Vivint Solar (VSLR) 10-Q 8 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	VSLR
Entity Registrant Name	Vivint Solar, Inc.
Entity Central Index Key	1,607,716
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		115,328,684

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 78,466	$ 108,452
Accounts receivable, net		18,236	19,665
Inventories		15,790	22,597
Prepaid expenses and other current assets		22,234	34,049
Total current assets		134,726	184,763
Restricted cash and cash equivalents		47,773	46,486
Solar energy systems, net		1,727,479	1,673,532
Property and equipment, net		13,315	15,078
Intangible assets, net		725	862
Prepaid tax asset, net			505,883
Other non-current assets, net		41,763	37,325
TOTAL ASSETS	[1]	1,965,781	2,463,929
Current liabilities:
Accounts payable		40,751	40,736
Accounts payable—related party		529	163
Distributions payable to non-controlling interests and redeemable non-controlling interests		7,501	16,437
Accrued compensation		19,890	20,992
Current portion of long-term debt		13,566	13,585
Current portion of deferred revenue		24,255	41,846
Current portion of capital lease obligation		3,439	4,166
Accrued and other current liabilities		25,989	29,675
Total current liabilities		135,920	167,600
Long-term debt, net of current portion		959,187	925,964
Deferred revenue, net of current portion		11,311	29,200
Capital lease obligation, net of current portion		1,226	1,599
Deferred tax liability, net		356,984	342,382
Other non-current liabilities		12,623	13,674
Total liabilities	[1]	1,477,251	1,480,419
Commitments and contingencies (Note 17)
Redeemable non-controlling interests		130,107	122,444
Stockholders’ equity:
Common stock, $0.01 par value—1,000,000 authorized, 115,329 shares issued and outstanding as of March 31, 2018; 1,000,000 authorized, 115,099 shares issued and outstanding as of December 31, 2017		1,153	1,151
Additional paid-in capital		562,962	559,788
Accumulated other comprehensive income		13,694	6,905
(Accumulated deficit) retained earnings		(277,015)	213,107
Total stockholders’ equity		300,794	780,951
Non-controlling interests		57,629	80,115
Total equity		358,423	861,066
TOTAL LIABILITIES, REDEEMABLE NON-CONTROLLING INTERESTS AND EQUITY		$ 1,965,781	$ 2,463,929
[1]	The Company’s assets as of March 31, 2018 and December 31, 2017 include $1,563.5 million and $1,516.2 million consisting of assets of variable interest entities, or VIEs, that can only be used to settle obligations of the VIEs. These assets include solar energy systems, net, of $1,532.9 million and $1,486.0 million as of March 31, 2018 and December 31, 2017; cash and cash equivalents of $12.9 million and $17.3 million as of March 31, 2018 and December 31, 2017; accounts receivable, net, of $9.4 million and $5.1 million as of March 31, 2018 and December 31, 2017; other non-current assets, net of $7.6 million and $6.8 million as of March 31, 2018 and December 31, 2017; and prepaid expenses and other current assets of $0.8 million and $1.0 million as of March 31, 2018 and December 31, 2017. The Company’s liabilities as of March 31, 2018 and December 31, 2017 included $23.9 million and $58.4 million of liabilities of VIEs whose creditors have no recourse to the Company. These liabilities include distributions payable to non-controlling interests and redeemable non-controlling interests of $7.5 million and $16.4 million as of March 31, 2018 and December 31, 2017; deferred revenue of $10.5 million and $36.0 million as of March 31, 2018 and December 31, 2017; accrued and other current liabilities of $4.5 million as of March 31, 2018 and December 31, 2017; and other non-current liabilities of $1.5 million and $1.4 million as of March 31, 2018 and December 31, 2017. For further information see Note 12—Investment Funds.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Common stock, par value		$ 0.01	$ 0.01
Common stock, shares authorized		1,000,000,000	1,000,000,000
Common stock, shares issued		115,329,000	115,099,000
Common stock, shares outstanding		115,329,000	115,099,000
Total assets	[1]	$ 1,965,781	$ 2,463,929
Solar energy systems, net		1,727,479	1,673,532
Cash and cash equivalents		78,466	108,452
Accounts receivable, net		18,236	19,665
Other non-current assets, net		41,763	37,325
Prepaid expenses and other current assets		22,234	34,049
Total liabilities	[1]	1,477,251	1,480,419
Distributions payable to non-controlling interests and redeemable non-controlling interests		7,501	16,437
Accrued and other current liabilities		25,989	29,675
Other non-current liabilities		12,623	13,674
Variable Interest Entities
Total assets		1,563,518	1,516,190
Solar energy systems, net		1,532,897	1,486,023
Cash and cash equivalents		12,937	17,280
Accounts receivable, net		9,350	5,143
Other non-current assets, net		7,560	6,792
Prepaid expenses and other current assets		774	952
Total liabilities		23,893	58,382
Distributions payable to non-controlling interests and redeemable non-controlling interests		7,501	16,437
Deferred revenue		10,500	36,000
Accrued and other current liabilities		4,457	4,478
Other non-current liabilities		$ 1,458	$ 1,444
[1]	The Company’s assets as of March 31, 2018 and December 31, 2017 include $1,563.5 million and $1,516.2 million consisting of assets of variable interest entities, or VIEs, that can only be used to settle obligations of the VIEs. These assets include solar energy systems, net, of $1,532.9 million and $1,486.0 million as of March 31, 2018 and December 31, 2017; cash and cash equivalents of $12.9 million and $17.3 million as of March 31, 2018 and December 31, 2017; accounts receivable, net, of $9.4 million and $5.1 million as of March 31, 2018 and December 31, 2017; other non-current assets, net of $7.6 million and $6.8 million as of March 31, 2018 and December 31, 2017; and prepaid expenses and other current assets of $0.8 million and $1.0 million as of March 31, 2018 and December 31, 2017. The Company’s liabilities as of March 31, 2018 and December 31, 2017 included $23.9 million and $58.4 million of liabilities of VIEs whose creditors have no recourse to the Company. These liabilities include distributions payable to non-controlling interests and redeemable non-controlling interests of $7.5 million and $16.4 million as of March 31, 2018 and December 31, 2017; deferred revenue of $10.5 million and $36.0 million as of March 31, 2018 and December 31, 2017; accrued and other current liabilities of $4.5 million as of March 31, 2018 and December 31, 2017; and other non-current liabilities of $1.5 million and $1.4 million as of March 31, 2018 and December 31, 2017. For further information see Note 12—Investment Funds.

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue:
Operating leases and incentives	$ 31,114	$ 30,389
Solar energy system and product sales	37,136	22,725
Total revenue	68,250	53,114
Cost of revenue:
Cost of revenue—operating leases and incentives	38,687	35,070
Cost of revenue—solar energy system and product sales	26,045	18,665
Total cost of revenue	64,732	53,735
Gross profit (loss)	3,518	(621)
Operating expenses:
Sales and marketing	11,125	8,818
Research and development	486	896
General and administrative	19,851	20,579
Amortization of intangible assets	136	140
Total operating expenses	31,598	30,433
Loss from operations	(28,080)	(31,054)
Interest expense	16,922	14,721
Other (income) expense, net	(2,261)	276
Loss before income taxes	(42,741)	(46,051)
Income tax expense	18,643	9,401
Net loss	(61,384)	(55,452)
Net loss attributable to non-controlling interests and redeemable non-controlling interests	(48,408)	(68,744)
Net (loss attributable) income available to common stockholders	$ (12,976)	$ 13,292
Net (loss attributable) income available per share to common stockholders:
Basic	$ (0.11)	$ 0.12
Diluted	$ (0.11)	$ 0.11
Weighted-average shares used in computing net (loss attributable) income available per share to common stockholders:
Basic	115,155	110,765
Diluted	115,155	116,398

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net (loss attributable) income available to common stockholders	$ (12,976)	$ 13,292
Other comprehensive income (loss):
Unrealized gains (losses) on cash flow hedging instruments (net of tax effect of $1,394 and $(18))	3,749	(28)
Less: Interest income (expense) on derivatives recognized into earnings (net of tax effect of $103 and $(60))	278	(90)
Total other comprehensive income (loss)	3,471	(118)
Comprehensive (loss) income	$ (9,505)	$ 13,174

