Alarm.com (ALRM) 10-Q 7 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	ALARM.COM HOLDINGS, INC.
Entity Central Index Key	1,459,200
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		48,003,133

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue:
Total revenue		$ 111,848	$ 89,962	$ 309,092	$ 250,144
Cost of revenue:
Total cost of revenue	[1]	41,992	31,833	106,857	88,303
Operating expenses:
Sales and marketing		14,128	10,426	39,562	32,639
General and administrative		43,662	12,974	77,943	41,799
Research and development		22,869	19,257	64,767	53,840
Amortization and depreciation		5,891	5,071	16,154	12,781
Total operating expenses		86,550	47,728	198,426	141,059
Operating (loss) / income		(16,694)	10,401	3,809	20,782
Interest expense		(736)	(658)	(2,159)	(1,548)
Other income, net		717	342	1,533	716
(Loss) / income before income taxes		(16,713)	10,085	3,183	19,950
Benefit from income taxes		(9,061)	(5,018)	(10,413)	(8,981)
Net (loss) / income		(7,652)	15,103	13,596	28,931
Income allocated to participating securities		0	(6)	(2)	(14)
Net (loss) / income attributable to common stockholders		$ (7,652)	$ 15,097	$ 13,594	$ 28,917
Net (loss) / income per share:
Basic (in dollars per share)		$ (0.16)	$ 0.32	$ 0.29	$ 0.62
Diluted (in dollars per share)		$ (0.16)	$ 0.31	$ 0.27	$ 0.59
Weighted average common shares outstanding:
Basic (in shares)		47,812,642	46,886,345	47,494,926	46,520,469
Diluted (in shares)		47,812,642	49,259,701	49,593,918	49,074,279
SaaS and license
Revenue:
Total revenue		$ 74,292	$ 61,924	$ 213,248	$ 171,078
Cost of revenue:
Total cost of revenue	[1]	11,501	9,545	33,334	26,137
Hardware and other
Revenue:
Total revenue		37,556	28,038	95,844	79,066
Cost of revenue:
Total cost of revenue	[1]	$ 30,491	$ 22,288	$ 73,523	$ 62,166
[1]	Exclusive of amortization and depreciation shown in operating expenses below.

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 124,243	$ 96,329
Accounts receivable, net	55,461	40,634
Inventory, net	16,906	14,177
Other current assets	16,864	12,796
Total current assets	213,474	163,936
Property and equipment, net	28,349	23,459
Intangible assets, net	82,868	94,286
Goodwill	63,591	63,591
Deferred tax assets	26,596	18,444
Other assets	12,482	7,925
Total Assets	427,360	371,641
Current liabilities:
Accounts payable, accrued expenses and other current liabilities	57,994	29,084
Accrued compensation	11,473	12,127
Deferred revenue	3,539	3,292
Total current liabilities	73,006	44,503
Deferred revenue	8,335	9,386
Long-term debt	68,000	71,000
Other liabilities	13,278	13,925
Total liabilities	162,619	138,814
Commitments and contingencies
Stockholders’ equity
Preferred stock, $0.001 par value, 10,000,000 shares authorized; no shares issued and outstanding as of September 30, 2018 and December 31, 2017.	0	0
Common stock, $0.01 par value, 300,000,000 shares authorized; 48,003,929 and 47,215,720 shares issued; and 47,999,924 and 47,202,310 shares outstanding as of September 30, 2018 and December 31, 2017, respectively.	480	472
Additional paid-in capital	336,220	321,032
Accumulated deficit	(71,959)	(88,677)
Total stockholders’ equity	264,741	232,827
Total liabilities and stockholders’ equity	$ 427,360	$ 371,641

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	48,003,929	47,215,720
Common stock, shares outstanding (in shares)	47,999,924	47,202,310

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 13,596	$ 28,931
Adjustments to reconcile net income to net cash from operating activities:
Provision for doubtful accounts	108	(360)
Reserve for product returns	210	1,732
Amortization on patents and tooling	701	817
Amortization and depreciation	16,154	12,781
Amortization of debt issuance costs	81	70
Deferred income taxes	(9,108)	(6,360)
Undistributed losses from equity investees	0	120
Stock-based compensation	9,670	5,134
Disposal of property and equipment	285	0
Changes in operating assets and liabilities (net of business acquisitions):
Accounts receivable	(15,145)	(1,342)
Inventory	(2,729)	(2,775)
Other assets	(5,072)	(8,122)
Accounts payable, accrued expenses and other current liabilities	28,472	7,975
Deferred revenue	(804)	(493)
Other liabilities	(1,441)	437
Cash flows from operating activities	34,978	38,545
Cash flows used in investing activities:
Business acquisitions, net of cash acquired	0	(154,289)
Additions to property and equipment	(9,317)	(7,652)
Investment in cost and equity method investees	0	(42)
Issuances of notes receivable	0	(5,000)
Receipt of payment on notes receivable	0	4,000
Cash flows used in investing activities	(9,317)	(162,983)
Cash flows from financing activities:
Proceeds from credit facility	0	67,000
Repayments of credit facility	(3,000)	(1,700)
Repurchases of common stock	(1)	(9)
Issuances of common stock from equity based plans	5,254	3,153
Cash flows from financing activities	2,253	68,444
Net increase / (decrease) in cash and cash equivalents	27,914	(55,994)
Cash and cash equivalents at beginning of the period	96,329	140,634
Cash and cash equivalents at end of the period	$ 124,243	$ 84,640

Organization

Organization	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Alarm.com Holdings, Inc. (referred to herein as Alarm.com, the Company, or we) is the leading platform for the intelligently connected property. We offer a comprehensive suite of cloud-based solutions for the smart residential and commercial property , including interactive security, video monitoring, intelligent automation and energy management. Millions of property owners depend on our technology to intelligently secure, monitor and manage their residential and commercial properties. Our solutions are delivered through an established network of over 7,000 trusted service provider partners, who are experts at selling, installing and supporting our solutions. We derive revenue from the sale of our cloud-based Software-as-a-Service, or SaaS, services, license fees, software, hardware, activation fees and other revenue. Our fiscal year ends on December 31.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Basis of Presentation The accompanying unaudited condensed consolidated financial statements include our accounts and those of our majority-owned and controlled subsidiaries after elimination of intercompany accounts and transactions. These unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP, for interim financial information and the applicable rules and regulations of the Securities and Exchange Commission, or SEC. Accordingly, they do not include all the information and footnotes required by GAAP for annual financial statements. They should be read together with our audited consolidated financial statements and related notes thereto for the year ended December 31, 2017 included in our Annual Report on Form 10-K filed with the SEC on February 28, 2018 , or the 2017 Annual Report. The condensed consolidated balance sheet as of December 31, 2017 was derived from our audited financial statements, but does not include all disclosures required by GAAP for annual financial statements. In the opinion of management, these condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of the results of operations, financial position and cash flows. The results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that can be expected for our entire fiscal year ending December 31, 2018 . Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Our estimates, judgments and assumptions are continually evaluated based on available information and experience. Because of the use of estimates inherent in the financial reporting process, actual results could differ from those estimates. Estimates are used when accounting for revenue recognition, allowances for doubtful accounts, allowance for hardware returns, estimates of obsolete inventory, long-term incentive compensation, stock-based compensation, income taxes, legal reserves, contingent consideration and goodwill and intangible assets. Significant Accounting Policies Except for as disclosed herein, there have been no other material changes to our significant accounting policies during the three and nine months ended September 30, 2018 from those disclosed in our 2017 Annual Report. Revenue Recognition We derive our revenue from three primary sources: the sale of cloud-based SaaS services on our integrated Alarm.com platform, the sale of licenses and services on the Connect software platform and the sale of hardware products. We sell our platform and hardware solutions to service provider partners that resell our solutions and hardware to residential and commercial property owners, who are the service provider partners’ customers. Our subscribers consist of all of the properties maintained by those residential and commercial property owners to which we are delivering at least one of our solutions. We also sell our hardware to distributors who resell the hardware to service provider partners. We enter into contracts with our service provider partners that establish pricing for access to our platform solutions and for the sale of hardware. These contracts typically have an initial term of one year, with subsequent renewal terms of one year. Our service provider partners typically enter into contracts with our subscribers, which our service provider partners have indicated range from three to five years in length. Our hardware includes cellular radio modules that enable access to our cloud-based platforms, as well as video cameras, image sensors and other peripherals. Our service provider partners may purchase our hardware in anticipation of installing the hardware in a residential or commercial property when they create a new subscriber account, or for use in existing subscriber properties. The purchase of hardware occurs in a transaction that is separate and typically in advance of the purchase of our platform services. The performance obligation is satisfied when the hardware is received by our service provider partner or distributor. Service provider partners transact with us to purchase our platform solutions and resell our solutions to a new subscriber, or to upgrade or downgrade the solutions of an existing subscriber, at which time the subscriber’s access to our platform solutions is enabled and the delivery of the services commences. Our performance obligation related to providing our platform solutions is satisfied on a daily basis as the subscriber uses the platform services. The purchase of platform solutions and the purchase of hardware are separate transactions as revenue is recognized when control of the promised goods or services are transferred to our customers, in an amount that reflects the consideration that we expect to receive in exchange for those goods or services. We generate all of our revenue from contracts with customers. SaaS and license revenue associated with our contracts is invoiced and revenue is recognized at an amount that corresponds directly with the value of the performance completed to date. Additionally, the consideration received from hardware sales corresponds directly with the stand-alone selling price of the hardware. As a result, we have elected to use the practical expedient related to the amount of transaction price allocated to the unsatisfied performance obligations and therefore, we have not disclosed the total remaining revenue expected to be recognized on all contracts or the expected period over which the remaining revenue would be recognized for the current period or any period presented before January 1, 2018. To determine the transaction price, we analyze all of the performance obligations included in the contract. We consider the terms of the contract and our customary business practices, which typically do not include financing components or non-cash consideration. We have variable consideration in the form of retrospective volume discounts, rebate incentives, restocking fees and assurance-type warranties. The significant inputs related to variable consideration include the volume and amount of products and services sold historically and expected to be sold in the future, the availability and performance of our services and the historical and expected number of returns. Depending on the type of variable consideration and its predictability, we may apply an “expected value” approach or a “most likely amount” approach. We estimate the variable consideration at the onset of a contract and include the variable consideration within the transaction price if it is probable that a significant reversal of the variable consideration would not occur in the future. When determining whether the amount of variable consideration included in the transaction price should be constrained, we look at the history of hardware purchased and subscribers added by our service provider partners to estimate the likelihood of those service provider partners obtaining the retrospective volume discounts and rebates. At times, our contracts include consideration payable to a customer in the form of fixed discounts or rebates. We record the consideration payable to a customer as a reduction to the transaction price resulting in a reduction to revenue over the service period. If we enter into contracts that contain multiple promised services, we evaluate which of the promised services represent separate performance obligations based on whether or not the promised services are distinct and whether or not the services are separable from other promises in the contract. If these criteria are met, then we allocate the transaction price to the performance obligations using the relative stand-alone selling price method at contract inception. In determining the relative estimated selling prices, we consider market conditions, entity-specific factors and information about the customer or class of customer. Any discount within the contract is allocated proportionately to all of the separate performance obligations in the contract unless the terms of discount relate specifically to the entity’s efforts to satisfy some but not all of the performance obligations. For our standard service provider agreements, we have used a portfolio approach for purposes of revenue recognition, as each agreement has similar characteristics and we do not expect the effects of applying this approach would have a material impact on our financial statements as compared to assessing each agreement individually. SaaS and License Revenue We generate the majority of our SaaS and license revenue primarily from monthly fees charged to our service provider partners sold on a per subscriber basis for access to our cloud-based intelligently connected property platform and related solutions. Our fees per subscriber vary based upon the service plan and features utilized. Under the terms of our contractual arrangements with our service provider partners, we bill a monthly fee to our service provider partners in advance of the month of service, with the exception of the initial partial month of service, which is paid in arrears. Due to the limited period of time between receipt of payment and delivery of service, we have not accounted for these advance payments as significant financing components. We typically transfer the promised SaaS services to our customers over time, which is evidenced by the fact that the customers receive and consume the benefits provided by our performance of the services as such services are rendered. As a result, we recognize revenue from SaaS services on a monthly basis as we satisfy our performance obligations. We have demonstrated that we can sell our SaaS offering on a stand-alone basis, as it can be sold separately from hardware and activation services. As there is neither a minimum required initial service term nor a stated renewal term in our contractual arrangements, we recognize revenue over the period of service, which is monthly. Our service provider partners typically incur and pay the same monthly fee per subscriber account for the entire period a subscriber account is active. We offer multiple service level packages for our platform solutions including a range of solutions and a range of a la carte add-ons for additional features. The fee paid by our service provider partners each month for the delivery of our solutions is based on the combination of packages and add-ons enabled for each subscriber. We utilize tiered pricing plans where our service provider partners may receive prospective pricing discounts driven by volume. We also generate SaaS and license revenue from the fees paid to us when we license our intellectual property to third parties for use of our patents. We bill a monthly fee to third parties based on the number of customers that were active during the prior month. We apply the usage-based royalty exception to recognize license revenue because the sole or predominant item to which the royalty relates is the license of intellectual property. Under the usage-based royalty exception, we recognize revenue on a monthly basis over the period of service. In addition, in certain markets our EnergyHub subsidiary sells its demand response service for an annual service fee, with pricing based on the number of subscribers or amount of aggregate electricity demand made available for a utility’s or market’s control. Software License Revenue Our SaaS and license revenue also includes our software license revenue from monthly fees charged to service providers sold on a per subscriber basis for access to our Connect software platform. The Connect software for interactive security, automation and related solutions is typically deployed and operated by the service provider in its own network operations center. Our agreements for the Connect platform solution typically include software and services, such as post-contract customer support, or PCS. Software sales that include multiple elements are typically allocated to the various elements using the relative stand-alone selling price method. We apply the usage-based royalty exception to recognize license revenue associated with software hosted by our customers because the predominant item to which the royalty relates is the license of intellectual property. Under the usage-based royalty exception, we recognize revenue on a monthly basis over the period during which the services are expected to be performed. Under the terms of our contractual arrangements with our service provider partners, we are entitled to payment of a monthly fee that is billed per subscriber for the month of service. Our software license revenue during the three and nine months ended September 30, 2018 was $10.5 million and $30.6 million , respectively, as compared to $9.3 million and $20.1 million for the same periods in the prior year. Hardware and Other Revenue We generate hardware and other revenue primarily from the sale of video cameras and cellular radio modules that provide access to our cloud-based platforms and, to a lesser extent, the sale of other devices, including image sensors and peripherals. We primarily transfer hardware to our customers upon delivery to the customer, which corresponds with the time at which the customer obtains control of the hardware. As a result, we recognize hardware and other revenue as we satisfy our performance obligations, which occurs when the hardware is received by our service provider partner or distributor, net of a reserve for estimated returns. There are a few contracts in which we provide shipping and handling services to the customer after control of the hardware transfers to the customer. In these instances, we have elected to account for shipping and handling costs as activities performed to fulfill the promise to transfer hardware to the customer and not as a separate promised service. Amounts due from the sale of hardware are payable in accordance with the terms of our agreements with our service provider partners or distributors, and are not contingent on resale to end-users, or to service provider partners in the case of sales of hardware to distributors. Payment for our hardware is typically due within 30 days from shipment, with the exception of certain hardware finance arrangements, which are paid over a 36-month period. Our terms for hardware sales sold directly to either service provider partners or distributors typically allow for the return of hardware up to one year past the date of sale. Our distributors sell directly to our service provider partners under terms between the two parties. When determining the amount of consideration we expect to be entitled to for the sale of our hardware, we estimate the variable consideration associated with customer returns. We record a reserve against revenue for hardware returns based on historical returns. For each of the twelve months ended September 30, 2018 and 2017 , our reserve against revenue for hardware returns was 2% of hardware and other revenue. We evaluate our hardware reserve on a quarterly basis or if there is an indication of significant changes in return experience. Historically, our returns of hardware have not significantly differed from our estimated reserve. In general, we provide assurance-type warranties related to the intended functionality of the products and services provided. These warranties were not identified as separate performance obligations. Hardware and other revenue also includes activation fees charged to service provider partners for activation of a new subscriber account on our platforms, as well as fees paid by service provider partners for our marketing services. Our service provider partners use services on our platforms, such as support tools and applications, to assist in the installation of our solutions in subscriber properties. This installation marks the beginning of the service period on our platforms and, on occasion, we earn activation revenue for fees charged for this service. The activation fee is non-refundable, separately negotiated and specified in our contractual arrangements with our service provider partners and is charged to the service provider partner for each subscriber activated on our platforms. The decision whether to charge an activation fee is based in part on the expected number of subscribers to be added by our service provider partners and as a result, many of our largest service provider partners do not pay an activation fee. Activation fees are not offered on a stand-alone basis separate from our SaaS offering and are billed and received at the beginning of the arrangement. We record activation fees initially as deferred revenue and we recognize these fees ratably over the expected term of the subscribers’ account which we estimate is ten years based on our annual attrition rate. The portion of these activation fees included in current and long-term deferred revenue as of our balance sheet date represents the amounts that will be recognized ratably as revenue over the following twelve months, or longer as appropriate, until the ten-year expected term is complete. The balance of deferred revenue for activation fees was $9.5 million and $10.5 million as of September 30, 2018 and December 31, 2017 , respectively, which combines current and long-term balances. Cost of Revenue Our cost of SaaS and license revenue primarily includes the amounts paid to wireless network providers and, to a lesser extent, the costs of running our network operation centers which are expensed as incurred, as well as royalty costs in connection with technology licensed from third-party providers. Our cost of SaaS and license revenue also includes our cost of software license revenue, which primarily includes the payroll and payroll-related costs of the department dedicated to providing service exclusively to those service providers that host the Connect platform. Our cost of software license revenue during the three and nine months ended September 30, 2018 was $0.4 million and $1.3 million , respectively, as compared to $0.4 million and $0.8 million for the same periods in the prior year. Our cost of hardware and other revenue primarily includes cost of raw materials and amounts paid to our third-party manufacturer for production and fulfillment of our cellular radio modules and image sensors, and procurement costs for our video cameras, which we purchase from an original equipment manufacturer, and other devices. Our cost of hardware and other revenue also includes royalty costs in connection with technology licensed from third-party providers. We record the cost of SaaS and license revenue as expenses are incurred, which corresponds to the delivery period of our services to our subscribers. We record the cost of hardware and other revenue when the hardware and other services are delivered to the service provider partner, which occurs when control of the hardware and other services transfers to the service provider partner. Our cost of revenue excludes amortization and depreciation. Contract Asset and Contract Liability Balances At contract inception, we assess the goods and services promised in our contracts with customers and identify a performance obligation for each distinct promise to transfer a good or service, or bundle of goods or services. To identify the performance obligations, we consider all of the goods or services promised in the contract, whether explicitly stated or implied based on customary business practices. We record a contract asset when we satisfy a performance obligation by transferring a promised good or service. Contract assets can be conditional or unconditional depending on whether another performance obligation must be satisfied before payment can be received. We receive payments from our service provider partners based on the billing schedule established in our contracts. All of the accounts receivable presented in the balance sheet represent unconditional rights to consideration. We do not have any assets from contracts containing conditional rights and we do not have any assets from satisfied performance obligations that have not been invoiced. Our contract assets consist of capitalized commission costs, which are discussed below in the “ Costs to Obtain or Fulfill a Contract ” section of Note 2 . The changes in our contract assets are as follows (in thousands): Three Months Ended Nine Months Ended Beginning of period balance $ 2,879 $ — Commission costs capitalized in period 489 4,344 Amortization of capitalized commission costs (490 ) (1,466 ) End of period balance $ 2,878 $ 2,878 Contract liabilities include payments received in advance of performance under the contract, and are realized with the associated revenue recognized under the contract. All of the deferred revenue presented in the balance sheet represents contract liabilities resulting from advance cash receipts from customers or amounts billed in advance to customers from the sale of services. Changes in deferred revenue are due to our performance under the contract as well as to cash received from new contracts for which services have not been provided. The changes in our contract liabilities are as follows (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning of period balance $ 11,971 $ 12,701 $ 12,678 $ 12,625 Revenue deferred in period 1,225 1,971 2,706 4,286 Revenue recognized from amounts included in contract liabilities (1,322 ) (1,970 ) (3,510 ) (4,209 ) End of period balance $ 11,874 $ 12,702 $ 11,874 $ 12,702 The revenue recognized from amounts included in contract liabilities primarily relates to prepayment contracts with customers as well as payments of activation fees. Costs to Obtain or Fulfill a Contract We recognize an asset related to the costs incurred to obtain a contract only if we expect to recover those costs and we would not have incurred those costs if the contract had not been obtained. We recognize an asset from the costs incurred to fulfill a contract if the costs (i) are specifically identifiable to a contract, (ii) enhance resources that will be used in satisfying performance obligations in future and (iii) are expected to be recovered. Based on the policy above, we capitalize a portion of our commission costs as an incremental cost of obtaining a contract. When calculating the incremental cost of obtaining a contract, we exclude any commission costs related to metrics that could be satisfied without obtaining a contract, including training-related metrics. We amortize our commission costs over a period of three years, which is consistent with the period over which the products and services related to the commission are transferred to the customer. The three-year period was determined based on our review of historical enhancements and upgrades to our products and services. We applied the portfolio approach to account for the amortization of contract costs as each contract has similar characteristics. The current portion of capitalized commission costs is included in other current assets within our condensed consolidated balance sheets. The non-current portion of capitalized commission costs is reflected in other assets within our condensed consolidated balance sheets. We amortized capitalized commission costs of $0.5 million and $1.5 million during the three and nine months ended September 30, 2018 , respectively. There were no amortized commission costs during the three and nine months ended September 30, 2017 . We review the capitalized costs for impairment at least annually. Impairment exists if the carrying amount of the asset recognized from contract costs exceeds the remaining amount of consideration we expect to receive in exchange for providing the goods and services to which such asset relates, less the costs that relate directly to providing those good and services and that have not been recognized as an expense. We did no t record an impairment loss on our capitalized commission costs or any other contract assets during the three and nine months ended September 30, 2018 and 2017 . Recent Accounting Pronouncements Adopted Revenue from Contracts with Customers (Topic 606): In May 2014, the Financing Accounting Standards Board, or FASB, and International Accounting Standards Board jointly issued Accounting Standards Update, or ASU, 2014-09, " Revenue from Contracts with Customers (Topic 606) ," a new revenue recognition standard that provides a framework for addressing revenue issues, improves the comparability of revenue recognition practices across industries, provides useful information to users of financial statements through improved disclosure requirements and simplifies the presentation of financial statements. From March to December 2016, amendments to Topic 606 were issued to clarify numerous accounting topics, including, but not limited to: (i) the implementation guidance on principal versus agent considerations, (ii) the identification of performance obligations, (iii) the licensing implementation guidance, (iv) the objective of the collectability criterion, (v) the application of the variable consideration guidance and modified retrospective transition method, (vi) the way in which impairment testing is performed and (vii) the disclosure requirements for revenue recognized from performance obligations. This guidance permits the use of either a full retrospective method or a modified retrospective method. This guidance was effective beginning January 1, 2018. On January 1, 2018, we adopted Topic 606 by applying the modified retrospective transition method to all of our contracts. Comparative information has not been restated and continues to be reported under the accounting standards in effect for the periods presented. The adoption of Topic 606 did not have a material impact on our revenue recognition policies, however, as a result of adopting the new standard, we changed our treatment of commissions paid to employees, which we previously expensed as incurred. Under the new standard, we capitalize a portion of our commission costs as an incremental cost of obtaining a contract and amortize our commission costs over a period of three years, which is consistent with the period over which the products and services related to the commission are transferred to the customer. Based on the results of our evaluation, the adoption of Topic 606 did not have a material impact on our condensed consolidated financial statements for the three and nine months ended September 30, 2018 . Additionally, the cumulative effect to the opening balance sheet on January 1, 2018 from the adoption of Topic 606 was not material. Other Accounting Standards : On May 10, 2017, the FASB issued ASU 2017-09, "Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting , " which amends the scope of modification accounting for share-based payment arrangements. The update provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under Accounting Standards Codification, or ASC, Topic 718. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions and classification of the awards are the same immediately before and after the modification. The amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. We adopted ASU 2017-09 during the first quarter of 2018 and the adoption of this ASU did no t have a material impact on our financial statements and related disclosures. On January 5, 2017, the FASB issued ASU 2017-01, "Business Combinations (Topic 805) - Clarifying the Definition of a Business , " which provides guidance to assist entities in evaluating when a set of transferred assets and activities is a business. To be considered a business, an acquisition would have to include an input and a substantive process that together significantly contribute to the ability to create outputs. The amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. We adopted ASU 2017-01 during the first quarter of 2018 and the adoption of this ASU did no t have a material impact on our financial statements and related disclosures. In January 2016, the FASB issued ASU 2016-01, " Recognition and Measurement of Financial Assets and Financial Liabilities (Topic 825-10) " and in February 2018, the FASB issued ASU 2018-03, "Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10)." These ASUs require entities to carry all investments in equity securities at fair value and recognize any changes in fair value in net income. Under these standards, equity investments that do not have readily determinable fair values are measured at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for an identical or a similar investment of the same issuer. The guidance in ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance in ASU 2018-03 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years beginning after June 15, 2018. We adopted ASU 2016-01 and ASU 2018-03 in 2018 and the adoption of these ASUs did no t have a material impact on our financial statements and related disclosures. Not Yet Adopted On June 16, 2016, the FASB issued ASU 2016-13, " Financial Instruments - Credit Losses (Topic 326)," which provides guidance designed to provide financial statement users with more information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. When determining such expected credit losses, the guidance requires companies to apply a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendment is effective on a modified retrospective basis for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted for fiscal years and interim periods beginning after December 15, 2018. We are currently assessing the impact this pronouncement may have on our trade receivables and notes receivables. On February 25, 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” or Topic 842, which requires lessees to recognize operating and financing lease liabilities and corresponding right-of-use assets on the balance sheet. The update also requires improved disclosures to help users of financial statements better understand the amount, timing and uncertainty of cash flows arising from leases. The amendments in this update are effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with early adoption permitted. We plan to adopt Topic 842 effective January 1, 2019. The update must be adopted using a modified retrospective approach. In July 2018, the FASB amended the update to allow entities to apply the transition requirements of Topic 842 at the adoption date rather than at the beginning of the earliest comparative period presented. We plan to use this optional transition method, which will require us to record the effect of initially applying Topic 842 as a cumulative-effect adjustment to retained earnings on January 1, 2019. We plan to use the package of practical expedients for the adoption of Topic 842, which will allow us not to reassess: (i) whether any expired or existing contracts are or contain leases, (ii) lease classification for any expired or existing leases and (iii) whether initial direct costs for any existing leases qualify for capitalization under Topic 842. Additionally, we plan to use the hindsight practical expedient when determining the lease term and assessing impairment of right-of-use assets. While we are still evaluating the impact the update will have on our consolidated financial statement

