) (24,463 ) (2,290 ) 111,037 (85,150 ) Income tax expense (benefit) — — 172 (605 ) — (433 ) Net loss (84,717 ) (84,717 ) (24,635 ) (1,685 ) 111,037 (84,717 ) Other comprehensive loss, net of tax effects: Net loss (84,717 ) (84,717 ) (24,635 ) (1,685 ) 111,037 (84,717 ) Foreign currency translation adjustment (659 ) (659 ) — (659 ) 1,318 (659 ) Total other comprehensive loss (659 ) (659 ) — (659 ) 1,318 (659 ) Comprehensive loss $ (85,376 ) $ (85,376 ) $ (24,635 ) $ (2,344 ) $ 112,355 $ (85,376 )
Supplemental Condensed Consolidating Statements of Cash Flows	Supplemental Condensed Consolidating Statements of Cash Flows For the Three Months Ended March 31, 2019 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (43,058 ) $ 41 $ — $ (43,017 ) Cash flows from investing activities: Capital expenditures — — (1,391 ) — — (1,391 ) Proceeds from sale of capital assets — — (51 ) — — (51 ) Investment in subsidiary (118 ) (46,487 ) — — 46,605 — Acquisition of intangible assets — — (369 ) — — (369 ) Net cash used in investing activities (118 ) (46,487 ) (1,811 ) — 46,605 (1,811 ) Cash flows from financing activities: Repayment on notes payable — (2,025 ) — — — (2,025 ) Borrowings from revolving credit facility — 40,000 — — — 40,000 Proceeds from capital contribution — — 46,369 — (46,369 ) — Repayments of finance lease obligations — — (2,064 ) (72 ) — (2,136 ) Return of capital 118 118 (118 ) — (236 ) (118 ) Net cash provided by (used in) financing activities 118 38,093 44,187 (72 ) (46,605 ) 35,721 Effect of exchange rate changes on cash — — — 25 — 25 Net decrease in cash and cash equivalents — (8,394 ) (682 ) (6 ) — (9,082 ) Cash and cash equivalents: Beginning of period — 11,130 682 961 — 12,773 End of period $ — $ 2,736 $ — $ 955 $ — $ 3,691 Supplemental Condensed Consolidating Statements of Cash Flows For the Three Months Ended March 31, 2018 (in thousands) (unaudited) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (59,159 ) $ (423 ) $ — $ (59,582 ) Cash flows from investing activities: Capital expenditures — — (6,407 ) — — (6,407 ) Investment in subsidiary 966 (16,450 ) — — 15,484 — Acquisition of intangible assets — — (849 ) — — (849 ) Proceeds from sale of intangibles — — 53,693 — — 53,693 Proceeds from sale of capital assets — — 149 — — 149 Net cash provided by (used in) investing activities 966 (16,450 ) 46,586 — 15,484 46,586 Cash flows from financing activities: Borrowings from revolving credit facility — 57,000 — — — 57,000 Repayments on revolving credit facility — (40,000 ) — — — (40,000 ) Proceeds from capital contributions — — 17,416 — (17,416 ) — Repayments of capital lease obligations — — (3,305 ) (113 ) — (3,418 ) Return of capital (966 ) (966 ) (966 ) — 1,932 (966 ) Net cash (used in) provided by financing activities (966 ) 16,034 13,145 (113 ) (15,484 ) 12,616 Effect of exchange rate changes on cash — — — (19 ) — (19 ) Net (decrease) increase in cash and cash equivalents — (416 ) 572 (555 ) — (399 ) Cash and cash equivalents: Beginning of period — 3,661 (572 ) 783 — 3,872 End of period $ — $ 3,245 $ — $ 228 $ — $ 3,473	Condensed Consolidating Statements of Cash Flows For the Year ended December 31, 2018 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (220,952 ) $ 453 $ — $ (220,499 ) Cash flows from investing activities: Capital expenditures — — (19,409 ) (3 ) — (19,412 ) Proceeds from sale of intangibles — — 53,693 — — 53,693 Proceeds from sale of capital assets — — 127 — — 127 Investment in subsidiary (1,571 ) (201,292 ) — — 202,863 — Acquisition of intangible assets — — (1,486 ) — — (1,486 ) Net cash (used in) provided by investing activities (1,571 ) (201,292 ) 32,925 (3 ) 202,863 32,922 Cash flows from financing activities: Proceeds from notes payable — 810,000 — — — 810,000 Repayment on notes payable — (522,191 ) — — — (522,191 ) Borrowings from revolving line of credit — 201,000 — — — 201,000 Repayment of revolving line of credit — (261,000 ) — — — (261,000 ) Proceeds from capital contribution 4,700 4,700 204,421 — (209,121 ) 4,700 Repayments of capital lease obligations — — (12,011 ) (343 ) — (12,354 ) Financing costs — (11,317 ) — — — (11,317 ) Deferred financing costs — (9,302 ) — — — (9,302 ) Return of capital (3,129 ) (3,129 ) (3,129 ) — 6,258 (3,129 ) Net cash provided by (used in) financing activities 1,571 208,761 189,281 (343 ) (202,863 ) 196,407 Effect of exchange rate changes on cash — — — 71 — 71 Net increase in cash — 7,469 1,254 178 — 8,901 Cash: Beginning of period — 3,661 (572 ) 783 — 3,872 End of period $ — $ 11,130 $ 682 $ 961 $ — $ 12,773 Condensed Consolidating Statements of Cash Flows For the Year ended December 31, 2017 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (313,290 ) $ 3,958 $ — $ (309,332 ) Cash flows from investing activities: Capital expenditures — — (20,391 ) — — (20,391 ) Proceeds from sale of capital assets — — 776 — — 776 Investment in subsidiary 1,151 (325,222 ) — — 324,071 — Acquisition of intangible assets — — (1,745 ) — — (1,745 ) Other assets — — (301 ) — — (301 ) Net cash provided by (used in) investing activities 1,151 (325,222 ) (21,661 ) — 324,071 (21,661 ) Cash flows from financing activities: Proceeds from notes payable — 724,750 — — — 724,750 Repayment on notes payable — (450,000 ) — — — (450,000 ) Borrowings from revolving line of credit — 196,895 — — — 196,895 Repayment of revolving line of credit — (136,895 ) — — — (136,895 ) Proceeds from capital contribution — — 326,373 — (326,373 ) — Payment of intercompany settlement — — (2,983 ) — — (2,983 ) Intercompany receivable — 3,621 — (3,621 ) — Intercompany payable — — — (3,621 ) 3,621 — Repayments of capital lease obligations — — (9,667 ) (340 ) — (10,007 ) Financing costs — (18,277 ) — — — (18,277 ) Deferred financing costs — (11,119 ) — — — (11,119 ) Return of capital (1,151 ) (1,151 ) (1,151 ) — 2,302 (1,151 ) Net cash (used in) provided by financing activities (1,151 ) 304,203 316,193 (3,961 ) (324,071 ) 291,213 Effect of exchange rate changes on cash — — — 132 — 132 Net increase (decrease) in cash — (21,019 ) (18,758 ) 129 — (39,648 ) Cash: Beginning of period — 24,680 18,186 654 — 43,520 End of period $ — $ 3,661 $ (572 ) $ 783 $ — $ 3,872 Condensed Consolidating Statements of Cash Flows For the Year ended December 31, 2016 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ — $ — $ (380,508 ) $ 14,802 $ — $ (365,706 ) Cash flows from investing activities: Subscriber acquisition costs – company owned equipment — — (5,243 ) — — (5,243 ) Capital expenditures — — (11,642 ) — — (11,642 ) Proceeds from sale of capital assets — — 3,080 43 — 3,123 Investment in subsidiary (100,407 ) (408,214 ) — — 508,621 — Acquisition of intangible assets — — (1,385 ) — — (1,385 ) Net cash used in investing activities (100,407 ) (408,214 ) (15,190 ) 43 508,621 (15,147 ) Cash flows from financing activities: Proceeds from notes payable — 604,000 — — — 604,000 Repayment on notes payable — (235,535 ) — — — (235,535 ) Borrowings from revolving line of credit — 57,000 — — — 57,000 Repayment of revolving line of credit — (77,000 ) — — — (77,000 ) Proceeds from capital contribution 100,407 100,407 — — (100,407 ) 100,407 Payment of intercompany settlement — — 3,000 (3,000 ) — — Intercompany receivable — — 12,906 — (12,906 ) — Intercompany payable — — 408,214 (12,906 ) (395,308 ) — Repayments of capital lease obligations — — (8,295 ) (20 ) — (8,315 ) Financing costs — (9,036 ) — — — (9,036 ) Deferred financing costs — (9,241 ) — — — (9,241 ) Net cash provided by (used in) financing activities 100,407 430,595 415,825 (15,926 ) (508,621 ) 422,280 Effect of exchange rate changes on cash — — — (466 ) — (466 ) Net increase (decrease) in cash — 22,381 20,127 (1,547 ) — 40,961 Cash: Beginning of period — 2,299 (1,941 ) 2,201 — 2,559 End of period $ — $ 24,680 $ 18,186 $ 654 $ — $ 43,520
Condensed Consolidating Statements of Operations and Comprehensive Loss		Condensed Consolidating Statements of Operations and Comprehensive Loss For the Year ended December 31, 2018 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 998,190 $ 54,818 $ (2,567 ) $ 1,050,441 Costs and expenses — — 1,240,570 54,497 (2,567 ) 1,292,500 (Loss) income from operations — — (242,380 ) 321 — (242,059 ) Loss from subsidiaries (467,914 ) (211,665 ) — — 679,579 — Other expense (income), net — 256,249 (35,936 ) 7,153 — 227,466 Loss before income taxes (467,914 ) (467,914 ) (206,444 ) (6,832 ) 679,579 (469,525 ) Income tax expense (benefit) — — 512 (2,123 ) — (1,611 ) Net loss $ (467,914 ) $ (467,914 ) $ (206,956 ) $ (4,709 ) $ 679,579 $ (467,914 ) Other comprehensive loss, net of tax effects: Foreign currency translation adjustment (2,218 ) (2,218 ) — (2,218 ) 4,436 (2,218 ) Total other comprehensive loss, net of tax effects (2,218 ) (2,218 ) — (2,218 ) 4,436 (2,218 ) Comprehensive loss $ (470,132 ) $ (470,132 ) $ (206,956 ) $ (6,927 ) $ 684,015 $ (470,132 ) Condensed Consolidating Statements of Operations and Comprehensive Loss For the Year ended December 31, 2017 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 841,658 $ 43,015 $ (2,690 ) $ 881,983 Costs and expenses — — 997,247 42,919 (2,690 ) 1,037,476 (Loss) income from operations — — (155,589 ) 96 — (155,493 ) Loss from subsidiaries (410,199 ) (165,497 ) — — 575,696 — Other expense (income), net — 244,702 13,545 (4,619 ) — 253,628 (Loss) income before income taxes (410,199 ) (410,199 ) (169,134 ) 4,715 575,696 (409,121 ) Income tax expense (benefit) — — (228 ) 1,306 — 1,078 Net (loss) income $ (410,199 ) $ (410,199 ) $ (168,906 ) $ 3,409 $ 575,696 $ (410,199 ) Other comprehensive income (loss), net of tax effects: Foreign currency translation adjustment 3,155 3,155 — 3,155 (6,310 ) 3,155 Unrealized gain on marketable securities (1,693 ) (1,693 ) (1,693 ) — 3,386 (1,693 ) Total other comprehensive income (loss), net of tax effects 1,462 1,462 (1,693 ) 3,155 (2,924 ) 1,462 Comprehensive (loss) income $ (408,737 ) $ (408,737 ) $ (170,599 ) $ 6,564 $ 572,772 $ (408,737 ) Condensed Consolidating Statements of Operations and Comprehensive Loss For the Year ended December 31, 2016 (In thousands) Parent APX Group, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ — $ 715,072 $ 45,539 $ (2,704 ) $ 757,907 Costs and expenses — — 787,138 44,575 (2,704 ) 829,009 (Loss) income from operations — — (72,066 ) 964 — (71,102 ) Loss from subsidiaries (275,957 ) (69,637 ) — — 345,594 — Other expense (income), net — 206,320 (1,207 ) (325 ) — 204,788 Loss before income taxes (275,957 ) (275,957 ) (70,859 ) 1,289 345,594 (275,890 ) Income tax expense (benefit) — — 545 (478 ) — 67 Net (loss) income $ (275,957 ) $ (275,957 ) $ (71,404 ) $ 1,767 $ 345,594 $ (275,957 ) Other comprehensive income, net of tax effects: Foreign currency translation adjustment 2,482 2,482 — 2,482 (4,964 ) 2,482 Unrealized gain on marketable securities 1,011 1,011 1,011 — (2,022 ) 1,011 Total other comprehensive income, net of tax effects 3,493 3,493 1,011 2,482 (6,986 ) 3,493 Comprehensive loss $ (272,464 ) $ (272,464 ) $ (70,393 ) $ 4,249 $ 338,608 $ (272,464 )

Significant Accounting Polici_2

Significant Accounting Policies (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Changes in Company's Allowance for Accounts Receivable	The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Three Months Ended March 31, 2019 Twelve Months Ended December 31, 2018 Beginning balance $ 5,594 $ 5,356 Provision for doubtful accounts 5,918 19,405 Write-offs and adjustments (5,704 ) (19,167 ) Balance at end of period $ 5,808 $ 5,594 The following table summarizes the RIC receivables (in thousands): March 31, 2019 December 31, 2018 RIC receivables, gross $ 173,254 $ 175,250 Deferred interest (29,612 ) (34,163 ) RIC receivables, net of deferred interest $ 143,642 $ 141,087 Classified on the condensed consolidated unaudited balance sheets as: Accounts and notes receivable, net $ 35,370 $ 32,185 Long-term notes receivables and other assets, net 108,272 108,902 RIC receivables, net $ 143,642 $ 141,087	The changes in the Company’s allowance for accounts receivable were as follows for the periods ended (in thousands): Year ended December 31, 2018 2017 2016 Beginning balance $ 5,356 $ 4,138 $ 3,541 Provision for doubtful accounts 19,405 22,465 19,624 Write-offs and adjustments (19,167 ) (21,247 ) (19,027 ) Balance at end of period $ 5,594 $ 5,356 $ 4,138 The following table summarizes the installment receivables (in thousands): December 31, 2018 December 31, 2017 RIC receivables, gross $ 175,250 $ 131,024 Deferred interest (34,163 ) (36,048 ) RIC receivables, net of deferred interest $ 141,087 $ 94,976 Classified on the consolidated balance sheets as: Accounts and notes receivable, net $ 32,185 $ 16,469 Long-term notes receivables and other assets, net 108,902 78,507 RIC receivables, net $ 141,087 $ 94,976
Schedule Of Depreciation And Amortization Expense	The Company’s depreciation and amortization included in the consolidated statements of operations consisted of the following (in thousands): Three Months Ended March 31, 2019 2018 Amortization of capitalized contract costs $ 105,028 $ 95,363 Amortization of definite-lived intangibles 20,272 22,720 Depreciation of property, plant and equipment 5,921 6,175 Total depreciation and amortization $ 131,221 $ 124,258	The Company’s depreciation and amortization included in the consolidated statements of operations consisted of the following (in thousands): Year ended December 31, 2018 2017 2016 Amortization of capitalized contract costs $ 398,174 $ — $ — Amortization of subscriber acquisition costs — 206,153 154,877 Amortization of definite-lived intangibles 90,945 101,827 116,865 Depreciation of property, plant and equipment 24,963 21,275 16,800 Total depreciation and amortization $ 514,082 $ 329,255 $ 288,542

Revenue and Capitalized Contr_2

Revenue and Capitalized Contract Costs (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Schedule of New Accounting Pronouncement	The Company adopted Topic 606 using the modified retrospective method. The cumulative effect of applying the new standard to all contracts with subscribers that were not completed as of January 1, 2018 was recorded as an adjustment to accumulated deficit as of the adoption date. As a result of applying the modified retrospective method to adopt the new revenue guidance, the following cumulative catch-up adjustments were made to select consolidated balance sheet line items as of January 1, 2018 (in thousands): Consolidated Balance Sheets As Reported Adjustments Adjusted December 31, 2017 January 1, 2018 Assets Capitalized contract costs, net $ — $ 1,020,408 $ 1,020,408 Subscriber acquisition costs, net 1,308,558 (1,308,558 ) — Long-term notes receivables and other assets, net 88,723 2,713 91,436 Liabilities and Stockholders' Deficit Accrued expenses and other current liabilities 74,321 10,329 84,650 Deferred revenue 88,337 39,868 128,205 Deferred revenue, net of current portion 264,555 (53,062 ) 211,493 Deferred income tax liabilities 9,041 (5,641 ) 3,400 Accumulated deficit (1,358,571 ) (276,931 ) (1,635,502 ) The following tables compare the select reported consolidated balance sheets, statements of operations and cash flows line items to the amounts had the previous guidance been in effect (in thousands): Consolidated Balance Sheets December 31, 2018 As Reported Balances Without Adoption of Topic 606 Effect of Change Higher/(Lower) Assets Capitalized contract costs, net $ 1,115,775 $ — $ 1,115,775 Subscriber acquisition costs, net — 1,518,188 (1,518,188 ) Liabilities and Stockholders' Deficit Accrued expenses and other current liabilities 136,715 126,900 9,815 Deferred revenue 186,953 126,582 60,371 Deferred revenue, net of current portion 323,585 440,474 (116,889 ) Deferred income tax liabilities 1,096 8,682 (7,586 ) Accumulated deficit (2,104,097 ) (1,754,426 ) (349,671 ) Accumulated other comprehensive loss (28,837 ) (30,384 ) 1,547 Consolidated Statements of Operations and Comprehensive Loss Year ended December 31, 2018 As Reported Balances Without Adoption of Topic 606 Effect of Change Higher/(Lower) Revenues: Recurring and other revenue $ 1,050,441 $ 950,661 $ 99,780 Service and other sales revenue — 46,177 (46,177 ) Activation fees — 9,705 (9,705 ) Total revenues 1,050,441 1,006,543 43,898 Costs and expenses: Operating expenses 355,813 385,672 (29,859 ) Depreciation and amortization 514,082 367,879 146,203 Loss from operations (242,059 ) (169,613 ) (72,446 ) Income tax (benefit) expense (1,611 ) 806 (2,417 ) Net loss (467,914 ) (397,885 ) (70,029 ) Other comprehensive loss, net of tax effects: Foreign currency translation adjustment (2,218 ) (3,765 ) 1,547 Total other comprehensive (loss) income (2,218 ) (3,765 ) 1,547 Comprehensive loss (470,132 ) (401,650 ) (68,482 ) Consolidated Statements of Cashflows Year ended December 31, 2018 As Reported Balances Without Adoption of Topic 606 Effect of Change Cash flows from operating activities: Net loss $ (467,914 ) $ (397,885 ) $ (70,029 ) Adjustments to reconcile net loss to net cash used in operating activities: Amortization of capitalized contract costs 398,174 — 398,174 Amortization of subscriber acquisition costs — 251,971 (251,971 ) Changes in operating assets and liabilities: Capitalized contract costs – deferred contract costs (499,252 ) — (499,252 ) Subscriber acquisition costs – deferred contract costs — (469,393 ) 469,393 Accrued expenses and other current liabilities 91,469 93,886 (2,417 ) Deferred revenue 172,905 216,803 (43,898 ) Net cash used in operating activities (220,499 ) (220,499 ) —