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Unrealized losses on cash flow hedging instruments, tax	$ 1,394	$ (18)
Interest expense on derivatives recognized into earnings, tax	$ 103	$ (60)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (61,384)	$ (55,452)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	16,307	14,162
Amortization of intangible assets	136	140
Deferred income taxes	18,969	36,125
Stock-based compensation	2,969	3,922
Loss on solar energy systems and property and equipment	570	2,025
Non-cash interest and other expense	2,007	2,126
Reduction in lease pass-through financing obligation	(687)	(649)
(Gains) losses on interest rate swaps	(2,262)	276
Changes in operating assets and liabilities:
Accounts receivable, net	1,429	(4,481)
Inventories	6,807	(2,115)
Prepaid expenses and other current assets	11,746	27,901
Prepaid tax asset, net		(24,181)
Other non-current assets, net	385	(3,861)
Accounts payable	374	641
Accrued compensation	(2,351)	(1,763)
Deferred revenue	(9,083)	2,109
Accrued and other liabilities	(103)	6,473
Net cash (used in) provided by operating activities	(14,171)	3,398
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments for the cost of solar energy systems	(72,208)	(75,140)
Payments for property and equipment	(40)	(278)
Proceeds from disposals of solar energy systems and property and equipment	775	171
Net cash used in investing activities	(71,473)	(75,247)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from investment by non-controlling interests and redeemable non-controlling interests	42,771	58,560
Distributions paid to non-controlling interests and redeemable non-controlling interests	(18,122)	(15,027)
Proceeds from long-term debt	40,000	253,750
Payments on long-term debt	(7,748)	(141,159)
Payments for debt issuance and deferred offering costs		(10,430)
Proceeds from lease pass-through financing obligation	852	852
Principal payments on capital lease obligations	(1,015)	(1,196)
Proceeds from issuance of common stock	207	147
Net cash provided by financing activities	56,945	145,497
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS, INCLUDING RESTRICTED AMOUNTS	(28,699)	73,648
CASH AND CASH EQUIVALENTS, INCLUDING RESTRICTED AMOUNTS—Beginning of period	154,938	123,439
CASH AND CASH EQUIVALENTS, INCLUDING RESTRICTED AMOUNTS—End of period	126,239	197,087
NONCASH INVESTING AND FINANCING ACTIVITIES:
Accrued distributions to non-controlling interests and redeemable non-controlling interests	(8,936)	(10,228)
Change in fair value of interest rate swaps	7,024	(473)
Costs of solar energy systems included in changes in accounts payable, accounts payable—related party, accrued compensation and accrued and other liabilities	(2,518)	(5,266)
Vehicles acquired under capital leases	199	98
Solar energy system sales
NONCASH INVESTING AND FINANCING ACTIVITIES:
Receivable for state tax credits recorded as a reduction to solar energy system costs	$ 4	$ 52

Organization

Organization	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	1 . Organization Vivint Solar, Inc. and its subsidiaries are collectively referred to as the “Company.” The Company most commonly offers solar energy to residential customers through long-term customer contracts, such as power purchase agreements (“PPAs”) and legal-form leases (“Solar Leases”). The Company also offers its customers the option to purchase solar energy systems (“System Sales”) through third-party loan offerings or a cash purchase. The Company enters into customer contracts through a sales organization that primarily uses a direct-to-home sales model. The long-term customer contracts under PPAs and Solar Leases are typically for 20 years and require the customer to make monthly payments to the Company. The Company has formed various investment funds and entered into long-term debt facilities to monetize the recurring customer payments under its long-term customer contracts and the investment tax credits, accelerated tax depreciation and other incentives associated with residential solar energy systems. The Company uses the cash received from the investment funds, long-term debt facilities and cash generated from operations, including System Sales, to finance a portion of the Company’s variable and fixed costs associated with installing solar energy systems.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2 . Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, these unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s annual report on Form 10-K dated as of March 7, 2018. The unaudited condensed consolidated financial statements were prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments (all of which were considered of normal recurring nature) considered necessary to present fairly the Company’s financial results. The results of the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the fiscal year ending December 31, 2018 or for any other interim period or other future year. The unaudited condensed consolidated financial statements reflect the accounts and operations of the Company and those of its subsidiaries in which the Company has a controlling financial interest. The Company uses a qualitative approach in assessing the consolidation requirement for variable interest entities (“VIEs”). This approach focuses on determining whether the Company has the power to direct the activities of the VIE that most significantly affect the VIE’s economic performance and whether the Company has the obligation to absorb losses, or the right to receive benefits, that could potentially be significant to the VIE. All of these determinations involve significant management judgments and estimates. The Company has determined that it is the primary beneficiary in the operational VIEs in which it has an equity interest. The Company evaluates its relationships with the VIEs on an ongoing basis to ensure that it continues to be the primary beneficiary. All intercompany transactions and balances have been eliminated in consolidation. For additional information, see Note 12—Investment Funds. Certain prior period amounts have been reclassified to conform to current year presentation. These reclassifications did not have a significant impact on the consolidated financial statements. Use of Estimates The preparation of the condensed consolidated financial statements requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. The Company regularly makes significant estimates and assumptions including, but not limited to, investment tax credits (“ITCs”); revenue recognition; solar energy systems, net; the impairment analysis of long-lived assets; stock-based compensation; the provision for income taxes; the valuation of derivative financial instruments; the recognition and measurement of loss contingencies; and non-controlling interests and redeemable non-controlling interests. The Company bases its estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ materially from those estimates. Liquidity In order to grow, the Company requires cash to finance the deployment of solar energy systems. As of the date of this filing, the Company will require additional sources of cash beyond current cash balances, and currently available financing facilities to fund long-term planned growth. If the Company is unable to secure additional financing when needed, or upon desirable terms, the Company may be unable to finance installation of customers’ systems in a manner consistent with past performance, cost of capital could increase, or the Company may be required to significantly reduce the scope of operations, any of which would have a material adverse effect on its business, financial condition, results of operations and prospects. While the Company believes additional financing is available and will continue to be available to support current levels of operations, the Company believes it has the ability and intent to reduce operations to the level of available financial resources for at least the next 12 months from the date of this report, if necessary. Revenue from Contracts with Customers The Company adopted ASU 2014-09, Revenue from Contracts with Customers, The Company currently accounts for PPAs, Solar Leases, and associated rebates and incentives as minimum lease payments from operating leases under ASC 840, Leases Leases, The Company has analyzed the impact of Topic 606 on System Sales and other product sales and has concluded that the revenue recognition associated with these product sales did not change in the condensed consolidated financial statements. The Company will continue to show this revenue stream as solar energy system and product sales in the condensed consolidated statement of operations. The Company’s principal performance obligation for System Sales is to design and install a solar energy system that is interconnected to the local power grid and granted permission to operate to the customer. When the solar energy system has been granted permission to operate, the customer retains all of the significant risks and rewards of ownership of the solar energy system. For certain System Sales, the Company provides limited post-sale services to monitor the productivity of the solar energy system for 20 years after it has been placed in service. The Company collects cash during the installation process and recognizes revenue for System Sales and other product sales at the placed in-service date or product delivery date less any revenue allocated to monitoring services. The Company allocates a portion of the transaction price to the monitoring services by estimating the fair market price that the Company would charge for these services if offered separately from the sale of the solar energy system. As of March 31, 2018 and December 31, 2017, the Company had allocated deferred revenue of $2.5 million and $2.1 million to monitoring services that will be recognized over the term of the monitoring services. All costs to obtain and fulfill contracts associated with System Sales and other product sales are expensed as a cost of revenue when the Company has fulfilled its performance obligation and the products have been placed into service or delivered to the customer. The Company has assessed the impact of Topic 606 as it relates to the sales of ITCs through its lease pass-through fund arrangement. The Company has concluded that revenue related to the sale of ITCs through its lease pass-through arrangement is recognized when the related solar energy systems are placed in service as the Company has completed its performance obligation to transfer ITCs to the fund investors at that time. The fund investors contributed cash to the investment fund during the installation process as payment for the ITCs. The transaction price for the ITCs was estimated using the tax credit rate of 30% multiplied by the fair market value of the solar energy systems that were placed into service in the lease pass-through fund. All of the related solar energy systems were placed in service and all related revenue would have been recognized prior to September 30, 2016 under Topic 606. Prior to the adoption of Topic 606, the Company recognized this revenue evenly over the five-year ITC recapture period. This earlier recognition of the ITC lease pass-through revenue decreased revenue for the three months ended March 31, 2018 by $2.4 million and would have decreased revenue for the three months ended March 31, 2017 by $2.4 million. As all ITC sales revenue would have been recognized prior to September 30, 2016 under Topic 606, there is no deferred revenue related to ITC sales as of March 31, 2018, and there would have been no deferred revenue as of December 31, 2017. As shown below, the cumulative adjustment related to ITC revenue recognized into retained earnings, net of tax, as of January 1, 2018 was $19.2 million. As noted above, the Company adopted Topic 606 on a modified retrospective basis. However, if the Company adjusted the comparative period to reflect the adoption of Topic 606, the following adjustments would have been made to the condensed consolidated statement of operations for the three months ended March 31, 2017 (in thousands, except per share data): As Previously Revenue Reported Adjustment As Adjusted Revenue $ 53,114 $ (2,364 ) $ 50,750 Income tax expense 9,401 (946 ) 8,455 Net income available to common shareholders 13,292 (1,418 ) 11,874 Diluted earnings per share 0.11 (0.01 ) 0.10 Additionally, the following adjustments would have been made to the condensed consolidated balance sheet as of December 31, 2017 (in thousands): As Previously Revenue Reported Adjustment As Adjusted Current portion of deferred revenue $ 41,846 $ (7,707 ) $ 34,139 Deferred revenue, net of current portion 29,200 (18,690 ) 10,510 Deferred tax liability, net 342,382 7,160 349,542 Retained earnings 213,107 (19,237 ) 193,870 Income Taxes The Company adopted ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory The adoption of ASU 2016-16 had the following effect on the Company’s condensed consolidated statement of operations for the three months ended March 31, 2018 (in thousands, except per share data): Pre-Adoption Effect of Accounting Adoption As Reported Income tax expense $ 5,781 $ 12,862 $ 18,643 Net loss (48,522 ) (12,862 ) (61,384 ) Net loss attributable to common shareholders (114 ) (12,862 ) (12,976 ) Basic earnings per share (0.00 ) (0.11 ) (0.11 ) Diluted earnings per share (0.00 ) (0.11 ) (0.11 ) The Company adopted ASU 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , Derivative Financial Instruments The Company adopted ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities Restricted Cash The Company adopted ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force) (“ASU 2016-18”) , effective January 1, 2018. This update clarified that transfers between cash and restricted cash are not reported as cash flow activities in the statements of cash flows. As such, restricted cash amounts are included with cash and cash equivalents in the beginning-of-period and end-of-period total amounts on the statements of cash flows. The Company applied this update retrospectively, which resulted in an adjustment to the beginning-of-period and end-of-period total amounts on the condensed consolidated statement of cash flows for the three months ended March 31, 2017 to include restricted cash balances from those periods. Recent Accounting Pronouncements New Lease Guidance In February 2016, the Financial Accounting Standards Board (the “FASB”) issued ASU 2016-02, Leases (Topic 842)