Accounts Receivable, Net

Accounts Receivable, Net	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Accounts Receivable, Net	Accounts Receivable, Net The components of accounts receivable, net are as follows (in thousands): September 30, December 31, Accounts receivable $ 58,913 $ 44,554 Allowance for doubtful accounts (1,502 ) (1,449 ) Allowance for product returns (1,950 ) (2,471 ) Accounts receivable, net $ 55,461 $ 40,634 For the three and nine months ended September 30, 2018 , we recorded a provision for doubtful accounts of less than $0.1 million and $0.1 million , respectively. For each of the three and nine months ended September 30, 2017 , we recorded a reduction to the provision for doubtful accounts of $0.4 million . For the three and nine months ended September 30, 2018 , we recorded a reserve for product returns in our hardware and other revenue of less than $0.1 million and $0.2 million , respectively, as compared to $0.6 million and $1.7 million for the same periods in the prior year. Historically, we have not experienced write-offs for uncollectible accounts or sales returns that have differed significantly from our estimates.

Inventory

Inventory	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Inventory	Inventory, Net The components of inventory, net are as follows (in thousands): September 30, December 31, Raw materials $ 5,973 $ 7,484 Finished goods 10,933 6,693 Total inventory, net $ 16,906 $ 14,177

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions	Acquisitions Connect and Piper Business Units from Icontrol Networks, Inc. On March 8, 2017 , in accordance with the asset purchase agreement we entered into with Icontrol Networks, Inc., or Icontrol, on June 23, 2016, we acquired certain assets and assumed certain liabilities of the Connect line of business and all of the outstanding equity interests of the two subsidiaries through which Icontrol conducted its Piper line of business, or the Acquisition. Connect provides an interactive security and home automation platform for service providers. Piper provides an all-in-one video and home automation hub. We expect the addition of new technology infrastructure, talent, key relationships and hardware devices to help accelerate our development of intelligent, data-driven smart residential and commercial property services. The cash consideration was $148.5 million , after the estimated working capital adjustment, of which $14.5 million was deposited in escrow and was released in accordance with the asset purchase agreement upon the finalization of indemnification obligations of Icontrol stockholders and the final determination of closing working capital. We used $81.5 million of cash on hand and drew $67.0 million under our senior line of credit with Silicon Valley Bank, or SVB, and a syndicate of lenders to fund the Acquisition. The Acquisition also included non-cash consideration. In accordance with the terms of the asset purchase agreement, we were obligated to assume the Icontrol 2013 Equity Incentive Plan and Icontrol 2003 Stock Plan, or collectively, the Icontrol Plans, and converted the 2,001,387 unvested employee stock options into 70,406 Alarm.com stock options using a conversion ratio stated in the agreement to convert the original exercise price and number of options. The fair value of the unvested stock options on the date of the Acquisition was $1.7 million calculated using a Black-Scholes model with a volatility and risk-free interest rate over the expected term of the options and the closing price of the Alarm.com common stock on the date of acquisition. We applied our graded vesting accounting policy to the fair value of these assumed options and determined $1.4 million of the fair value was attributable to pre-combination services and was included as a component of total purchase consideration. The remaining $0.3 million of the fair value was determined to be attributable to post-combination services and will be recognized over the remaining service periods of the stock options. The following table summarizes the assumptions used for estimating the fair value of stock options assumed from the Connect business unit of Icontrol: Nine Months Ended Volatility 42.7 - 44.4% Expected term 2.5 - 5.0 years Risk-free interest rate 1.4 - 2.0% Dividend rate — % The table below sets forth the purchase consideration and the fair value allocation of the tangible and intangible net assets acquired (in thousands): March 8, 2017 Calculation of Purchase Consideration: Cash paid, net of working capital adjustment $ 148,500 Assumed stock options 1,375 Total consideration $ 149,875 Estimated Tangible and Intangible Net Assets: Cash $ 211 Accounts receivable 11,421 Current assets 883 Long-term assets 4,446 Customer relationships 93,260 Developed technology 4,770 Trade name 170 Current liabilities (1,608 ) Long-term liabilities (288 ) Goodwill 36,610 Total estimated tangible and intangible net assets $ 149,875 Goodwill of $36.6 million reflects the value of acquired workforce and synergies we expect to achieve from integrating support for Connect's security service providers and for the Connect platform. The goodwill will be deductible for tax purposes. We allocated goodwill to reporting units based on expected benefit from our synergies, and have allocated the goodwill to the Alarm.com segment. The purchase price allocation for the Acquisition was finalized during the third quarter of 2017. The final fair value of the assets and liabilities related to the Acquisition reflects an increase of $0.1 million in tangible assets, net and a decrease of $0.1 million in goodwill based on working capital adjustments identified by us. Fair Value of Net Assets Acquired and Intangibles In accordance with ASC 805, the business units acquired in the Acquisition constituted a business and the assets and liabilities were recorded at their respective fair values as of March 8, 2017 . We developed our estimate of the fair value of intangible net assets using a multi-period excess earnings method for customer relationships, the relief from royalty method for the developed technology and the relief from royalty method for the trade name. Customer Relationships We recorded the customer relationships intangible separately from goodwill based on determination of the length, strength and contractual nature of the relationship that Connect shared with its customers. We valued two groups of customer relationships using the multi-period excess earnings method, an income approach. We used several assumptions in the income approach, including attrition and renewal rate, margin and discount rate. We are amortizing the first customer relationship, valued at $92.5 million , on an attribution basis derived from the discounted cash flows of the model over an estimated useful life of twelve years and the second group of customer relationships, valued at $0.8 million , on the same basis, over an estimated useful life of four years. Developed Technology Developed technology primarily consists of intellectual property of proprietary software that is marketed for sale. The Connect platform is software for interactive security, automation and related solutions that is typically deployed and operated by the service provider in its own network operations center. We valued the developed technology by applying the relief from royalty method, an income approach. We used several assumptions in the relief from royalty method, which included royalty rate and discount rate. We are amortizing the Connect developed technology, valued at $4.4 million , on an attribution method based on the discounted cash flows of the model over an estimated useful life of three years. Other developed technologies, valued at $0.3 million , were also acquired. Trade Name We determined that there was no fair value for the Connect trade name as the largest service provider partner for Connect had re-branded the interactive security and automation platform and marketed it under the service provider partner 's own name. We valued the other trade names acquired using a relief from royalty method. We used several assumptions in the income approach, including royalty and discount rates. We are amortizing the other trade names, valued at $0.2 million , on an attribution basis derived from the discounted cash flows of the model over an estimated useful life of three years. Deferred Tax Asset The equity interests in the subsidiaries we acquired provided for a carryover tax basis in goodwill and intangible assets that arose from a previous acquisition. We recorded a deferred tax asset of $4.1 million that represents the excess of the carryover tax basis in those previously acquired goodwill and intangible assets over the fair value of goodwill and intangible assets we recorded on the date of the Acquisition. ObjectVideo On January 1, 2017 , in accordance with an asset purchase agreement, we acquired certain assets of ObjectVideo, Inc., or ObjectVideo, that constituted a business now called ObjectVideo Labs, LLC, or ObjectVideo Labs, including products, technology portfolio and engineering team. ObjectVideo is a pioneer in the fields of video analytics and computer vision with technology that extracts meaning and intelligence from video streams in real-time to enable object tracking, pattern recognition and activity identification. We anticipate that the ObjectVideo Labs engineering team's capabilities and expertise will accelerate our research and development of video services and video analytic applications. In addition, ObjectVideo Labs will continue to perform advanced research and engineering services for the federal government. The consideration included $6.0 million of cash paid at closing. The table below sets forth the purchase consideration and the fair value allocation of the tangible and intangible net assets acquired (in thousands): January 1, 2017 Calculation of Purchase Consideration: Cash paid, net of working capital adjustment $ 6,000 Estimated Tangible and Intangible Net Assets: Developed technology $ 3,800 Current liabilities (58 ) Goodwill 2,258 Total estimated tangible and intangible net assets $ 6,000 Goodwill of $2.3 million reflects the value of acquired workforce and expected synergies from pairing ObjectVideo Labs' video analytics capabilities with our offerings. The goodwill will be deductible for tax purposes. The purchase price allocation for the ObjectVideo Labs acquisition was finalized during the third quarter of 2017. The final fair value of the assets and liabilities related to the ObjectVideo Labs acquisition reflects an increase of $0.4 million in developed technology and a decrease of $0.4 million in goodwill as well as a corresponding change to amortization of the developed technology based on our use of the replacement cost method to value the developed technology. Fair Value of Net Assets Acquired and Intangibles In accordance with ASC 805, the assets and liabilities of ObjectVideo Labs we acquired were recorded at their respective fair values as of January 1, 2017 , the date of the acquisition. We developed our estimate of the fair value of intangible assets using the replacement cost method for the developed technology. Developed Technology Developed technology recorded separately from goodwill consists of intellectual property such as proprietary software used internally for revenue producing activities. ObjectVideo Labs proprietary software consists of source code and video analytics testing programs used internally to provide video analytics consulting services and research and development to customers and for the SaaS Alarm.com platform. We valued the developed technology by applying the replacement cost method. We used several assumptions in this cost approach, which included analyzing costs that a company would expect to incur to recreate an asset of equivalent utility. We are amortizing the developed technology, valued at $3.8 million , on a straight-line basis over an estimated useful life of two years which coincides with the rapidly developing technology of video analytics. Unaudited Pro Forma Information The following unaudited pro forma data is presented as if the Acquisition and ObjectVideo Labs were included in our historical consolidated statements of operations beginning January 1, 2016. These pro forma results do not necessarily represent what would have occurred if all the business combinations had taken place on January 1, 2016, nor do they represent the results that may occur in the future. This pro forma financial information includes our historical financial statements and those of our business combinations with the following adjustments: (i) we adjusted the pro forma amounts for income taxes, (ii) we applied interest expense as if the additional borrowing for the acquisitions were as of January 1, 2016, (iii) we adjusted for amortization expense assuming the fair value adjustments to intangible assets had been applied beginning January 1, 2016, and (iv) we adjusted for transaction fees incurred and reclassified them to January 1, 2016. The pro forma adjustments were based on available information and upon assumptions that we believe are reasonable to reflect the impact of these acquisitions on our historical financial information on a supplemental pro forma basis, as follows (in thousands): Pro Forma Revenue $ 261,214 Net income 35,380 Net income per diluted share $ 0.72 Business Combinations in Operations The operations of each of the business combinations discussed above were included in the condensed consolidated financial statements as of each of their respective acquisition dates. The following table presents the revenue and earnings of the business combinations in the year of acquisition as reported within the condensed consolidated financial statements (in thousands): Nine Months Ended Revenue $ 22,996 Net loss (3,021 ) For the Acquisition, we included the results of Connect's operations since its acquisition date in the Alarm.com segment and the results of Piper's operations since its acquisition date in the Other segment. We included the results of ObjectVideo Labs operations since its acquisition date in the Alarm.com segment.