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule Of Other Expense And Loss On Extinguishment And Deferred Financing Costs		In accordance with ASC 470-50 Debt – Modifications and Extinguishments, the Company performed analyses for the September 2018, August 2017 and February 2017 issuances to determine if the notes repurchased with the proceeds from those issuances were substantially different than the notes issued to determine the appropriate accounting treatment of associated issuance fees. As a result of these analyses, the Company recorded the following amounts of other expense and loss on extinguishment and deferred financing costs during the years ended December 31, 2018 , 2017 and 2016 (in thousands): Other expense and loss on extinguishment Deferred financing costs Issuance Original premium extinguished Previously deferred financing costs extinguished New financing costs Total other expense and loss on extinguishment Previously deferred financing rolled over New deferred financing costs Total deferred financing costs For the year ended December 31, 2018 September 2018 issuance $ (953 ) $ 4,207 $ 11,317 $ 14,571 $ — $ 10,275 $ 10,275 For the year ended December 31, 2017 August 2017 issuance $ — $ 1,408 $ 8,881 $ 10,289 $ 473 $ 4,569 $ 5,042 February 2017 issuance — 3,259 9,491 12,750 1,476 6,076 7,552 Total $ — $ 4,667 $ 18,372 $ 23,039 $ 1,949 $ 10,645 $ 12,594 For the year ended December 31, 2016 May 2016 issuance $ 355 $ 695 $ 9,036 $ 10,086 $ 3,423 $ 6,628 $ 10,051
Schedule of Deferred Financing Activity	The following table presents deferred financing activity for the three months ended March 31, 2019 and year ended December 31, 2018 (in thousands): Unamortized Deferred Financing Costs Balance December 31, 2018 Additions Early Extinguishment Amortized Balance March 31, 2019 Revolving Credit Facility $ 2,058 $ — $ — $ (261 ) $ 1,797 2020 Notes 5,380 — — (702 ) 4,678 2022 Private Placement Notes 602 — — (38 ) 564 2022 Notes 12,799 — — (816 ) 11,983 2023 Notes 3,922 — — (210 ) 3,712 Term Loan 9,662 — (460 ) 9,202 Total Deferred Financing Costs $ 34,423 $ — $ — $ (2,487 ) $ 31,936 Unamortized Deferred Financing Costs Balance December 31, 2017 Additions Early Extinguishment Amortized Balance December 31, 2018 Revolving Credit Facility $ 3,099 $ — $ — $ (1,041 ) $ 2,058 2019 Notes 2,877 — (1,877 ) (1,000 ) — 2020 Notes 11,209 — (2,330 ) (3,499 ) 5,380 2022 Private Placement Notes 752 — — (150 ) 602 2022 Notes 16,067 — — (3,268 ) 12,799 2023 Notes 4,762 — — (840 ) 3,922 Term Loan — 10,275 — (613 ) 9,662 Total Deferred Financing Costs $ 38,766 $ 10,275 $ (4,207 ) $ (10,411 ) $ 34,423	The following table presents deferred financing activity for the year ended December 31, 2018 and 2017 (in thousands): Unamortized Deferred Financing Costs Balance 12/31/2017 Additions Refinances Early Extinguishment Amortized Balance 12/31/2018 Revolving Credit Facility $ 3,099 $ — $ — $ — $ (1,041 ) $ 2,058 2019 Notes 2,877 — — (1,877 ) (1,000 ) — 2020 Notes 11,209 — — (2,330 ) (3,499 ) 5,380 2022 Private Placement Notes 752 — — — (150 ) 602 2022 Notes 16,067 — — — (3,268 ) 12,799 2023 Notes 4,762 — — — (840 ) 3,922 Term Loan — 10,275 — — (613 ) 9,662 Total Deferred Financing Costs $ 38,766 $ 10,275 $ — $ (4,207 ) $ (10,411 ) $ 34,423 Unamortized Deferred Financing Costs Balance 12/31/2016 Additions Refinances Early Extinguishment Amortized Balance 12/31/2017 Revolving Credit Facility $ 4,420 $ 399 $ — $ — $ (1,720 ) $ 3,099 2019 Notes 11,693 — (1,949 ) (4,667 ) (2,200 ) 2,877 2020 Notes 15,053 — — — (3,844 ) 11,209 2022 Private Placement Notes 903 — — — (151 ) 752 2022 Notes 11,714 6,076 1,476 — (3,199 ) 16,067 2023 Notes — 4,569 473 — (280 ) 4,762 Total Deferred Financing Costs $ 43,783 $ 11,044 $ — $ (4,667 ) $ (11,394 ) $ 38,766
Summary of Debt	The Company’s debt at March 31, 2019 and December 31, 2018 consisted of the following (in thousands): March 31, 2019 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount Senior Secured Revolving Credit Facilities $ 40,000 $ — $ — $ 40,000 8.75% Senior Notes due 2020 679,299 1,958 (4,678 ) 676,579 8.875% Senior Secured Notes Due 2022 270,000 (2,006 ) (564 ) 267,430 7.875% Senior Secured Notes Due 2022 900,000 19,028 (11,983 ) 907,045 7.625% Senior Notes Due 2023 400,000 — (3,712 ) 396,288 Senior Secured Term Loan - noncurrent 797,850 — (9,202 ) 788,648 Total Long-Term Debt 3,087,149 18,980 (30,139 ) 3,075,990 Senior Secured Term Loan - current 8,100 — — 8,100 Total Debt $ 3,095,249 $ 18,980 $ (30,139 ) $ 3,084,090 December 31, 2018 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount 8.75% Senior Notes due 2020 $ 679,299 $ 2,230 $ (5,380 ) $ 676,149 8.875% Senior Secured Notes due 2022 270,000 (2,122 ) (602 ) 267,276 7.875% Senior Secured Notes due 2022 900,000 20,178 (12,799 ) 907,379 7.625% Senior Notes Due 2023 400,000 — (3,922 ) 396,078 Senior Secured Term Loan - noncurrent 799,875 — (9,662 ) 790,213 Total Long-Term Debt 3,049,174 20,286 (32,365 ) 3,037,095 Senior Secured Term Loan - current 8,100 — — 8,100 Total Debt $ 3,057,274 $ 20,286 $ (32,365 ) $ 3,045,195 (1) Unamortized deferred financing costs related to the revolving credit facilities included in deferred financing costs, net on the condensed consolidated balance sheets at March 31, 2019 and December 31, 2018 were $1.8 million and $2.1 million , respectively.	The Company’s debt at December 31, 2018 and 2017 consisted of the following (in thousands): December 31, 2018 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount 8.75% Senior Notes due 2020 $ 679,299 $ 2,230 $ (5,380 ) $ 676,149 8.875% Senior Secured Notes Due 2022 270,000 (2,122 ) (602 ) 267,276 7.875% Senior Secured Notes Due 2022 900,000 20,178 (12,799 ) 907,379 7.625% Senior Notes Due 2023 400,000 — (3,922 ) 396,078 Term Loan - noncurrent 799,875 — (9,662 ) 790,213 Total Long-Term Debt 3,049,174 20,286 (32,365 ) 3,037,095 Term Loan - current 8,100 — — 8,100 Total Debt $ 3,057,274 $ 20,286 $ (32,365 ) $ 3,045,195 December 31, 2017 Outstanding Principal Unamortized Premium (Discount) Unamortized Deferred Financing Costs (1) Net Carrying Amount Series D Revolving Credit Facility due 2019 $ 3,000 $ — $ — $ 3,000 Series A, B Revolving Credit Facilities due 2021 57,000 — — 57,000 6.375% Senior Secured Notes due 2019 269,465 — (2,877 ) 266,588 8.75% Senior Notes due 2020 930,000 4,465 (11,209 ) 923,256 8.875% Senior Secured Notes Due 2022 270,000 (2,559 ) (752 ) 266,689 7.875% Senior Secured Notes Due 2022 900,000 24,593 (16,067 ) 908,526 7.625% Senior Notes Due 2023 400,000 — (4,762 ) 395,238 Total Debt $ 2,829,465 $ 26,499 $ (35,667 ) $ 2,820,297 (1) Unamortized deferred financing costs related to the revolving credit facilities included in deferred financing costs, net on the consolidated balance sheets at December 31, 2018 and 2017 was $2.1 million and $3.1 million , respectively.

Restructuring and Asset Impai_2

Restructuring and Asset Impairment Charges (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Restructuring and Related Activities [Abstract]
Schedule of Restructuring and Asset Impairment Charges		Restructuring and asset impairment charges were as follows (in thousands): Year ended December 31, 2018 2017 2016 Wireless restructuring recoveries: Asset recoveries $ — $ — $ (710 ) Contract termination recoveries — — (751 ) Employee severance and termination benefits recoveries — — (77 ) Total wireless restructuring recoveries — — (1,538 ) Loss on subscriber contract sales — — 2,551 Employee severance and termination benefits charges 4,683 — — Total restructuring and asset impairment charges $ 4,683 $ — $ 1,013
Summary of Restructuring Activity	The following table presents accrued restructuring activity for the three months ended March 31, 2019 and the twelve months ended December 31, 2018 (in thousands): Contract termination costs Employee severance and termination benefits Total Accrued restructuring balance as of December 31, 2017 $ 558 $ — $ 558 Restructuring expenses — 4,683 4,683 Cash payments (91 ) (4,341 ) (4,432 ) Accrued restructuring balance as of December 31, 2018 467 342 809 Cash payments (23 ) (257 ) (280 ) Accrued restructuring balance as of March 31, 2019 $ 444 $ 85 $ 529	The following table presents accrued restructuring activity for the years ended December 31, 2018 and 2017 . Asset impairments Contract termination costs Employee severance and termination benefits Total Accrued restructuring balance as of December 31, 2015 $ — $ 3,954 $ 321 $ 4,275 Restructuring and impairment recoveries (710 ) (751 ) (77 ) (1,538 ) Cash payments — (2,554 ) (244 ) (2,798 ) Non-cash settlements 710 — — 710 Accrued restructuring balance as of December 31, 2016 — 649 — 649 Cash payments — (91 ) — (91 ) Accrued restructuring balance as of December 31, 2017 — 558 — 558 Restructuring expenses — — 4,683 4,683 Cash payments — (91 ) (4,341 ) (4,432 ) Accrued restructuring balance as of December 31, 2018 $ — $ 467 $ 342 $ 809

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax Provision	The income tax (benefit) expense consisted of the following (in thousands): Year ended December 31, 2018 2017 2016 Current income tax: Federal $ — $ — $ — State 512 151 545 Foreign (52 ) (24 ) 95 Total 460 127 640 Deferred income tax: Federal — (326 ) — State — (53 ) — Foreign (2,071 ) 1,330 (573 ) Total (2,071 ) 951 (573 ) Income tax (benefit) expense $ (1,611 ) $ 1,078 $ 67
Reconciliation of Tax Expense Computed at Statutory Federal Rate and Company's Tax Expense	The following reconciles the tax expense computed at the statutory federal rate and the Company’s tax expense (in thousands): Year ended December 31, 2018 2017 2016 Computed expected tax expense $ (98,598 ) $ (139,100 ) $ (93,770 ) State income taxes, net of federal tax effect 404 65 360 Foreign income taxes (690 ) (299 ) (949 ) Other reconciling items — (344 ) 666 Permanent differences 4,406 2,008 1,688 Effect of Federal law change — 166,876 — Change in valuation allowance 92,867 (28,128 ) 92,072 Income tax (benefit) expense $ (1,611 ) $ 1,078 $ 67
Significant Portions of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities were as follows (in thousands) December 31, 2018 2017 Gross deferred tax assets: Net operating loss carryforwards $ 591,244 $ 591,619 Deferred subscriber income 113,103 72,389 Interest expense limitation 56,381 — Accrued expenses and allowances 18,766 17,633 Purchased intangibles and deferred financing costs 17,788 15,191 Inventory reserves 4,688 6,662 Property and equipment — 1,176 Research and development credits 41 41 Valuation allowance (467,705 ) (304,509 ) Total 334,306 400,202 Gross deferred tax liabilities: Deferred capitalized contract costs (332,547 ) (408,610 ) Property and equipment (2,242 ) — Prepaid expenses (613 ) (633 ) Total (335,402 ) (409,243 ) Net deferred tax liabilities $ (1,096 ) $ (9,041 )
Summary of Net Operating Loss Carryforwards	The Company had net operating loss carryforwards as follows (in thousands): December 31, 2018 2017 Net operating loss carryforwards: Federal $ 2,405,380 $ 2,355,153 States 1,656,333 1,715,004 Canada 19,753 27,326 Total $ 4,081,466 $ 4,097,483

Stock-Based Compensation and _2

Stock-Based Compensation and Equity (Tables)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Summary of Incentive Unit Activity		A summary of the Incentive Unit activity for the years ended December 31, 2018 and 2017 is presented below: Incentive Units Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Life (Years) Aggregate Intrinsic Value Outstanding, December 31, 2016 85,882,836 $ 1.19 6.81 $ — Forfeited (70,000 ) 1.30 Outstanding, December 31, 2017 85,812,836 1.19 5.81 — Forfeited (450,000 ) 1.93 Outstanding, December 31, 2018 85,362,836 1.18 4.81 — Unvested shares expected to vest after December 31, 2018 59,663,659 1.22 4.93 — Exercisable at December 31, 2018 25,699,177 $ 1.11 4.50 $ —
Stock-Based Compensation Expense	Stock-based compensation expense in connection with all stock-based awards is presented as follows (in thousands): Three Months Ended March 31, 2019 2018 Operating expenses $ 43 $ 18 Selling expenses 87 45 General and administrative expenses 727 141 Total stock-based compensation $ 857 $ 204	Stock-based compensation expense in connection with all stock-based awards for the years ended December 31, 2018 , 2017 and 2016 is allocated as follows (in thousands): Year ended December 31, 2018 2017 2016 Operating expenses $ 129 $ 65 $ 68 Selling expenses 285 217 (127 ) General and administrative expenses 2,091 1,313 3,927 Total stock-based compensation $ 2,505 $ 1,595 $ 3,868
Vivint Stock Appreciation Rights
Summary of the SAR Activity		A summary of the Vivint Group SAR activity for the years ended December 31, 2018 and 2017 is presented below: Stock Appreciation Rights Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Life (Years) Aggregate Intrinsic Value Outstanding, December 31, 2016 21,993,158 $ 0.96 8.23 $ — Granted 13,250,640 1.74 Forfeited (2,374,864 ) 1.12 Exercised (114,644 ) 0.72 Outstanding, December 31, 2017 32,754,290 1.26 9.21 — Granted 14,630,000 1.79 Forfeited (9,255,137 ) 1.31 Exercised (117,274 ) 0.89 Outstanding, December 31, 2018 38,011,879 1.46 8.07 — Unvested shares expected to vest after December 31, 2018 33,813,668 1.51 8.28 — Exercisable at December 31, 2018 4,198,211 $ 1.02 6.30 $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	As of December 31, 2018 , future minimum lease payments were as follows (in thousands): Operating Capital Total 2019 $ 16,709 $ 8,193 $ 24,902 2020 15,478 5,209 20,687 2021 14,926 363 15,289 2022 13,655 7 13,662 2023 13,701 — 13,701 Thereafter 28,824 — 28,824 Amounts representing interest — (459 ) (459 ) Total lease payments $ 103,293 $ 13,313 $ 116,606