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	3 . Fair Value Measurements The Company measures and reports its cash equivalents at fair value. The following tables set forth the fair value of the Company’s financial assets and liabilities measured on a recurring basis by level within the fair value hierarchy (in thousands): March 31, 2018 Level 1 Level 2 Level 3 Total Financial Assets Interest rate swaps $ — $ 19,772 $ — $ 19,772 December 31, 2017 Level 1 Level 2 Level 3 Total Financial Assets Interest rate swaps $ — $ 14,028 $ — $ 14,028 Financial Liabilities Interest rate swaps $ — $ 1,280 $ — $ 1,280 The interest rate swaps (Level 2) were valued using a discounted cash flow model which incorporates an assessment of the risk of non-performance by the interest rate swap counterparties and the Company. The valuation model uses various observable inputs including contractual terms, interest rate curves, credit spreads and measures of volatility. The Company did not realize gains or losses related to financial assets for any of the periods presented. The carrying values and fair values of the Company’s long-term debt were as follows (in thousands): March 31, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value Floating-rate long-term debt $ 792,191 $ 792,191 $ 757,044 $ 757,044 Fixed-rate long-term debt 196,168 225,629 199,063 238,618 Total $ 988,359 $ 1,017,820 $ 956,107 $ 995,662 The Company’s outstanding principal balance of long-term debt is carried at cost. The Company estimated the fair values of its floating-rate debt facilities to approximate their carrying values as interest accrues at floating rates based on market rates. The Company’s fixed-rate debt facilities (Level 2) were valued using quoted prices for corporate debt with similar terms.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Inventories	4 . Inventories Inventories consisted of the following (in thousands): March 31, December 31, 2018 2017 Solar energy systems held for sale $ 14,982 $ 21,971 Photovoltaic installation products 808 626 Total inventories $ 15,790 $ 22,597 Solar energy systems held for sale are solar energy systems under construction that have yet to be interconnected to the power grid and that will be sold to customers. Solar energy systems held for sale are stated at the lower of cost, on a first-in, first-out basis, or net realizable value. Photovoltaic installation products are stated at the lower of cost, on an average cost basis, or net realizable value.

Solar Energy Systems

Solar Energy Systems	3 Months Ended
	Mar. 31, 2018
Solar Energy Systems Disclosure [Abstract]
Solar Energy Systems	5 . Solar Energy Systems Solar energy systems, net consisted of the following (in thousands): March 31, December 31, 2018 2017 System equipment costs $ 1,484,019 $ 1,437,419 Initial direct costs related to solar energy systems 355,164 336,136 1,839,183 1,773,555 Less: Accumulated depreciation and amortization (145,016 ) (129,640 ) 1,694,167 1,643,915 Solar energy system inventory 33,312 29,617 Solar energy systems, net $ 1,727,479 $ 1,673,532 Solar energy system inventory represents the solar components and materials used in the installation of solar energy systems prior to being installed on customers’ roofs. As such, no depreciation is recorded related to this line item. The Company recorded depreciation and amortization expense related to solar energy systems of $15.4 million and $12.8 million for the three months ended March 31, 2018 and 2017.

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2018
Property Plant And Equipment [Abstract]
Property and Equipment	6 . Property and Equipment Property and equipment, net consisted of the following (in thousands): Estimated March 31, December 31, Useful Lives 2018 2017 Vehicles acquired under capital leases 3-5 years $ 13,729 $ 15,113 Leasehold improvements 1-12 years 12,284 15,071 Furniture and computer and other equipment 3 years 4,166 6,492 30,179 36,676 Less: Accumulated depreciation and amortization (16,864 ) (21,598 ) Property and equipment, net $ 13,315 $ 15,078 The Company recorded depreciation and amortization related to property and equipment of $1.7 million and $2.4 million for the three months ended March 31, 2018 and 2017 . The Company leases fleet vehicles that are accounted for as capital leases and are included in property and equipment, net. Of total property and equipment depreciation and amortization, depreciation on vehicles under capital leases of $0.7 million and $1.1 million was capitalized in solar energy systems, net for the three months ended March 31, 2018 and 2017.

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	7 . Intangible Assets Intangible assets, net consisted of the following (in thousands): March 31, December 31, 2018 2017 Cost: Internal-use software $ 1,199 $ 1,314 Developed technology 522 522 Trademarks/trade names 201 201 Customer relationships 164 164 Total carrying value 2,086 2,201 Accumulated amortization: Internal-use software (863 ) (872 ) Developed technology (274 ) (258 ) Trademarks/trade names (85 ) (79 ) Customer relationships (139 ) (130 ) Total accumulated amortization (1,361 ) (1,339 ) Total intangible assets, net $ 725 $ 862 The Company recorded amortization expense of $0.1 million for the three months ended March 31, 2018 and 2017, which was included in amortization of intangible assets.

Accrued Compensation

Accrued Compensation	3 Months Ended
	Mar. 31, 2018
Accrued Compensation Disclosure [Abstract]
Accrued Compensation	8 . Accrued Compensation Accrued compensation consisted of the following (in thousands): March 31, December 31, 2018 2017 Accrued payroll $ 10,985 $ 13,064 Accrued commissions 8,905 7,928 Total accrued compensation $ 19,890 $ 20,992

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	3 Months Ended
	Mar. 31, 2018
Payables And Accruals [Abstract]
Accrued and Other Current Liabilities	9 . Accrued and Other Current Liabilities Accrued and other current liabilities consisted of the following (in thousands): March 31, December 31, 2018 2017 Accrued unused commitment fees and interest $ 7,816 $ 7,445 Current portion of lease pass-through financing obligation 4,953 4,931 Accrued professional fees 4,012 3,977 Sales, use and property taxes payable 2,732 3,046 Accrued workers' compensation 1,887 1,446 Workmanship accrual 1,404 1,359 Current portion of deferred rent 934 937 Accrued inventory 496 4,122 Other accrued expenses 1,755 2,412 Total accrued and other current liabilities $ 25,989 $ 29,675