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Net	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, Net	Goodwill and Intangible Assets, Net The changes in goodwill by reportable segment are outlined below (in thousands): Alarm.com Other Total Balance as of January 1, 2018 $ 63,591 $ — $ 63,591 Goodwill acquired — — — Balance as of September 30, 2018 $ 63,591 $ — $ 63,591 There were no impairments of goodwill during the three and nine months ended September 30, 2018 and 2017 . The following table reflects changes in the net carrying amount of the components of intangible assets (in thousands): Customer Developed Trade Name Total Balance as of January 1, 2018 $ 88,526 $ 5,532 $ 228 $ 94,286 Amortization (8,446 ) (2,895 ) (77 ) (11,418 ) Balance as of September 30, 2018 $ 80,080 $ 2,637 $ 151 $ 82,868 We recorded $3.8 million and $11.4 million of amortization related to our intangible assets for the three and nine months ended September 30, 2018 , respectively, as compared to $3.7 million and $8.7 million for the same periods in the prior year. There were no impairments of long-lived intangible assets during the three and nine months ended September 30, 2018 and 2017 . The following tables reflect the weighted average remaining life and carrying value of finite-lived intangible assets (in thousands): September 30, 2018 Gross Accumulated Net Weighted- Customer relationships $ 103,926 $ (23,846 ) $ 80,080 10.2 Developed technology 13,959 (11,322 ) 2,637 1.8 Trade name 1,084 (933 ) 151 2.6 Other 234 (234 ) — — Total intangible assets $ 119,203 $ (36,335 ) $ 82,868 December 31, 2017 Gross Accumulated Net Weighted- Customer relationships $ 103,926 $ (15,400 ) $ 88,526 10.8 Developed technology 13,959 (8,427 ) 5,532 2.1 Trade name 1,084 (856 ) 228 3.3 Other 234 (234 ) — — Total intangible assets $ 119,203 $ (24,917 ) $ 94,286

Other Assets

Other Assets	9 Months Ended
	Sep. 30, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets Patent Licenses From time to time, we enter into agreements to license patents. The carrying value, net of amortization, was $2.0 million and $2.4 million as of September 30, 2018 and December 31, 2017 , respectively. As of September 30, 2018 and December 31, 2017 , $0.4 million and $0.5 million of patent licenses were included in other current assets and $1.6 million and $1.9 million of patent licenses were included in other assets, respectively. We have $4.9 million of historical cost in patent licenses related to such agreements. We are amortizing the patent licenses over the estimated useful lives of the patents, which range from 3 years to 11 years . Amortization expense on patent licenses was $0.1 million and $0.4 million for the three and nine months ended September 30, 2018 , respectively, as compared to $0.2 million and $0.6 million for the same periods in the prior year, which is included in cost of SaaS and license revenue in our condensed consolidated statements of operations. Loan to a Distribution Partner In September 2016, we entered into dealer and loan agreements with a distribution partner. The dealer agreement enables the distribution partner to resell our SaaS services and hardware to their subscribers. Under the loan agreements, we agreed to loan the distribution partner up to $4.0 million , collateralized by all assets owned by the distribution partner. The advance period for the loan was amended in August 2017 to begin each year on September 1 and end each year on December 31. Interest on the outstanding principal accrued at a rate per annum equal to the greater of 6.0% or the Eurodollar Base Rate, or LIBOR, plus 4.0% , as determined on the first date of each annual advance period. The repayment of principal and accrued interest was due in three installments beginning in July and ending in August following the advance period. The term date of the loan was August 31, 2019; however, the borrower had the option to extend the term of the loan for two successive terms of one year each. In May 2018, the loan agreement with our distribution partner was amended to convert the entire $4.0 million note receivable outstanding into a $4.0 million term loan. The term loan matures on July 31, 2022 and requires annual principal repayments of $1.0 million on July 31 of each year, commencing on July 31, 2019. The term loan also requires monthly interest payments, with interest accruing on the outstanding principal balance at a rate per annum equal to 6.0% through June 30, 2018 and a rate per annum equal to the LIBOR rate on the first of any interest period plus 7.0% beginning on July 1, 2018. As of September 30, 2018 , $1.0 million and $3.0 million of the note receivable balance was included in other current assets and other assets in our condensed consolidated balance sheets, respectively. As of December 31, 2017 , the $4.0 million note receivable balance was included in other current assets. In April 2017, we entered into a subordinated credit agreement with an affiliated entity of the distribution partner and loaned the affiliated entity $3.0 million , with a maturity date of November 21, 2022. Interest on the outstanding principal balance accrues at a rate of 8.5% per annum and requires monthly interest payments. The $3.0 million loan receivable balance was included in other assets as of September 30, 2018 and December 31, 2017 . For the three and nine months ended September 30, 2018 , we recognized $0.2 million and $0.9 million of revenue from the distribution partners associated with these loans, respectively, as compared to $0.2 million and $1.0 million for the same periods in the prior year. Prepaid Expenses As of September 30, 2018 , $9.4 million of prepaid expenses were included in other current assets, of which $3.8 million related to prepayments for inventory. As of December 31, 2017 , $3.8 million of prepaid expenses were included in other current assets.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following table presents our assets and liabilities measured at fair value on a recurring basis (in thousands): Fair Value Measurements on a Recurring Basis as of Fair value measurements in: Level 1 Level 2 Level 3 Total Assets: Money market account $ 83,022 $ — $ — $ 83,022 Total $ 83,022 $ — $ — $ 83,022 Liabilities: Subsidiary unit awards $ — $ — $ 389 $ 389 Total $ — $ — $ 389 $ 389 Fair Value Measurements on a Recurring Basis as of Fair value measurements in: Level 1 Level 2 Level 3 Total Assets: Money market account $ 65,620 $ — $ — $ 65,620 Total $ 65,620 $ — $ — $ 65,620 Liabilities: Subsidiary unit awards $ — $ — $ 3,160 $ 3,160 Total $ — $ — $ 3,160 $ 3,160 The following table summarizes the change in fair value of the Level 3 liabilities for subsidiary unit awards with significant unobservable inputs (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning of period balance $ 389 $ 2,912 $ 3,160 $ 2,768 Total losses included in earnings — 139 31 283 Settlements — — (2,802 ) — End of period balance $ 389 $ 3,051 $ 389 $ 3,051 The money market account is included in our cash and cash equivalents in our condensed consolidated balance sheets. Our money market assets are valued using quoted prices in active markets. The liability for the subsidiary unit awards relates to agreements established with employees of our subsidiaries for cash awards contingent upon the subsidiary companies meeting certain financial milestones such as revenue, working capital, EBITDA and EBITDA margin. We account for these subsidiary awards using fair value and establish liabilities for the future payment for the repurchase of subsidiary units under the terms of the agreements based on estimating revenue, working capital, EBITDA and EBITDA margin of the subsidiary units over the periods of the awards through the anticipated repurchase dates. We estimated the fair value of each liability by using a Monte Carlo simulation model for determining each of the projected measures by using an expected distribution of potential outcomes. The fair value of each liability is calculated with thousands of projected outcomes, the results of which are averaged and then discounted to estimate the present value. At each reporting date until the respective payment dates, we will remeasure these liabilities, using the same valuation approach based on the applicable subsidiary's revenue and future collection of financed customer receivables, the unobservable inputs, and we will record any changes in the employee's compensation expense. Some of the awards are subject to the employees' continued employment and therefore recorded on a straight-line basis over the remaining service period. During the nine months ended September 30, 2018 , we settled $2.8 million of the liability related to the subsidiary unit awards. The remaining liability balances are included in either accounts payable, accrued expenses and other current liabilities or other liabilities in our condensed consolidated balance sheets (see Note 10 ). We monitor the availability of observable market data to assess the appropriate classification of financial instruments within the fair value hierarchy. Changes in economic conditions or model-based valuation techniques may require the transfer of financial instruments from one fair value level to another. In such instances, the transfer is reported at the beginning of the reporting period. There were no transfers between Levels 1, 2 or 3 during the three and nine months ended September 30, 2018 and 2017 . We also monitor the value of the investments for other-than-temporary impairment on a quarterly basis. No other-than-temporary impairments occurred during the three and nine months ended September 30, 2018 and 2017 .

Liabilities

Liabilities	9 Months Ended
	Sep. 30, 2018
Payables and Accruals [Abstract]
Liabilities	Liabilities The components of accounts payable, accrued expenses and other current liabilities are as follows (in thousands): September 30, December 31, Accounts payable $ 19,646 $ 17,008 Accrued expenses 35,007 4,301 Subsidiary unit awards 225 2,802 Other current liabilities 3,116 4,973 Accounts payable, accrued expenses and other current liabilities $ 57,994 $ 29,084 The components of other liabilities are as follows (in thousands): September 30, December 31, Deferred rent $ 11,550 $ 12,279 Other liabilities 1,728 1,646 Other liabilities $ 13,278 $ 13,925