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2019USD ($)paymentunit	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)paymentunit	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Accounts and notes receivable, net	$ 20,000,000		$ 16,500,000	$ 24,300,000
Allowance for doubtful accounts	5,808,000		5,594,000	5,356,000	$ 4,138,000	$ 3,541,000
Accounts receivable classified as held for sale			0
Provision for doubtful accounts	$ 5,918,000	$ 3,968,000	19,405,000	22,465,000	19,624,000
Capitalized contract costs, expected period of benefit	5 years
Equity method investments	$ 6,100,000		3,900,000
Amortization of deferred financing costs and bond premiums and discounts	1,180,000	1,343,000	5,152,000	6,586,000	10,447,000
Sales commission included in accrued expenses and other liabilities	3,100,000		4,900,000	3,300,000
Other long-term obligations	16,800,000		17,600,000	18,500,000
Advertising expenses incurred	$ 12,700,000	13,700,000	$ 47,200,000	42,500,000	33,000,000
Uncertain income tax position, percentage	50.00%
Number of reporting units | unit	2		2
Translation (gain) loss	$ (1,701,000)	2,075,000
Issued and unused letters of credit	$ 13,900,000		$ 13,800,000	9,500,000
Vivint Sky Control Panels
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of installed panels	82.00%
2GIG Sale
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of installed panels	17.00%		19.00%
Other Panels
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of installed panels	1.00%
Interest Expense
Basis Of Presentation And Significant Accounting Policies [Line Items]
Amortization of deferred financing costs and bond premiums and discounts	$ 2,500,000	$ 2,700,000	$ 10,400,000	11,400,000	$ 11,600,000
Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	5 years		5 years
Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	10 years		10 years
Notes Payable
Basis Of Presentation And Significant Accounting Policies [Line Items]
Deferred financing cost, net	$ 30,100,000		$ 32,400,000	35,700,000
Deferred financing cost, accumulated amortization	$ 56,800,000		$ 54,600,000	45,200,000
Vivint Flex Pay
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of payment options | payment	3		3
Installment loans available to qualified customers, maximum amount provided by third party	$ 4,000		$ 4,000
Vivint Flex Pay | Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Installment loans available to qualified customers, term of loan	42 months		42 months
Vivint Flex Pay | Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Installment loans available to qualified customers, term of loan	60 months		60 months
Subscriber Contracts | Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Contract with customer, term	3 years
Subscriber Contracts | Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Contract with customer, term	5 years
Revolving Credit Facility
Basis Of Presentation And Significant Accounting Policies [Line Items]
Issued and unused letters of credit	$ 249,700,000		$ 289,800,000
Line of Credit | Revolving Credit Facility
Basis Of Presentation And Significant Accounting Policies [Line Items]
Deferred financing cost, net	1,800,000		2,100,000
Deferred financing cost, accumulated amortization	9,900,000		9,600,000	$ 8,600,000
Fair Value, Inputs, Level 3
Basis Of Presentation And Significant Accounting Policies [Line Items]
Equity method investments	$ 700,000		$ 700,000

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies - Accounts Receivable (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance	$ 5,594	$ 5,356	$ 5,356	$ 4,138	$ 3,541
Provision for doubtful accounts	5,918	$ 3,968	19,405	22,465	19,624
Write-offs and adjustments	(5,704)		(19,167)	(21,247)	(19,027)
Balance at end of period	$ 5,808		$ 5,594	$ 5,356	$ 4,138

Basis of Presentation and Sig_6

Basis of Presentation and Significant Accounting Policies - Depreciation and Amortization (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total depreciation and amortization	$ 131,221	$ 124,258	$ 514,082	$ 329,255	$ 288,542
Depreciation of property, plant and equipment
Property, Plant and Equipment [Line Items]
Total depreciation and amortization	5,921	6,175	24,963	21,275	16,800
Amortization of capitalized contract costs
Property, Plant and Equipment [Line Items]
Total depreciation and amortization	105,028	95,363
Amortization of definite-lived intangibles
Property, Plant and Equipment [Line Items]
Total depreciation and amortization	$ 20,272	$ 22,720	$ 90,945	$ 101,827	$ 116,865

Basis of Presentation and Sig_7

Basis of Presentation and Significant Accounting Policies - Recently Adopted Accounting Standards (Details) - ASU 2016-02 adoption $ in Millions	Jan. 01, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use lease asset	$ 75.5
Operating and finance lease liability	$ 85.9

Revenue and Capitalized Contr_3

Revenue and Capitalized Contract Costs - Remaining Performance Obligations Percentages (Details)	Mar. 31, 2019	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percentage revenue of related to remaining performance obligation expected to recognized over the next 24 months	63.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percentage revenue of related to remaining performance obligation expected to recognized over the next 24 months		62.50%

Revenue and Capitalized Contr_4

Revenue and Capitalized Contract Costs - Remaining Performance Obligations Periods (Details)	Mar. 31, 2019	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period		2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period		3 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 years

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail)	May 10, 2019USD ($)	Nov. 16, 2012USD ($)	Sep. 30, 2018USD ($)	Aug. 31, 2017USD ($)	Dec. 31, 2013USD ($)Offerings	May 31, 2013USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2014USD ($)	Apr. 01, 2019USD ($)	Dec. 31, 2017USD ($)	Aug. 10, 2017USD ($)	Feb. 28, 2017USD ($)	Aug. 31, 2016USD ($)	May 31, 2016USD ($)	Oct. 31, 2015USD ($)	Mar. 06, 2015USD ($)
Debt Instrument [Line Items]
Outstanding borrowings							$ 3,084,090,000	$ 3,045,195,000			$ 2,820,297,000
Issued and unused letters of credit							$ 13,900,000	$ 13,800,000			9,500,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, aggregate principal amount		$ 200,000,000										$ 324,300,000					$ 289,400,000
Debt instrument, term		5 years
Step down margin percentage							0.25%	0.25%
Commitment fee, percentage							0.125%
Outstanding borrowings							$ 40,000,000	$ 0
Issued and unused letters of credit							$ 249,700,000	$ 289,800,000
Revolving Credit Facility | Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage							0.50%	0.50%
Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage							1.00%	1.00%
Series A- Revolving Commitments | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, aggregate principal amount							$ 267,000,000	$ 267,000,000
Series A- Revolving Commitments | Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage							3.00%	3.00%
Series A- Revolving Commitments | Revolving Credit Facility | Base Rate-based Borrowings
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage							2.00%	2.00%
Series D- Revolving Commitments | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, aggregate principal amount								$ 15,400,000
Series B- Revolving Commitments | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, aggregate principal amount							$ 21,200,000	$ 21,200,000
Series B- Revolving Commitments | Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage							4.00%	4.00%
Series B- Revolving Commitments | Revolving Credit Facility | Base Rate-based Borrowings
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage							3.00%	3.00%
Senior Notes
Debt Instrument [Line Items]
Debt instrument interest rate, percentage								7.625%
Senior Notes | 8.75% Senior Notes Due 2020
Debt Instrument [Line Items]
Principal amount							$ 679,299,000
Debt instrument interest rate, percentage							8.75%	8.75%
Repurchased face amount			$ 250,700,000
Senior Notes | 8.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Principal amount							$ 270,000,000									$ 300,000,000
Debt instrument interest rate, percentage							8.875%	8.875%								8.875%
Principal amount outstanding threshold for accelerated maturity							$ 190,000,000	$ 190,000,000
Repurchased face amount			250,700,000												$ 29,500,000
Outstanding borrowings											266,689,000
Senior Notes | 7.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Principal amount							$ 900,000,000								$ 500,000,000
Debt instrument interest rate, percentage							7.875%	7.875%							7.875%
Outstanding borrowings											908,526,000
Senior Notes | 7.625% Senior Notes Due 2023
Debt Instrument [Line Items]
Principal amount				$ 400,000,000			$ 400,000,000
Debt instrument interest rate, percentage				7.625%			7.625%	7.625%
Outstanding borrowings											395,238,000
Senior Notes | 6.375% Senior Secured Notes due 2019
Debt Instrument [Line Items]
Debt instrument interest rate, percentage							6.375%
Repurchased face amount			269,500,000										$ 300,000,000
Repayments of long-term debt				$ 150,000,000
Senior Notes | 6.375% Senior Secured Notes Due 2019
Debt Instrument [Line Items]
Principal amount		$ 925,000,000
Debt instrument interest rate, percentage		6.375%						6.375%
Repurchased face amount			269,500,000	$ 150,000,000									$ 300,000,000		$ 205,500,000
Outstanding borrowings											266,588,000
Senior Notes | 8.75% Senior Notes Due 2020
Debt Instrument [Line Items]
Principal amount		$ 380,000,000			$ 250,000,000	$ 200,000,000			$ 100,000,000
Debt instrument interest rate, percentage		8.75%					8.875%	8.75%
Repurchased face amount			$ 250,700,000
Outstanding borrowings											$ 923,256,000
Debt instrument, redemption price, percentage					101.50%	101.75%			102.00%
Number of offerings | Offerings					2
Senior Notes | 2019 Senior Notes And 2022 Private Placement Notes
Debt Instrument [Line Items]
Repurchased face amount															$ 235,000,000
Senior Notes | 7.875 Senior Notes Due August 2022
Debt Instrument [Line Items]
Principal amount														$ 100,000,000
Debt instrument interest rate, percentage														104.00%
Issuance price, percentage													108.25%
Term Loan | Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage			0.50%					0.50%
Term Loan | LIBOR | LIBOR Referenced To US Dollar Deposits
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage			1.00%					1.00%
Term Loan | LIBOR | LIBOR Referenced To LIBOR For Dollars In Period Of Borrowing
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage			5.00%					5.00%
Term Loan | Base Rate-based Borrowings | LIBOR Referenced To LIBOR For Dollars In Period Of Borrowing
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage			4.00%					4.00%
Term Loan | Term Loan
Debt Instrument [Line Items]
Credit facility, aggregate principal amount			$ 810,000,000
Debt instrument, redemption price, percentage of principal amount redeemed			0.25%
Letter of Credit
Debt Instrument [Line Items]
Outstanding borrowings							$ 13,900,000
Subsequent Event | Series D- Revolving Commitments | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, aggregate principal amount										$ 15,400,000
Subsequent Event | Senior Notes | 8.75% Senior Notes Due 2020
Debt Instrument [Line Items]
Repayments of long-term debt	$ 225,000,000
February 2017 Issuance of 7.875% Notes Due 2022 | Senior Notes | 7.875 Senior Notes Due August 2022
Debt Instrument [Line Items]
Principal amount													$ 300,000,000

Retail Installment Contract R_3

Retail Installment Contract Receivables - Installment Receivables (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred interest	$ (29,612)		$ (34,164)	$ (36,049)
Retail Installment Contracts
Accounts, Notes, Loans and Financing Receivable [Line Items]
RIC receivables, gross	173,254		175,250	131,024
Deferred interest	(29,612)		(34,163)	(36,048)
RIC receivables, net of deferred interest	143,642		141,087	94,976
Classified on the condensed consolidated unaudited balance sheets as:
Accounts and notes receivable, net	35,370		32,185	16,469
Long-term notes receivables and other assets, net	108,272		108,902	78,507
RIC receivables, net	143,642		141,087	94,976
Interest income	$ (3,500)	$ (3,300)	$ (14,900)	$ (7,300)
Minimum | Vivint Flex Pay
Accounts, Notes, Loans and Financing Receivable [Line Items]
Installment loans available to qualified customers, term of loan	42 months		42 months
Maximum | Vivint Flex Pay
Accounts, Notes, Loans and Financing Receivable [Line Items]
Installment loans available to qualified customers, term of loan	60 months		60 months

Retail Installment Contract R_4

Retail Installment Contract Receivables - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Change in deferred interest on short-term and long-term RIC receivables	$ 9,820	$ 33,793	$ 172,905	$ 247,500	$ 24,613
Retail Installment Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Deferred interest, beginning of period	34,163	$ 36,048	36,048	0
Write-offs, net of recoveries	(6,923)		(26,360)	(6,055)
Change in deferred interest on short-term and long-term RIC receivables	2,372		24,475	42,103
Deferred interest, end of period	$ 29,612		$ 34,163	$ 36,048	$ 0

Balance Sheet Components (Detai

Balance Sheet Components (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Prepaid expenses and other current assets
Prepaid expenses	$ 12,984	$ 7,183		$ 8,000
Deposits	1,353	904		1,596
Other	791	3,362		6,554
Total prepaid expenses and other current assets	15,128	11,449		16,150
Capitalized contract costs
Capitalized contract costs	2,445,784	2,361,795		0
Accumulated amortization	(1,352,919)	(1,246,020)		0
Capitalized contract costs, net	1,092,865	1,115,775	$ 1,020,408	0
Long-term notes receivables and other assets
RIC receivables, gross	137,884	143,065		114,556
Deferred interest	(29,612)	(34,164)		(36,049)
Security deposits	7,126	6,586		6,427
Investments	6,099	3,865		3,429
Other	299	467		360
Total long-term notes receivables and other assets, net	121,796	119,819	91,436	88,723
Accrued payroll and commissions
Accrued commissions	11,432	28,726		27,485
Accrued payroll	25,849	36,753		30,267
Total accrued payroll and commissions	37,281	65,479		57,752
Accrued expenses and other current liabilities
Accrued interest payable	55,157	28,885		28,737
Current portion of derivative liability	70,137	67,710		25,473
Service warranty accrual	8,825	8,813		0
Current portion of notes payable	8,100	8,100		0
Loss contingencies	2,131	3,131		2,156
Other	14,647	20,076		5,391
Total accrued expenses and other current liabilities	$ 158,997	$ 136,715	$ 84,650	$ 74,321

Property Plant and Equipment -

Property Plant and Equipment - Components of Property Plant and Equipment (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 151,785	$ 156,096	$ 139,211
Accumulated depreciation and amortization	(87,171)	(82,695)	(61,130)
Property, plant and equipment, net	64,614	73,401	78,081
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 44,594	$ 45,050	42,008
Vehicles | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years	3 years
Vehicles | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years	5 years
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 55,459	$ 53,891	46,651
Computer equipment and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years	3 years
Computer equipment and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 27,609	$ 26,401	20,783
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	2 years	2 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	15 years	15 years
Office furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 19,918	$ 19,532	17,202
Estimated Useful Lives	7 years	7 years
Build-to-suit lease building
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 0	$ 8,247	8,268
Estimated Useful Lives	10 years 6 months	10 years 6 months
Construction in process
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 4,205	$ 2,975	$ 4,299

Property Plant and Equipment _2

Property Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 151,785		$ 156,096	$ 139,211
Accumulated depreciation	87,171		82,695	61,130
Depreciation and amortization expense	5,900	$ 6,200	25,000	21,275	$ 16,800
Reduction in property, plant and equipment	(64,614)		(73,401)	(78,081)
Reduction in finance lease obligations	(11,066)
Assets Under Finance Lease Obligations
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	22,200		26,200
Accumulated depreciation	$ 23,200		22,200
Assets Under Capital Lease Obligations
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross			23,700	26,200
Accumulated depreciation			$ 22,200	$ 16,600
ASU 2016-02 adoption
Property, Plant and Equipment [Line Items]
Reduction in property, plant and equipment						$ 6,100
Accrued expenses and other current liabilities | ASU 2016-02 adoption
Property, Plant and Equipment [Line Items]
Reduction in finance lease obligations						$ 6,600

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 1,004,932	$ 1,003,240	$ 1,007,780
Accumulated Amortization	(769,972)	(748,778)	(662,205)
Definite-lived intangible assets, net carrying amount	234,960	254,462	345,575
Indefinite-lived intangible assets:	623	623	31,876
Total intangible assets, gross carrying amount	1,005,555	1,003,863	1,039,656
Total intangible assets, net carrying amount	235,583	255,085	377,451
Customer contracts
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	965,670	964,100	970,147
Accumulated Amortization	(737,443)	(717,648)	(637,780)
Definite-lived intangible assets, net carrying amount	$ 228,227	$ 246,452	332,367
Estimated useful lives of intangible asset	10 years	10 years
2GIG 2.0 technology
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 17,000	$ 17,000	17,000
Accumulated Amortization	(15,603)	(15,292)	(13,274)
Definite-lived intangible assets, net carrying amount	$ 1,397	$ 1,708	3,726
Estimated useful lives of intangible asset	8 years	8 years
Other technology
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 2,917	$ 2,917	2,917
Accumulated Amortization	(1,771)	(1,667)	(1,250)
Definite-lived intangible assets, net carrying amount	1,146	1,250	1,667
Space Monkey technology
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	7,100	7,100	7,100
Accumulated Amortization	(6,019)	(5,756)	(4,066)
Definite-lived intangible assets, net carrying amount	$ 1,081	$ 1,344	3,034
Estimated useful lives of intangible asset	6 years	6 years
Patents
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 12,245	$ 12,123	10,616
Accumulated Amortization	(9,136)	(8,415)	(5,835)
Definite-lived intangible assets, net carrying amount	$ 3,109	$ 3,708	4,781
Estimated useful lives of intangible asset	5 years	5 years
Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	5 years	5 years
Minimum | Other technology
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	5 years	5 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	10 years	10 years
Maximum | Other technology
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	7 years	7 years
IP addresses
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets:	$ 564	$ 564	564
Domain names
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets:	$ 59	$ 59	$ 59

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Future Amortization Expense (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2019 - Remaining Period	$ 59,216
2020	67,990	$ 67,807
2021	58,709	58,578
2022	48,759	48,674
2023	28	47
Thereafter	0	$ 11
Total estimated amortization expense	$ 234,702

Financial Instruments - Valuati

Financial Instruments - Valuation Approach Applied to Each Class of Security (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash	$ 3,599		$ 6,681	$ 3,866
Adjusted Cost	6,872		16,258	7,890
Unrealized Gains	2,212		0	0
Unrealized Losses	0		(304)	(1,315)
Fair Value	9,084		15,954	6,575
Cash and Cash Equivalents	3,691		12,773	3,872
Long-Term Notes Receivables and Other Assets, net	5,393		3,181	2,703
Available-for-sale securities, gross unrealized gain (loss)	2,200	$ 300	(300)	(1,300)	$ 1,000
Privately Held Company | Convertible Debt Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cost method investments	3,000
Level 1:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjusted Cost	3,273		9,577	4,024
Unrealized Gains	2,212		0	0
Unrealized Losses	0		(304)	(1,315)
Fair Value	5,485		9,273	2,709
Cash and Cash Equivalents	92		6,092	6
Long-Term Notes Receivables and Other Assets, net	5,393		3,181	2,703
Money market funds | Level 1:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjusted Cost	92		6,092	6
Unrealized Gains	0		0	0
Unrealized Losses	0		0	0
Fair Value	92		6,092	6
Cash and Cash Equivalents	92		6,092	6
Long-Term Notes Receivables and Other Assets, net	0		0	0
Corporate securities | Level 1:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjusted Cost	3,181		3,485	4,018
Unrealized Gains	2,212		0	0
Unrealized Losses	0		(304)	(1,315)
Fair Value	5,393		3,181	2,703
Cash and Cash Equivalents	0		0	0
Long-Term Notes Receivables and Other Assets, net	$ 5,393		$ 3,181	$ 2,703