Debt Obligations

Debt Obligations	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Debt Obligations	10 . Debt Obligations Debt obligations consisted of the following as of March 31, 2018 (in thousands, except interest rates): Principal Unamortized Debt Unused Borrowings Issuance Costs Net Carrying Value Borrowing Interest Maturity Outstanding Current Long-term Current Long-term Capacity Rate Date 2017 Term loan facility $ 194,873 $ (172 ) $ (4,901 ) $ 6,733 $ 183,067 $ — 6.0 % January 2035 2016 Term loan facility (1) 283,566 (125 ) (7,149 ) 4,850 271,442 — 4.6 August 2021 Subordinated HoldCo facility 197,125 (32 ) (3,090 ) 1,968 192,035 — 9.7 March 2020 Credit agreement 1,295 (2 ) (135 ) 15 1,143 — 6.5 February 2023 Revolving lines of credit (2) Aggregation facility 175,000 — — — 175,000 200,000 4.8 September 2020 Working capital facility (3) 136,500 — — — 136,500 — 5.1 March 2020 Total debt $ 988,359 $ (331 ) $ (15,275 ) $ 13,566 $ 959,187 $ 200,000 Debt obligations consisted of the following as of December 31, 2017 (in thousands, except interest rates): Principal Unamortized Debt Unused Borrowings Issuance Costs Net Carrying Value Borrowing Interest Maturity Outstanding Current Long-term Current Long-term Capacity Rate Date 2017 Term loan facility $ 197,764 $ (176 ) $ (4,990 ) $ 6,644 $ 185,954 $ — 6.0 % January 2035 2016 Term loan facility (1) 287,919 (141 ) (7,623 ) 4,962 275,193 — 4.3 August 2021 Subordinated HoldCo facility 197,625 (35 ) (3,451 ) 1,965 192,174 — 9.3 March 2020 Credit agreement 1,299 (2 ) (140 ) 14 1,143 — 6.5 February 2023 Revolving lines of credit (2) Aggregation facility 135,000 — — — 135,000 240,000 4.7 September 2020 Working capital facility (3) 136,500 — — — 136,500 — 4.8 March 2020 Total debt $ 956,107 $ (354 ) $ (16,204 ) $ 13,585 $ 925,964 $ 240,000 (1) The interest rate of this facility is partially hedged to an effective interest rate of 4.0% for $260.1 million of the principal borrowings. See Note 11—Derivative Financial Instruments. (2) Revolving lines of credit are not presented net of unamortized debt issuance costs. (3) Facility is recourse debt, which refers to debt that is collateralized by the Company’s general assets. All of the Company’s other debt obligations are non-recourse, which refers to debt that is only collateralized by specified assets or subsidiaries of the Company. The Company’s debt facilities include customary events of default, conditions to borrowing and covenants, including covenants that restrict, subject to certain exceptions, the Company’s ability to incur indebtedness, incur liens, make investments, make fundamental changes to their business, dispose of assets, make certain types of restricted payments or enter into certain related party transactions. Additionally, the Company is required to maintain certain financial measurements and interest rate swaps for certain debt facilities. These restrictions do not impact the Company’s ability to enter into investment funds, including those that are similar to those entered into previously. The Company’s debt facilities are secured by net cash flows from long-term customer contracts. The Company was in compliance with all debt covenants as of March 31, 2018. 2017 Term Loan Facility In January 2017, a wholly owned subsidiary of the Company entered into a long-term fixed rate credit agreement (the “2017 Term Loan Facility”). Interest on borrowings accrues at an annual fixed rate equal to 6.0% and is payable in arrears. Certain principal payments are due on a quarterly basis, subject to the occurrence of certain events. As of March 31, 2018, the Company had $19.3 million in required reserves 2016 Term Loan Facility In August 2016, a wholly owned subsidiary of the Company entered into a credit agreement (the “2016 Term Loan Facility”). For the initial four years of the term of the 2016 Term Loan Facility, interest on borrowings accrues at an annual rate equal to the London Interbank Offered Rate (“LIBOR”) plus 3.00%. Thereafter, interest accrues at an annual rate equal to LIBOR plus 3.25%. Certain principal payments are due on a quarterly basis subject to the occurrence of certain events, including proceeds received by the borrower or subsidiary guarantors in respect of casualties, proceeds received for purchased systems, and failure to meet certain distribution conditions. As of March 31, 2018, the Company had $2.6 million in required reserves outstanding in collateral accounts with the administrative agent, which were included in restricted cash and cash equivalents. Subordinated HoldCo Facility In March 2016, a wholly owned subsidiary of the Company entered into a financing agreement (the “Subordinated HoldCo Facility”). a floating rate of LIBOR Credit Agreement In February 2016, a wholly owned subsidiary of the Company entered into a fixed rate credit agreement (the “Credit Agreement”). Principal and interest payments under the Credit Agreement are paid quarterly over the term of the loan. Interest accrues on borrowings at a fixed rate of 6.50%. Aggregation Facility In September 2014, a wholly owned subsidiary of the Company entered into an aggregation credit facility (as amended, the “Aggregation Facility”), pursuant to which the Company may borrow up to an aggregate of $375.0 million and, upon the satisfaction of certain conditions and the approval of the lenders, up to an additional aggregate of $175.0 million in borrowings. Prepayments are permitted under the Aggregation Facility. Under the Aggregation Facility, interest on borrowings accrues at a floating rate equal to either (1)(a) LIBOR or (b) the greatest of (i) the Federal Funds Rate plus 0.5%, (ii) the administrative agent’s prime rate and (iii) LIBOR plus 1% and (2) a margin that varies between 3.25% during the period during which the Company may incur borrowings and 3.75% after such period. As of March 31, 2018, the Company had $5.3 million in required reserves outstanding in collateral accounts with the administrative agent, which were included in restricted cash and cash equivalents. Working Capital Facility In March 2015, a wholly owned subsidiary of the Company entered into a revolving credit agreement (the “Working Capital Facility”) pursuant to which the Company may borrow up to an aggregate principal amount of $150.0 million from certain financial institutions. In addition to the outstanding borrowings as of March 31, 2018, the Company had established letters of credit under the Working Capital Facility for up to $13.5 million related to insurance contracts. Prepayments are permitted under the Working Capital Facility. Interest accrues on borrowings at a floating rate equal to, depending on the type of borrowing, (1) a rate equal to the Eurodollar Rate for the interest period divided by one minus the Eurodollar Reserve Percentage, plus a margin of 3.25%; or (2) the highest of (a) the Federal Funds Rate plus 0.50%, (b) the Citibank prime rate and (c) the one-month interest period Eurodollar rate plus 1.00%, plus a margin of 2.25%. Interest is payable depending on the type of borrowing at the end of (1) the interest period that the Company may elect as a term, not to exceed three months, (2) quarterly or (3) at maturity of the Working Capital Facility. The Company is required to maintain $30.0 million in cash and cash equivalents and certain investments as of the last day of each quarter. As of March 31, 2018, the Company was in compliance with such covenants.

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	11 . Derivative Financial Instruments Derivative financial instruments consisted of the following at fair value (in thousands): March 31, 2018 Fair Value Balance Sheet Location Derivatives designated as hedging instruments: Interest rate swaps $ 18,790 Other non-current assets, net Derivatives not designated as hedging instruments: Interest rate swaps $ 982 Other non-current assets, net December 31, 2017 Fair Value Balance Sheet Location Derivatives designated as hedging instruments: Interest rate swaps $ 14,028 Other non-current assets, net Derivatives not designated as hedging instruments: Interest rate swaps $ 1,280 Other non-current liabilities The Company is exposed to interest rate risk relating to its outstanding debt facilities that have variable interest rates. In connection with the 2016 Term Loan Facility, the Company entered into interest rate swaps to offset changes in the variable interest rate for a portion of the Company’s LIBOR-indexed floating-rate loans. As of March 31, 2018, the notional amount of these interest rate swaps was $260.1 million. The notional amount of the interest rate swaps decreases through July 31, 2028 similar to the Company’s estimated monthly and quarterly principal payments on its loans through that date. The interest rate swaps are designated as cash flow hedges, and unrealized gains or losses are recorded in other comprehensive income (“OCI”). The amount of AOCI expected to be reclassified to interest expense within the next 12 months is approximately $2.9 million. The Company will discontinue the hedge accounting designation of these derivatives if interest payments on LIBOR-indexed floating rate loans compared to the payments under the derivatives are no longer highly effective. In connection with the March 2017 amendment of the Aggregation Facility, the Company is required to maintain interest rate swaps such that at least 75% of the outstanding loan balance of the Aggregation Facility is hedged. The Company is required to meet this threshold within 15 business days after the end of each quarterly period. As of March 31, 2018, the Company had entered into interest rate swaps with an aggregate notional amount of $150.0 million. The interest rate swaps terminate when the Aggregation Facility matures in September 2020. The Company did not designate these interest rate swaps as hedge instruments and accounts for any changes in fair value in other expense, net. The Company adopted ASU 2017-12 as of January 1, 2018. Among other changes, this update eliminated the separate measurement of hedge ineffectiveness. The Company adopted this update using a modified retrospective method with a cumulative-effect adjustment to retained earnings as of January 1, 2018. As a result, the Company ceased measuring hedge ineffectiveness beginning January 1, 2018, while prior period measurements remain unchanged. See Note 2—Summary of Significant Accounting Policies. The Company records derivatives at fair value. The (gains) losses on derivatives designated as cash flow hedges recognized in OCI, before tax effect, consisted of the following (in thousands): Three Months Ended March 31, 2018 2017 Derivatives designated as cash flow hedges: Interest rate swaps $ (5,143 ) $ 46 The (gains) losses on derivative financial instruments recognized in the condensed consolidated statements of operations, before tax effect, consisted of the following (in thousands): Three Months Ended March 31, 2018 2017 Interest expense Other (income) expense, net Interest expense Other (income) expense, net Total amounts presented in the income statement line items $ 16,922 $ (2,261 ) $ 14,721 $ 276 Derivatives designated as cash flow hedges: Interest rate swaps (Gains) losses reclassified from AOCI into income $ (381 ) $ — $ 150 $ — (Gains) recognized in income - ineffective portion: — — — (676 ) Derivatives not designated as hedging instruments: Interest rate swaps (Gains) losses recognized in income — (2,262 ) — 952 Total (gains) losses $ (381 ) $ (2,262 ) $ 150 $ 276