Debt, Commitments and Contingen

Debt, Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Debt, Commitments and Contingencies Disclosure [Abstract]
Debt, Commitments and Contingencies	Debt, Commitments and Contingencies The debt, commitments and contingencies described below would require us, or our subsidiaries, to make payments to third parties under certain circumstances. Debt On October 6, 2017, we entered into a $125.0 million senior secured revolving credit facility, or the 2017 Facility, with SVB, as administrative agent, PNC Bank, National Association, as documentation agent, and a syndicate of lenders. Upon entry into the 2017 Facility, we borrowed $72.0 million , which was used to repay the previously outstanding balance under our previous credit facility. The 2017 Facility matures in October 2022 and includes an option to further increase the borrowing capacity to $175.0 million with the consent of the lenders. Costs incurred in connection with the 2017 Facility were capitalized and are being amortized as interest expense over the term of the 2017 Facility. The 2017 Facility is secured by substantially all of our assets, including our intellectual property. During the three and nine months ended September 30, 2018 , we repaid $1.0 million and $3.0 million of the outstanding balance of the 2017 Facility, respectively, as compared to repayments of $0.7 million and $1.7 million under our prior facility during the same periods in the prior year. The outstanding principal balance on the 2017 Facility accrues interest at a rate equal to, at our option, either (1) LIBOR, plus an applicable margin based on our consolidated leverage ratio, or (2) the highest of (a) the Wall Street Journal prime rate, (b) the Federal Funds rate plus 0.50% , or (c) LIBOR plus 1.00% plus an applicable margin based on our consolidated leverage ratio. For the three and nine months ended September 30, 2018 , we elected for the outstanding principal balance to accrue interest at LIBOR plus 1.50% , LIBOR plus 1.75% , LIBOR plus 2.00% , and LIBOR plus 2.50% when our consolidated leverage ratio is less than 1.00 :1.00, greater than or equal to 1.00 :1.00 but less than 2.00 :1.00, greater than or equal to 2.00 :1.00 but less than 3.00 :1.00 and greater than or equal to 3.00 :1.00, respectively. The 2017 Facility also carries an unused line commitment fee of 0.20% . For the nine months ended September 30, 2018 , the effective interest rate on the credit facilities was 4.05% , as compared to 4.38% for the same period in the prior year. The carrying value of the 2017 Facility was $68.0 million and $71.0 million as of September 30, 2018 and December 31, 2017 , respectively. The 2017 Facility includes a variable interest rate that approximates market rates and, as such, we classified the liability as Level 2 within the fair value hierarchy and determined that the carrying amount of the 2017 Facility approximated its fair value as of September 30, 2018 and December 31, 2017 . The 2017 Facility contains various financial and other covenants that require us to maintain a maximum consolidated leverage ratio not to exceed 3.50 :1.00 and a consolidated fixed charge coverage ratio of at least 1.25 :1.00. As of September 30, 2018 , we were in compliance with all financial and non-financial covenants and there were no events of default. Commitments and Contingencies Repurchase of Subsidiary Units In 2011, we formed a subsidiary that offers to professional residential property management and vacation rental management companies technology solutions for remote monitoring and control of properties, including access control and energy management. Since its formation, we granted an award of subsidiary stock to the founder and president. The vesting of the award is based upon the subsidiary meeting certain minimum financial targets from the date of commercial availability, which was determined to be June 1, 2013, until the fourth anniversary. In 2016, we amended the term of the award, extending the valuation date for the first payment in cash to December 31, 2017, amending the financial targets and allowing for payments in cash based on the future collection of financed customer receivables from 2018 to 2020 that existed as of the valuation date. During the nine months ended September 30, 2018 , we settled $2.8 million of the liability related to the subsidiary unit awards. We recorded a liability of $0.2 million in accounts payable, accrued expenses and other current liabilities and $0.2 million in other liabilities related to this commitment in our condensed consolidated balance sheet as of September 30, 2018 . We recorded a liability of $2.8 million in accounts payable, accrued expenses and other current liabilities and a liability of $0.4 million in other liabilities related to this commitment in our condensed consolidated balance sheet as of December 31, 2017 . At each reporting date until the respective payment dates, we will remeasure these liabilities, and we will record any changes in fair value in general and administrative expense (see Note 8 ). Leases We lease office space and office equipment under non-cancelable operating leases with various expiration dates through 2026. We recognize rent expense for lease payments on a straight-line basis over the expected lease term and amortize tenant improvement allowances over the term of the lease. In August 2014, we signed a lease for new office space in Tysons, Virginia, where we relocated our headquarters in February 2016. The lease term ends in 2026 and includes a five -year renewal option, an $8.0 million tenant improvement allowance and scheduled rent increases. During 2016, we entered into amendments to this lease which provided for 30,662 square feet of additional office space and an additional $1.7 million in tenant improvement allowance. We took possession of the additional space in February 2017 and we were allowed to utilize the tenant improvement allowance for design prior to moving into the space. In October 2018, we entered into another amendment to the lease for our corporate headquarters, which provides for 23,493 square feet of additional office space and an additional $1.1 million in tenant improvement allowance. We took possession of the additional space in November 2018 and have not utilized the tenant improvement allowance. The amended lease term ends in 2026 and includes future minimum lease payments of approximately $0.1 million for the year ending September 30, 2019, $1.8 million for the two-year period ending September 30, 2021, $2.0 million for the two-year period ending September 30, 2023 and $2.9 million beyond September 30, 2023. As of September 30, 2018 , $9.7 million of the total $10.8 million tenant improvement allowance was utilized. For the three and nine months ended September 30, 2018 , rent expense was $1.1 million and $4.5 million , respectively, as compared to $1.6 million and $4.5 million for the same periods in the prior year. Indemnification Agreements We have various agreements that may obligate us to indemnify the other party to the agreement with respect to certain matters. Generally, these indemnification provisions are included in contracts arising in the normal course of business. Although we cannot predict the maximum potential amount of future payments that may become due under these indemnification agreements, we do not believe any potential liability that might arise from such indemnity provisions is probable or material. Letters of Credit As of September 30, 2018 and December 31, 2017 , we had no outstanding letters of credit under our 2017 Facility. Legal Proceedings In September 2014, Icontrol filed a Complaint in the United States District Court, District of Delaware, asserting that SecureNet infringes certain U.S. Patents owned by Icontrol, patents now owned by Alarm.com through a subsidiary. In March 2015, Icontrol voluntarily agreed to dismiss the case, reserving the right to refile. In September 2015, Icontrol refiled the case against SecureNet in the same district court alleging infringement of some of the same patents. SecureNet filed petitions for inter partes review, or IPR, of the patents-in-suit before the U.S. Patent Trial and Appeal Board, or PTAB. Proceedings as to one of the patents in suit (United States Patent Number 7,855,635) was instituted, resulting in the cancellation of some, but not all, claims of that patent. That decision is currently before the Court of Appeals for the Federal Circuit. The PTAB has rejected the remaining applications for inter partes review. SecureNet requested rehearing of the rejection as to one of the patents in suit, which request has been rejected by the PTAB. In April 2018, the Court issued an order construing certain patent claim terms. On October 30, 2018, SecureNet filed motions for summary judgment and to exclude portions of the opinions submitted by Alarm.com’s experts. The Court has scheduled a hearing on the motions for December 3, 2018. The Court has scheduled commencement of trial in February 2019. On June 2, 2015, Vivint, Inc., or Vivint, filed a lawsuit against us in U.S. District Court, District of Utah, alleging that our technology directly and indirectly infringes six patents that Vivint purchased. Vivint is seeking permanent injunctions, enhanced damages and attorneys' fees. We answered the complaint on July 23, 2015. Among other things, we asserted defenses based on non-infringement and invalidity of the patents in question. On August 19, 2016, the U.S. District Court, District of Utah stayed the litigation pending inter partes review by the PTAB of five of the patents in suit. In March 2017, the PTAB issued final written decisions relating to two patents finding all challenged claims unpatentable. In May 2017, the PTAB issued final written decisions relating to the remaining patents that found certain claims unpatentable, while certain other claims were not found to be unpatentable. Vivint has appealed the decisions to the U.S. Court of Appeals for the Federal Circuit, or the Federal Circuit, and we have cross-appealed. In July 2018, the Federal Circuit issued orders affirming the PTAB’s March 2017 decisions that invalidated all challenged claims of two patents. The Federal Circuit scheduled oral argument for December 3, 2018 on the appeal relating to three of the remaining patents in suit. The U.S. District Court, District of Utah lifted the stay on the litigation on June 26, 2017, and Vivint is proceeding with its case on four of the six patents in its complaint. Fact discovery is scheduled to close on or about December 7, 2018, and no trial date has been set. In September 2017, the U.S. Patent and Trademark Office, or PTO, ordered ex parte reexaminations of certain claims of two of the remaining patents in suit, at our request. On October 30, 2018 and November 5, 2018, the PTO issued final office actions in the pending reexaminations rejecting all claims being examined as unpatentable over the prior art. Should Vivint prevail on its claims that one or more elements of our solution infringe one or more of its patents, we could be required to pay damages of Vivint’s lost profits and/or a reasonable royalty for sales of our solution, enjoined from making, using and selling our solution if a license or other right to continue selling such elements is not made available to us or we are unable to design around such patents, and required to pay ongoing royalties and comply with unfavorable terms if such a license is made available to us. The outcome of the legal claim and proceeding against us cannot be predicted with certainty. We believe we have valid defenses to Vivint’s claims. Based on currently available information, we determined a loss is not probable or reasonably estimable at this time. On December 30, 2015, a putative class action lawsuit was filed against us in the U.S. District Court for the Northern District of California, or the Court, alleging violations of the Telephone Consumer Protection Act, or TCPA. The complaint does not allege that Alarm.com itself violated the TCPA, but instead seeks to hold us responsible for the marketing activities of one of our service providers as well as calls made by one of this service provider’s sub-dealer agents under principles of agency and vicarious liability. On August 30, 2018, we reached an agreement in principle to settle the case for total cash consideration of $28.0 million . On October 25, 2018, we entered into a definitive settlement agreement, or Settlement Agreement, and submitted it to the Court for approval. In entering into the definitive settlement agreement, we are making no admission of liability. Pursuant to the Settlement Agreement, among other things, (1) we agreed to pay total cash consideration of $28.0 million into a settlement fund, (2) we agreed to implement certain business practice changes to increase awareness of TCPA compliance, (3) each party to the Settlement Agreement agreed to a mutual release of claims relating to any claim or potential claim relating to the marketing activities described in the complaint, and (4) each party covenanted not to sue the other with regard to the released claims. In addition, we have agreed to no longer allow the service provider identified in the litigation as purportedly violating the TCPA to continue activating new accounts for Alarm.com products and services after preliminary Court approval of the Settlement Agreement. We will be required to make an initial payment of $5.0 million to the settlement administrator within ten business days of preliminary approval by the Court of the Settlement Agreement. The remaining payment will take place ten business days after the effective date of the Settlement Agreement, which is five business days following the later of the following events: (1) the date upon which the time expires for filing a notice of appeal of the Court’s Final Approval Order and Judgment; or (2) if there is an appeal or appeals of the Final Approval Order and Judgment, and the appellate court enters an order either dismissing the appeal(s) or affirming the Final Approval Order and Judgment without material modification, the date upon which the time expires for seeking review of that order. The release of claims includes all alleged damages incurred related to the lawsuit. Any attorneys’ fees awarded by the Court and all costs of notice and claims administration will be paid from the settlement fund. The Settlement Agreement is subject to approval by the Court. If the Court preliminarily approves the settlement, the Settlement Agreement provides for a period of time during which class members will be notified of the settlement and given an opportunity to file a claim form to receive a settlement payment, opt out of the class, object to the settlement or do nothing. We expect that the Court will schedule a fairness hearing to occur after the notice period, at which time the parties will request final approval of the settlement and at which any objectors to the settlement will be heard. If the Court gives final approval to the settlement, the release will be effective as to all class members who do not validly opt out of the class, regardless of whether they filed a claim form and received a payment. The $28.0 million settlement is reflected in general and administrative expenses within our condensed consolidated statements of operations for the three and nine months ended September 30, 2018 . The unpaid amount of the settlement is reflected as an accrued expense in accounts payable, accrued expenses and other current liabilities within our condensed consolidated balance sheet as of September 30, 2018 . On August 14, 2017, Alarm.com filed a lawsuit against ABS Capital Partners, Inc., ABS Partners V, LLC, ABS Partners VII, LLC, and Ralph Terkowitz in the Delaware Court of Chancery, or the Chancery Court. The complaint sought declaratory and injunctive relief preventing the defendants from using Alarm.com’s confidential information and trade secrets to compete with Alarm.com, and preventing the defendants from executing their planned transaction to invest in two companies (ipDatatel, LLC, or ipDatatel, and Resolution Products, Inc., or Resolution Products). The complaint alleged claims of breach of fiduciary duty, aiding and abetting a breach of fiduciary duty, misappropriation of trade secrets, and misappropriation of confidential information, in connection with the defendants’ planned investment. On September 22, 2017, Alarm.com filed an amended complaint against ABS Capital Partners, Inc., ABS Partners V, LLC, and ABS Partners VII, LLC, alleging claims for misappropriation of trade secrets and misappropriation of confidential information. The amended complaint seeks damages, declaratory relief, and injunctive relief enjoining ABS Capital Partners, Inc., ABS Partners V, LLC, and ABS Partners VII, LLC from using Alarm.com’s trade secrets and confidential information to compete with Alarm.com. On October 6, 2017, the defendants filed a motion to dismiss the lawsuit. On June 15, 2018, the Chancery Court dismissed our complaint. On July 13, 2018, Alarm.com filed a Notice of Appeal with the Delaware Supreme Court. On August 30, 2018, Alarm.com filed its Opening Brief in the Delaware Supreme Court. The defendants filed a response on October 1, 2018, and Alarm.com filed a reply on October 16, 2018. On August 24, 2017, Alarm.com Incorporated and its wholly owned subsidiary ICN Acquisition, LLC, filed a patent infringement complaint against ipDatatel, in the United States District Court for the Eastern District of Texas. The parties subsequently stipulated to transfer the case to the Southern District of Texas. The complaint seeks injunctive relief to stop the further sale of the infringing ipDatatel’s products and systems, and damages for the infringement of Alarm.com’s patents. The complaint asserts that the technology in the ipDatatel products infringe one or more claims of Alarm.com’s patents: United States Patent Numbers 7,113,090; 7,633,385; 7,956,736; 8,478,871; and 9,141,276. If the litigation is successful, Alarm.com will be entitled to receive monetary damages, injunctive relief, and any other relief, including attorneys' fees, from ipDatatel. The Court has scheduled commencement of trial in August 2019. ipDatatel's motion for dismissal based on alleged patent ineligibility as to each patent in suit was denied without prejudice but ipDatatel renewed the motion. On July 26, 2018, ipDatatel answered the complaint by denying the patent infringement allegations and asserting several affirmative defenses, including invalidity and unenforceability. ipDatatel also asserted antitrust counterclaims based on alleged inequitable conduct in connection with the prosecution of one or more patents-in-suit. In September 2018, ipDataTel filed petitions for inter partes review of four of the patents-in-suit before the PTAB. On October 19, 2018, the Court issued a claim construction which, among other things, determined that certain claim terms of two of the patents-in-suit were indefinite. On April 25, 2017, Alarm.com Incorporated and its wholly owned subsidiary ICN Acquisition, LLC, filed a patent infringement complaint against Protect America, Inc., or Protect America, and SecureNet Technologies, LLC, or SecureNet, in the United States District Court for the Eastern District of Virginia. The complaint seeks injunctive relief to stop the further sale of the infringing Protect America and SecureNet products and systems, and damages for the infringement of Alarm.com’s patents. The complaint asserts that the technology in the Protect America and SecureNet Alarm Systems products infringe one or more claims of Alarm.com’s patents: United States Patent Numbers 7,113,090; 7,633,385; 8,395,494; 8,493,202; 8,612,591; 8,860,804; and 9,141,276. If the litigation is successful, Alarm.com will be entitled to receive monetary damages, injunctive relief, and any other relief, including attorneys' fees, from Protect America and SecureNet. In June 2017, Alarm.com filed an amended complaint against Protect America only and voluntarily dismissed SecureNet from the suit, reserving the right to refile. In September 2017, Alarm.com voluntarily dismissed the amended complaint in the United States District Court of the Eastern District of Virginia and refiled a complaint against Protect America, with substantially the same allegations, in the United States District Court of the Eastern District of Texas. The parties subsequently stipulated to transfer the case to the Western District of Texas. The Court has scheduled a claim construction hearing for May 2019, but has not yet scheduled a jury trial. On March 29, 2018, a putative class action lawsuit was filed against us by Nick Fisher in the U.S. District Court for the Northern District of Illinois, alleging violations of the TCPA, and the Telemarketing And Consumer Fraud and Abuse Prevention Act, or TCFAPA. The complaint alleges that Alarm.com and another defendant, Nortek Security & Control LLC, violated the TCPA and TCFAPA through purportedly unauthorized telephone calls to Fisher, and seeks to hold us responsible for the alleged calls, including under principles of agency and vicarious liability. The complaint seeks monetary damages under the TCPA and TCFAPA, injunctive relief, and other relief, including attorneys' fees. We answered the complaint and filed a motion to dismiss the complaint on June 18, 2018. On November 1, 2018, the Court granted our motion to dismiss the complaint without prejudice as to Plaintiff’s claims alleging vicarious liability for violations of the TCPA, and with prejudice as to Plaintiff’s remaining claims. In addition, we may be a party to litigation and subject to claims incident to the ordinary course of business, and we may be required to provide indemnification to certain of our service provider partners for certain claims regarding our solutions. Although the results of litigation and claims cannot be predicted with certainty, we currently believe that the final outcome of these ordinary course matters will not have a material adverse effect on our business. Other than the preceding matters, we are not a party to any lawsuit or proceeding that, in the opinion of management, is reasonably possible or probable of having a material adverse effect on our financial position, results of operations or cash flows. We reserve for contingent liabilities based on ASC 450, “ Contingencies ,” when it is determined that a liability, inclusive of defense costs, is probable and reasonably estimable. Litigation is subject to many factors that are difficult to predict, so there can be no assurance that, in the event of a material unfavorable result in one or more claims, we will not incur material costs.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense is included in the following line items in the condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Sales and marketing $ 301 $ 181 $ 855 $ 359 General and administrative 1,191 584 3,700 1,908 Research and development 1,965 1,141 5,115 2,867 Total stock-based compensation expense $ 3,457 $ 1,906 $ 9,670 $ 5,134 The following table summarizes the components of non-cash stock-based compensation expense (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Stock options and assumed options $ 850 $ 939 $ 2,666 $ 3,005 Restricted stock units 2,585 936 6,900 2,029 Restricted stock awards — — 1 19 Employee stock purchase plan 22 31 103 81 Total stock-based compensation expense $ 3,457 $ 1,906 $ 9,670 $ 5,134 Tax benefit from stock-based awards $ 2,958 $ 6,059 $ 6,899 $ 11,645 We granted an aggregate of 4,000 and 180,500 stock options pursuant to our 2015 Equity Incentive Plan, or 2015 Plan, during the three and nine months ended September 30, 2018 , respectively, as compared to an aggregate of 8,050 and 245,600 stock options for the same periods in the prior year. There were 281,709 and 721,573 stock options exercised during the three and nine months ended September 30, 2018 , respectively, as compared to 425,376 and 943,797 stock options for the same periods in the prior year. We granted an aggregate of 54,300 and 266,470 restricted stock units during the three and nine months ended September 30, 2018 , respectively, as compared to an aggregate of 40,150 and 367,350 restricted stock units for the same periods in the prior year. There were 8,168 and 21,714 restricted stock units that vested during the three and nine months ended September 30, 2018 , respectively. No restricted stock units vested during the three and nine months ended September 30, 2017 .

Earnings (Loss) Per Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share Basic and Diluted Earnings (Loss) Per Share The components of basic and diluted earnings (loss) per share, or EPS, are as follows (in thousands, except share and per share amounts): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net (loss) / income $ (7,652 ) $ 15,103 $ 13,596 $ 28,931 Less: income allocated to participating securities — (6 ) (2 ) (14 ) Net (loss) / income attributable to common stockholders (A) $ (7,652 ) $ 15,097 $ 13,594 $ 28,917 Weighted average common shares outstanding — basic (B) 47,812,642 46,886,345 47,494,926 46,520,469 Dilutive effect of stock options, RSUs and RSAs — 2,373,356 2,098,992 2,553,810 Weighted average common shares outstanding — diluted (C) 47,812,642 49,259,701 49,593,918 49,074,279 Net (loss) / income per share: Basic (A/B) $ (0.16 ) $ 0.32 $ 0.29 $ 0.62 Diluted (A/C) $ (0.16 ) $ 0.31 $ 0.27 $ 0.59 The following securities have been excluded from the calculation of diluted weighted average common shares outstanding as the inclusion of these securities would have an anti-dilutive effect: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Stock options 191,169 189,117 191,469 318,917 RSAs — 192 — 192 RSUs 33,100 — 33,100 39,350 Common stock subject to repurchase 4,005 16,716 4,005 16,716 Participating securities are composed of certain stock options granted under the 2015 Plan, and previously granted under the 2009 Equity Incentive Plan, that may be exercised before the options have vested. Unvested shares have a non-forfeitable right to dividends. Unvested shares issued as a result of early exercise are subject to repurchase by us upon termination of employment or services at the original exercise price. The common stock subject to repurchase is no longer classified as participating securities when shares revert to common stock outstanding as the awards vest and our repurchase right lapses.