Financial Instruments - Debt Fa

Financial Instruments - Debt Fair Value and Carrying Value (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2017	May 31, 2016	Oct. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 3,084,090,000	$ 3,045,195,000	$ 2,820,297,000
Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Long-term debt	3,055,249,000	3,057,274,000	2,769,465,000
Estimated Fair Value	$ 2,992,913,000	$ 2,889,616,000	2,893,547,000
Senior Notes
Debt Instrument [Line Items]
Stated Interest Rate		7.625%
Senior Notes | 8.75% Senior Notes Due 2020
Debt Instrument [Line Items]
Stated Interest Rate	8.75%	8.75%
Senior Notes | 8.75% Senior Notes Due 2020 | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Long-term debt	$ 679,299,000	$ 679,299,000
Estimated Fair Value	$ 669,110,000	$ 643,568,000
Senior Notes | 8.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Long-term debt			266,689,000
Stated Interest Rate	8.875%	8.875%				8.875%
Senior Notes | 8.875% Senior Secured Notes Due 2022 | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Long-term debt	$ 270,000,000	$ 270,000,000	270,000,000
Estimated Fair Value	$ 271,323,000	$ 257,073,000	276,486,000
Senior Notes | 7.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Long-term debt			908,526,000
Stated Interest Rate	7.875%	7.875%			7.875%
Senior Notes | 7.875% Senior Secured Notes Due 2022 | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Long-term debt	$ 900,000,000	$ 900,000,000	900,000,000
Estimated Fair Value	$ 904,410,000	$ 855,000,000	966,420,000
Senior Notes | 7.625% Senior Notes Due 2023
Debt Instrument [Line Items]
Long-term debt			395,238,000
Stated Interest Rate	7.625%	7.625%		7.625%
Senior Notes | 7.625% Senior Notes Due 2023 | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Long-term debt	$ 400,000,000	$ 400,000,000	400,000,000
Estimated Fair Value	342,120,000	326,000,000	425,000,000
Term Loan | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Long-term debt	805,950,000	807,975,000	0
Estimated Fair Value	$ 805,950,000	$ 807,975,000	$ 0

Financial Instruments - Derivat

Financial Instruments - Derivative Fair Value (Details) - Fair Value, Inputs, Level 2 - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, gross	$ 120,671	$ 117,620	$ 46,496
Derivative, notional amount	385,955	368,708	163,032
Accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, gross	70,137	67,710	25,473
Other long-term obligations
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, gross	$ 50,534	$ 49,910	$ 21,023

Financial Instruments - Level 3

Financial Instruments - Level 3 (Details) - Fair Value, Inputs, Level 3 - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	$ 117,620	$ 46,496	$ 0
Additions	16,480	93,095	44,913
Settlements	(14,856)	(34,587)	(7,972)
Losses included in earnings	1,427	12,616	9,555
Balance, end of period	$ 120,671	$ 117,620	$ 46,496

Income Taxes (Detail)

Income Taxes (Detail)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate, percentage	0.34%	0.51%

Commitments and Contingencies_2

Commitments and Contingencies (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments And Contingencies [Line Items]
Loss contingency accrual	$ 2.1		$ 3.1	$ 2.2
Operating leases, rent expense		$ 4.3	16.5	17	$ 16
Capital lease obligation			$ 13.3	$ 21.7
Vehicles
Commitments And Contingencies [Line Items]
Lease agreements term	36 months		36 months
Average remaining life for fleet	10 months		19 months

Leases - Components of Lease E

Leases - Components of Lease Expense (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating and finance leases, renewal term	10 years
Operating and finance leases, options to terminate lease, term	1 year
Operating lease cost	$ 4,298
Finance lease cost:
Amortization of right-of-use assets	1,376
Interest on lease liabilities	154
Total finance lease cost	$ 1,530
Minimum
Lessee, Lease, Description [Line Items]
Operating and finance leases, remaining lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating and finance leases, remaining lease term	9 years

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ (4,375)
Operating cash flows from finance leases	(154)
Financing cash flows from finance leases	(2,136)
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	584
Finance leases	$ 230

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets and Liabilities, Lessee [Abstract]
Operating lease right-of-use assets	$ 72,891	$ 0
Current operating lease liabilities	11,749	0
Operating lease liabilities	71,964	0
Total	83,713
Property, plant and equipment, gross	45,440
Accumulated depreciation	(23,205)
Property, plant and equipment, net	22,235
Current finance lease liabilities	7,114	7,743
Finance lease liabilities	3,952	$ 5,571
Total	$ 11,066
Operating leases, weighted average remaining lease term	7 years
Finance leases, weighted average remaining lease term	1 year 6 months
Operating leases, weighted average discount rate, percentage	7.00%
Finance leases, weighted average discount rate, percentage	4.00%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) $ in Thousands	Mar. 31, 2019USD ($)
Leases [Abstract]
Lessor, Operating Lease, Lease Not yet Commenced, Assumption and Judgment, Value of Underlying Asset, Description	$ 600
Operating Leases
2019 (excluding the three months ended March 31, 2019)	13,163
2020	16,345
2021	15,649
2022	14,514
2023	14,553
Thereafter	32,404
Total lease payments	106,628
Less imputed interest	(22,915)
Total	83,713
Finance Leases
2019 (excluding the three months ended March 31, 2019)	5,827
2020	5,167
2021	384
2022	38
2023	0
Thereafter	0
Total lease payments	11,416
Less imputed interest	(350)
Total	$ 11,066
Operating lease not yet commenced, term of contract (in years)	5 years

Employee Benefit Plan (Detail)

Employee Benefit Plan (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Postemployment Benefits [Abstract]
Employer matching contribution, percent of employees' gross pay	1.00%		1.00%
Employer matching contribution, amount for every employees' dollar contributed	$ 0.50		$ 0.50
Employer matching contribution, percent of employees' gross pay for 50% matching for every dollar contributed	5.00%		5.00%
Maximum annual contributions per employee, percent	3.50%		3.50%
Award vesting service period	2 years		2 years
Matching contributions to the plan	$ 1,900,000	$ 1,600,000	$ 6,000,000	$ 0	$ 0

Restructuring and Asset Impai_3

Restructuring and Asset Impairment Charges (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning balance	$ 809	$ 558	$ 649	$ 4,275
Cash-based restructuring charges		4,683
Cash payments	(280)	(4,432)	(91)	(2,798)
Accrued restructuring, ending balance	529	809	558	649
Contract termination costs
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning balance	467	558	649	3,954
Cash-based restructuring charges		0
Cash payments	(23)	(91)	(91)	(2,554)
Accrued restructuring, ending balance	444	467	558	649
Employee severance and termination benefits
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning balance	342	0	0	321
Cash-based restructuring charges		4,683	0	0
Cash payments	(257)	(4,341)	0	(244)
Accrued restructuring, ending balance	$ 85	$ 342	$ 0	$ 0

Segment Reporting and Busines_3

Segment Reporting and Business Concentrations (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019USD ($)regionsegment	Mar. 31, 2018USD ($)segment	Dec. 31, 2018Segment	Dec. 31, 2017Segment	Dec. 31, 2016Segment
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments	1	1	1	1	1
Number of geographic regions | region	2
Revenue from external customers	$ 276,249	$ 246,597
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from external customers	258,436	228,542
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from external customers	$ 17,813	$ 18,055

Guarantor and Non-Guarantor S_3

Guarantor and Non-Guarantor Supplemental Financial Information - Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Current assets	$ 168,442	$ 123,498			$ 175,965
Property, plant and equipment, net	64,614	73,401			78,081
Capitalized contract costs, net	1,092,865	1,115,775			0
Subscriber acquisition costs, net		0		$ 0	1,308,558
Deferred financing costs, net	1,797	2,058			3,099
Investment in subsidiaries	0	0
Intercompany receivable	0	0
Intangible assets, net	235,583	255,085			377,451
Goodwill	835,404	834,855			836,970	$ 835,233
Operating lease right-of-use assets	72,891	0
Long-term notes receivables and other assets, net	121,796	119,819		91,436	88,723
Total assets	2,593,392	2,524,491			2,868,847
LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY
Current liabilities	524,709	463,536			338,371
Intercompany payable	0	0
Notes payable and revolving credit facility, net of current portion	3,075,990	3,037,095			2,820,297
Finance lease liabilities	3,952	5,571
Deferred revenue, net of current portion	326,631	323,585		211,493	264,555
Operating lease liabilities	71,964	0
Other long-term obligations	73,390	90,209			79,020
Accumulated losses of investee, net	0	0
Deferred income tax liability	1,120	1,096		$ 3,400	9,041
Total stockholders’ deficit	(1,484,364)	(1,396,601)	$ (1,022,235)		(653,526)	$ (245,182)	$ (76,993)
Total liabilities and stockholders’ deficit	2,593,392	2,524,491			2,868,847
Capital lease obligations, net of current portion		5,571			11,089
Eliminations
ASSETS
Current assets	(289,784)	(262,674)			(162,413)
Property, plant and equipment, net	0	0			0
Capitalized contract costs, net	0	0
Subscriber acquisition costs, net					0
Deferred financing costs, net	0	0			0
Investment in subsidiaries	(1,650,064)	(1,662,367)			(2,188,221)
Intercompany receivable	(6,303)	(6,303)			(6,303)
Intangible assets, net	0	0			0
Goodwill	0	0			0
Operating lease right-of-use assets	0
Long-term notes receivables and other assets, net	(106)	(106)			(106)
Total assets	(1,946,257)	(1,931,450)			(2,357,043)
LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY
Current liabilities	(289,784)	(262,674)			(162,413)
Intercompany payable	(6,303)	(6,303)			(6,303)
Notes payable and revolving credit facility, net of current portion	0	0			0
Finance lease liabilities	0	0
Deferred revenue, net of current portion	0	0			0
Operating lease liabilities	0
Other long-term obligations	0	0			0
Accumulated losses of investee, net	(1,484,364)	(1,396,601)			(653,526)
Deferred income tax liability	(106)	(106)			(106)
Total stockholders’ deficit	(165,700)	(265,766)			(1,534,695)
Total liabilities and stockholders’ deficit	(1,946,257)	(1,931,450)			(2,357,043)
Capital lease obligations, net of current portion		0			0
Parent | Reportable Legal Entities
ASSETS
Current assets	0	0			0
Property, plant and equipment, net	0	0			0
Capitalized contract costs, net	0	0
Subscriber acquisition costs, net					0
Deferred financing costs, net	0	0			0
Investment in subsidiaries	0	0			0
Intercompany receivable	0	0			0
Intangible assets, net	0	0			0
Goodwill	0	0			0
Operating lease right-of-use assets	0
Long-term notes receivables and other assets, net	0	0			0
Total assets	0	0			0
LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY
Current liabilities	0	0			0
Intercompany payable	0	0			0
Notes payable and revolving credit facility, net of current portion	0	0			0
Finance lease liabilities	0	0
Deferred revenue, net of current portion	0	0			0
Operating lease liabilities	0
Other long-term obligations	0	0			0
Accumulated losses of investee, net	1,484,364	1,396,601			653,526
Deferred income tax liability	0	0			0
Total stockholders’ deficit	(1,484,364)	(1,396,601)			(653,526)
Total liabilities and stockholders’ deficit	0	0			0
Capital lease obligations, net of current portion		0			0
Guarantor Subsidiaries | Reportable Legal Entities
ASSETS
Current assets	335,398	269,770			284,293
Property, plant and equipment, net	64,188	72,937			77,345
Capitalized contract costs, net	1,027,364	1,047,532
Subscriber acquisition costs, net					1,214,678
Deferred financing costs, net	0	0			0
Investment in subsidiaries	0	0			0
Intercompany receivable	6,303	6,303			6,303
Intangible assets, net	218,194	236,677			350,710
Goodwill	809,678	809,678			809,678
Operating lease right-of-use assets	72,661
Long-term notes receivables and other assets, net	104,486	102,695			78,173
Total assets	2,638,272	2,545,592			2,821,180
LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY
Current liabilities	558,398	507,063			343,398
Intercompany payable	0	0			0
Notes payable and revolving credit facility, net of current portion	0	0			0
Finance lease liabilities	3,952	5,570
Deferred revenue, net of current portion	309,896	306,653			248,643
Operating lease liabilities	71,878
Other long-term obligations	73,043	90,209			79,020
Accumulated losses of investee, net
Deferred income tax liability	106	106			106
Total stockholders’ deficit	1,620,999	1,635,991			2,139,222
Total liabilities and stockholders’ deficit	2,638,272	2,545,592			2,821,180
Capital lease obligations, net of current portion		5,570			10,791
Non-Guarantor Subsidiaries | Reportable Legal Entities
ASSETS
Current assets	119,909	103,451			49,935
Property, plant and equipment, net	426	464			736
Capitalized contract costs, net	65,501	68,243
Subscriber acquisition costs, net					93,880
Deferred financing costs, net	0	0			0
Investment in subsidiaries	0	0			0
Intercompany receivable	0	0			0
Intangible assets, net	17,389	18,408			26,741
Goodwill	25,726	25,177			27,292
Operating lease right-of-use assets	230
Long-term notes receivables and other assets, net	17,310	17,124			10,550
Total assets	246,491	232,867			209,134
LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY
Current liabilities	192,835	182,159			128,581
Intercompany payable	6,303	6,303			6,303
Notes payable and revolving credit facility, net of current portion	0	0			0
Finance lease liabilities	0	1
Deferred revenue, net of current portion	16,735	16,932			15,912
Operating lease liabilities	86
Other long-term obligations	347	0			0
Accumulated losses of investee, net
Deferred income tax liability	1,120	1,096			9,041
Total stockholders’ deficit	29,065	26,376			48,999
Total liabilities and stockholders’ deficit	246,491	232,867			209,134
Capital lease obligations, net of current portion		1			298
APX Group, Inc. | Reportable Legal Entities
ASSETS
Current assets	2,919	12,951			4,150
Property, plant and equipment, net	0	0			0
Capitalized contract costs, net	0	0
Subscriber acquisition costs, net					0
Deferred financing costs, net	1,797	2,058			3,099
Investment in subsidiaries	1,650,064	1,662,367			2,188,221
Intercompany receivable	0	0			0
Intangible assets, net	0	0			0
Goodwill	0	0			0
Operating lease right-of-use assets	0
Long-term notes receivables and other assets, net	106	106			106
Total assets	1,654,886	1,677,482			2,195,576
LIABILITIES AND STOCKHOLDERS’ (DEFICIT) EQUITY
Current liabilities	63,260	36,988			28,805
Intercompany payable	0	0			0
Notes payable and revolving credit facility, net of current portion	3,075,990	3,037,095			2,820,297
Finance lease liabilities	0	0
Deferred revenue, net of current portion	0	0			0
Operating lease liabilities	0
Other long-term obligations	0	0			0
Accumulated losses of investee, net
Deferred income tax liability	0	0			0
Total stockholders’ deficit	(1,484,364)	(1,396,601)			(653,526)
Total liabilities and stockholders’ deficit	$ 1,654,886	1,677,482			2,195,576
Capital lease obligations, net of current portion		$ 0			$ 0