Investment Funds

Investment Funds	3 Months Ended
	Mar. 31, 2018
Summarized Financial Data Of Subsidiary [Abstract]
Investment Funds	12 . Investment Funds As of March 31, 2018 and December 31, 2017, the Company had formed investment funds for the purpose of funding the purchase of solar energy systems under long-term customer contracts. The aggregate carrying value of these funds’ assets and liabilities (after elimination of intercompany transactions and balances) in the Company’s condensed consolidated balance sheets were as follows (in thousands): March 31, December 31, 2018 2017 Assets Current assets: Cash and cash equivalents $ 12,937 $ 17,280 Accounts receivable, net 9,350 5,143 Prepaid expenses and other current assets 774 952 Total current assets 23,061 23,375 Solar energy systems, net 1,532,897 1,486,023 Other non-current assets, net 7,560 6,792 Total assets $ 1,563,518 $ 1,516,190 Liabilities Current liabilities: Distributions payable to non-controlling interests and redeemable non-controlling interests $ 7,501 $ 16,437 Current portion of deferred revenue 1,950 9,176 Accrued and other current liabilities 4,457 4,478 Total current liabilities 13,908 30,091 Deferred revenue, net of current portion 8,527 26,847 Other non-current liabilities 1,458 1,444 Total liabilities $ 23,893 $ 58,382 Under the fund agreements, cash distributions of income and other receipts by the funds, net of agreed-upon expenses and estimated expenses, tax benefits and detriments of income and loss, and tax benefits of tax credits, are assigned to the fund investors and the Company’s subsidiaries as specified in contractual arrangements. As such, the cash held in investment funds is not readily available to the Company due to the timing of distributions. Certain of these fund arrangements have call and put options to acquire the investor’s equity interest as specified in the contractual agreements. Once the investor’s equity interest is acquired by the Company, the assets, liabilities and operations of the investment fund become wholly owned and no longer require an assessment of non-controlling interests. Fund investors for three of the funds are managed indirectly by The Blackstone Group L.P. (the “Sponsor”) and are considered related parties. As of March 31, 2018 and December 31, 2017, the cumulative total of contributions into the VIEs by all investors was $1,307.4 million and $1,264.6 million. Of these contributions, a cumulative total of $110.0 million was contributed by related parties in prior periods. A third-party provider has agreed to perform backup maintenance services for all funds, if necessary. Lease Pass-Through Financing Obligation During 2015, a wholly owned subsidiary of the Company entered into a lease pass-through fund arrangement under which the Company contributed solar energy systems and the investor contributed cash. The net carrying value of the related solar energy systems was $ million and $58.2 million as of March 31, 2018 and December 31, 2017. The Company adopted Topic 606 as of January 1, 2018. The Company has assessed the impact of Topic 606 as it relates to the sales of ITCs through its lease pass-through fund arrangement. The Company has concluded that revenue related to the sale of ITCs through its lease pass-through arrangement is recognized when the related solar energy systems are placed in service as the Company has completed its performance obligation to transfer ITCs to the funds investors at that time. The fund investors contributed cash to the investment fund during the installation process as payment for the ITCs. The transaction price for the ITCs was estimated using the tax credit rate of 30% times the fair market value of the solar energy systems that were placed into service in the lease pass-through fund. All of the related solar energy systems were placed in service and all related revenue would have been recognized prior to September 30, 2016 under Topic 606. Prior to the adoption of Topic 606, the Company recognized this revenue evenly over the five-year ITC recapture period. The Company adopted Topic 606 on a modified retrospective basis with a cumulative adjustment to retained earnings as of January 1, 2018. As all ITC sales revenue would have been recognized prior to September 30, 2016 under Topic 606, there was no deferred revenue related to ITC sales as of March 31, 2018. See Note 2—Summary of Significant Accounting Policies. The Company accounts for the residual of the large upfront payments, net of amounts allocated to the ITCs, and subsequent periodic payments received from the fund investor as a borrowing by recording the proceeds received as a lease pass-through financing obligation, which will be repaid through customer payments that will be received by the investor. Under this approach, the Company continues to account for the arrangement with the customers in its condensed consolidated financial statements, whether the cash generated from the customer arrangements is received by the Company’s wholly owned subsidiary or paid directly to the fund investor. A portion of the amounts received by the fund investor from customer payments is applied to reduce the lease pass-through financing obligation, and the balance is allocated to interest expense. The customer payments are recognized into revenue based on cash receipts during the period as required by GAAP. Interest is calculated on the lease pass-through financing obligation using the effective interest rate method. The effective interest rate is the interest rate that equates the present value of the cash amounts to be received by a fund investor over the master lease term with the present value of the cash amounts paid by the investor to the Company, adjusted for any payments made by the Company. Any additional master lease prepayments by the investor would be recorded as an additional lease pass-through financing obligation, while any refunds of master lease prepayments would reduce the lease pass-through financing obligation. The lease pass-through financing obligation is nonrecourse. As of March 31, 2018, the Company had recorded financing liabilities of $5.8 million related to this fund arrangement, which was the lease pass-through financing obligation recorded in other liabilities. As of December 31, 2017, the Company had recorded financing liabilities of $32.1 million related to this fund arrangement, of which $26.4 million was deferred revenue and $5.8 million was the lease pass-through financing obligation recorded in other liabilities. Guarantees With respect to the investment funds, the Company and the fund investors have entered into guaranty agreements under which the Company guarantees the performance of certain financial obligations of its subsidiaries to the investment funds. These guarantees do not result in the Company being required to make payments to the fund investors unless such payments are mandated by the investment fund governing documents and the investment fund fails to make such payment. Each of the Company’s investment funds and financing subsidiaries maintains separate books and records from each other and from the Company. The assets of each investment fund are not available to satisfy the debts or obligations of any other investment fund, subsidiary or the Company. The Company is contractually obligated to make certain VIE investors whole for losses that the investors may suffer in certain limited circumstances resulting from the disallowance or recapture of ITCs. The Company has concluded that the likelihood of a significant recapture event is remote and consequently has not recorded any liability in the condensed consolidated financial statements for any potential recapture exposure. The maximum potential future payments that the Company could have to make under this obligation would depend on the Internal Revenue Service (“IRS”) successfully asserting upon audit that the fair market values of the solar energy systems sold or transferred to the funds as determined by the Company exceeded the allowable basis for the systems for purposes of claiming ITCs. The fair market values of the solar energy systems and related ITCs are determined and the ITCs are allocated to the fund investors in accordance with the funds’ governing agreements. Due to uncertainties associated with estimating the timing and amounts of distributions, the likelihood of an event that may trigger repayment, forfeiture or recapture of ITCs to such investors, and the fact that the Company cannot determine how the IRS will evaluate system values used in claiming ITCs, the Company cannot determine the potential maximum future payments that are required under these guarantees. As of March 31, 2018, the Company has not made any payments under these guarantees. From time to time, the Company incurs penalties for non-performance, which non-performance may include delays in the installation process and interconnection to the power grid of solar energy systems and other factors. Based on the terms of the investment fund agreements, the Company will either reimburse a portion of the fund investor’s capital or pay the fund investor a non-performance fee. Distributions paid to reimburse fund investors totaled $10.0 million during the three months ended March 31, 2018. As of March 31, 2018, As a result of the guaranty arrangements in certain funds, the Company was required to hold a minimum cash balance of $10.0 million as of March 31, 2018 and December 31, 2017, which is classified as restricted cash and cash equivalents.