Significant Service Provider Pa

Significant Service Provider Partners	9 Months Ended
	Sep. 30, 2018
Risks and Uncertainties [Abstract]
Significant Service Provider Partners	Significant Service Providers During the three and nine months ended September 30, 2018 , our 10 largest revenue service provider partners accounted for 57% and 58% of our revenue, respectively, as compared to 60% for the same periods in the prior year. One of our service provider partners within the Alarm.com segment individually represented greater than 15% but not more than 20% of our revenue for the three and nine months ended September 30, 2018 . One of our service provider partners within the Alarm.com segment individually represented greater than 10% but not more than 15% of our revenue for the three months ended September 30, 2017 . One of our service provider partners within the Alarm.com segment individually represented greater than 15% but not more than 20% of our revenue for the three months ended September 30, 2017 . Two of our service provider partners within the Alarm.com segment individually represented greater than 10% but not more than 15% of our revenue for the nine months ended September 30, 2017 . One individual service provider partner in the Alarm.com segment represented more than 10% of accounts receivable as of September 30, 2018 and December 31, 2017 .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For purposes of interim reporting, our annual effective income tax rate is estimated in accordance with ASC 740-270, "Interim Reporting." This rate is applied to the pre-tax book income of the entities expected to be benefited during the year. Discrete items that impact the tax provision are recorded in the period incurred. The Tax Cuts and Jobs Act, or the Tax Act, was signed into law on December 22, 2017. This legislation made significant changes in U.S. tax law, including a reduction in the corporate tax rate, changes to net operating loss carryforwards and carrybacks and a repeal of the corporate alternative minimum tax. The legislation reduced the U.S. corporate income tax rate from 35% to 21%. As a result of the enacted Tax Act, we were required to revalue deferred tax assets and liabilities at the rate in effect when the deferred tax balances are scheduled to reverse. This revaluation resulted in an additional $8.8 million of income tax expense and a corresponding reduction in the deferred tax asset which was recorded during the year ended December 31, 2017 . Additionally, on December 22, 2017, the Securities and Exchange Commission staff issued Staff Accounting Bulletin No. 118, or SAB 118, to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete the accounting for certain income tax effects of the Tax Act. Specifically, SAB 118 provides a measurement period for companies to evaluate the impacts of the Tax Act on their financial statements. We completed the accounting for the tax effects of the Tax Act during the three months ended September 30, 2018 and decreased our provisional estimate from $8.8 million to $8.7 million . For the three and nine months ended September 30, 2018 , we recorded a benefit for income taxes of $9.1 million and $10.4 million , respectively, resulting in effective income tax rates of 54.2% and (327.1)% , respectively. Our effective income tax rates were (49.8)% and (45.0)% for the three and nine months ended September 30, 2017 , respectively. Our effective tax rates were different from the statutory rate primarily due to the tax windfall benefits from employee stock-based payment transactions, research and development tax credits claimed and state taxes, partially offset by the impact of non-deductible meal and entertainment expenses. We recognize a valuation allowance if, based on the weight of available evidence, both positive and negative, it is more likely than not that some portion, or all, of net deferred tax assets will not be realized. Based on our historical and expected future taxable earnings, we believe it is more likely than not that we will realize all of the benefit of the existing deferred tax assets as of September 30, 2018 and December 31, 2017 . Accordingly, we have no t recorded a valuation allowance as of September 30, 2018 and December 31, 2017 . We apply guidance for uncertainty in income taxes that requires the application of a more likely than not threshold to the recognition and de-recognition of uncertain tax positions. If the recognition threshold is met, this guidance permits us to recognize a tax benefit measured at the largest amount of the tax benefit that, in our judgment, is more likely than not to be realized upon settlement. We recorded a reduction to the unrecognized tax benefit of $0.2 million for research and development tax credits claimed during the nine months ended September 30, 2018 . For the three and nine months ended September 30, 2018 , we recorded interest for the period on prior year research and development tax credits we claimed. As of September 30, 2018 and December 31, 2017 , we had accrued less than $0.1 million of total interest expense related to unrecognized tax benefits. We recognize interest and penalties related to unrecognized tax benefits as a component of income tax expense.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information We have two reportable segments: • Alarm.com segment • Other segment Our chief operating decision maker is our chief executive officer. Management determined the operational data used by the chief operating decision maker is that of the two reportable segments. Management bases strategic goals and decisions on these segments and the data presented below is used to measure financial results. Our Alarm.com segment represents our cloud-based platforms for the intelligently connected property and related solutions that contributed approximately 93% and 94% of our revenue for the three and nine months ended September 30, 2018 , respectively, as compared to approximately 94% for the same periods in the prior year. Our Other segment is focused on researching, developing and offering residential and commercial automation solutions and energy management products and services in adjacent markets. Inter-segment revenue includes sales of hardware between our segments. Management evaluates the performance of its segments and allocates resources to them based on operating income (loss) as compared to prior periods and current performance levels. The reportable segment operational data is presented in the table below (in thousands): Three Months Ended September 30, 2018 Alarm.com Other Intersegment Alarm.com Intersegment Other Total SaaS and license revenue $ 70,884 $ 3,408 $ — $ — $ 74,292 Hardware and other revenue 34,642 5,978 (1,343 ) (1,721 ) 37,556 Total revenue 105,526 9,386 (1,343 ) (1,721 ) 111,848 Operating income / (loss) (15,593 ) (1,084 ) 26 (43 ) (16,694 ) Three Months Ended September 30, 2017 Alarm.com Other Intersegment Alarm.com Intersegment Other Total SaaS and license revenue $ 59,774 $ 2,150 $ — $ — $ 61,924 Hardware and other revenue 25,513 4,161 (794 ) (842 ) 28,038 Total revenue 85,287 6,311 (794 ) (842 ) 89,962 Operating income / (loss) 12,500 (2,095 ) (11 ) 7 10,401 Nine Months Ended September 30, 2018 Alarm.com Other Intersegment Intersegment Total SaaS and license revenue $ 204,622 $ 8,626 $ — $ — $ 213,248 Hardware and other revenue 88,245 15,143 (3,585 ) (3,959 ) 95,844 Total revenue 292,867 23,769 (3,585 ) (3,959 ) 309,092 Operating income / (loss) 8,335 (4,548 ) (211 ) 233 3,809 Nine Months Ended September 30, 2017 Alarm.com Other Intersegment Intersegment Total SaaS and license revenue $ 165,764 $ 5,314 $ — $ — $ 171,078 Hardware and other revenue 71,373 10,884 (1,939 ) (1,252 ) 79,066 Total revenue 237,137 16,198 (1,939 ) (1,252 ) 250,144 Operating income / (loss) 27,903 (7,302 ) (68 ) 249 20,782 Alarm.com Other Intersegment Intersegment Total Assets as of September 30, 2018 $ 469,366 $ 18,207 $ (60,212 ) $ (1 ) $ 427,360 Assets as of December 31, 2017 405,915 19,144 (53,267 ) (151 ) 371,641 Our SaaS and license revenue for the Alarm.com segment included software license revenue of $10.5 million and $30.6 million for the three and nine months ended September 30, 2018 , respectively, as compared to $9.3 million and $20.1 million for the same periods in the prior year. There was no software license revenue recorded for the Other segment during the three and nine months ended September 30, 2018 and 2017 . Depreciation and amortization expense was $5.8 million and $15.9 million for the Alarm.com segment for the three and nine months ended September 30, 2018 , respectively, as compared to $5.0 million and $12.6 million for the same periods in the prior year. Depreciation and amortization expense was $0.1 million and $0.2 million for the Other segment for the three and nine months ended September 30, 2018 , respectively, as compared to $0.1 million and $0.2 million for the same periods in the prior year. Additions to property and equipment were $3.9 million and $10.1 million for the Alarm.com segment for the three and nine months ended September 30, 2018 , respectively, as compared to $2.2 million and $7.2 million for the same periods in the prior year. Additions to property and equipment were less than $0.1 million and $0.1 million for the Other segment for the three and nine months ended September 30, 2018 , respectively, as compared to $0.1 million for each of the three and nine months ended September 30, 2017 . We derived substantially all revenue from North America for the three and nine months ended September 30, 2018 and 2017 . Substantially all our long-lived assets were in North America as of September 30, 2018 and December 31, 2017 .