Guarantor and Non-Guarantor S_4

Guarantor and Non-Guarantor Supplemental Financial Information - Cash Flows (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Aug. 31, 2016	Apr. 30, 2016	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net cash (used in) provided by operating activities			$ (43,017)	$ (59,582)	$ (220,499)	$ (309,332)	$ (365,706)
Cash flows from investing activities:
Capital expenditures			(1,391)	(6,407)	(19,412)	(20,391)	(11,642)
Proceeds from sale of capital assets			(51)	149	127	776	3,123
Investment in subsidiary			0		0	0	0
Acquisition of intangible assets			(369)	(849)	(1,486)	(1,745)	(1,385)
Investment in subsidiary				0
Proceeds from the sale of intangible assets			0	53,693	53,693	0	0
Net cash (used in) provided by investing activities			(1,811)	46,586	32,922	(21,661)	(15,147)
Cash flows from financing activities:
Repayments of notes payable			(2,025)	0	(522,191)	(450,000)	(235,535)
Borrowings from revolving credit facility			40,000	57,000	201,000	196,895	57,000
Repayments on revolving credit facility			0	(40,000)	(261,000)	(136,895)	(77,000)
Proceeds from capital contribution	$ 30,600	$ 69,800	0	0	4,700	0	100,407
Repayments of capital lease obligations				(3,418)	(12,354)	(10,007)	(8,315)
Repayments of finance lease obligations			(2,136)
Return of capital			(118)	(966)	(3,129)	(1,151)	0
Net cash provided by financing activities			35,721	12,616	196,407	291,213	422,280
Effect of exchange rate changes on cash			25	(19)	71	132	(466)
Net decrease in cash and cash equivalents			(9,082)	(399)	8,901	(39,648)	40,961
Cash and cash equivalents:
Beginning of period			12,773	3,872	3,872	43,520	2,559
End of period			3,691	3,473	12,773	3,872	43,520
Reportable Legal Entities
Cash flows from financing activities:
Repayments of notes payable							0
Eliminations
Cash flows from operating activities:
Net cash (used in) provided by operating activities			0	0
Cash flows from investing activities:
Capital expenditures			0	0	0	0	0
Proceeds from sale of capital assets			0	0	0	0	0
Investment in subsidiary			46,605		202,863	324,071	508,621
Acquisition of intangible assets			0	0	0	0	0
Investment in subsidiary				15,484
Proceeds from the sale of intangible assets				0	0
Net cash (used in) provided by investing activities			46,605	15,484
Cash flows from financing activities:
Repayments of notes payable			0		0	0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			(46,369)	(17,416)	(209,121)	(326,373)	(100,407)
Repayments of capital lease obligations				0	0	0	0
Repayments of finance lease obligations			0
Return of capital			(236)	1,932
Net cash provided by financing activities			(46,605)	(15,484)
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			0	0	0	0	0
Cash and cash equivalents:
Beginning of period			0	0	0	0	0
End of period			0	0	0	0	0
Parent | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities			0	0
Cash flows from investing activities:
Capital expenditures			0	0	0	0	0
Proceeds from sale of capital assets			0	0	0	0	0
Investment in subsidiary			(118)		(1,571)	1,151	(100,407)
Acquisition of intangible assets			0	0	0	0	0
Investment in subsidiary				966
Proceeds from the sale of intangible assets				0	0
Net cash (used in) provided by investing activities			(118)	966
Cash flows from financing activities:
Repayments of notes payable			0		0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			0	0	4,700	0	100,407
Repayments of capital lease obligations				0	0	0	0
Repayments of finance lease obligations			0
Return of capital			118	(966)
Net cash provided by financing activities			118	(966)
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			0	0	0	0	0
Cash and cash equivalents:
Beginning of period			0	0	0	0	0
End of period			0	0	0	0	0
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities			(43,058)	(59,159)
Cash flows from investing activities:
Capital expenditures			(1,391)	(6,407)	(19,409)	(20,391)	(11,642)
Proceeds from sale of capital assets			(51)	149	127	776	3,080
Investment in subsidiary			0		0	0	0
Acquisition of intangible assets			(369)	(849)	(1,486)	(1,745)	(1,385)
Investment in subsidiary				0
Proceeds from the sale of intangible assets				53,693	53,693
Net cash (used in) provided by investing activities			(1,811)	46,586
Cash flows from financing activities:
Repayments of notes payable			0		0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			46,369	17,416	204,421	326,373	0
Repayments of capital lease obligations				(3,305)	(12,011)	(9,667)	(8,295)
Repayments of finance lease obligations			(2,064)
Return of capital			(118)	(966)
Net cash provided by financing activities			44,187	13,145
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			(682)	572	1,254	(18,758)	20,127
Cash and cash equivalents:
Beginning of period			682	(572)	(572)	18,186	(1,941)
End of period			0	0	682	(572)	18,186
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities			41	(423)
Cash flows from investing activities:
Capital expenditures			0	0	(3)	0	0
Proceeds from sale of capital assets			0	0	0	0	43
Investment in subsidiary			0		0	0	0
Acquisition of intangible assets			0	0	0	0	0
Investment in subsidiary				0
Proceeds from the sale of intangible assets				0	0
Net cash (used in) provided by investing activities			0	0
Cash flows from financing activities:
Repayments of notes payable			0		0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			0	0	0	0	0
Repayments of capital lease obligations				(113)	(343)	(340)	(20)
Repayments of finance lease obligations			(72)
Return of capital			0	0
Net cash provided by financing activities			(72)	(113)
Effect of exchange rate changes on cash			25	(19)	71	132	(466)
Net decrease in cash and cash equivalents			(6)	(555)	178	129	(1,547)
Cash and cash equivalents:
Beginning of period			961	783	783	654	2,201
End of period			955	228	961	783	654
APX Group, Inc. | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities			0	0
Cash flows from investing activities:
Capital expenditures			0	0	0	0	0
Proceeds from sale of capital assets			0	0	0	0	0
Investment in subsidiary			(46,487)		(201,292)	(325,222)	(408,214)
Acquisition of intangible assets			0	0	0	0	0
Investment in subsidiary				(16,450)
Proceeds from the sale of intangible assets				0	0
Net cash (used in) provided by investing activities			(46,487)	(16,450)
Cash flows from financing activities:
Repayments of notes payable			(2,025)		(522,191)	(450,000)	(235,535)
Borrowings from revolving credit facility			40,000	57,000	201,000	196,895	57,000
Repayments on revolving credit facility				(40,000)	(261,000)	(136,895)	(77,000)
Proceeds from capital contribution			0	0	4,700	0	100,407
Repayments of capital lease obligations				0	0	0	0
Repayments of finance lease obligations			0
Return of capital			118	(966)
Net cash provided by financing activities			38,093	16,034
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			(8,394)	(416)	7,469	(21,019)	22,381
Cash and cash equivalents:
Beginning of period			11,130	3,661	3,661	24,680	2,299
End of period			$ 2,736	$ 3,245	$ 11,130	$ 3,661	$ 24,680

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2019USD ($)payment	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)payment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2015USD ($)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Accounts receivable	$ 20,000,000		$ 16,500,000	$ 24,300,000
Allowance for doubtful accounts	5,808,000		5,594,000	5,356,000	$ 4,138,000		$ 3,541,000
Provision for doubtful accounts	$ 5,918,000	$ 3,968,000	$ 19,405,000	22,465,000	19,624,000
Capitalized contract cost, amortization period	5 years		5 years
Intangible assets, impairment loss			$ 0		0
Long lived asset impairment			0	0	0
Equity securities			3,900,000	3,400,000
Equity securities without readily determinable fair value, amount			700,000	700,000
Equity securities without readily determinable fair value, impairment loss			0
Amortization of deferred financing costs and bond premiums and discounts	$ 1,180,000	1,343,000	5,152,000	6,586,000	10,447,000
Sales commission included in accrued expenses and other liabilities	3,100,000		4,900,000	3,300,000
Other long-term obligations	16,800,000		17,600,000	18,500,000
Advertising expenses incurred	12,700,000	13,700,000	47,200,000	42,500,000	33,000,000
Goodwill, impairment loss			0	0	0
Intercompany translation gains (losses)			(7,100,000)	4,900,000	2,100,000
Issued and unused letters of credit	13,900,000		13,800,000	9,500,000
Other (income) loss, net	$ (2,246,000)	(45,240,000)	(17,323,000)	27,986,000	7,255,000
Previously Reported [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Allowance for doubtful accounts			5,594,000
Sales commission included in accrued expenses and other liabilities			4,500,000
Other long-term obligations			$ 13,000,000
SkyControl Panels
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of installed panels			80.00%
2GIG Sale
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of installed panels	17.00%		19.00%
Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	5 years		5 years
Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	10 years		10 years
Interest Expense
Basis Of Presentation And Significant Accounting Policies [Line Items]
Amortization of deferred financing costs and bond premiums and discounts	$ 2,500,000	$ 2,700,000	$ 10,400,000	11,400,000	$ 11,600,000
Notes Payable
Basis Of Presentation And Significant Accounting Policies [Line Items]
Deferred financing cost, net	30,100,000		32,400,000	35,700,000
Deferred financing cost, accumulated amortization	56,800,000		54,600,000	45,200,000
Revolving Credit Facility
Basis Of Presentation And Significant Accounting Policies [Line Items]
Issued and unused letters of credit	249,700,000		289,800,000
Revolving Credit Facility | Line of Credit
Basis Of Presentation And Significant Accounting Policies [Line Items]
Deferred financing cost, net	1,800,000		2,100,000
Deferred financing cost, accumulated amortization	$ 9,900,000		9,600,000	$ 8,600,000
Revolving Credit Facility | Line of Credit | Previously Reported [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Deferred financing cost, net			$ 2,058,000
Vivint Flex Pay
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of payment options | payment	3		3
Installment loans available to qualified customers, maximum amount provided by third party	$ 4,000		$ 4,000
Vivint Flex Pay | Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Installment loans available to qualified customers, term of loan	42 months		42 months
Vivint Flex Pay | Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Installment loans available to qualified customers, term of loan	60 months		60 months
ASU 2016-01 adoption
Basis Of Presentation And Significant Accounting Policies [Line Items]
New accounting pronouncement, cumulative effect of change on accumulated deficit						$ 700,000
Other (income) loss, net			$ 300,000

Significant Accounting Polici_4

Significant Accounting Policies - Depreciation and Amortization (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Amortization of capitalized contract costs	$ 105,031	$ 95,363	$ 398,174	$ 0	$ 0
Total depreciation and amortization	131,221	124,258	514,082	329,255	288,542
Depreciation of property, plant and equipment
Property, Plant and Equipment [Line Items]
Total depreciation and amortization	5,921	6,175	24,963	21,275	16,800
Amortization of subscriber acquisition costs
Property, Plant and Equipment [Line Items]
Total depreciation and amortization			0	206,153	154,877
Amortization of definite-lived intangibles
Property, Plant and Equipment [Line Items]
Total depreciation and amortization	$ 20,272	$ 22,720	$ 90,945	$ 101,827	$ 116,865

Revenue and Capitalized Contr_5

Revenue and Capitalized Contract Costs - Impact of New Accounting Pronouncement on Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract costs, net	$ 1,092,865	$ 1,115,775	$ 1,020,408	$ 0
Subscriber acquisition costs, net		0	0	1,308,558
Long-term notes receivables and other assets, net	121,796	119,819	91,436	88,723
Accrued expenses and other current liabilities	158,997	136,715	84,650	74,321
Deferred revenue	194,326	186,953	128,205	88,337
Deferred revenue, net of current portion	326,631	323,585	211,493	264,555
Deferred income tax liabilities	1,120	1,096	3,400	9,041
Accumulated deficit	(2,193,169)	(2,104,097)	$ (1,635,502)	(1,358,571)
Accumulated other comprehensive loss	$ (28,267)	(28,837)		(27,301)
Restatement Adjustment | ASU 2014-09 adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract costs, net				1,020,408
Subscriber acquisition costs, net				(1,308,558)
Long-term notes receivables and other assets, net				2,713
Accrued expenses and other current liabilities				10,329
Deferred revenue				39,868
Deferred revenue, net of current portion				(53,062)
Deferred income tax liabilities				(5,641)
Accumulated deficit				(276,931)
Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract costs, net				0
Subscriber acquisition costs, net				1,308,558
Long-term notes receivables and other assets, net				88,723
Accrued expenses and other current liabilities				74,321
Deferred revenue				88,337
Deferred revenue, net of current portion				264,555
Deferred income tax liabilities				9,041
Accumulated deficit				$ (1,358,571)
Calculated under Revenue Guidance in Effect before Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract costs, net		0
Subscriber acquisition costs, net		1,518,188
Accrued expenses and other current liabilities		126,900
Deferred revenue		126,582
Deferred revenue, net of current portion		440,474
Deferred income tax liabilities		8,682
Accumulated deficit		(1,754,426)
Accumulated other comprehensive loss		(30,384)
Difference between Revenue Guidance in Effect before and after Topic 606 | ASU 2014-09 adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract costs, net		1,115,775
Subscriber acquisition costs, net		(1,518,188)
Accrued expenses and other current liabilities		9,815
Deferred revenue		60,371
Deferred revenue, net of current portion		(116,889)
Deferred income tax liabilities		(7,586)
Accumulated deficit		(349,671)
Accumulated other comprehensive loss		$ 1,547

Revenue and Capitalized Contr_6

Revenue and Capitalized Contract Costs - Impact of New Accounting Pronouncement On Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:	$ 276,249	$ 246,597	$ 1,050,441	$ 881,983	$ 757,907
Operating expenses (exclusive of depreciation and amortization shown separately below)	83,076	83,760	355,813	321,476	264,865
Depreciation and amortization	131,221	124,258	514,082	329,255	288,542
Loss from operations	(27,978)	(71,631)	(242,059)	(155,493)	(71,102)
Income tax (benefit) expense	(301)	(433)	(1,611)	1,078	67
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Foreign currency translation adjustment	570	(659)	(2,218)	3,155	2,482
Total other comprehensive (loss) income	570	(659)	(2,218)	1,462	3,493
Comprehensive loss	(88,586)	(85,376)	(470,132)	(408,737)	(272,464)
Recurring and other revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:	$ 276,249	$ 246,597	1,050,441	843,420	724,478
Service and other sales revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			0	26,988	22,855
Activation fees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			0	$ 11,575	$ 10,574
Calculated under Revenue Guidance in Effect before Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			1,006,543
Operating expenses (exclusive of depreciation and amortization shown separately below)			385,672
Depreciation and amortization			367,879
Loss from operations			(169,613)
Income tax (benefit) expense			806
Net loss			(397,885)
Foreign currency translation adjustment			(3,765)
Total other comprehensive (loss) income			(3,765)
Comprehensive loss			(401,650)
Calculated under Revenue Guidance in Effect before Topic 606 | Recurring and other revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			950,661
Calculated under Revenue Guidance in Effect before Topic 606 | Service and other sales revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			46,177
Calculated under Revenue Guidance in Effect before Topic 606 | Activation fees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			9,705
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			43,898
Operating expenses (exclusive of depreciation and amortization shown separately below)			(29,859)
Depreciation and amortization			146,203
Loss from operations			(72,446)
Income tax (benefit) expense			(2,417)
Net loss			(70,029)
Foreign currency translation adjustment			1,547
Total other comprehensive (loss) income			1,547
Comprehensive loss			(68,482)
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09 | Recurring and other revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			99,780
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09 | Service and other sales revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			(46,177)
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09 | Activation fees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues:			$ (9,705)

Revenue and Capitalized Contr_7

Revenue and Capitalized Contract Costs - Impact of New Accounting Pronouncement On Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	$ (89,156)	$ (84,717)	$ (467,914)	$ (410,199)	$ (275,957)
Amortization of capitalized contract costs	105,031	95,363	398,174	0	0
Amortization of subscriber acquisition costs			0	206,153	154,877
Capitalized contract costs – deferred contract costs	(80,614)	(84,986)	(499,252)	0	0
Subscriber acquisition costs – deferred contract costs			0	(457,679)	(419,509)
Accrued expenses and other current liabilities	(8,113)	30,252	91,469	62,208	12,702
Deferred revenue	9,820	33,793	172,905	247,500	24,613
Net cash used in operating activities	$ (43,017)	$ (59,582)	(220,499)	$ (309,332)	$ (365,706)
Calculated under Revenue Guidance in Effect before Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net loss			(397,885)
Amortization of capitalized contract costs			0
Amortization of subscriber acquisition costs			251,971
Capitalized contract costs – deferred contract costs			0
Subscriber acquisition costs – deferred contract costs			(469,393)
Accrued expenses and other current liabilities			93,886
Deferred revenue			216,803
Net cash used in operating activities			(220,499)
Difference between Revenue Guidance in Effect before and after Topic 606 | ASU 2014-09 adoption
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net loss			(70,029)
Amortization of capitalized contract costs			398,174
Amortization of subscriber acquisition costs			(251,971)
Capitalized contract costs – deferred contract costs			(499,252)
Subscriber acquisition costs – deferred contract costs			469,393
Accrued expenses and other current liabilities			(2,417)
Deferred revenue			(43,898)
Net cash used in operating activities			$ 0

Revenue and Capitalized Contr_8

Revenue and Capitalized Contract Costs - Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue recognized that were included in deferred revenue	$ 86.4	$ 59.8		$ 144.1
Revenue expected to be recognized from remaining performance obligations for subscription contracts	$ 2,200		$ 2,200
Capitalized contract cost, amortization period	5 years		5 years
Expected life of customers			15 years
Depreciation rate using declining balance method (percentage)			2.4
Minimum | Subscriber Contracts
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, term	3 years
Maximum | Subscriber Contracts
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, term	5 years

Long-Term Debt - Other Expense

Long-Term Debt - Other Expense and Loss on Extinguishment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Previously deferred financing costs extinguished	$ 0	$ 4,207	$ 4,667
New financing costs		(9,302)	(11,119)	$ (9,241)
Senior Notes
Debt Instrument [Line Items]
Original premium extinguished			0
Previously deferred financing costs extinguished			4,667
New financing costs			18,372
Total other expense and loss on extinguishment			23,039
Previously deferred financing rolled over			1,949
New deferred financing costs			10,645
Total deferred financing costs			12,594
Senior Notes | 7.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Previously deferred financing costs extinguished	$ 0	0	0
Term Loan | Senior Notes | 6.375% Senior Secured Notes due 2019
Debt Instrument [Line Items]
Original premium extinguished		(953)
Previously deferred financing costs extinguished		4,207
New financing costs		11,317
Total other expense and loss on extinguishment		14,571
Previously deferred financing rolled over		0
New deferred financing costs		10,275
Total deferred financing costs		$ 10,275
August 2017 Issuance of 7.625 Notes Due 2023 | Senior Notes | 6.375% Senior Secured Notes due 2019
Debt Instrument [Line Items]
Original premium extinguished			0
Previously deferred financing costs extinguished			1,408
New financing costs			8,881
Total other expense and loss on extinguishment			10,289
Previously deferred financing rolled over			473
New deferred financing costs			4,569
Total deferred financing costs			5,042
February 2017 Issuance of 7.875% Notes Due 2022 | Senior Notes | 6.375% Senior Secured Notes due 2019
Debt Instrument [Line Items]
Original premium extinguished			0
Previously deferred financing costs extinguished			3,259
New financing costs			9,491
Total other expense and loss on extinguishment			12,750
Previously deferred financing rolled over			1,476
New deferred financing costs			6,076
Total deferred financing costs			$ 7,552
May 2016 Issuance of 7.875% Senior Secured Notes Due 2022 | Senior Notes | 7.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Original premium extinguished				355
Previously deferred financing costs extinguished				695
New financing costs				9,036
Total other expense and loss on extinguishment				10,086
Previously deferred financing rolled over				3,423
New deferred financing costs				6,628
Total deferred financing costs				$ 10,051