Redeemable Non-Controlling Inte

Redeemable Non-Controlling Interests and Equity	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Redeemable Non-Controlling Interests and Equity	13 . Redeemable Non-Controlling Interests and Equity Common Stock The Company had reserved shares of common stock for issuance as follows (in thousands): March 31, December 31, 2018 2017 Shares available for grant under equity incentive plans 16,333 12,774 Restricted stock units issued and outstanding 7,142 6,688 Stock options issued and outstanding 4,199 3,837 Long-term incentive plan 2,706 2,706 Total 30,380 26,005 Redeemable Non-Controlling Interests, Equity and Non-Controlling Interests The changes in redeemable non-controlling interests were as follows (in thousands): Balance as of December 31, 2017 $ 122,444 Contributions from redeemable non-controlling interests 42,771 Distributions to redeemable non-controlling interests (2,093 ) Net loss (33,015 ) Balance as of March 31, 2018 $ 130,107 The changes in stockholders’ equity and non-controlling interests were as follows (in thousands): Total Stockholders' Non-Controlling Equity Interests Total Equity Balance as of December 31, 2017 $ 780,951 $ 80,115 $ 861,066 Cumulative-effect adjustment from adoption of new ASUs (473,828 ) — (473,828 ) Stock-based compensation expense 2,969 — 2,969 Issuance of common stock 207 — 207 Distributions to non-controlling interests — (7,093 ) (7,093 ) Total other comprehensive income 3,471 — 3,471 Net loss (12,976 ) (15,393 ) (28,369 ) Balance as of March 31, 2018 $ 300,794 $ 57,629 $ 358,423 Accumulated Other Comprehensive Income The changes in AOCI are related to the Company’s cash flow hedges. The changes in AOCI, net of tax, were as follows (in thousands): Accumulated Other Comprehensive Income Balance as of December 31, 2017 $ 6,905 Cumulative-effect adjustment from adoption of new ASUs 3,318 Other comprehensive income before reclassifications 3,749 Less: Amounts reclassified from AOCI 278 Balance as of March 31, 2018 $ 13,694 Redeemable Non-Controlling Interests and Non-Controlling Interests Seven of the investment funds include a right for the non-controlling interest holder to require the Company’s wholly owned subsidiary to purchase all of its membership interests in the fund (each, a “Put Option”). The purchase price for the fund investor’s interest in the seven investment funds under the Put Options is the greater of fair market value at the time the option is exercised and a specified amount, ranging from $2.1 million to $4.1 million. The Put Options for these seven investment funds are exercisable beginning on the date that specified conditions are met for each respective fund. None of the Put Options are expected to become exercisable prior to 2021. Because the Put Options represent redemption features that are not solely within the control of the Company, the non-controlling interests in these investment funds are presented outside of permanent equity. Redeemable non-controlling interests are recorded using the greater of their carrying value at each reporting date (which is impacted by attribution under the hypothetical liquidation at book value (“HLBV”) method) or their estimated redemption value in each reporting period. In all investment funds except one, the Company’s wholly owned subsidiary has the right to require the non-controlling interest holder to sell all of its membership units to the Company’s wholly owned subsidiary (each, a “Call Option”). The purchase price for the fund investors’ interests under the Call Options varies by fund, but is generally the greater of a specified amount, which ranges from approximately $1.2 million to $7.0 million, the fair market value of such interest at the time the option is exercised, or an amount that causes the fund investor to achieve a specified return on investment. The Call Options are exercisable beginning on the date that specified conditions are met for each respective fund. None of the Call Options are expected to become exercisable prior to 2020.

Equity Compensation Plans

Equity Compensation Plans	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity Compensation Plans	14 . Equity Compensation Plans Equity Incentive Plans 2014 Equity Incentive Plan The Company currently grants equity awards through its 2014 Equity Incentive Plan (the “2014 Plan”). Under the 2014 Plan, the Company may grant stock options, restricted stock, restricted stock units (“RSUs”), stock appreciation rights, performance stock units, performance shares and performance awards to its employees, directors and consultants, and its parent and subsidiary corporations’ employees and consultants. As of March 31, 2018, a total of 16.3 million shares of common stock were available to grant under the 2014 Plan, subject to adjustment in the case of certain events. The number of shares available to grant under the 2014 Plan is subject to an annual increase on the first day of each year. In accordance with the annual increase, an additional 4.6 million shares became available to grant in January 2018 under the 2014 Plan. Stock Options Stock Option Activity Stock option activity for the three months ended March 31, 2018 was as follows (in thousands, except term and per share amounts): Weighted- Weighted- Average Shares Average Remaining Aggregate Underlying Exercise Contractual Intrinsic Options Price Term (in years) Value Outstanding—December 31, 2017 3,837 $ 2.01 $ 8,522 Granted 517 3.15 Exercised (155 ) 1.34 Cancelled — — Outstanding—March 31, 2018 4,199 $ 2.17 7.1 $ 6,938 Options vested and exercisable—March 31, 2018 1,902 $ 1.71 5.9 $ 4,235 RSUs RSU activity for the three months ended March 31, 2018 was as follows (awards in thousands): Weighted- Average Number of Grant Date Awards Fair Value Outstanding at December 31, 2017 6,688 $ 3.20 Granted 613 3.26 Vested (75 ) 6.35 Forfeited (84 ) 3.23 Outstanding at March 31, 2018 7,142 $ 3.17 Stock-Based Compensation Expense Stock-based compensation was included in operating expenses as follows (in thousands): Three Months Ended March 31, 2018 2017 Cost of revenue $ 274 $ 281 Sales and marketing 831 992 General and administrative 1,820 2,514 Research and development 44 135 Total stock-based compensation $ 2,969 $ 3,922 Unrecognized stock-based compensation expense for time-based stock options and RSUs as of March 31, 2018 was as follows (in thousands, except years): Unrecognized Weighted- Stock-Based Average Period Compensation of Recognition Expense (in years) RSUs $ 10,756 1.7 Time-based stock options 2,547 1.8 Total unrecognized stock-based compensation expense $ 13,303 The preceding table does not include $1.3 million of unrecognized stock-based compensation expense related to RSUs with performance conditions that the Company has determined are not probable of being achieved.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	15 . Income Taxes The income tax expense for the three months ended March 31, 2018 and 2017 was calculated on a discrete basis resulting in a consolidated quarterly effective income tax rate of (43.6)% and (20.4)%. The variations between the consolidated effective income tax rate and the U.S. federal statutory rate for the three months ended March 31, 2018 and 2017 were primarily attributable to the net effects of adopting ASU 2016-16, non-controlling interests and redeemable non-controlling interests, federal investment tax credits and the TCJA reducing the federal corporate income tax rate from 35% to 21% beginning in 2018. The TCJA made significant changes to the U.S. tax code, which include, but are not limited to, a reduced U.S. federal corporate tax rate, a provision that limits the amount of deductible interest expense, full expensing of acquired property, limitations on the utilization of net operating loss carryforwards, the repeal of the domestic production activity deduction, limitations on the deductibility of certain executive compensation, and the tax year of income inclusion. The Company recorded a provisional net tax benefit of $187.5 million related to the remeasurement of its deferred tax balances to reflect the corporate rate reduction in the period ended December 31, 2017. Although the Company is able to make a reasonable estimate of the impacts of the TCJA, it continues to analyze the temporary differences that existed on the date of enactment and the other previously mentioned provisions that come into effect for tax years starting after 2017 to determine if these items would impact the effective tax rate. The impact of the TCJA may differ from the Company’s estimates, possibly materially, due to, among other things, changes in interpretations and assumptions the Company has made, guidance that may be issued and actions the Company may take as a result of the TCJA. The Company sells solar energy systems to the investment funds for income tax purposes. As the investment funds are consolidated by the Company, the gain on the sale of the solar energy systems is eliminated in the condensed consolidated financial statements. However, this gain is recognized for tax reporting purposes. With the adoption of ASU 2016-16, the Company now accounts for the income tax consequences of these intra-entity transfers, both current and deferred, as a component of income tax expense and deferred tax liability, net during the period in which the transfers occur. Prior to the adoption of ASU 2016-16, any tax expense incurred related to these intra-entity sales was deferred and amortized over the estimated useful life of the underlying solar energy systems, which was estimated to be 30 years. Accordingly, the Company had recorded a prepaid tax asset, net, of $505.9 million as of December 31, 2017, which was removed as of January 1, 2018 when the Company adopted ASU 2016-16. See Note 2—Summary of Significant Accounting Policies. Uncertain Tax Positions As of March 31, 2018 and December 31, 2017, the Company had no unrecognized tax benefits. There was no interest or penalties accrued for any uncertain tax positions as of March 31, 2018 and December 31, 2017. The Company does not have any tax positions for which it is reasonably possible the total amount of gross unrecognized benefits will increase or decrease within the next 12 months. The Company is subject to taxation and files income tax returns in the United States, and various state and local jurisdictions. The U.S. and state jurisdictions in which the Company operates have statutes of limitations that generally range from three to four years. The Company’s federal, state and local income tax returns starting with the 2014 tax year are subject to audit. The Company’s 2013 income tax returns for two states are also subject to audit.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	16 . Related Party Transactions The Company’s condensed consolidated statements of operations included the following related party transactions (in thousands): Three Months Ended March 31, 2018 2017 Cost of revenue—operating leases and incentives $ — $ 398 Sales and marketing 701 698 General and administrative — 75 Vivint Services The Company has negotiated and entered into a number of agreements with its sister company, Vivint, Inc. (“Vivint”). Some of those agreements related to the Company’s use of certain of Vivint’s information technology and infrastructure services; however, the Company stopped using such services in July 2017. In August 2017, the Company entered into a sales dealer agreement with Vivint, pursuant to which each company will act as a non-exclusive dealer for the other party to market, promote and sell each other’s products. The agreement has an initial term of two years and replaces substantially all of the activities being undertaken under the parties’ former marketing and customer relations agreement. The Company and Vivint also agreed to extend the term of the non-solicitation provisions under an existing non-competition agreement to match the term of the sales dealer agreement. The Company incurred fees under agreements with Vivint of $1.0 million and $0.7 million for the three months ended March 31, 2018 and 2017, which reflect the amount of services provided by Vivint on behalf of the Company. Payables to Vivint recorded in accounts payable—related party were $0.5 million and $0.2 million as of March 31, 2018 and December 31, 2017. These payables include amounts due to Vivint related to the services agreements and other miscellaneous intercompany payables. Advances Receivable — Net amounts due from direct-sales personnel were $4.7 million and $6.6 million as of March 31, 2018 and December 31, 2017. The Company provided a reserve of $1.1 million and $1.0 million as of March 31, 2018 and December 31, 2017 related to advances to direct-sales personnel who have terminated their employment agreement with the Company. Investment Funds Fund investors for three of the investment funds are indirectly managed by the Sponsor and accordingly are considered related parties. The Company accrued equity distributions to these entities of $1.1 million and $1.2 million as of March 31, 2018 and December 31, 2017, included in distributions payable to non-controlling and redeemable non-controlling interests. See Note 12—Investment Funds.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	17 . Commitments and Contingencies Non-Cancellable Operating Leases The Company has entered into operating lease agreements for corporate and operating facilities, warehouses and related equipment in states in which the Company conducts operations. The aggregate expense incurred under these operating leases was $3.9 million and $4.3 million for the three months ended March 31, 2018 and 2017. Letters of Credit As of March 31, 2018, the Company had established letters of credit under the Working Capital Facility for up to $13.5 million related to insurance contracts and under the 2016 Term Loan Facility for $12.1 million related to the debt service reserve for the 2016 Term Loan Facility. See Note 10—Debt Obligations. Indemnification Obligations From time to time, the Company enters into contracts that contingently require it to indemnify parties against claims. These contracts primarily relate to provisions in the Company’s services agreements with related parties that may require the Company to indemnify the related parties against services rendered; and certain agreements with the Company’s officers and directors under which the Company may be required to indemnify such persons for liabilities. In addition, under the terms of the agreements related to the Company’s investment funds and other material contracts, the Company may also be required to indemnify fund investors and other third parties for liabilities. For further information see Note 12—Investment Funds. Legal Proceedings In September 2015, two of the Company’s customers, on behalf of themselves and a purported class, named the Company in a putative class action, Case No. BCV-15-100925 (Cal. Super. Ct., Kern County), alleging violation of California Business and Professions Code Section 17200 and requesting relief pursuant to Section 1689 of the California Civil Code. The complaint sought: (1) rescission of their PPAs along with restitution to the plaintiffs individually and (2) declaratory and injunctive relief. In October 2015, the Company moved to compel arbitration of the plaintiffs’ claims pursuant to the provisions set forth in the PPAs, which the Court granted and dismissed the class claims without prejudice. The plaintiffs appealed the Court’s order. On July 26, 2017, the Court of Appeal for the Fifth Appellate District ruled that all issues concerning the interpretation, validity, or enforceability of the PPAs, including the arbitrability of class claims, must be submitted to arbitration. The appellate court vacated the portion of the trial court's order dismissing class claims, requiring that issue to be determined by an arbitrator. The case is now proceeding in arbitration administered by JAMS. The Company is unable to estimate the amount or range of potential loss, if any, at this time. In March 2016, the Company filed suit in the Court of Chancery State of Delaware against SunEdison and SEV Merger Sub Inc. alleging that SunEdison willfully breached its obligations under the Merger Agreement pursuant to which the Company was to be acquired and breached its implied covenant of good faith and fair dealing. In April 2016, SunEdison filed for Chapter 11 bankruptcy, which stayed prosecution of the Company’s litigation in the Delaware court. In September 2016, the Company submitted a proof of claim in the bankruptcy case for an unsecured claim in the initial amount of $1.0 billion, which was subject to dispute, for damages for breach of the Merger Agreement. In April 2018, the Company reached a settlement with the litigation trustee in the bankruptcy case under which the Company’s claim will be allowed in the amount of $590.0 million. This settlement resolves both the lawsuit in the Delaware Chancery Court and the dispute about the amount of the Company’s unsecured creditor claim in the bankruptcy. In April 2018, the Company received an initial distribution of $2.1 million and expects to receive further distributions as assets are distributed to unsecured creditors under the court-approved plan of reorganization in the SunEdison bankruptcy case. While the exact amount to be distributed for this claim is unknown at this time, the payout is expected to be a small fraction of the $590.0 million claim. In March 2018, the New Mexico Attorney General’s office filed an action against the Company and several of its officers alleging violation of state consumer protection statutes and other claims. The Company disputes the allegations in the lawsuit and intends to defend itself in the action. The Company is unable to estimate a range of loss, if any, were there to be an adverse final decision. If an unfavorable outcome were to occur in this case, it is possible that the impact could be material to the Company’s results of operations in the period(s) in which any such outcome becomes probable and estimable. In November 2016, a customer of the Company filed a putative class action lawsuit in Superior Court in Alameda County, California, purportedly on behalf of all customers of a particular Company sales representative in California, claiming that the representative’s sales practices were improper under California consumer protection law. The Company moved to dismiss that action to compel arbitration. In March 2017, the original plaintiff filed an amended complaint adding an additional plaintiff, purporting to expand the proposed class to include all customers who are eligible for the California Alternate Rates for Energy program, and adding claims of misconduct in the Company’s sales practices apart from the individual representative identified in the original complaint. The Company moved to compel arbitration of the new plaintiff’s claims as well. The Company disputed the allegations in both the original and amended complaints. In January 2018, the parties reached a settlement with the two individual plaintiffs. Under the settlement, in addition to certain changes to its sales process and immaterial compensation payments to the individual plaintiffs, the Company agreed to pay attorneys’ fees in an amount that has yet to be determined but is expected to be immaterial to the Company’s results of operations. In addition to the matters discussed above, in the normal course of business, the Company has from time to time been named as a party to various legal claims, actions and complaints. While the outcome of these matters cannot be predicted with certainty, the Company does not currently believe that the outcome of any of these claims will have a material adverse effect, individually or in the aggregate, on its consolidated financial position, results of operations or cash flows. The Company accrues for losses that are probable and can be reasonably estimated. The Company evaluates the adequacy of its legal reserves based on its assessment of many factors, including interpretations of the law and assumptions about the future outcome of each case based on available information.