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Installation Partner Our installation partner in which we have a 48.2% ownership interest performs installation services for security dealers and also provides installation services for us and certain of our subsidiaries. We account for this investment using the equity method. As of September 30, 2018 and December 31, 2017 , our investment balance in our installation partner was zero . During the three and nine months ended September 30, 2018 , we recorded $0.1 million and $0.3 million of cost of hardware and other revenue in connection with this installation partner, respectively, as compared to $0.1 million and $0.6 million for the same periods in the prior year. As of September 30, 2018 and December 31, 2017 , the accounts payable balance to our installation partner was less than $0.1 million . In September 2014, we loaned $0.3 million to our installation partner under a secured promissory note that accrued interest at 8.0% . Interest was payable monthly with the entire principal balance plus accrued but unpaid interest due at maturity in September 2018.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include our accounts and those of our majority-owned and controlled subsidiaries after elimination of intercompany accounts and transactions. These unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP, for interim financial information and the applicable rules and regulations of the Securities and Exchange Commission, or SEC. Accordingly, they do not include all the information and footnotes required by GAAP for annual financial statements. They should be read together with our audited consolidated financial statements and related notes thereto for the year ended December 31, 2017 included in our Annual Report on Form 10-K filed with the SEC on February 28, 2018 , or the 2017 Annual Report. The condensed consolidated balance sheet as of December 31, 2017 was derived from our audited financial statements, but does not include all disclosures required by GAAP for annual financial statements. In the opinion of management, these condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of the results of operations, financial position and cash flows. The results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that can be expected for our entire fiscal year ending December 31, 2018 .
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Our estimates, judgments and assumptions are continually evaluated based on available information and experience. Because of the use of estimates inherent in the financial reporting process, actual results could differ from those estimates. Estimates are used when accounting for revenue recognition, allowances for doubtful accounts, allowance for hardware returns, estimates of obsolete inventory, long-term incentive compensation, stock-based compensation, income taxes, legal reserves, contingent consideration and goodwill and intangible assets.
Revenue Recognition, SaaS and License Revenue, Software License Revenue, and Hardware and Other Revenue	Revenue Recognition We derive our revenue from three primary sources: the sale of cloud-based SaaS services on our integrated Alarm.com platform, the sale of licenses and services on the Connect software platform and the sale of hardware products. We sell our platform and hardware solutions to service provider partners that resell our solutions and hardware to residential and commercial property owners, who are the service provider partners’ customers. Our subscribers consist of all of the properties maintained by those residential and commercial property owners to which we are delivering at least one of our solutions. We also sell our hardware to distributors who resell the hardware to service provider partners. We enter into contracts with our service provider partners that establish pricing for access to our platform solutions and for the sale of hardware. These contracts typically have an initial term of one year, with subsequent renewal terms of one year. Our service provider partners typically enter into contracts with our subscribers, which our service provider partners have indicated range from three to five years in length. Our hardware includes cellular radio modules that enable access to our cloud-based platforms, as well as video cameras, image sensors and other peripherals. Our service provider partners may purchase our hardware in anticipation of installing the hardware in a residential or commercial property when they create a new subscriber account, or for use in existing subscriber properties. The purchase of hardware occurs in a transaction that is separate and typically in advance of the purchase of our platform services. The performance obligation is satisfied when the hardware is received by our service provider partner or distributor. Service provider partners transact with us to purchase our platform solutions and resell our solutions to a new subscriber, or to upgrade or downgrade the solutions of an existing subscriber, at which time the subscriber’s access to our platform solutions is enabled and the delivery of the services commences. Our performance obligation related to providing our platform solutions is satisfied on a daily basis as the subscriber uses the platform services. The purchase of platform solutions and the purchase of hardware are separate transactions as revenue is recognized when control of the promised goods or services are transferred to our customers, in an amount that reflects the consideration that we expect to receive in exchange for those goods or services. We generate all of our revenue from contracts with customers. SaaS and license revenue associated with our contracts is invoiced and revenue is recognized at an amount that corresponds directly with the value of the performance completed to date. Additionally, the consideration received from hardware sales corresponds directly with the stand-alone selling price of the hardware. As a result, we have elected to use the practical expedient related to the amount of transaction price allocated to the unsatisfied performance obligations and therefore, we have not disclosed the total remaining revenue expected to be recognized on all contracts or the expected period over which the remaining revenue would be recognized for the current period or any period presented before January 1, 2018. To determine the transaction price, we analyze all of the performance obligations included in the contract. We consider the terms of the contract and our customary business practices, which typically do not include financing components or non-cash consideration. We have variable consideration in the form of retrospective volume discounts, rebate incentives, restocking fees and assurance-type warranties. The significant inputs related to variable consideration include the volume and amount of products and services sold historically and expected to be sold in the future, the availability and performance of our services and the historical and expected number of returns. Depending on the type of variable consideration and its predictability, we may apply an “expected value” approach or a “most likely amount” approach. We estimate the variable consideration at the onset of a contract and include the variable consideration within the transaction price if it is probable that a significant reversal of the variable consideration would not occur in the future. When determining whether the amount of variable consideration included in the transaction price should be constrained, we look at the history of hardware purchased and subscribers added by our service provider partners to estimate the likelihood of those service provider partners obtaining the retrospective volume discounts and rebates. At times, our contracts include consideration payable to a customer in the form of fixed discounts or rebates. We record the consideration payable to a customer as a reduction to the transaction price resulting in a reduction to revenue over the service period. If we enter into contracts that contain multiple promised services, we evaluate which of the promised services represent separate performance obligations based on whether or not the promised services are distinct and whether or not the services are separable from other promises in the contract. If these criteria are met, then we allocate the transaction price to the performance obligations using the relative stand-alone selling price method at contract inception. In determining the relative estimated selling prices, we consider market conditions, entity-specific factors and information about the customer or class of customer. Any discount within the contract is allocated proportionately to all of the separate performance obligations in the contract unless the terms of discount relate specifically to the entity’s efforts to satisfy some but not all of the performance obligations. For our standard service provider agreements, we have used a portfolio approach for purposes of revenue recognition, as each agreement has similar characteristics and we do not expect the effects of applying this approach would have a material impact on our financial statements as compared to assessing each agreement individually. SaaS and License Revenue We generate the majority of our SaaS and license revenue primarily from monthly fees charged to our service provider partners sold on a per subscriber basis for access to our cloud-based intelligently connected property platform and related solutions. Our fees per subscriber vary based upon the service plan and features utilized. Under the terms of our contractual arrangements with our service provider partners, we bill a monthly fee to our service provider partners in advance of the month of service, with the exception of the initial partial month of service, which is paid in arrears. Due to the limited period of time between receipt of payment and delivery of service, we have not accounted for these advance payments as significant financing components. We typically transfer the promised SaaS services to our customers over time, which is evidenced by the fact that the customers receive and consume the benefits provided by our performance of the services as such services are rendered. As a result, we recognize revenue from SaaS services on a monthly basis as we satisfy our performance obligations. We have demonstrated that we can sell our SaaS offering on a stand-alone basis, as it can be sold separately from hardware and activation services. As there is neither a minimum required initial service term nor a stated renewal term in our contractual arrangements, we recognize revenue over the period of service, which is monthly. Our service provider partners typically incur and pay the same monthly fee per subscriber account for the entire period a subscriber account is active. We offer multiple service level packages for our platform solutions including a range of solutions and a range of a la carte add-ons for additional features. The fee paid by our service provider partners each month for the delivery of our solutions is based on the combination of packages and add-ons enabled for each subscriber. We utilize tiered pricing plans where our service provider partners may receive prospective pricing discounts driven by volume. We also generate SaaS and license revenue from the fees paid to us when we license our intellectual property to third parties for use of our patents. We bill a monthly fee to third parties based on the number of customers that were active during the prior month. We apply the usage-based royalty exception to recognize license revenue because the sole or predominant item to which the royalty relates is the license of intellectual property. Under the usage-based royalty exception, we recognize revenue on a monthly basis over the period of service. In addition, in certain markets our EnergyHub subsidiary sells its demand response service for an annual service fee, with pricing based on the number of subscribers or amount of aggregate electricity demand made available for a utility’s or market’s control. Software License Revenue Our SaaS and license revenue also includes our software license revenue from monthly fees charged to service providers sold on a per subscriber basis for access to our Connect software platform. The Connect software for interactive security, automation and related solutions is typically deployed and operated by the service provider in its own network operations center. Our agreements for the Connect platform solution typically include software and services, such as post-contract customer support, or PCS. Software sales that include multiple elements are typically allocated to the various elements using the relative stand-alone selling price method. We apply the usage-based royalty exception to recognize license revenue associated with software hosted by our customers because the predominant item to which the royalty relates is the license of intellectual property. Under the usage-based royalty exception, we recognize revenue on a monthly basis over the period during which the services are expected to be performed. Under the terms of our contractual arrangements with our service provider partners, we are entitled to payment of a monthly fee that is billed per subscriber for the month of service. Our software license revenue during the three and nine months ended September 30, 2018 was $10.5 million and $30.6 million , respectively, as compared to $9.3 million and $20.1 million for the same periods in the prior year. Hardware and Other Revenue We generate hardware and other revenue primarily from the sale of video cameras and cellular radio modules that provide access to our cloud-based platforms and, to a lesser extent, the sale of other devices, including image sensors and peripherals. We primarily transfer hardware to our customers upon delivery to the customer, which corresponds with the time at which the customer obtains control of the hardware. As a result, we recognize hardware and other revenue as we satisfy our performance obligations, which occurs when the hardware is received by our service provider partner or distributor, net of a reserve for estimated returns. There are a few contracts in which we provide shipping and handling services to the customer after control of the hardware transfers to the customer. In these instances, we have elected to account for shipping and handling costs as activities performed to fulfill the promise to transfer hardware to the customer and not as a separate promised service. Amounts due from the sale of hardware are payable in accordance with the terms of our agreements with our service provider partners or distributors, and are not contingent on resale to end-users, or to service provider partners in the case of sales of hardware to distributors. Payment for our hardware is typically due within 30 days from shipment, with the exception of certain hardware finance arrangements, which are paid over a 36-month period. Our terms for hardware sales sold directly to either service provider partners or distributors typically allow for the return of hardware up to one year past the date of sale. Our distributors sell directly to our service provider partners under terms between the two parties. When determining the amount of consideration we expect to be entitled to for the sale of our hardware, we estimate the variable consideration associated with customer returns. We record a reserve against revenue for hardware returns based on historical returns. For each of the twelve months ended September 30, 2018 and 2017 , our reserve against revenue for hardware returns was 2% of hardware and other revenue. We evaluate our hardware reserve on a quarterly basis or if there is an indication of significant changes in return experience. Historically, our returns of hardware have not significantly differed from our estimated reserve. In general, we provide assurance-type warranties related to the intended functionality of the products and services provided. These warranties were not identified as separate performance obligations. Hardware and other revenue also includes activation fees charged to service provider partners for activation of a new subscriber account on our platforms, as well as fees paid by service provider partners for our marketing services. Our service provider partners use services on our platforms, such as support tools and applications, to assist in the installation of our solutions in subscriber properties. This installation marks the beginning of the service period on our platforms and, on occasion, we earn activation revenue for fees charged for this service. The activation fee is non-refundable, separately negotiated and specified in our contractual arrangements with our service provider partners and is charged to the service provider partner for each subscriber activated on our platforms. The decision whether to charge an activation fee is based in part on the expected number of subscribers to be added by our service provider partners and as a result, many of our largest service provider partners do not pay an activation fee. Activation fees are not offered on a stand-alone basis separate from our SaaS offering and are billed and received at the beginning of the arrangement. We record activation fees initially as deferred revenue and we recognize these fees ratably over the expected term of the subscribers’ account which we estimate is ten years based on our annual attrition rate. The portion of these activation fees included in current and long-term deferred revenue as of our balance sheet date represents the amounts that will be recognized ratably as revenue over the following twelve months, or longer as appropriate, until the ten-year expected term is complete. The balance of deferred revenue for activation fees was $9.5 million and $10.5 million as of September 30, 2018 and December 31, 2017 , respectively, which combines current and long-term balances.
Cost of Revenue, Contract Asset and Contract Liability Balances, and Costs to Obtain or Fulfill a Contract	Cost of Revenue Our cost of SaaS and license revenue primarily includes the amounts paid to wireless network providers and, to a lesser extent, the costs of running our network operation centers which are expensed as incurred, as well as royalty costs in connection with technology licensed from third-party providers. Our cost of SaaS and license revenue also includes our cost of software license revenue, which primarily includes the payroll and payroll-related costs of the department dedicated to providing service exclusively to those service providers that host the Connect platform. Our cost of software license revenue during the three and nine months ended September 30, 2018 was $0.4 million and $1.3 million , respectively, as compared to $0.4 million and $0.8 million for the same periods in the prior year. Our cost of hardware and other revenue primarily includes cost of raw materials and amounts paid to our third-party manufacturer for production and fulfillment of our cellular radio modules and image sensors, and procurement costs for our video cameras, which we purchase from an original equipment manufacturer, and other devices. Our cost of hardware and other revenue also includes royalty costs in connection with technology licensed from third-party providers. We record the cost of SaaS and license revenue as expenses are incurred, which corresponds to the delivery period of our services to our subscribers. We record the cost of hardware and other revenue when the hardware and other services are delivered to the service provider partner, which occurs when control of the hardware and other services transfers to the service provider partner. Our cost of revenue excludes amortization and depreciation. Contract Asset and Contract Liability Balances At contract inception, we assess the goods and services promised in our contracts with customers and identify a performance obligation for each distinct promise to transfer a good or service, or bundle of goods or services. To identify the performance obligations, we consider all of the goods or services promised in the contract, whether explicitly stated or implied based on customary business practices. We record a contract asset when we satisfy a performance obligation by transferring a promised good or service. Contract assets can be conditional or unconditional depending on whether another performance obligation must be satisfied before payment can be received. We receive payments from our service provider partners based on the billing schedule established in our contracts. All of the accounts receivable presented in the balance sheet represent unconditional rights to consideration. We do not have any assets from contracts containing conditional rights and we do not have any assets from satisfied performance obligations that have not been invoiced. Our contract assets consist of capitalized commission costs, which are discussed below in the “ Costs to Obtain or Fulfill a Contract ” section of Note 2 . The changes in our contract assets are as follows (in thousands): Three Months Ended Nine Months Ended Beginning of period balance $ 2,879 $ — Commission costs capitalized in period 489 4,344 Amortization of capitalized commission costs (490 ) (1,466 ) End of period balance $ 2,878 $ 2,878 Contract liabilities include payments received in advance of performance under the contract, and are realized with the associated revenue recognized under the contract. All of the deferred revenue presented in the balance sheet represents contract liabilities resulting from advance cash receipts from customers or amounts billed in advance to customers from the sale of services. Changes in deferred revenue are due to our performance under the contract as well as to cash received from new contracts for which services have not been provided. The changes in our contract liabilities are as follows (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning of period balance $ 11,971 $ 12,701 $ 12,678 $ 12,625 Revenue deferred in period 1,225 1,971 2,706 4,286 Revenue recognized from amounts included in contract liabilities (1,322 ) (1,970 ) (3,510 ) (4,209 ) End of period balance $ 11,874 $ 12,702 $ 11,874 $ 12,702 The revenue recognized from amounts included in contract liabilities primarily relates to prepayment contracts with customers as well as payments of activation fees. Costs to Obtain or Fulfill a Contract We recognize an asset related to the costs incurred to obtain a contract only if we expect to recover those costs and we would not have incurred those costs if the contract had not been obtained. We recognize an asset from the costs incurred to fulfill a contract if the costs (i) are specifically identifiable to a contract, (ii) enhance resources that will be used in satisfying performance obligations in future and (iii) are expected to be recovered. Based on the policy above, we capitalize a portion of our commission costs as an incremental cost of obtaining a contract. When calculating the incremental cost of obtaining a contract, we exclude any commission costs related to metrics that could be satisfied without obtaining a contract, including training-related metrics. We amortize our commission costs over a period of three years, which is consistent with the period over which the products and services related to the commission are transferred to the customer. The three-year period was determined based on our review of historical enhancements and upgrades to our products and services. We applied the portfolio approach to account for the amortization of contract costs as each contract has similar characteristics. The current portion of capitalized commission costs is included in other current assets within our condensed consolidated balance sheets. The non-current portion of capitalized commission costs is reflected in other assets within our condensed consolidated balance sheets. We amortized capitalized commission costs of $0.5 million and $1.5 million during the three and nine months ended September 30, 2018 , respectively. There were no amortized commission costs during the three and nine months ended September 30, 2017 . We review the capitalized costs for impairment at least annually. Impairment exists if the carrying amount of the asset recognized from contract costs exceeds the remaining amount of consideration we expect to receive in exchange for providing the goods and services to which such asset relates, less the costs that relate directly to providing those good and services and that have not been recognized as an expense. We did no t record an impairment loss on our capitalized commission costs or any other contract assets during the three and nine months ended September 30, 2018 and 2017 .
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted Revenue from Contracts with Customers (Topic 606): In May 2014, the Financing Accounting Standards Board, or FASB, and International Accounting Standards Board jointly issued Accounting Standards Update, or ASU, 2014-09, " Revenue from Contracts with Customers (Topic 606) ," a new revenue recognition standard that provides a framework for addressing revenue issues, improves the comparability of revenue recognition practices across industries, provides useful information to users of financial statements through improved disclosure requirements and simplifies the presentation of financial statements. From March to December 2016, amendments to Topic 606 were issued to clarify numerous accounting topics, including, but not limited to: (i) the implementation guidance on principal versus agent considerations, (ii) the identification of performance obligations, (iii) the licensing implementation guidance, (iv) the objective of the collectability criterion, (v) the application of the variable consideration guidance and modified retrospective transition method, (vi) the way in which impairment testing is performed and (vii) the disclosure requirements for revenue recognized from performance obligations. This guidance permits the use of either a full retrospective method or a modified retrospective method. This guidance was effective beginning January 1, 2018. On January 1, 2018, we adopted Topic 606 by applying the modified retrospective transition method to all of our contracts. Comparative information has not been restated and continues to be reported under the accounting standards in effect for the periods presented. The adoption of Topic 606 did not have a material impact on our revenue recognition policies, however, as a result of adopting the new standard, we changed our treatment of commissions paid to employees, which we previously expensed as incurred. Under the new standard, we capitalize a portion of our commission costs as an incremental cost of obtaining a contract and amortize our commission costs over a period of three years, which is consistent with the period over which the products and services related to the commission are transferred to the customer. Based on the results of our evaluation, the adoption of Topic 606 did not have a material impact on our condensed consolidated financial statements for the three and nine months ended September 30, 2018 . Additionally, the cumulative effect to the opening balance sheet on January 1, 2018 from the adoption of Topic 606 was not material. Other Accounting Standards : On May 10, 2017, the FASB issued ASU 2017-09, "Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting , " which amends the scope of modification accounting for share-based payment arrangements. The update provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under Accounting Standards Codification, or ASC, Topic 718. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions and classification of the awards are the same immediately before and after the modification. The amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. We adopted ASU 2017-09 during the first quarter of 2018 and the adoption of this ASU did no t have a material impact on our financial statements and related disclosures. On January 5, 2017, the FASB issued ASU 2017-01, "Business Combinations (Topic 805) - Clarifying the Definition of a Business , " which provides guidance to assist entities in evaluating when a set of transferred assets and activities is a business. To be considered a business, an acquisition would have to include an input and a substantive process that together significantly contribute to the ability to create outputs. The amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. We adopted ASU 2017-01 during the first quarter of 2018 and the adoption of this ASU did no t have a material impact on our financial statements and related disclosures. In January 2016, the FASB issued ASU 2016-01, " Recognition and Measurement of Financial Assets and Financial Liabilities (Topic 825-10) " and in February 2018, the FASB issued ASU 2018-03, "Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10)." These ASUs require entities to carry all investments in equity securities at fair value and recognize any changes in fair value in net income. Under these standards, equity investments that do not have readily determinable fair values are measured at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for an identical or a similar investment of the same issuer. The guidance in ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance in ASU 2018-03 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years beginning after June 15, 2018. We adopted ASU 2016-01 and ASU 2018-03 in 2018 and the adoption of these ASUs did no t have a material impact on our financial statements and related disclosures. Not Yet Adopted On June 16, 2016, the FASB issued ASU 2016-13, " Financial Instruments - Credit Losses (Topic 326)," which provides guidance designed to provide financial statement users with more information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. When determining such expected credit losses, the guidance requires companies to apply a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendment is effective on a modified retrospective basis for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted for fiscal years and interim periods beginning after December 15, 2018. We are currently assessing the impact this pronouncement may have on our trade receivables and notes receivables. On February 25, 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” or Topic 842, which requires lessees to recognize operating and financing lease liabilities and corresponding right-of-use assets on the balance sheet. The update also requires improved disclosures to help users of financial statements better understand the amount, timing and uncertainty of cash flows arising from leases. The amendments in this update are effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with early adoption permitted. We plan to adopt Topic 842 effective January 1, 2019. The update must be adopted using a modified retrospective approach. In July 2018, the FASB amended the update to allow entities to apply the transition requirements of Topic 842 at the adoption date rather than at the beginning of the earliest comparative period presented. We plan to use this optional transition method, which will require us to record the effect of initially applying Topic 842 as a cumulative-effect adjustment to retained earnings on January 1, 2019. We plan to use the package of practical expedients for the adoption of Topic 842, which will allow us not to reassess: (i) whether any expired or existing contracts are or contain leases, (ii) lease classification for any expired or existing leases and (iii) whether initial direct costs for any existing leases qualify for capitalization under Topic 842. Additionally, we plan to use the hindsight practical expedient when determining the lease term and assessing impairment of right-of-use assets. While we are still evaluating the impact the update will have on our consolidated financial statements, we expect the adoption of Topic 842 will result in the recognition of right-of-use assets and lease liabilities within the consolidated balance sheets, which may be material. However, we do not expect the adoption of Topic 842 to have a material impact on our consolidated statements of operations. On August 28, 2018, the FASB issued ASU 2018-13, " Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement," which provides guidance designed to improve the effectiveness of fair value measurement disclosures in notes to the financial statements. The update removes several existing disclosure requirements, including, but not limited to: (i) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, (ii) the policy for timing of transfers between levels and (iii) the valuation processes for Level 3 fair value measurements. The update also adds additional disclosure requirements for public companies, including but not limited to: (i) the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and (ii) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The update also modifies and clarifies several existing disclosure requirements. The amendment in this update is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The additional disclosure requirements and one of the modifications to an existing disclosure requirement should be applied prospectively while all other disclosure changes should be applied retrospectively to all periods presented upon the effective date. Early adoption is permitted. We are currently assessing the impact this pronouncement may have on our fair value measurement disclosures; however, this pronouncement is not expected to have a material impact on our consolidated financial statements.
Fair Value Measurement	The liability for the subsidiary unit awards relates to agreements established with employees of our subsidiaries for cash awards contingent upon the subsidiary companies meeting certain financial milestones such as revenue, working capital, EBITDA and EBITDA margin. We account for these subsidiary awards using fair value and establish liabilities for the future payment for the repurchase of subsidiary units under the terms of the agreements based on estimating revenue, working capital, EBITDA and EBITDA margin of the subsidiary units over the periods of the awards through the anticipated repurchase dates. We estimated the fair value of each liability by using a Monte Carlo simulation model for determining each of the projected measures by using an expected distribution of potential outcomes. The fair value of each liability is calculated with thousands of projected outcomes, the results of which are averaged and then discounted to estimate the present value. At each reporting date until the respective payment dates, we will remeasure these liabilities, using the same valuation approach based on the applicable subsidiary's revenue and future collection of financed customer receivables, the unobservable inputs, and we will record any changes in the employee's compensation expense. Some of the awards are subject to the employees' continued employment and therefore recorded on a straight-line basis over the remaining service period.
Leases	We recognize rent expense for lease payments on a straight-line basis over the expected lease term and amortize tenant improvement allowances over the term of the lease.
Income Taxes	We recognize a valuation allowance if, based on the weight of available evidence, both positive and negative, it is more likely than not that some portion, or all, of net deferred tax assets will not be realized.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Schedule of Contract Assets	The changes in our contract assets are as follows (in thousands): Three Months Ended Nine Months Ended Beginning of period balance $ 2,879 $ — Commission costs capitalized in period 489 4,344 Amortization of capitalized commission costs (490 ) (1,466 ) End of period balance $ 2,878 $ 2,878 The changes in our contract liabilities are as follows (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning of period balance $ 11,971 $ 12,701 $ 12,678 $ 12,625 Revenue deferred in period 1,225 1,971 2,706 4,286 Revenue recognized from amounts included in contract liabilities (1,322 ) (1,970 ) (3,510 ) (4,209 ) End of period balance $ 11,874 $ 12,702 $ 11,874 $ 12,702

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Schedule of Components of Accounts Receivable	The components of accounts receivable, net are as follows (in thousands): September 30, December 31, Accounts receivable $ 58,913 $ 44,554 Allowance for doubtful accounts (1,502 ) (1,449 ) Allowance for product returns (1,950 ) (2,471 ) Accounts receivable, net $ 55,461 $ 40,634

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Schedule of Components of Inventory	The components of inventory, net are as follows (in thousands): September 30, December 31, Raw materials $ 5,973 $ 7,484 Finished goods 10,933 6,693 Total inventory, net $ 16,906 $ 14,177

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Summary of Assumptions Used for Estimating Fair Value of Stock Options	The following table summarizes the assumptions used for estimating the fair value of stock options assumed from the Connect business unit of Icontrol: Nine Months Ended Volatility 42.7 - 44.4% Expected term 2.5 - 5.0 years Risk-free interest rate 1.4 - 2.0% Dividend rate — %
Schedule of Consideration Paid and Estimated Fair Value of Tangible and Intangible Net Assets Acquired	The table below sets forth the purchase consideration and the fair value allocation of the tangible and intangible net assets acquired (in thousands): January 1, 2017 Calculation of Purchase Consideration: Cash paid, net of working capital adjustment $ 6,000 Estimated Tangible and Intangible Net Assets: Developed technology $ 3,800 Current liabilities (58 ) Goodwill 2,258 Total estimated tangible and intangible net assets $ 6,000 The table below sets forth the purchase consideration and the fair value allocation of the tangible and intangible net assets acquired (in thousands): March 8, 2017 Calculation of Purchase Consideration: Cash paid, net of working capital adjustment $ 148,500 Assumed stock options 1,375 Total consideration $ 149,875 Estimated Tangible and Intangible Net Assets: Cash $ 211 Accounts receivable 11,421 Current assets 883 Long-term assets 4,446 Customer relationships 93,260 Developed technology 4,770 Trade name 170 Current liabilities (1,608 ) Long-term liabilities (288 ) Goodwill 36,610 Total estimated tangible and intangible net assets $ 149,875
Business Acquisition, Pro Forma Information	The pro forma adjustments were based on available information and upon assumptions that we believe are reasonable to reflect the impact of these acquisitions on our historical financial information on a supplemental pro forma basis, as follows (in thousands): Pro Forma Revenue $ 261,214 Net income 35,380 Net income per diluted share $ 0.72 The following table presents the revenue and earnings of the business combinations in the year of acquisition as reported within the condensed consolidated financial statements (in thousands): Nine Months Ended Revenue $ 22,996 Net loss (3,021 )

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in goodwill by reportable segment are outlined below (in thousands): Alarm.com Other Total Balance as of January 1, 2018 $ 63,591 $ — $ 63,591 Goodwill acquired — — — Balance as of September 30, 2018 $ 63,591 $ — $ 63,591
Schedule of Intangible Assets	The following tables reflect the weighted average remaining life and carrying value of finite-lived intangible assets (in thousands): September 30, 2018 Gross Accumulated Net Weighted- Customer relationships $ 103,926 $ (23,846 ) $ 80,080 10.2 Developed technology 13,959 (11,322 ) 2,637 1.8 Trade name 1,084 (933 ) 151 2.6 Other 234 (234 ) — — Total intangible assets $ 119,203 $ (36,335 ) $ 82,868 December 31, 2017 Gross Accumulated Net Weighted- Customer relationships $ 103,926 $ (15,400 ) $ 88,526 10.8 Developed technology 13,959 (8,427 ) 5,532 2.1 Trade name 1,084 (856 ) 228 3.3 Other 234 (234 ) — — Total intangible assets $ 119,203 $ (24,917 ) $ 94,286 The following table reflects changes in the net carrying amount of the components of intangible assets (in thousands): Customer Developed Trade Name Total Balance as of January 1, 2018 $ 88,526 $ 5,532 $ 228 $ 94,286 Amortization (8,446 ) (2,895 ) (77 ) (11,418 ) Balance as of September 30, 2018 $ 80,080 $ 2,637 $ 151 $ 82,868

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents our assets and liabilities measured at fair value on a recurring basis (in thousands): Fair Value Measurements on a Recurring Basis as of Fair value measurements in: Level 1 Level 2 Level 3 Total Assets: Money market account $ 83,022 $ — $ — $ 83,022 Total $ 83,022 $ — $ — $ 83,022 Liabilities: Subsidiary unit awards $ — $ — $ 389 $ 389 Total $ — $ — $ 389 $ 389 Fair Value Measurements on a Recurring Basis as of Fair value measurements in: Level 1 Level 2 Level 3 Total Assets: Money market account $ 65,620 $ — $ — $ 65,620 Total $ 65,620 $ — $ — $ 65,620 Liabilities: Subsidiary unit awards $ — $ — $ 3,160 $ 3,160 Total $ — $ — $ 3,160 $ 3,160
Summary of Fair Value of Level 3 Liability	The following table summarizes the change in fair value of the Level 3 liabilities for subsidiary unit awards with significant unobservable inputs (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning of period balance $ 389 $ 2,912 $ 3,160 $ 2,768 Total losses included in earnings — 139 31 283 Settlements — — (2,802 ) — End of period balance $ 389 $ 3,051 $ 389 $ 3,051