Long-Term Debt - Deferred Finan

Long-Term Debt - Deferred Financing Activity (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Financing Activity [Roll Forward]
Beginning balance	$ 34,423	$ 38,766	$ 43,783
Additions	0	10,275	11,044
Refinances		0	0
Early Extinguishment	0	(4,207)	(4,667)
Amortized	(2,487)	(10,411)	(11,394)
Ending balance	31,936	34,423	38,766
Senior Notes
Deferred Financing Activity [Roll Forward]
Early Extinguishment			(4,667)
Senior Notes | 6.375% Senior Secured Notes Due 2019
Deferred Financing Activity [Roll Forward]
Beginning balance	0	2,877	11,693
Additions		0	0
Refinances		0	(1,949)
Early Extinguishment		(1,877)	(4,667)
Amortized		(1,000)	(2,200)
Ending balance		0	2,877
Senior Notes | 8.75% Senior Notes Due 2020
Deferred Financing Activity [Roll Forward]
Beginning balance	5,380	11,209	15,053
Additions	0	0	0
Refinances		0	0
Early Extinguishment	0	(2,330)	0
Amortized	(702)	(3,499)	(3,844)
Ending balance	4,678	5,380	11,209
Senior Notes | 8.875% Senior Secured Notes Due 2022
Deferred Financing Activity [Roll Forward]
Beginning balance	602	752	903
Additions	0	0	0
Refinances		0	0
Early Extinguishment	0	0	0
Amortized	(38)	(150)	(151)
Ending balance	564	602	752
Senior Notes | 7.875% Senior Secured Notes Due 2022
Deferred Financing Activity [Roll Forward]
Beginning balance	12,799	16,067	11,714
Additions	0	0	6,076
Refinances		0	1,476
Early Extinguishment	0	0	0
Amortized	(816)	(3,268)	(3,199)
Ending balance	11,983	12,799	16,067
Senior Notes | 7.625% Senior Notes Due 2023
Deferred Financing Activity [Roll Forward]
Beginning balance	3,922	4,762	0
Additions	0	0	4,569
Refinances		0	473
Early Extinguishment	0	0	0
Amortized	(210)	(840)	(280)
Ending balance	3,712	3,922	4,762
Term Loan | Term Loan
Deferred Financing Activity [Roll Forward]
Beginning balance	9,662	0
Additions		10,275
Refinances		0
Early Extinguishment	0	0
Amortized	(460)	(613)
Ending balance	9,202	9,662	0
Revolving Credit Facility | Line of Credit
Deferred Financing Activity [Roll Forward]
Beginning balance	2,058	3,099	4,420
Additions	0	0	399
Refinances		0	0
Early Extinguishment	0	0	0
Amortized	(261)	(1,041)	(1,720)
Ending balance	$ 1,797	$ 2,058	$ 3,099

Long-Term Debt - Revolving Cred

Long-Term Debt - Revolving Credit Facility (Details) - USD ($)	Nov. 16, 2012	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 10, 2017	Mar. 06, 2015
Debt Instrument [Line Items]
Issued and unused letters of credit		$ 13,900,000	$ 13,800,000	$ 9,500,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, aggregate principal amount	$ 200,000,000				$ 324,300,000	$ 289,400,000
Debt instrument, term	5 years
Step down margin percentage		0.25%	0.25%
Commitment fee, step down percentage			0.125%
Outstanding borrowings			$ 0	$ 3,000,000
Issued and unused letters of credit		$ 249,700,000	$ 289,800,000
Revolving Credit Facility | Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage		0.50%	0.50%
Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage		1.00%	1.00%
Revolving Credit Facility | Series A- Revolving Commitments
Debt Instrument [Line Items]
Credit facility, aggregate principal amount		$ 267,000,000	$ 267,000,000
Revolving Credit Facility | Series A- Revolving Commitments | LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage		3.00%	3.00%
Revolving Credit Facility | Series A- Revolving Commitments | Base Rate-based Borrowings
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage		2.00%	2.00%
Revolving Credit Facility | Series B- Revolving Commitments
Debt Instrument [Line Items]
Credit facility, aggregate principal amount		$ 21,200,000	$ 21,200,000
Revolving Credit Facility | Series B- Revolving Commitments | LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage		4.00%	4.00%
Revolving Credit Facility | Series B- Revolving Commitments | Base Rate-based Borrowings
Debt Instrument [Line Items]
Basis spread on variable interest rate percentage		3.00%	3.00%
Revolving Credit Facility | Series D- Revolving Commitments
Debt Instrument [Line Items]
Credit facility, aggregate principal amount			$ 15,400,000
Revolving Credit Facility | Series C- Revolving Commitments
Debt Instrument [Line Items]
Credit facility, aggregate principal amount			$ 20,800,000

Long-Term Debt - Summary of Deb

Long-Term Debt - Summary of Debt (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2017	May 31, 2016	Oct. 31, 2015	Nov. 16, 2012
Debt Instrument [Line Items]
Outstanding Principal, excluding current maturities	$ 3,087,149,000	$ 3,049,174,000
Outstanding Principal, including current maturities	3,095,249,000	3,057,274,000	$ 2,829,465,000
Unamortized Premium (Discount)	18,980,000	20,286,000	26,499,000
Unamortized Deferred Financing Costs	(30,139,000)	(32,365,000)	(35,667,000)
Net Carrying Amount, noncurrent	3,075,990,000	3,037,095,000	2,820,297,000
Net Carrying Amount	3,084,090,000	$ 3,045,195,000	2,820,297,000
Senior Notes
Debt Instrument [Line Items]
Debt instrument interest rate, percentage		7.625%
Senior Notes | 8.75% Senior Notes due 2020
Debt Instrument [Line Items]
Outstanding Principal, excluding current maturities	679,299,000	$ 679,299,000
Outstanding Principal, including current maturities			930,000,000
Unamortized Premium (Discount)	1,958,000	2,230,000	4,465,000
Unamortized Deferred Financing Costs	(4,678,000)	(5,380,000)	(11,209,000)
Net Carrying Amount, noncurrent	$ 676,579,000	$ 676,149,000
Net Carrying Amount			923,256,000
Debt instrument interest rate, percentage	8.875%	8.75%					8.75%
Senior Notes | 8.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Outstanding Principal, excluding current maturities	$ 270,000,000	$ 270,000,000
Outstanding Principal, including current maturities			270,000,000
Unamortized Premium (Discount)	(2,006,000)	(2,122,000)	(2,559,000)
Unamortized Deferred Financing Costs	(564,000)	(602,000)	(752,000)
Net Carrying Amount, noncurrent	$ 267,430,000	$ 267,276,000
Net Carrying Amount			266,689,000
Debt instrument interest rate, percentage	8.875%	8.875%				8.875%
Senior Notes | 7.875% Senior Secured Notes Due 2022
Debt Instrument [Line Items]
Outstanding Principal, excluding current maturities	$ 900,000,000	$ 900,000,000
Outstanding Principal, including current maturities			900,000,000
Unamortized Premium (Discount)	19,028,000	20,178,000	24,593,000
Unamortized Deferred Financing Costs	(11,983,000)	(12,799,000)	(16,067,000)
Net Carrying Amount, noncurrent	$ 907,045,000	$ 907,379,000
Net Carrying Amount			908,526,000
Debt instrument interest rate, percentage	7.875%	7.875%			7.875%
Senior Notes | 7.625% Senior Notes Due 2023
Debt Instrument [Line Items]
Outstanding Principal, excluding current maturities	$ 400,000,000	$ 400,000,000
Outstanding Principal, including current maturities			400,000,000
Unamortized Premium (Discount)	0	0	0
Unamortized Deferred Financing Costs	(3,712,000)	(3,922,000)	(4,762,000)
Net Carrying Amount, noncurrent	$ 396,288,000	$ 396,078,000
Net Carrying Amount			395,238,000
Debt instrument interest rate, percentage	7.625%	7.625%		7.625%
Senior Notes | 6.375% Senior Secured Notes due 2019
Debt Instrument [Line Items]
Outstanding Principal, including current maturities			269,465,000
Unamortized Premium (Discount)			0
Unamortized Deferred Financing Costs			(2,877,000)
Net Carrying Amount			266,588,000
Debt instrument interest rate, percentage		6.375%					6.375%
Senior Notes | Senior Secured Revolving Credit Facilities
Debt Instrument [Line Items]
Outstanding Principal, excluding current maturities	$ 40,000,000
Unamortized Premium (Discount)	0
Unamortized Deferred Financing Costs	0
Net Carrying Amount, noncurrent	40,000,000
Term Loan | Term Loan
Debt Instrument [Line Items]
Outstanding Principal, excluding current maturities	797,850,000	$ 799,875,000
Unamortized Premium (Discount)	0	0
Unamortized Deferred Financing Costs	(9,202,000)	(9,662,000)
Net Carrying Amount, noncurrent	788,648,000	790,213,000
Outstanding Principal, current maturities	8,100,000	8,100,000
Revolving Credit Facility
Debt Instrument [Line Items]
Net Carrying Amount	40,000,000	0
Deferred financing costs, net	$ 1,800,000	$ 2,100,000	3,100,000
Revolving Credit Facility | Series D Revolving Credit Facility due 2019
Debt Instrument [Line Items]
Outstanding Principal, including current maturities			3,000,000
Unamortized Premium (Discount)			0
Unamortized Deferred Financing Costs			0
Net Carrying Amount			3,000,000
Revolving Credit Facility | Series A, B Revolving Credit Facilities due 2021
Debt Instrument [Line Items]
Outstanding Principal, including current maturities			57,000,000
Unamortized Premium (Discount)			0
Unamortized Deferred Financing Costs			0
Net Carrying Amount			$ 57,000,000

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Balance Sheet Component Balances (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Prepaid expenses	$ 12,984	$ 7,183		$ 8,000
Deposits	1,353	904		1,596
Other	791	3,362		6,554
Total prepaid expenses and other current assets	15,128	11,449		16,150
Capitalized contract costs
Capitalized contract costs	2,445,784	2,361,795		0
Accumulated amortization	(1,352,919)	(1,246,020)		0
Capitalized contract costs, net	1,092,865	1,115,775	$ 1,020,408	0
Subscriber acquisition costs
Subscriber acquisition costs		0		1,837,388
Accumulated amortization		0		(528,830)
Subscriber acquisition costs, net		0	0	1,308,558
Long-term notes receivables and other assets
RIC receivables, gross	137,884	143,065		114,556
Deferred interest	(29,612)	(34,164)		(36,049)
Security deposits	7,126	6,586		6,427
Investments	6,099	3,865		3,429
Other	299	467		360
Total long-term notes receivables and other assets, net	121,796	119,819	91,436	88,723
Accrued payroll and commissions
Accrued payroll	25,849	36,753		30,267
Accrued commissions	11,432	28,726		27,485
Total accrued payroll and commissions	37,281	65,479		57,752
Accrued expenses and other current liabilities
Accrued interest payable	55,157	28,885		28,737
Current portion of derivative liability	70,137	67,710		25,473
Service warranty accrual	8,825	8,813		0
Current portion of notes payable	8,100	8,100		0
Blackstone monitoring fee, a related party	1,000	4,793		933
Accrued taxes		5,351		4,585
Spectrum license obligation		0		3,861
Accrued payroll taxes and withholdings		5,097		3,185
Loss contingencies	2,131	3,131		2,156
Other	14,647	20,076		5,391
Total accrued expenses and other current liabilities	$ 158,997	136,715	$ 84,650	$ 74,321
Previously Reported [Member]
Accrued expenses and other current liabilities
Other		$ 4,835

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill beginning balance	$ 836,970	$ 835,233
Effect of Foreign Currency Translation	(2,115)	1,737
Goodwill ending balance	$ 834,855	$ 836,970

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Additional Information (Detail) $ in Thousands	Jan. 10, 2018USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)market	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)market
Finite-Lived Intangible Assets [Line Items]
Proceeds from the sale of intangible assets		$ 0	$ 53,693	$ 53,693	$ 0	$ 0
Amortization expense related to intangible assets		$ 20,300	22,700	$ 90,900	101,800	116,900
Definite-lived intangible assets, remaining amortization period		4 years		3 years 10 months 10 days
Finite-lived patents, gross		$ 300		$ 300
Goodwill		$ 835,404		$ 834,855	836,970	$ 835,233
Spectrum Licenses
Finite-Lived Intangible Assets [Line Items]
Number of mid-sized metropolitan markets | market				40		40
Indefinite-lived Intangible Assets Acquired						$ 31,300
Lease agreements term						7 years
Patents
Finite-Lived Intangible Assets [Line Items]
Acquisition of intangible assets				$ 1,700	$ 2,000
Spectrum Leases | Verizon | Spectrum Licenses
Finite-Lived Intangible Assets [Line Items]
Proceeds from the sale of intangible assets	$ 55,000		55,000
Extinguishment of debt, amount	(27,900)		(27,900)
Indefinite-lived intangible assets, written off related to sale of business unit	31,300		31,300
Indefinite-lived intangible assets, regulatory costs	1,300		1,200
Net gain (loss) on disposal	$ 50,400		$ 50,400

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Schedule of Intangible Asset Balances (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 1,004,932	$ 1,003,240	$ 1,007,780
Accumulated Amortization	(769,972)	(748,778)	(662,205)
Definite-lived intangible assets, net carrying amount	234,960	254,462	345,575
Indefinite-lived intangible assets:	623	623	31,876
Total intangible assets, gross carrying amount	1,005,555	1,003,863	1,039,656
Total intangible assets, net carrying amount	$ 235,583	$ 255,085	377,451
Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	5 years	5 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	10 years	10 years
Spectrum Licenses
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets:		$ 0	31,253
IP addresses
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets:	$ 564	564	564
Domain names
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets:	59	59	59
Customer contracts
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	965,670	964,100	970,147
Accumulated Amortization	(737,443)	(717,648)	(637,780)
Definite-lived intangible assets, net carrying amount	$ 228,227	$ 246,452	332,367
Estimated useful lives of intangible asset	10 years	10 years
2GIG 2.0 technology
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 17,000	$ 17,000	17,000
Accumulated Amortization	(15,603)	(15,292)	(13,274)
Definite-lived intangible assets, net carrying amount	$ 1,397	$ 1,708	3,726
Estimated useful lives of intangible asset	8 years	8 years
Other technology
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 2,917	$ 2,917	2,917
Accumulated Amortization	(1,771)	(1,667)	(1,250)
Definite-lived intangible assets, net carrying amount	$ 1,146	$ 1,250	1,667
Other technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	5 years	5 years
Other technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible asset	7 years	7 years
Space Monkey technology
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 7,100	$ 7,100	7,100
Accumulated Amortization	(6,019)	(5,756)	(4,066)
Definite-lived intangible assets, net carrying amount	$ 1,081	$ 1,344	3,034
Estimated useful lives of intangible asset	6 years	6 years
Patents
Finite-Lived Intangible Assets [Line Items]
Definite-lived intangible assets, gross carrying amount	$ 12,245	$ 12,123	10,616
Accumulated Amortization	(9,136)	(8,415)	(5,835)
Definite-lived intangible assets, net carrying amount	$ 3,109	$ 3,708	$ 4,781
Estimated useful lives of intangible asset	5 years	5 years

Goodwill and Intangible Asset_7

Goodwill and Intangible Assets - Schedule of Estimated Future Amortization Expense of Intangible Assets Excluding Patents Currently in Process (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2019		$ 79,062
2020	$ 67,990	67,807
2021	58,709	58,578
2022	48,759	48,674
2023	28	47
Thereafter	$ 0	11
Total estimated amortization expense		$ 254,179

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, gross unrealized gain (loss)	$ 2.2	$ 0.3	$ (0.3)	$ (1.3)	$ 1
Available-for-sale securities adjustment, net of tax				$ (0.3)
Convertible Debt Securities | Privately Held Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			$ 3

Financial Instruments - Compone

Financial Instruments - Components of Long-Term Debt Including Associated Interest Rates and Related Fair Values (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2017	May 31, 2016	Oct. 31, 2015	Nov. 16, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value	$ 3,084,090,000	$ 3,045,195,000	$ 2,820,297,000
Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated Interest Rate		7.625%
Senior Notes | 6.375% Senior Secured Notes Due 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value			266,588,000
Stated Interest Rate		6.375%					6.375%
Senior Notes | 8.75% Senior Notes Due 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value			923,256,000
Stated Interest Rate	8.875%	8.75%					8.75%
Senior Notes | 8.875% Senior Secured Notes Due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value			266,689,000
Stated Interest Rate	8.875%	8.875%				8.875%
Senior Notes | 7.875% Senior Secured Notes Due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value			908,526,000
Stated Interest Rate	7.875%	7.875%			7.875%
Senior Notes | 7.625% Senior Notes Due 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value			395,238,000
Stated Interest Rate	7.625%	7.625%		7.625%
Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value	$ 3,055,249,000	$ 3,057,274,000	2,769,465,000
Estimated Fair Value	2,992,913,000	2,889,616,000	2,893,547,000
Fair Value, Inputs, Level 2 | Senior Notes | 6.375% Senior Secured Notes Due 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value		0	269,465,000
Estimated Fair Value		0	273,507,000
Fair Value, Inputs, Level 2 | Senior Notes | 8.75% Senior Notes Due 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value		679,299,000	930,000,000
Estimated Fair Value		643,568,000	952,134,000
Fair Value, Inputs, Level 2 | Senior Notes | 8.875% Senior Secured Notes Due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value	270,000,000	270,000,000	270,000,000
Estimated Fair Value	271,323,000	257,073,000	276,486,000
Fair Value, Inputs, Level 2 | Senior Notes | 7.875% Senior Secured Notes Due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value	900,000,000	900,000,000	900,000,000
Estimated Fair Value	904,410,000	855,000,000	966,420,000
Fair Value, Inputs, Level 2 | Senior Notes | 7.625% Senior Notes Due 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value	400,000,000	400,000,000	400,000,000
Estimated Fair Value	342,120,000	326,000,000	425,000,000
Fair Value, Inputs, Level 2 | Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face Value	805,950,000	807,975,000	0
Estimated Fair Value	$ 805,950,000	$ 807,975,000	$ 0