Basic and Diluted Net (Loss) In

Basic and Diluted Net (Loss) Income Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Basic and Diluted Net (Loss) Income Per Share	18 . Basic and Diluted Net (Loss) Income Per Share The following table sets forth the computation of the Company’s basic and diluted net (loss attributable) income available per share to common stockholders for the three months ended March 31, 2018 and 2017 (in thousands, except per share amounts): Three Months Ended March 31, 2018 2017 Numerator: Net (loss attributable) income available to common stockholders $ (12,976 ) $ 13,292 Denominator: Shares used in computing net (loss attributable) income available per share to common stockholders, basic 115,155 110,765 Weighted-average effect of potentially dilutive shares to purchase common stock — 5,633 Shares used in computing net (loss attributable) income available per share to common stockholders, diluted 115,155 116,398 Net (loss attributable) income available per share to common stockholders: Basic $ (0.11 ) $ 0.12 Diluted $ (0.11 ) $ 0.11 For the three months ended March 31, 2018, the Company incurred a net loss attributable to common stockholders. As such, the potentially dilutive shares were anti-dilutive and were not considered in the weighted-average number of common shares outstanding for the period. For the three months ended March 31, 2017, 0.8 million shares were excluded from the dilutive share calculations as the effect on net income per share would have been anti-dilutive.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	19 . Subsequent Events Investment Fund In April 2018, a wholly owned subsidiary of the Company entered into an investment fund arrangement with a new fund investor. The total commitment under the investment fund arrangement is $101.0 million. The Company’s wholly owned subsidiary has the right to elect to require the fund investor to sell all of its membership units to the Company’s wholly owned subsidiary once certain conditions have been met. The purchase price for the fund investor’s interests is determined based on the fair market value of those interests at the time the option is exercised. The Company has not yet completed its assessment of whether the investment fund arrangement is a VIE.