Liabilities (Tables)

Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Payables and Accruals [Abstract]
Schedule of Accounts Payable. Accrued Expenses and Other Current Liabilities	The components of accounts payable, accrued expenses and other current liabilities are as follows (in thousands): September 30, December 31, Accounts payable $ 19,646 $ 17,008 Accrued expenses 35,007 4,301 Subsidiary unit awards 225 2,802 Other current liabilities 3,116 4,973 Accounts payable, accrued expenses and other current liabilities $ 57,994 $ 29,084 The components of other liabilities are as follows (in thousands): September 30, December 31, Deferred rent $ 11,550 $ 12,279 Other liabilities 1,728 1,646 Other liabilities $ 13,278 $ 13,925

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock-Based Compensation Expense	Stock-based compensation expense is included in the following line items in the condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Sales and marketing $ 301 $ 181 $ 855 $ 359 General and administrative 1,191 584 3,700 1,908 Research and development 1,965 1,141 5,115 2,867 Total stock-based compensation expense $ 3,457 $ 1,906 $ 9,670 $ 5,134 The following table summarizes the components of non-cash stock-based compensation expense (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Stock options and assumed options $ 850 $ 939 $ 2,666 $ 3,005 Restricted stock units 2,585 936 6,900 2,029 Restricted stock awards — — 1 19 Employee stock purchase plan 22 31 103 81 Total stock-based compensation expense $ 3,457 $ 1,906 $ 9,670 $ 5,134 Tax benefit from stock-based awards $ 2,958 $ 6,059 $ 6,899 $ 11,645

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Components of Basic and Diluted EPS	The components of basic and diluted earnings (loss) per share, or EPS, are as follows (in thousands, except share and per share amounts): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net (loss) / income $ (7,652 ) $ 15,103 $ 13,596 $ 28,931 Less: income allocated to participating securities — (6 ) (2 ) (14 ) Net (loss) / income attributable to common stockholders (A) $ (7,652 ) $ 15,097 $ 13,594 $ 28,917 Weighted average common shares outstanding — basic (B) 47,812,642 46,886,345 47,494,926 46,520,469 Dilutive effect of stock options, RSUs and RSAs — 2,373,356 2,098,992 2,553,810 Weighted average common shares outstanding — diluted (C) 47,812,642 49,259,701 49,593,918 49,074,279 Net (loss) / income per share: Basic (A/B) $ (0.16 ) $ 0.32 $ 0.29 $ 0.62 Diluted (A/C) $ (0.16 ) $ 0.31 $ 0.27 $ 0.59
Schedule of Securities Excluded from Calculation of Diluted Weighted Average Common Shares Outstanding Due to Anti-dilutive Effect	The following securities have been excluded from the calculation of diluted weighted average common shares outstanding as the inclusion of these securities would have an anti-dilutive effect: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Stock options 191,169 189,117 191,469 318,917 RSAs — 192 — 192 RSUs 33,100 — 33,100 39,350 Common stock subject to repurchase 4,005 16,716 4,005 16,716

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Schedule of Reportable Segment Operational Data	The reportable segment operational data is presented in the table below (in thousands): Three Months Ended September 30, 2018 Alarm.com Other Intersegment Alarm.com Intersegment Other Total SaaS and license revenue $ 70,884 $ 3,408 $ — $ — $ 74,292 Hardware and other revenue 34,642 5,978 (1,343 ) (1,721 ) 37,556 Total revenue 105,526 9,386 (1,343 ) (1,721 ) 111,848 Operating income / (loss) (15,593 ) (1,084 ) 26 (43 ) (16,694 ) Three Months Ended September 30, 2017 Alarm.com Other Intersegment Alarm.com Intersegment Other Total SaaS and license revenue $ 59,774 $ 2,150 $ — $ — $ 61,924 Hardware and other revenue 25,513 4,161 (794 ) (842 ) 28,038 Total revenue 85,287 6,311 (794 ) (842 ) 89,962 Operating income / (loss) 12,500 (2,095 ) (11 ) 7 10,401 Nine Months Ended September 30, 2018 Alarm.com Other Intersegment Intersegment Total SaaS and license revenue $ 204,622 $ 8,626 $ — $ — $ 213,248 Hardware and other revenue 88,245 15,143 (3,585 ) (3,959 ) 95,844 Total revenue 292,867 23,769 (3,585 ) (3,959 ) 309,092 Operating income / (loss) 8,335 (4,548 ) (211 ) 233 3,809 Nine Months Ended September 30, 2017 Alarm.com Other Intersegment Intersegment Total SaaS and license revenue $ 165,764 $ 5,314 $ — $ — $ 171,078 Hardware and other revenue 71,373 10,884 (1,939 ) (1,252 ) 79,066 Total revenue 237,137 16,198 (1,939 ) (1,252 ) 250,144 Operating income / (loss) 27,903 (7,302 ) (68 ) 249 20,782 Alarm.com Other Intersegment Intersegment Total Assets as of September 30, 2018 $ 469,366 $ 18,207 $ (60,212 ) $ (1 ) $ 427,360 Assets as of December 31, 2017 405,915 19,144 (53,267 ) (151 ) 371,641

Organization (Details)

Organization (Details)	Sep. 30, 2018service_provider
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of trusted service providers (more than)	7,000

Basis of Presentation Narrative

Basis of Presentation Narrative (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		$ 111,848,000	$ 89,962,000	$ 309,092,000	$ 250,144,000
Deferred revenue		11,874,000	12,702,000	11,874,000	12,702,000	$ 11,874,000	$ 12,702,000	$ 11,971,000	$ 12,678,000	$ 12,701,000	$ 12,625,000
Cost of software revenue	[1]	41,992,000	31,833,000	106,857,000	88,303,000
Amortized commission costs		490,000		1,466,000
Activation Fees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue		9,500,000		9,500,000		$ 9,500,000			$ 10,500,000
Commission
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortized commission costs		500,000	0	1,500,000	0
Software License Revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		10,500,000	9,300,000	30,600,000	20,100,000
Cost of software revenue		400,000	400,000	1,300,000	800,000
Hardware and other revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		37,556,000	28,038,000	95,844,000	79,066,000
Reserve for sales returns, percentage						2.00%	2.00%
Cost of software revenue	[1]	$ 30,491,000	$ 22,288,000	$ 73,523,000	$ 62,166,000
[1]	Exclusive of amortization and depreciation shown in operating expenses below.

Basis of Presentation Contract

Basis of Presentation Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Change in Contract Asset Balance
Beginning of period balance	$ 2,879		$ 0
Commission costs capitalized in period	489		4,344
Amortization of capitalized commission costs	(490)		(1,466)
End of period balance	2,878		2,878
Change in Contract Liability Balance
Beginning of period balance	11,971	$ 12,701	12,678	$ 12,625
Revenue deferred in period	1,225	1,971	2,706	4,286
Revenue recognized from amounts included in contract liabilities	(1,322)	(1,970)	(3,510)	(4,209)
End of period balance	$ 11,874	$ 12,702	$ 11,874	$ 12,702

Accounts Receivable, Net - Sche

Accounts Receivable, Net - Schedule of Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Receivables [Abstract]
Accounts receivable	$ 58,913	$ 44,554
Allowance for doubtful accounts	(1,502)	(1,449)
Allowance for product returns	(1,950)	(2,471)
Accounts receivable, net	$ 55,461	$ 40,634

Accounts Receivable, Net - Narr

Accounts Receivable, Net - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision (provision reduction) for doubtful accounts	$ 100	$ (400)	$ 108	$ (360)
Reserve for product returns			210	1,732
Hardware and other revenue
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reserve for product returns	$ 100	$ 600	$ 200	$ 1,700

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 5,973	$ 7,484
Finished goods	10,933	6,693
Total inventory, net	$ 16,906	$ 14,177

Acquisitions - Connect and Pipe

Acquisitions - Connect and Piper Business Units from Icontrol Networks (Details) $ in Thousands	Mar. 08, 2017USD ($)business_unitshares	Mar. 07, 2017USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Proceeds from line of credit				$ 0	$ 67,000
Goodwill				$ 63,591		$ 63,591
Connect And Piper
Business Acquisition [Line Items]
Number of business units | business_unit	2
Consideration	$ 148,500
Escrow deposit	14,500
Cash on hand paid to acquire business	81,500
Proceeds from line of credit		$ 67,000
Assumed options from business acquisition	1,375
Goodwill	$ 36,610
Increase in intangible assets			$ 100
Increase (decrease) in goodwill			$ (100)
Connect
Business Acquisition [Line Items]
Unvested employee options converted (in shares) | shares	2,001,387
Assumed (in shares) | shares	70,406
Fair value of unvested stock options	$ 1,700
Assumed options from business acquisition	1,400
Piper
Business Acquisition [Line Items]
Deferred tax asset	4,100
Customer Relationships Group 1 | Connect
Business Acquisition [Line Items]
Intangible assets acquired	$ 92,500
Weighted-average estimated useful life of intangible assets acquired	12 years
Customer Relationships Group 2 | Connect
Business Acquisition [Line Items]
Intangible assets acquired	$ 800
Weighted-average estimated useful life of intangible assets acquired	4 years
Developed Technology | Connect And Piper
Business Acquisition [Line Items]
Intangible assets acquired	$ 4,770
Developed Technology | Connect
Business Acquisition [Line Items]
Intangible assets acquired	$ 4,400
Weighted-average estimated useful life of intangible assets acquired	3 years
Developed Technology | Piper
Business Acquisition [Line Items]
Intangible assets acquired	$ 300
Trade Name | Connect And Piper
Business Acquisition [Line Items]
Intangible assets acquired	170
Trade Name | Piper
Business Acquisition [Line Items]
Intangible assets acquired	$ 200
Weighted-average estimated useful life of intangible assets acquired	3 years
Options to be recognized over future vesting periods | Connect
Business Acquisition [Line Items]
Compensation cost not yet recognized on nonvested awards	$ 300

Acquisitions - Assumptions for

Acquisitions - Assumptions for Estimating Fair Value (Details) - Stock options - Connect	9 Months Ended
	Sep. 30, 2017
Business Acquisition [Line Items]
Volatility, minimum	42.70%
Volatility, maximum	44.40%
Risk-free interest rate, minimum	1.40%
Risk-free interest rate, maximum	2.00%
Dividend rate	0.00%
Minimum
Business Acquisition [Line Items]
Expected term	2 years 6 months
Maximum
Business Acquisition [Line Items]
Expected term	5 years

Acquisitions - Schedule of Cons

Acquisitions - Schedule of Consideration Paid to Icontrol and Estimated Fair Value of Tangible and Intangible Net Assets Acquired (Details) - USD ($) $ in Thousands	Mar. 08, 2017	Sep. 30, 2018	Dec. 31, 2017
Estimated Tangible and Intangible Net Assets:
Goodwill		$ 63,591	$ 63,591
Connect And Piper
Calculation of Purchase Consideration:
Cash paid, net of working capital adjustment	$ 148,500
Assumed options from business acquisition	1,375
Total consideration	149,875
Estimated Tangible and Intangible Net Assets:
Cash	211
Accounts receivable	11,421
Current assets	883
Long-term assets	4,446
Current liabilities	(1,608)
Long-term liabilities	(288)
Goodwill	36,610
Total estimated tangible and intangible net assets	149,875
Connect And Piper | Customer Relationships
Estimated Tangible and Intangible Net Assets:
Intangible assets acquired	93,260
Connect And Piper | Developed Technology
Estimated Tangible and Intangible Net Assets:
Intangible assets acquired	4,770
Connect And Piper | Trade Name
Estimated Tangible and Intangible Net Assets:
Intangible assets acquired	$ 170

Acquisitions - ObjectVideo Acqu

Acquisitions - ObjectVideo Acquisition (Details) - USD ($) $ in Thousands	Mar. 08, 2017	Jan. 01, 2017	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill				$ 63,591	$ 63,591
Connect And Piper
Business Acquisition [Line Items]
Cash paid, net of working capital adjustment	$ 148,500
Goodwill	36,610
Increase in intangible assets			$ 100
Increase (decrease) in goodwill			(100)
ObjectVideo
Business Acquisition [Line Items]
Cash paid, net of working capital adjustment		$ 6,000
Goodwill		2,258
Increase (decrease) in goodwill			(400)
Developed Technology | Connect And Piper
Business Acquisition [Line Items]
Intangible assets acquired	$ 4,770
Developed Technology | ObjectVideo
Business Acquisition [Line Items]
Increase in intangible assets			$ 400
Intangible assets acquired		$ 3,800
Weighted-average estimated useful life of intangible assets acquired		2 years

Acquisitions - Schedule of Co_2

Acquisitions - Schedule of Consideration Paid to ObjectVideo and Estimated Fair Value of Tangible and Intangible Net Assets Acquired (Details) - USD ($) $ in Thousands	Jan. 01, 2017	Sep. 30, 2018	Dec. 31, 2017
Estimated Tangible and Intangible Net Assets:
Goodwill		$ 63,591	$ 63,591
ObjectVideo
Calculation of Purchase Consideration:
Cash paid, net of working capital adjustment	$ 6,000
Estimated Tangible and Intangible Net Assets:
Current liabilities	(58)
Goodwill	2,258
Total estimated tangible and intangible net assets	6,000
Developed Technology | ObjectVideo
Estimated Tangible and Intangible Net Assets:
Developed technology	$ 3,800

Acquisitions - Unaudited Pro Fo

Acquisitions - Unaudited Pro Forma Information (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)$ / shares
Business Combinations [Abstract]
Revenue	$ 261,214
Net income	$ 35,380
Net income per diluted share (in dollars per share) | $ / shares	$ 0.72

Acquisitions - Business Combina

Acquisitions - Business Combinations in Operations (Details) - Connect and Piper, and ObjectVideo $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Business Acquisition [Line Items]
Revenue	$ 22,996
Net loss	$ (3,021)

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets, Net - Schedule of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 63,591
Goodwill acquired	0
Ending balance	63,591
Alarm.com
Goodwill [Roll Forward]
Beginning balance	63,591
Goodwill acquired	0
Ending balance	63,591
Other
Goodwill [Roll Forward]
Beginning balance	0
Goodwill acquired	0
Ending balance	$ 0

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets, Net - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Goodwill impairment	$ 0	$ 0	$ 0	$ 0
Amortization	3,800,000	3,700,000	11,418,000	8,700,000
Impairment of long-lived assets	$ 0	$ 0	$ 0	$ 0

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets, Net - Schedule of Net Carrying Amount of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Finite-lived Intangible Assets [Roll Forward]
Beginning balance			$ 94,286
Amortization	$ (3,800)	$ (3,700)	(11,418)	$ (8,700)
Ending balance	82,868		82,868
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Beginning balance			88,526
Amortization			(8,446)
Ending balance	80,080		80,080
Developed Technology
Finite-lived Intangible Assets [Roll Forward]
Beginning balance			5,532
Amortization			(2,895)
Ending balance	2,637		2,637
Trade Name
Finite-lived Intangible Assets [Roll Forward]
Beginning balance			228
Amortization			(77)
Ending balance	$ 151		$ 151

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets, Net - Schedule of Weighted Average Remaining Life and Carrying Value of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 119,203	$ 119,203
Accumulated Amortization	(36,335)	(24,917)
Net Carrying Value	82,868	94,286
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	103,926	103,926
Accumulated Amortization	(23,846)	(15,400)
Net Carrying Value	$ 80,080	$ 88,526
Customer Relationships | Weighted Average
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life	10 years 2 months 12 days	10 years 9 months 18 days
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 13,959	$ 13,959
Accumulated Amortization	(11,322)	(8,427)
Net Carrying Value	$ 2,637	$ 5,532
Developed Technology | Weighted Average
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life	1 year 9 months 18 days	2 years 1 month 6 days
Trade Name
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,084	$ 1,084
Accumulated Amortization	(933)	(856)
Net Carrying Value	$ 151	$ 228
Trade Name | Weighted Average
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life	2 years 7 months 6 days	3 years 3 months 18 days
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 234	$ 234
Accumulated Amortization	(234)	(234)
Net Carrying Value	$ 0	$ 0
Other | Weighted Average
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life	0 days	0 days

Other Assets - Patent Licenses

Other Assets - Patent Licenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-lived, intangible assets, net	$ 82,868		$ 82,868		$ 94,286
Finite-lived intangible assets, gross	119,203		119,203		119,203
Amortization on patents and tooling			701	$ 817
Patent Licenses
Finite-Lived Intangible Assets [Line Items]
Finite-lived, intangible assets, net	2,000		2,000		2,400
Finite-lived intangible assets, gross	4,900		4,900
Patent Licenses | Cost of SaaS and License Revenue
Finite-Lived Intangible Assets [Line Items]
Amortization on patents and tooling	$ 100	$ 200	400	$ 600
Patent Licenses | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	3 years
Patent Licenses | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	11 years
Other Current Assets | Patent Licenses
Finite-Lived Intangible Assets [Line Items]
Finite-lived, intangible assets, net	$ 400		400		500
Other Assets | Patent Licenses
Finite-Lived Intangible Assets [Line Items]
Finite-lived, intangible assets, net	$ 1,600		$ 1,600		$ 1,900