Restructuring and Asset Impai_4

Restructuring and Asset Impairment Charges - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Cash-based restructuring charges	$ 4,683
Loss on contract termination	5,500
Wireless restructuring costs	400
Restructuring reserve, noncurrent	400
Employee severance and termination benefits
Restructuring Cost and Reserve [Line Items]
Cash-based restructuring charges	$ 4,683	$ 0	$ 0
Subscriber Contracts In New Zealand And Puerto Rico
Restructuring Cost and Reserve [Line Items]
Amortization of subscriber acquisition costs			7,600
Loss on translation adjustment			1,100
Proceeds from sale of contracts			6,200
Net loss on disposal			$ 2,600

Restructuring and Asset Impai_5

Restructuring and Asset Impairment Charges - Summary of Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring, settlement and impairment provisions	$ 4,683	$ 0	$ 1,013
Restructuring expenses	4,683
Wireless Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring, settlement and impairment provisions	0	0	(1,538)
Subscriber Contracts
Restructuring Cost and Reserve [Line Items]
Restructuring, settlement and impairment provisions	0	0	2,551
Other Restructuring | Wireless Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring, settlement and impairment provisions	0	0	(710)
Contract termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0
Contract termination costs | Wireless Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring, settlement and impairment provisions	0	0	(751)
Employee severance and termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	4,683	0	0
Employee severance and termination benefits | Wireless Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring, settlement and impairment provisions	$ 0	$ 0	$ (77)

Restructuring and Asset Impai_6

Restructuring and Asset Impairment Charges - Summary of Restructuring Activity (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning balance	$ 809	$ 558	$ 649	$ 4,275
Restructuring and impairment recoveries				(1,538)
Cash payments	(280)	(4,432)	(91)	(2,798)
Non-cash settlements				710
Restructuring expenses		4,683
Accrued restructuring, ending balance	529	809	558	649
Asset impairments
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning balance	0	0	0	0
Restructuring and impairment recoveries				(710)
Cash payments		0	0	0
Non-cash settlements				710
Restructuring expenses		0
Accrued restructuring, ending balance		0	0	0
Contract termination costs
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning balance	467	558	649	3,954
Restructuring and impairment recoveries				(751)
Cash payments	(23)	(91)	(91)	(2,554)
Non-cash settlements				0
Restructuring expenses		0
Accrued restructuring, ending balance	444	467	558	649
Employee severance and termination benefits
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning balance	342	0	0	321
Restructuring and impairment recoveries				(77)
Cash payments	(257)	(4,341)	0	(244)
Non-cash settlements				0
Restructuring expenses		4,683	0	0
Accrued restructuring, ending balance	$ 85	$ 342	$ 0	$ 0

Income Taxes - Income Tax Provi

Income Taxes - Income Tax Provision (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current income tax:
Federal			$ 0	$ 0	$ 0
State			512	151	545
Foreign			(52)	(24)	95
Total			460	127	640
Deferred income tax:
Federal			0	(326)	0
State			0	(53)	0
Foreign			(2,071)	1,330	(573)
Total			(2,071)	951	(573)
Income tax (benefit) expense	$ (301)	$ (433)	$ (1,611)	$ 1,078	$ 67

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Tax Expense Computed at Statutory Federal Rate and Company's Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Computed expected tax expense			$ (98,598)	$ (139,100)	$ (93,770)
State income taxes, net of federal tax effect			404	65	360
Foreign income taxes			(690)	(299)	(949)
Other reconciling items			0	(344)	666
Permanent differences			4,406	2,008	1,688
Effect of Federal law change			0	166,876	0
Change in valuation allowance			92,867	(28,128)	92,072
Income tax (benefit) expense	$ (301)	$ (433)	$ (1,611)	$ 1,078	$ 67

Income Taxes - Significant Port

Income Taxes - Significant Portions of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Gross deferred tax assets:
Net operating loss carryforwards	$ 591,244	$ 591,619
Deferred subscriber income	113,103	72,389
Interest expense limitation	56,381	0
Accrued expenses and allowances	18,766	17,633
Purchased intangibles and deferred financing costs	17,788	15,191
Inventory reserves	4,688	6,662
Property and equipment	0	1,176
Research and development credits	41	41
Valuation allowance	(467,705)	(304,509)
Deferred tax assets, net of valuation allowance	334,306	400,202
Gross deferred tax liabilities:
Deferred capitalized contract costs	(332,547)	(408,610)
Property and equipment	(2,242)	0
Prepaid expenses	(613)	(633)
Deferred tax liabilities, net	(335,402)	(409,243)
Net deferred tax liabilities	$ (1,096)	$ (9,041)

Income Taxes - Summary of Net O

Income Taxes - Summary of Net Operating Loss Carryforwards (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Net operating loss carry forwards	$ 4,081,466	$ 4,097,483
Internal Revenue Service (IRS) | Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carry forwards	2,405,380	2,355,153
Internal Revenue Service (IRS) | States
Operating Loss Carryforwards [Line Items]
Net operating loss carry forwards	1,656,333	1,715,004
Canada Revenue Agency | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carry forwards	$ 19,753	$ 27,326

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Taxes And Tax Related [Line Items]
Tax Cuts And Jobs Act Of 2017, incomplete accounting, change in tax rate, deferred tax asset, provisional income tax expense		$ 166,900
Tax Cuts and Job Acts of 2017, additional gross income subject to taxation	$ 7,700
Valuation allowance	467,705	304,509
Federal
Income Taxes And Tax Related [Line Items]
Research and development credits	$ 41	$ 41

Stock-Based Compensation and _3

Stock-Based Compensation and Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended				3 Months Ended		12 Months Ended
	Mar. 31, 2019	Jun. 30, 2018	Aug. 31, 2016	Apr. 30, 2016	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, restricted stock units, number of shares exercisable							0
Compensation expense related to outstanding Incentive Units, recognized over a weighted-average period							4 years 3 months 13 days
Share-based compensation					$ 857	$ 204	$ 2,505	$ 1,595	$ 3,868
Proceeds from contributed capital			$ 30,600	$ 69,800	$ 0	$ 0	4,700	0	100,407
Capital contributions from parent							4,700	0	$ 100,407
Capital contributions returned to parent							3,100	$ 1,200
Incentive Units Performance Based Awards | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation, award vesting rights, percentage					33.33%
Incentive Units Time Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period					5 years
Incentive Units Time Based Awards | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation, award vesting rights, percentage					66.67%
Incentive Units Time Based Awards | Chief Executive Officer and President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive units issued as share-based compensation awards, outstanding (in shares)	42,169,456				42,169,456
Incentive Units Time Based Awards | Senior Management and Board Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive units issued as share-based compensation awards (in shares)					84,132,816
Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense							$ 10,700
Incentive Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, percentage					55.00%
Expected exercise term					3 years 11 months 16 days
Risk-free rate, percentage					0.62%
Incentive Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, percentage					125.00%
Expected exercise term					6 years
Risk-free rate, percentage					2.61%
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	53,621,891				53,621,891		53,621,891
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		3 years					3 years
Incentive units issued as share-based compensation awards (in shares)	236,111	360,000
Expected volatility, percentage		95.00%
Expected exercise term		3 years
Risk-free rate, percentage		2.61%
Unrecognized compensation expense							$ 100
Expected dividends, percentage		0.00%
Restricted stock units, recognition period							2 years 5 months 10 days
Restricted stock units, fair value at grant date (usd per share)		$ 0.48
313 Acquisition LLC | Incentive Units Performance Based Awards | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation, award vesting rights, percentage							66.67%
313 Acquisition LLC | Incentive Units Time Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period							5 years
313 Acquisition LLC | Incentive Units Time Based Awards | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation, award vesting rights, percentage							33.33%
Incentive units issued as share-based compensation awards (in shares)							85,362,836
313 Acquisition LLC | Incentive Units Time Based Awards | Chief Executive Officer and President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive units issued as share-based compensation awards (in shares)							42,169,456
313 Acquisition LLC | Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, minimum expected volatility rate							55.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, maximum expected volatility rate							125.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, minimum risk free interest rate							0.61%
Weighted average grant date fair value of the outstanding units (in dollars per share)							$ 0.36	$ 0.30
Share-based compensation arrangement by share-based payment award, fair value assumptions, maximum risk free interest rate							2.61%
313 Acquisition LLC | Incentive Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected exercise term							3 years 11 months 15 days
313 Acquisition LLC | Incentive Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected exercise term							6 years
Vivint | Stock Appreciation Rights Time Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period					5 years
Vivint | Stock Appreciation Rights Time Based Awards | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation, award vesting rights, percentage					66.67%		33.33%
Vivint | Stock Appreciation Rights Performance Based Awards | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation, award vesting rights, percentage					33.33%		66.67%
Vivint | Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, minimum expected volatility rate							55.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, maximum expected volatility rate							125.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, minimum risk free interest rate							0.61%
Unrecognized compensation expense							$ 4,600
Compensation expense related to outstanding Incentive Units, recognized over a weighted-average period							4 years 4 months 23 days
Weighted average grant date fair value of the outstanding units (in dollars per share)							$ 0.23	$ 0.19
Incentive units issued as share-based compensation awards, outstanding (in shares)	36,576,342				36,576,342		38,011,879
Expected dividends, percentage					0.00%		0.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, maximum risk free interest rate							2.61%
Vivint | Stock Appreciation Rights (SARs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, percentage					55.00%
Expected exercise term					6 years		6 years
Risk-free rate, percentage					0.61%
Vivint | Stock Appreciation Rights (SARs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, percentage					125.00%
Expected exercise term					6 years 5 months 20 days		6 years 6 months
Risk-free rate, percentage					2.61%
Vivint Wireless | Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive units issued as share-based compensation awards, outstanding (in shares)							0

Stock-Based Compensation and _4

Stock-Based Compensation and Equity - Summary of Incentive Unit Activity (Detail) - 313 Acquisition LLC - Incentive Units - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, Beginning Balance (shares)	85,812,836	85,882,836
Forfeited (shares)	(450,000)	(70,000)
Outstanding, Ending Balance (shares)	85,362,836	85,812,836	85,882,836
Unvested shares expected to vest (shares)	59,663,659
Exercisable (shares)	25,699,177
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average exercise price per share, outstanding, beginning balance (in dollars per share)	$ 1.19	$ 1.19
Weighted average exercise price per share, forfeited (in dollars per share)	1.93	1.30
Weighted average exercise price per share, outstanding, ending balance (in dollars per share)	1.18	$ 1.19	$ 1.19
Weighted average exercise price per share, unvested shares expected to vest (in dollars per share)	1.22
Weighted average exercise price per share, Exercisable (in dollars per share)	$ 1.11
Outstanding, weighted average remaining contractual life	4 years 9 months 23 days	5 years 9 months 23 days	6 years 9 months 23 days
Unvested shares expected to vest, weighted average remaining contractual life	4 years 10 months 36 days
Exercisable at end of period, weighted average remaining contractual life	4 years 6 months
Outstanding, aggregate intrinsic value	$ 0	$ 0	$ 0
Unvested shares expected to vest, aggregate intrinsic value	0
Exercisable, aggregate intrinsic value	$ 0

Stock-Based Compensation and _5

Stock-Based Compensation and Equity - Summary of the SAR Activity (Detail) - Vivint - Stock Appreciation Rights (SARs) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, Beginning Balance (shares)	32,754,290	21,993,158
Granted (shares)	14,630,000	13,250,640
Forfeited (shares)	(9,255,137)	(2,374,864)
Exercised (shares)	(117,274)	(114,644)
Outstanding, Ending Balance (shares)	38,011,879	32,754,290	21,993,158
Unvested shares expected to vest (shares)	33,813,668
Exercisable (shares)	4,198,211
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average exercise price per share, outstanding, beginning balance (in dollars per share)	$ 1.26	$ 0.96
Weighted average exercise price per share, granted (in dollars per share)	1.79	1.74
Weighted average exercise price per share, forfeited (in dollars per share)	1.31	1.12
Weighted average exercise price per share, exercised (in dollars per share)	0.89	0.72
Weighted average exercise price per share, outstanding, ending balance (in dollars per share)	1.46	$ 1.26	$ 0.96
Weighted average exercise price per share, unvested shares expected to vest (in dollars per share)	1.51
Weighted average exercise price per share, Exercisable (in dollars per share)	$ 1.02
Outstanding, weighted average remaining contractual life	8 years 24 days	9 years 2 months 16 days	8 years 2 months 22 days
Unvested shares expected to vest, weighted average remaining contractual life	8 years 2 months 40 days
Exercisable at end of period, weighted average remaining contractual life	6 years 2 months 50 days
Outstanding, aggregate intrinsic value	$ 0	$ 0	$ 0
Unvested shares expected to vest, aggregate intrinsic value	0
Exercisable, aggregate intrinsic value	$ 0

Stock-Based Compensation and _6

Stock-Based Compensation and Equity - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 857	$ 204	$ 2,505	$ 1,595	$ 3,868
Operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	43	18	129	65	68
Selling expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	87	45	285	217	(127)
General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 727	$ 141	$ 2,091	$ 1,313	3,927
Executive Officer | General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation					$ 2,200

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)market	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)market
Commitments And Contingencies [Line Items]
Loss contingency accrual	$ 2.1		$ 3.1	$ 2.2
Operating leases, rent expense		$ 4.3	16.5	17	$ 16
Capital lease obligation			13.3	$ 21.7
Previously Reported [Member]
Commitments And Contingencies [Line Items]
Loss contingency accrual			2.5
Software Licenses, Marketing Activities, and Other Goods and Services
Commitments And Contingencies [Line Items]
Other off-balance sheet obligations			$ 59.5
Vehicles
Commitments And Contingencies [Line Items]
Lease agreements term	36 months		36 months
Average remaining life for fleet	10 months		19 months
Spectrum Licenses
Commitments And Contingencies [Line Items]
Lease agreements term					7 years
Number of mid-sized metropolitan markets | market			40		40
Settled Litigation | Company vs. ADT Inc.
Commitments And Contingencies [Line Items]
Litigation settlement, amount			$ 10

Commitments and Contingencies_3

Commitments and Contingencies - Future Minimum Lease Payments (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Operating
2019	$ 16,709
2020	15,478
2021	14,926
2022	13,655
2023	13,701
Thereafter	28,824
Amounts representing interest	0
Total lease payments	103,293
Capital
2019	8,193
2020	5,209
2021	363
2022	7
2023	0
Thereafter	0
Amounts representing interest	(459)
Total lease payments	13,313
Total
2019	24,902
2020	20,687
2021	15,289
2022	13,662
2023	13,701
Thereafter	28,824
Amounts representing interest	(459)
Total lease payments	$ 116,606

Related Party Transactions (Det

Related Party Transactions (Detail) - USD ($)	1 Months Ended			3 Months Ended		12 Months Ended			73 Months Ended
	Sep. 30, 2018	Aug. 31, 2016	Apr. 30, 2016	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Jan. 01, 2018
Related Party Transaction [Line Items]
Additional expenses incurred for other related-party transactions				$ 400,000	$ 600,000	$ 2,700,000	$ 3,500,000	$ 4,200,000
Accrued expenses and other current liabilities				158,997,000		136,715,000	74,321,000		$ 136,715,000	$ 84,650,000
Prepaid expenses and other current assets						1,800,000	500,000		1,800,000
Monitoring fees				1,000,000		4,793,000	933,000		4,793,000
Long-term debt				3,084,090,000		3,045,195,000	2,820,297,000		3,045,195,000
Financing costs						11,317,000	18,277,000	9,036,000
Proceeds from contributed capital		$ 30,600,000	$ 69,800,000	0	0	4,700,000	0	100,407,000
Share-based compensation				857,000	204,000	$ 2,505,000	1,595,000	3,868,000
Expected repayment period						1 year
Amounts due from employees						$ 300,000	300,000		300,000
Prepaid expenses and other current assets				15,128,000		11,449,000	16,150,000		11,449,000
Vivint
Related Party Transaction [Line Items]
Accrued expenses and other current liabilities				100,000		200,000	1,400,000		200,000
Affiliated Entity | Minimum
Related Party Transaction [Line Items]
Annual monitoring base fee, minimum				2,700,000
General and administrative expenses
Related Party Transaction [Line Items]
Share-based compensation				727,000	141,000	2,091,000	1,313,000	3,927,000
General and administrative expenses | Executive Officer
Related Party Transaction [Line Items]
Share-based compensation								2,200,000
7.875% Senior Secured Notes Due 2022 | Senior Notes
Related Party Transaction [Line Items]
Long-term debt							908,526,000
7.875% Senior Secured Notes Due 2022 | Senior Notes | Blackstone Advisory Partners L.P.
Related Party Transaction [Line Items]
Deferred financing cost, net								500,000
Solar | Affiliated Entity
Related Party Transaction [Line Items]
Sublease and other administrative expenses				2,400,000	1,000,000	$ 17,300,000	2,800,000	4,600,000
Non-competition agreement, term						3 years
Product development and supply agreement term						3 years
Product development and supply agreement renewal term						1 year
Blackstone Management Partners L.L.C. | Affiliated Entity
Related Party Transaction [Line Items]
Prepaid expenses and other current assets				1,000,000	1,200,000	$ 4,100,000	3,500,000	3,700,000	4,100,000
Blackstone Management Partners L.L.C. | Affiliated Entity | Minimum
Related Party Transaction [Line Items]
Annual monitoring base fee, minimum						2,700,000
Blackstone Advisory Partners L.P.
Related Party Transaction [Line Items]
Aggregate interest payments to related party									900,000
Blackstone Advisory Partners L.P. | Affiliated Entity
Related Party Transaction [Line Items]
Deferred financing cost, net	$ 900,000					900,000			900,000
Blackstone Advisory Partners L.P. | Term Loan | Affiliated Entity
Related Party Transaction [Line Items]
Long-term debt				79,300,000		75,100,000			75,100,000
Blackstone Advisory Partners L.P. | 7.875% Senior Secured Notes Due 2022 | Senior Notes | Affiliated Entity
Related Party Transaction [Line Items]
Financing costs							$ 600,000
Vivint Smart Home, Inc. | Affiliated Entity
Related Party Transaction [Line Items]
Proceeds from contributed capital	4,700,000
Sales Dealer Agreement | Solar | Affiliated Entity
Related Party Transaction [Line Items]
Agreement period, term							2 years
Agreement period, renewal term							1 year
Agreement period, termination notice period							90 days
Blackstone Management Partners LLC Support and Services Agreement | Blackstone Management Partners L.L.C. | Affiliated Entity
Related Party Transaction [Line Items]
Fee paid for support services by BMP to Company				1,500,000		1,500,000			1,500,000
Expenses from transactions with related party				0	$ 0	0	$ 0	$ 0
Affiliated Entity | Blackstone Advisory Partners L.P.
Related Party Transaction [Line Items]
Long-term debt						75,100,000			75,100,000
Affiliated Entity | Vivint Smart Home, Inc.
Related Party Transaction [Line Items]
Proceeds from contributed capital	$ 4,700,000
Personal Use Of Corporate Jet
Related Party Transaction [Line Items]
Prepaid expenses and other current assets				$ 200,000		$ 1,800,000			$ 1,800,000