Other Assets - Loan to a Distri

Other Assets - Loan to a Distribution Partner and Prepaid Expenses (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)renewal_option	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	May 31, 2018USD ($)	Dec. 31, 2017USD ($)	Apr. 30, 2017USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenue from distribution partners		$ 111,848	$ 89,962	$ 309,092	$ 250,144
Prepayment for long lead-time parts related to inventory		$ 3,800		$ 3,800
Notes Receivable | Distribution Partner Two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable, maximum available	$ 4,000
Interest rate		6.00%		6.00%
Number of renewal options | renewal_option	2
Renewal term	1 year
Loan receivable, current						$ 4,000	$ 4,000
Notes Receivable | Distribution Partner Two | London Interbank Offered Rate (LIBOR)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Basis spread on variable rate (percent)				4.00%
Notes Receivable | Distribution Partner Three
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate		8.50%		8.50%
Loan receivable, noncurrent								$ 3,000
Notes Receivable | Distribution Partners Two and Three
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenue from distribution partners		$ 200	$ 200	$ 900	$ 1,000
Other Assets | Notes Receivable | Distribution Partner Two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan receivable, noncurrent		3,000		3,000
Other Assets | Notes Receivable | Distribution Partner Three
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan receivable, noncurrent		3,000		3,000			3,000
Other Current Assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prepaid expenses included in other current assets		9,400		9,400			$ 3,800
Other Current Assets | Notes Receivable | Distribution Partner Two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan receivable, current		$ 1,000		$ 1,000
Term Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate		6.00%		6.00%
Term Loan | London Interbank Offered Rate (LIBOR)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Basis spread on variable rate (percent)				7.00%
Term Loan | Distribution Partner Two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt instrument, face amount						$ 4,000
Annual principal repayment on loan		$ 1,000		$ 1,000

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Total	$ 83,022	$ 65,620
Liabilities:
Subsidiary unit awards	389	3,160
Total	389	3,160
Money market account
Assets:
Money market account	83,022	65,620
Level 1
Assets:
Total	83,022	65,620
Liabilities:
Subsidiary unit awards	0	0
Total	0	0
Level 1 | Money market account
Assets:
Money market account	83,022	65,620
Level 2
Assets:
Total	0	0
Liabilities:
Subsidiary unit awards	0	0
Total	0	0
Level 2 | Money market account
Assets:
Money market account	0	0
Level 3
Assets:
Total	0	0
Liabilities:
Subsidiary unit awards	389	3,160
Total	389	3,160
Level 3 | Money market account
Assets:
Money market account	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value of Level 3 Subsidiary Unit Awards and Contingent Consideration (Details) - Subsidiary unit awards - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning of period balance	$ 389	$ 2,912	$ 3,160	$ 2,768
Total losses included in earnings	0	139	31	283
Settlements	0	0	(2,802)	0
End of period balance	$ 389	$ 3,051	$ 389	$ 3,051

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other-than-temporary impairments	$ 0	$ 0	$ 0	$ 0
Subsidiary unit awards
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Settlements	$ 0	$ 0	2,802,000	$ 0
Founder and President | Subsidiary unit awards | Repurchase of Subsidiary Units, February 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Settlements			$ 2,800,000

Liabilities - Components of Acc

Liabilities - Components of Accounts Payable, Accrued Expenses, and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accounts payable	$ 19,646	$ 17,008
Accrued expenses	35,007	4,301
Subsidiary unit awards	225	2,802
Other current liabilities	3,116	4,973
Accounts payable, accrued expenses and other current liabilities	$ 57,994	$ 29,084

Liabilities - Other Liabilities

Liabilities - Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Deferred rent	$ 11,550	$ 12,279
Other liabilities	1,728	1,646
Other liabilities	$ 13,278	$ 13,925

Debt, Commitments and Conting_2

Debt, Commitments and Contingencies - Debt (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)	Oct. 06, 2017USD ($)
Debt Instrument [Line Items]
Repayments of lines of credit			$ 3,000	$ 1,700
Revolving Credit Facility | Line of Credit | 2017 Facility
Debt Instrument [Line Items]
Current borrowing capacity						$ 125,000
Maximum borrowing capacity						175,000
Effective interest rate (percent)			4.05%	4.38%
Repayments of lines of credit	$ 1,000	$ 700	$ 3,000	$ 1,700
Long-term debt	$ 68,000		$ 68,000		$ 71,000	$ 72,000
Unused line commitment fee (percentage)	0.20%
Consolidated leverage ratio covenant (not to exceed)	3.50		3.50
Consolidated fixed charge coverage ratio covenant (at least)	1.25
Revolving Credit Facility | Line of Credit | 2017 Facility | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			0.50%
Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			1.00%
Scenario One, Leverage Ratio | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Interest rate terms, leverage ratio	1		1
Scenario Two, Leverage Ratio | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument [Line Items]
Interest rate terms, leverage ratio	1		1
Scenario Two, Leverage Ratio | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR) | Maximum
Debt Instrument [Line Items]
Interest rate terms, leverage ratio	2		2
Scenario Three, Leverage Ratio | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument [Line Items]
Interest rate terms, leverage ratio	2		2
Scenario Three, Leverage Ratio | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR) | Maximum
Debt Instrument [Line Items]
Interest rate terms, leverage ratio	3		3
Scenario Four, Leverage Ratio | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR) | Maximum
Debt Instrument [Line Items]
Interest rate terms, leverage ratio	3		3
Greater Than Or Equal To 2.00 But Less Than 3.00 | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	2.00%		2.00%
Greater than or equal to 1.00 but less than 2.00 | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.75%		1.75%
Less than 1.00 | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.50%		1.50%
Greater Than Or Equal To 3.00 | Revolving Credit Facility | Line of Credit | 2017 Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	2.50%		2.50%

Debt, Commitments and Conting_3

Debt, Commitments and Contingencies - Repurchase of Subsidiary Units (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Founder and President | Repurchase of Subsidiary Units, February 2011
Related Party Transaction [Line Items]
Due to related parties, current	$ 200		$ 200		$ 2,800
Due to related parties, noncurrent	200		200		$ 400
Subsidiary unit awards
Related Party Transaction [Line Items]
Settlements	$ 0	$ 0	(2,802)	$ 0
Subsidiary unit awards | Founder and President | Repurchase of Subsidiary Units, February 2011
Related Party Transaction [Line Items]
Settlements			$ (2,800)

Debt, Commitments and Conting_4

Debt, Commitments and Contingencies - Leases (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Oct. 31, 2018USD ($)ft²	Dec. 31, 2016USD ($)ft²	Aug. 31, 2014USD ($)
Leases, Operating [Abstract]
Lease renewal term							5 years
Available leasehold improvement allowance	$ 10.8		$ 10.8				$ 8
Square footage of additional office space | ft²						30,662
Additional leasehold improvement allowance						$ 1.7
Available leasehold improvement allowance, amount utilized	9.7		9.7
Rent expense	$ 1.1	$ 1.6	$ 4.5	$ 4.5
Subsequent Event
Leases, Operating [Abstract]
Square footage of additional office space | ft²					23,493
Additional leasehold improvement allowance					$ 1.1
Future minimum lease payments, year ended September 30, 2019					0.1
Future minimum lease payments, two-year period ending September 30, 2021					1.8
Future minimum lease payments, two-year period ending September 30, 2023					2
Future minimum lease payments, beyond September 30, 2023					$ 2.9

Debt, Commitments and Conting_5

Debt, Commitments and Contingencies - Letters of Credit (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Line of Credit | Letter of Credit | 2017 Facility
Line of Credit Facility [Line Items]
Outstanding letters of credit	$ 0	$ 0

Debt, Commitments and Conting_6

Debt, Commitments and Contingencies - Legal Proceedings (Details) $ in Millions	Aug. 24, 2017claim	Jun. 26, 2017patent	Apr. 25, 2017claim	Aug. 19, 2016patent	Jun. 02, 2015patentelement	Sep. 30, 2017patent	Mar. 31, 2017patent	Sep. 30, 2015patent	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Pending Litigation | Vivint, Inc. vs. Alarm.com Holdings, Inc
Loss Contingencies [Line Items]
Number of patents allegedly infringed upon by the company		4		5	6		2
Number of patents under reexamination						2
Number of elements of a solution in a patent, potentially infringed (or more) | element					1
Number of patents allegedly infringed by elements in solution					1
Pending Litigation | Alarm.com and ICN Acquisition, LLC vs. ipDatatel
Loss Contingencies [Line Items]
Number of company's patents allegedly infringed | claim	1
Pending Litigation | Alarm.com and ICN Acquisition, LLC vs. Protect America,Inc. and SecureNet Technologies, LLC
Loss Contingencies [Line Items]
Number of company's patents allegedly infringed | claim			1
Pending Litigation | Icontrol vs. SecureNet
Loss Contingencies [Line Items]
Number of patents instituted in suit								1
Number of patents appealed								1
Settled Litigation | Alarm.com vs. U.S. District Court for the Northern District of California, Initial Payment
Loss Contingencies [Line Items]
Loss contingency, settlement | $									$ 5
General and administrative | Settled Litigation | Alarm.com vs. U.S. District Court for the Northern District of California
Loss Contingencies [Line Items]
Loss contingency, settlement | $									$ 28	$ 28

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 3,457	$ 1,906	$ 9,670	$ 5,134
Tax benefit from stock-based awards	2,958	6,059	6,899	11,645
Stock options and assumed options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	850	939	2,666	3,005
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	2,585	936	6,900	2,029
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	0	0	1	19
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	22	31	103	81
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	301	181	855	359
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,191	584	3,700	1,908
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,965	$ 1,141	$ 5,115	$ 2,867

Stock-Based Compensation Stock-

Stock-Based Compensation Stock-Based Compensation - Narrative (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stock options and assumed options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised (in shares)	281,709	425,376	721,573	943,797
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted (in shares)	54,300	40,150	266,470	367,350
Restricted stock units vested (in shares)	8,168	0	21,714	0
2015 Equity Incentive Plan | Stock options and assumed options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	4,000	8,050	180,500	245,600

Earnings (Loss) Per Share - Com

Earnings (Loss) Per Share - Components of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net (loss) / income	$ (7,652)	$ 15,103	$ 13,596	$ 28,931
Less: income allocated to participating securities	0	(6)	(2)	(14)
Net (loss) / income attributable to common stockholders	$ (7,652)	$ 15,097	$ 13,594	$ 28,917
Weighted average common shares outstanding - basic (in shares)	47,812,642	46,886,345	47,494,926	46,520,469
Dilutive effect of stock options, RSUs and RSAs (in shares)	0	2,373,356	2,098,992	2,553,810
Weighted average common shares outstanding - diluted (in shares)	47,812,642	49,259,701	49,593,918	49,074,279
Weighted average common shares outstanding — diluted (C)
Basic (in dollars per share)	$ (0.16)	$ 0.32	$ 0.29	$ 0.62
Diluted (in dollars per share)	$ (0.16)	$ 0.31	$ 0.27	$ 0.59

Earnings (Loss) Per Share - Sch

Earnings (Loss) Per Share - Schedule of Securities Excluded from Calculation of Diluted Weighted Average Common Shares Outstanding Due to Anti-dilutive Effect (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of diluted weighted average common shares outstanding	191,169	189,117	191,469	318,917
Restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of diluted weighted average common shares outstanding	0	192	0	192
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of diluted weighted average common shares outstanding	33,100	0	33,100	39,350
Common stock subject to repurchase
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of diluted weighted average common shares outstanding	4,005	16,716	4,005	16,716

Significant Service Provider _2

Significant Service Provider Partners (Details) - Service Provider Concentration Risk - Revenue	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Ten Largest Service Providers
Concentration Risk [Line Items]
Concentration risk percentage	57.00%	60.00%	58.00%	60.00%
Minimum | Service Provider B
Concentration Risk [Line Items]
Concentration risk percentage	15.00%	15.00%	15.00%
Minimum | Service Provider A
Concentration Risk [Line Items]
Concentration risk percentage		10.00%
Minimum | Service Provider A and B
Concentration Risk [Line Items]
Concentration risk percentage				10.00%
Maximum | Service Provider B
Concentration Risk [Line Items]
Concentration risk percentage	20.00%	20.00%	20.00%
Maximum | Service Provider A
Concentration Risk [Line Items]
Concentration risk percentage		15.00%
Maximum | Service Provider A and B
Concentration Risk [Line Items]
Concentration risk percentage				15.00%

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Provisional income tax expense	$ 8,700,000				$ 8,800,000
Income tax benefit	(9,061,000)	$ (5,018,000)	$ (10,413,000)	$ (8,981,000)
Accrued interest and penalties related to unrecognized tax benefits	$ 100,000		$ 100,000		100,000
Effective income tax rate (percent)	54.20%	(49.80%)	(327.10%)	(45.00%)
Valuation allowance	$ 0		$ 0		$ 0
Research Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Reduction to unrecognized tax benefits			$ 200,000

Segment Information (Details)

Segment Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)segment	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Total revenue	$ 111,848,000	$ 89,962,000	$ 309,092,000	$ 250,144,000
Number of reportable segments | segment	2
Operating income / (loss)	$ (16,694,000)	10,401,000	3,809,000	20,782,000
Total Assets	427,360,000		427,360,000		$ 371,641,000
Amortization and depreciation	5,891,000	5,071,000	16,154,000	12,781,000
Additions to property and equipment			9,317,000	7,652,000
Alarm.com
Segment Reporting Information [Line Items]
Amortization and depreciation	5,800,000	5,000,000	15,900,000	12,600,000
Additions to property and equipment	3,900,000	2,200,000	10,100,000	7,200,000
Other
Segment Reporting Information [Line Items]
Amortization and depreciation	100,000	100,000	200,000	200,000
Additions to property and equipment	100,000	100,000	100,000	100,000
Operating Segments | Alarm.com
Segment Reporting Information [Line Items]
Total revenue	105,526,000	85,287,000	292,867,000	237,137,000
Operating income / (loss)	(15,593,000)	12,500,000	8,335,000	27,903,000
Total Assets	469,366,000		469,366,000		405,915,000
Operating Segments | Other
Segment Reporting Information [Line Items]
Total revenue	9,386,000	6,311,000	23,769,000	16,198,000
Operating income / (loss)	(1,084,000)	(2,095,000)	(4,548,000)	(7,302,000)
Total Assets	18,207,000		18,207,000		19,144,000
Intersegment Eliminations | Alarm.com
Segment Reporting Information [Line Items]
Total revenue	(1,343,000)	(794,000)	(3,585,000)	(1,939,000)
Operating income / (loss)	26,000	(11,000)	(211,000)	(68,000)
Total Assets	(60,212,000)		(60,212,000)		(53,267,000)
Intersegment Eliminations | Other
Segment Reporting Information [Line Items]
Total revenue	(1,721,000)	(842,000)	(3,959,000)	(1,252,000)
Operating income / (loss)	(43,000)	$ 7,000	233,000	$ 249,000
Total Assets	$ (1,000)		$ (1,000)		$ (151,000)
Segment Concentration Risk | Revenue | Alarm.com
Segment Reporting Information [Line Items]
Concentration risk percentage	93.00%	94.00%	94.00%	94.00%
Software License Revenue
Segment Reporting Information [Line Items]
Total revenue	$ 10,500,000	$ 9,300,000	$ 30,600,000	$ 20,100,000
Software License Revenue | Alarm.com
Segment Reporting Information [Line Items]
Total revenue	10,500,000	9,300,000	30,600,000	20,100,000
Software License Revenue | Other
Segment Reporting Information [Line Items]
Total revenue	0	0	0	0
SaaS and license revenue
Segment Reporting Information [Line Items]
Total revenue	74,292,000	61,924,000	213,248,000	171,078,000
SaaS and license revenue | Operating Segments | Alarm.com
Segment Reporting Information [Line Items]
Total revenue	70,884,000	59,774,000	204,622,000	165,764,000
SaaS and license revenue | Operating Segments | Other
Segment Reporting Information [Line Items]
Total revenue	3,408,000	2,150,000	8,626,000	5,314,000
SaaS and license revenue | Intersegment Eliminations | Alarm.com
Segment Reporting Information [Line Items]
Total revenue	0	0	0	0
SaaS and license revenue | Intersegment Eliminations | Other
Segment Reporting Information [Line Items]
Total revenue	0	0	0	0
Hardware and other revenue
Segment Reporting Information [Line Items]
Total revenue	37,556,000	28,038,000	95,844,000	79,066,000
Hardware and other revenue | Operating Segments | Alarm.com
Segment Reporting Information [Line Items]
Total revenue	34,642,000	25,513,000	88,245,000	71,373,000
Hardware and other revenue | Operating Segments | Other
Segment Reporting Information [Line Items]
Total revenue	5,978,000	4,161,000	15,143,000	10,884,000
Hardware and other revenue | Intersegment Eliminations | Alarm.com
Segment Reporting Information [Line Items]
Total revenue	(1,343,000)	(794,000)	(3,585,000)	(1,939,000)
Hardware and other revenue | Intersegment Eliminations | Other
Segment Reporting Information [Line Items]
Total revenue	$ (1,721,000)	$ (842,000)	$ (3,959,000)	$ (1,252,000)

Related Party Transactions (Det

Related Party Transactions (Details) - Installation Partner - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Sep. 30, 2014
Related Party Transaction [Line Items]
Ownership percentage in equity method investment	48.20%		48.20%
Equity investment in installation partner	$ 0		$ 0		$ 0
Equity Method Investee
Related Party Transaction [Line Items]
Accounts payable to related party (less than)	100,000		100,000		$ 100,000
Equity Method Investee | Secured Promissory Note
Related Party Transaction [Line Items]
Related party notes receivable, face amount						$ 300,000
Notes receivable, interest rate						8.00%
Equity Method Investee | Cost of Hardware and Other Revenue
Related Party Transaction [Line Items]
Expenses incurred from related party	$ 100,000	$ 100,000	$ 300,000	$ 600,000