Segment Reporting and Busines_4

Segment Reporting and Business Concentrations - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2019segment	Mar. 31, 2018segment	Dec. 31, 2018SegmentCountry	Dec. 31, 2017Segment	Dec. 31, 2016Segment
Segment Reporting [Abstract]
Number of operating segments	1	1	1	1	1
Number of geographic region company has historically operated in			3

Segment Reporting and Busines_5

Segment Reporting and Business Concentrations - Revenues and Long-Lived Assets by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues from external customers	$ 276,249	$ 246,597	$ 1,050,441	$ 881,983	$ 757,907
United States
Segment Reporting Information [Line Items]
Revenues from external customers			977,877	816,026	700,471
Canada
Segment Reporting Information [Line Items]
Revenues from external customers			$ 72,564	$ 65,957	$ 57,436

Guarantor and Non-Guarantor S_5

Guarantor and Non-Guarantor Supplemental Financial Information - Condensed Consolidating Statements of Operations and Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Income Statements, Captions [Line Items]
Revenues:	$ 276,249	$ 246,597	$ 1,050,441	$ 881,983	$ 757,907
Costs and expenses	304,227	318,228	1,292,500	1,037,476	829,009
Loss from operations	(27,978)	(71,631)	(242,059)	(155,493)	(71,102)
Loss from subsidiaries	0	0	0	0	0
Other expense (income), net	61,479	13,519	227,466	253,628	204,788
Loss before income taxes	(89,457)	(85,150)	(469,525)	(409,121)	(275,890)
Income tax expense (benefit)	(301)	(433)	(1,611)	1,078	67
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Other comprehensive (loss) income, net of tax effects:
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Foreign currency translation adjustment	570	(659)	(2,218)	3,155	2,482
Unrealized (loss) gain on marketable securities			0	(1,693)	1,011
Total other comprehensive income (loss)	570	(659)	(2,218)	1,462	3,493
Comprehensive loss	(88,586)	(85,376)	(470,132)	(408,737)	(272,464)
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues:	(202)	(656)	(2,567)	(2,690)	(2,704)
Costs and expenses	(202)	(656)	(2,567)	(2,690)	(2,704)
Loss from operations	0	0	0	0	0
Loss from subsidiaries	115,137	111,037	679,579	575,696	345,594
Other expense (income), net	0	0	0	0	0
Loss before income taxes	115,137	111,037	679,579	575,696	345,594
Income tax expense (benefit)	0	0	0	0	0
Net loss	115,137	111,037	679,579	575,696	345,594
Other comprehensive (loss) income, net of tax effects:
Net loss	115,137	111,037	679,579	575,696	345,594
Foreign currency translation adjustment	(1,140)	1,318	4,436	(6,310)	(4,964)
Unrealized (loss) gain on marketable securities				3,386	(2,022)
Total other comprehensive income (loss)	(1,140)	1,318	4,436	(2,924)	(6,986)
Comprehensive loss	113,997	112,355	684,015	572,772	338,608
Parent | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenues:	0	0	0	0	0
Costs and expenses	0	0	0	0	0
Loss from operations	0	0	0	0	0
Loss from subsidiaries	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Other expense (income), net	0	0	0	0	0
Loss before income taxes	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Income tax expense (benefit)	0	0	0	0	0
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Other comprehensive (loss) income, net of tax effects:
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Foreign currency translation adjustment	570	(659)	(2,218)	3,155	2,482
Unrealized (loss) gain on marketable securities				(1,693)	1,011
Total other comprehensive income (loss)	570	(659)	(2,218)	1,462	3,493
Comprehensive loss	(88,586)	(85,376)	(470,132)	(408,737)	(272,464)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenues:	263,539	233,788	998,190	841,658	715,072
Costs and expenses	291,509	305,221	1,240,570	997,247	787,138
Loss from operations	(27,970)	(71,433)	(242,380)	(155,589)	(72,066)
Loss from subsidiaries	0	0	0	0	0
Other expense (income), net	(52)	(46,970)	(35,936)	13,545	(1,207)
Loss before income taxes	(27,918)	(24,463)	(206,444)	(169,134)	(70,859)
Income tax expense (benefit)	182	172	512	(228)	545
Net loss	(28,100)	(24,635)	(206,956)	(168,906)	(71,404)
Other comprehensive (loss) income, net of tax effects:
Net loss	(28,100)	(24,635)	(206,956)	(168,906)	(71,404)
Foreign currency translation adjustment	0	0	0	0	0
Unrealized (loss) gain on marketable securities				(1,693)	1,011
Total other comprehensive income (loss)	0	0	0	(1,693)	1,011
Comprehensive loss	(28,100)	(24,635)	(206,956)	(170,599)	(70,393)
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenues:	12,912	13,465	54,818	43,015	45,539
Costs and expenses	12,920	13,663	54,497	42,919	44,575
Loss from operations	(8)	(198)	321	96	964
Loss from subsidiaries	0	0	0	0	0
Other expense (income), net	(1,644)	2,092	7,153	(4,619)	(325)
Loss before income taxes	1,636	(2,290)	(6,832)	4,715	1,289
Income tax expense (benefit)	(483)	(605)	(2,123)	1,306	(478)
Net loss	2,119	(1,685)	(4,709)	3,409	1,767
Other comprehensive (loss) income, net of tax effects:
Net loss	2,119	(1,685)	(4,709)	3,409	1,767
Foreign currency translation adjustment	570	(659)	(2,218)	3,155	2,482
Unrealized (loss) gain on marketable securities				0	0
Total other comprehensive income (loss)	570	(659)	(2,218)	3,155	2,482
Comprehensive loss	2,689	(2,344)	(6,927)	6,564	4,249
APX Group, Inc. | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenues:	0	0	0	0	0
Costs and expenses	0	0	0	0	0
Loss from operations	0	0	0	0	0
Loss from subsidiaries	(25,981)	(26,320)	(211,665)	(165,497)	(69,637)
Other expense (income), net	63,175	58,397	256,249	244,702	206,320
Loss before income taxes	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Income tax expense (benefit)	0	0	0	0	0
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Other comprehensive (loss) income, net of tax effects:
Net loss	(89,156)	(84,717)	(467,914)	(410,199)	(275,957)
Foreign currency translation adjustment	570	(659)	(2,218)	3,155	2,482
Unrealized (loss) gain on marketable securities				(1,693)	1,011
Total other comprehensive income (loss)	570	(659)	(2,218)	1,462	3,493
Comprehensive loss	$ (88,586)	$ (85,376)	$ (470,132)	$ (408,737)	$ (272,464)

Guarantor and Non-Guarantor S_6

Guarantor and Non-Guarantor Supplemental Financial Information - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Aug. 31, 2016	Apr. 30, 2016	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net cash (used in) provided by operating activities					$ (220,499)	$ (309,332)	$ (365,706)
Cash flows from investing activities:
Subscriber acquisition costs – company owned equipment					0	0	(5,243)
Capital expenditures			$ (1,391)	$ (6,407)	(19,412)	(20,391)	(11,642)
Proceeds from sale of intangibles			0	53,693	53,693	0	0
Proceeds from sale of capital assets			(51)	149	127	776	3,123
Investment in subsidiary			0		0	0	0
Acquisition of intangible assets			(369)	(849)	(1,486)	(1,745)	(1,385)
Other assets						(301)
Net cash provided by (used in) investing activities					32,922	(21,661)	(15,147)
Cash flows from financing activities:
Proceeds from notes payable					810,000	724,750	604,000
Repayments of notes payable			(2,025)	0	(522,191)	(450,000)	(235,535)
Borrowings from revolving credit facility			40,000	57,000	201,000	196,895	57,000
Repayments on revolving credit facility			0	(40,000)	(261,000)	(136,895)	(77,000)
Proceeds from capital contribution	$ 30,600	$ 69,800	0	0	4,700	0	100,407
Payment of intercompany settlement						(2,983)	0
Intercompany receivable						0	0
Intercompany payable						0	0
Repayments of capital lease obligations				(3,418)	(12,354)	(10,007)	(8,315)
Financing costs					(11,317)	(18,277)	(9,036)
Deferred financing costs					(9,302)	(11,119)	(9,241)
Return of capital					(3,129)	(1,151)
Net cash provided by financing activities					196,407	291,213	422,280
Effect of exchange rate changes on cash			25	(19)	71	132	(466)
Net decrease in cash and cash equivalents			(9,082)	(399)	8,901	(39,648)	40,961
Cash and cash equivalents:
Beginning of period			12,773	3,872	3,872	43,520	2,559
End of period			3,691	3,473	12,773	3,872	43,520
Reportable Legal Entities
Cash flows from financing activities:
Repayments of notes payable							0
Financing costs							0
Eliminations
Cash flows from operating activities:
Net cash (used in) provided by operating activities					0	0	0
Cash flows from investing activities:
Subscriber acquisition costs – company owned equipment							0
Capital expenditures			0	0	0	0	0
Proceeds from sale of intangibles				0	0
Proceeds from sale of capital assets			0	0	0	0	0
Investment in subsidiary			46,605		202,863	324,071	508,621
Acquisition of intangible assets			0	0	0	0	0
Other assets						0
Net cash provided by (used in) investing activities					202,863	324,071	508,621
Cash flows from financing activities:
Proceeds from notes payable					0	0	0
Repayments of notes payable			0		0	0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			(46,369)	(17,416)	(209,121)	(326,373)	(100,407)
Payment of intercompany settlement						0	0
Intercompany receivable						(3,621)	(12,906)
Intercompany payable						3,621	(395,308)
Repayments of capital lease obligations				0	0	0	0
Financing costs					0	0	0
Deferred financing costs					0	0	0
Return of capital					6,258	2,302
Net cash provided by financing activities					(202,863)	(324,071)	(508,621)
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			0	0	0	0	0
Cash and cash equivalents:
Beginning of period			0	0	0	0	0
End of period			0	0	0	0	0
Parent Company | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities					0	0	0
Cash flows from investing activities:
Subscriber acquisition costs – company owned equipment							0
Capital expenditures			0	0	0	0	0
Proceeds from sale of intangibles				0	0
Proceeds from sale of capital assets			0	0	0	0	0
Investment in subsidiary			(118)		(1,571)	1,151	(100,407)
Acquisition of intangible assets			0	0	0	0	0
Other assets						0
Net cash provided by (used in) investing activities					(1,571)	1,151	(100,407)
Cash flows from financing activities:
Proceeds from notes payable					0	0	0
Repayments of notes payable			0		0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			0	0	4,700	0	100,407
Payment of intercompany settlement						0	0
Intercompany receivable						0	0
Intercompany payable						0	0
Repayments of capital lease obligations				0	0	0	0
Financing costs					0	0
Deferred financing costs					0	0	0
Return of capital					(3,129)	(1,151)
Net cash provided by financing activities					1,571	(1,151)	100,407
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			0	0	0	0	0
Cash and cash equivalents:
Beginning of period			0	0	0	0	0
End of period			0	0	0	0	0
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities					(220,952)	(313,290)	(380,508)
Cash flows from investing activities:
Subscriber acquisition costs – company owned equipment							(5,243)
Capital expenditures			(1,391)	(6,407)	(19,409)	(20,391)	(11,642)
Proceeds from sale of intangibles				53,693	53,693
Proceeds from sale of capital assets			(51)	149	127	776	3,080
Investment in subsidiary			0		0	0	0
Acquisition of intangible assets			(369)	(849)	(1,486)	(1,745)	(1,385)
Other assets						(301)
Net cash provided by (used in) investing activities					32,925	(21,661)	(15,190)
Cash flows from financing activities:
Proceeds from notes payable					0	0	0
Repayments of notes payable			0		0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			46,369	17,416	204,421	326,373	0
Payment of intercompany settlement						(2,983)	3,000
Intercompany receivable						3,621	12,906
Intercompany payable						0	408,214
Repayments of capital lease obligations				(3,305)	(12,011)	(9,667)	(8,295)
Financing costs					0	0
Deferred financing costs					0	0	0
Return of capital					(3,129)	(1,151)
Net cash provided by financing activities					189,281	316,193	415,825
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			(682)	572	1,254	(18,758)	20,127
Cash and cash equivalents:
Beginning of period			682	(572)	(572)	18,186	(1,941)
End of period			0	0	682	(572)	18,186
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities					453	3,958	14,802
Cash flows from investing activities:
Subscriber acquisition costs – company owned equipment							0
Capital expenditures			0	0	(3)	0	0
Proceeds from sale of intangibles				0	0
Proceeds from sale of capital assets			0	0	0	0	43
Investment in subsidiary			0		0	0	0
Acquisition of intangible assets			0	0	0	0	0
Other assets						0
Net cash provided by (used in) investing activities					(3)	0	43
Cash flows from financing activities:
Proceeds from notes payable					0	0	0
Repayments of notes payable			0		0	0
Borrowings from revolving credit facility			0	0	0	0	0
Repayments on revolving credit facility				0	0	0	0
Proceeds from capital contribution			0	0	0	0	0
Payment of intercompany settlement						0	(3,000)
Intercompany receivable						0	0
Intercompany payable						(3,621)	(12,906)
Repayments of capital lease obligations				(113)	(343)	(340)	(20)
Financing costs					0	0
Deferred financing costs					0	0	0
Return of capital					0	0
Net cash provided by financing activities					(343)	(3,961)	(15,926)
Effect of exchange rate changes on cash			25	(19)	71	132	(466)
Net decrease in cash and cash equivalents			(6)	(555)	178	129	(1,547)
Cash and cash equivalents:
Beginning of period			961	783	783	654	2,201
End of period			955	228	961	783	654
APX Group, Inc. | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities					0	0	0
Cash flows from investing activities:
Subscriber acquisition costs – company owned equipment							0
Capital expenditures			0	0	0	0	0
Proceeds from sale of intangibles				0	0
Proceeds from sale of capital assets			0	0	0	0	0
Investment in subsidiary			(46,487)		(201,292)	(325,222)	(408,214)
Acquisition of intangible assets			0	0	0	0	0
Other assets						0
Net cash provided by (used in) investing activities					(201,292)	(325,222)	(408,214)
Cash flows from financing activities:
Proceeds from notes payable					810,000	724,750	604,000
Repayments of notes payable			(2,025)		(522,191)	(450,000)	(235,535)
Borrowings from revolving credit facility			40,000	57,000	201,000	196,895	57,000
Repayments on revolving credit facility				(40,000)	(261,000)	(136,895)	(77,000)
Proceeds from capital contribution			0	0	4,700	0	100,407
Payment of intercompany settlement						0	0
Intercompany receivable							0
Intercompany payable						0	0
Repayments of capital lease obligations				0	0	0	0
Financing costs					(11,317)	(18,277)	(9,036)
Deferred financing costs					(9,302)	(11,119)	(9,241)
Return of capital					(3,129)	(1,151)
Net cash provided by financing activities					208,761	304,203	430,595
Effect of exchange rate changes on cash			0	0	0	0	0
Net decrease in cash and cash equivalents			(8,394)	(416)	7,469	(21,019)	22,381
Cash and cash equivalents:
Beginning of period			11,130	3,661	3,661	24,680	2,299
End of period			$ 2,736	$ 3,245	$ 11,130	$ 3,661	$ 24,680

Subsequent Events (Details)

Subsequent Events (Details) - Senior Notes - USD ($)	May 10, 2019	Mar. 31, 2019	Dec. 31, 2018
Subsequent Event [Line Items]
Debt instrument interest rate, percentage			7.625%
Senior Notes Due 2024 | Subsequent Event
Subsequent Event [Line Items]
Principal amount	$ 225,000,000
Debt instrument interest rate, percentage	8.50%
8.75% Senior Notes Due 2020
Subsequent Event [Line Items]
Principal amount		$ 679,299,000
Debt instrument interest rate, percentage		8.75%	8.75%
8.75% Senior Notes Due 2020 | Subsequent Event
Subsequent Event [Line Items]
Repayments of long-term debt	$ 225,000,000

Uncategorized Items - ck0001584

Label	Element	Value
Accounting Standards Update 2016-02 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 84,000
Accounting Standards Update 2016-02 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	84,000
Accounting Standards Update 2014-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(282,572,000)
Accounting Standards Update 2014-09 [Member] | Previously Reported [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(276,930,000)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(282,572,000)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member] | Previously Reported [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(276,930,000)
Accounting Standards Update 2016-01 [Member] | AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	680,000
Accounting Standards Update 2016-01 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (680,000)