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, these unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s annual report on Form 10-K dated as of March 7, 2018. The unaudited condensed consolidated financial statements were prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments (all of which were considered of normal recurring nature) considered necessary to present fairly the Company’s financial results. The results of the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the fiscal year ending December 31, 2018 or for any other interim period or other future year. The unaudited condensed consolidated financial statements reflect the accounts and operations of the Company and those of its subsidiaries in which the Company has a controlling financial interest. The Company uses a qualitative approach in assessing the consolidation requirement for variable interest entities (“VIEs”). This approach focuses on determining whether the Company has the power to direct the activities of the VIE that most significantly affect the VIE’s economic performance and whether the Company has the obligation to absorb losses, or the right to receive benefits, that could potentially be significant to the VIE. All of these determinations involve significant management judgments and estimates. The Company has determined that it is the primary beneficiary in the operational VIEs in which it has an equity interest. The Company evaluates its relationships with the VIEs on an ongoing basis to ensure that it continues to be the primary beneficiary. All intercompany transactions and balances have been eliminated in consolidation. For additional information, see Note 12—Investment Funds. Certain prior period amounts have been reclassified to conform to current year presentation. These reclassifications did not have a significant impact on the consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. The Company regularly makes significant estimates and assumptions including, but not limited to, investment tax credits (“ITCs”); revenue recognition; solar energy systems, net; the impairment analysis of long-lived assets; stock-based compensation; the provision for income taxes; the valuation of derivative financial instruments; the recognition and measurement of loss contingencies; and non-controlling interests and redeemable non-controlling interests. The Company bases its estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ materially from those estimates.
Liquidity	Liquidity In order to grow, the Company requires cash to finance the deployment of solar energy systems. As of the date of this filing, the Company will require additional sources of cash beyond current cash balances, and currently available financing facilities to fund long-term planned growth. If the Company is unable to secure additional financing when needed, or upon desirable terms, the Company may be unable to finance installation of customers’ systems in a manner consistent with past performance, cost of capital could increase, or the Company may be required to significantly reduce the scope of operations, any of which would have a material adverse effect on its business, financial condition, results of operations and prospects. While the Company believes additional financing is available and will continue to be available to support current levels of operations, the Company believes it has the ability and intent to reduce operations to the level of available financial resources for at least the next 12 months from the date of this report, if necessary.
Revenue from Contracts with Customers	Revenue from Contracts with Customers The Company adopted ASU 2014-09, Revenue from Contracts with Customers, The Company currently accounts for PPAs, Solar Leases, and associated rebates and incentives as minimum lease payments from operating leases under ASC 840, Leases Leases, The Company has analyzed the impact of Topic 606 on System Sales and other product sales and has concluded that the revenue recognition associated with these product sales did not change in the condensed consolidated financial statements. The Company will continue to show this revenue stream as solar energy system and product sales in the condensed consolidated statement of operations. The Company’s principal performance obligation for System Sales is to design and install a solar energy system that is interconnected to the local power grid and granted permission to operate to the customer. When the solar energy system has been granted permission to operate, the customer retains all of the significant risks and rewards of ownership of the solar energy system. For certain System Sales, the Company provides limited post-sale services to monitor the productivity of the solar energy system for 20 years after it has been placed in service. The Company collects cash during the installation process and recognizes revenue for System Sales and other product sales at the placed in-service date or product delivery date less any revenue allocated to monitoring services. The Company allocates a portion of the transaction price to the monitoring services by estimating the fair market price that the Company would charge for these services if offered separately from the sale of the solar energy system. As of March 31, 2018 and December 31, 2017, the Company had allocated deferred revenue of $2.5 million and $2.1 million to monitoring services that will be recognized over the term of the monitoring services. All costs to obtain and fulfill contracts associated with System Sales and other product sales are expensed as a cost of revenue when the Company has fulfilled its performance obligation and the products have been placed into service or delivered to the customer. The Company has assessed the impact of Topic 606 as it relates to the sales of ITCs through its lease pass-through fund arrangement. The Company has concluded that revenue related to the sale of ITCs through its lease pass-through arrangement is recognized when the related solar energy systems are placed in service as the Company has completed its performance obligation to transfer ITCs to the fund investors at that time. The fund investors contributed cash to the investment fund during the installation process as payment for the ITCs. The transaction price for the ITCs was estimated using the tax credit rate of 30% multiplied by the fair market value of the solar energy systems that were placed into service in the lease pass-through fund. All of the related solar energy systems were placed in service and all related revenue would have been recognized prior to September 30, 2016 under Topic 606. Prior to the adoption of Topic 606, the Company recognized this revenue evenly over the five-year ITC recapture period. This earlier recognition of the ITC lease pass-through revenue decreased revenue for the three months ended March 31, 2018 by $2.4 million and would have decreased revenue for the three months ended March 31, 2017 by $2.4 million. As all ITC sales revenue would have been recognized prior to September 30, 2016 under Topic 606, there is no deferred revenue related to ITC sales as of March 31, 2018, and there would have been no deferred revenue as of December 31, 2017. As shown below, the cumulative adjustment related to ITC revenue recognized into retained earnings, net of tax, as of January 1, 2018 was $19.2 million. As noted above, the Company adopted Topic 606 on a modified retrospective basis. However, if the Company adjusted the comparative period to reflect the adoption of Topic 606, the following adjustments would have been made to the condensed consolidated statement of operations for the three months ended March 31, 2017 (in thousands, except per share data): As Previously Revenue Reported Adjustment As Adjusted Revenue $ 53,114 $ (2,364 ) $ 50,750 Income tax expense 9,401 (946 ) 8,455 Net income available to common shareholders 13,292 (1,418 ) 11,874 Diluted earnings per share 0.11 (0.01 ) 0.10 Additionally, the following adjustments would have been made to the condensed consolidated balance sheet as of December 31, 2017 (in thousands): As Previously Revenue Reported Adjustment As Adjusted Current portion of deferred revenue $ 41,846 $ (7,707 ) $ 34,139 Deferred revenue, net of current portion 29,200 (18,690 ) 10,510 Deferred tax liability, net 342,382 7,160 349,542 Retained earnings 213,107 (19,237 ) 193,870
Income Taxes	Income Taxes The Company adopted ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory The adoption of ASU 2016-16 had the following effect on the Company’s condensed consolidated statement of operations for the three months ended March 31, 2018 (in thousands, except per share data): Pre-Adoption Effect of Accounting Adoption As Reported Income tax expense $ 5,781 $ 12,862 $ 18,643 Net loss (48,522 ) (12,862 ) (61,384 ) Net loss attributable to common shareholders (114 ) (12,862 ) (12,976 ) Basic earnings per share (0.00 ) (0.11 ) (0.11 ) Diluted earnings per share (0.00 ) (0.11 ) (0.11 ) The Company adopted ASU 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income ,
Derivative Financial Instruments	Derivative Financial Instruments The Company adopted ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities
Restricted Cash	Restricted Cash The Company adopted ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force) (“ASU 2016-18”) , effective January 1, 2018. This update clarified that transfers between cash and restricted cash are not reported as cash flow activities in the statements of cash flows. As such, restricted cash amounts are included with cash and cash equivalents in the beginning-of-period and end-of-period total amounts on the statements of cash flows. The Company applied this update retrospectively, which resulted in an adjustment to the beginning-of-period and end-of-period total amounts on the condensed consolidated statement of cash flows for the three months ended March 31, 2017 to include restricted cash balances from those periods.
Recent Accounting Pronouncements	Recent Accounting Pronouncements New Lease Guidance In February 2016, the Financial Accounting Standards Board (the “FASB”) issued ASU 2016-02, Leases (Topic 842)

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
ASU 2014-09
Schedule of Accounting Standards Update Adjustments to Financial Statements	As noted above, the Company adopted Topic 606 on a modified retrospective basis. However, if the Company adjusted the comparative period to reflect the adoption of Topic 606, the following adjustments would have been made to the condensed consolidated statement of operations for the three months ended March 31, 2017 (in thousands, except per share data): As Previously Revenue Reported Adjustment As Adjusted Revenue $ 53,114 $ (2,364 ) $ 50,750 Income tax expense 9,401 (946 ) 8,455 Net income available to common shareholders 13,292 (1,418 ) 11,874 Diluted earnings per share 0.11 (0.01 ) 0.10 Additionally, the following adjustments would have been made to the condensed consolidated balance sheet as of December 31, 2017 (in thousands): As Previously Revenue Reported Adjustment As Adjusted Current portion of deferred revenue $ 41,846 $ (7,707 ) $ 34,139 Deferred revenue, net of current portion 29,200 (18,690 ) 10,510 Deferred tax liability, net 342,382 7,160 349,542 Retained earnings 213,107 (19,237 ) 193,870
ASU 2016-16
Schedule of Accounting Standards Update Adjustments to Financial Statements	The adoption of ASU 2016-16 had the following effect on the Company’s condensed consolidated statement of operations for the three months ended March 31, 2018 (in thousands, except per share data): Pre-Adoption Effect of Accounting Adoption As Reported Income tax expense $ 5,781 $ 12,862 $ 18,643 Net loss (48,522 ) (12,862 ) (61,384 ) Net loss attributable to common shareholders (114 ) (12,862 ) (12,976 ) Basic earnings per share (0.00 ) (0.11 ) (0.11 ) Diluted earnings per share (0.00 ) (0.11 ) (0.11 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis	The Company measures and reports its cash equivalents at fair value. The following tables set forth the fair value of the Company’s financial assets and liabilities measured on a recurring basis by level within the fair value hierarchy (in thousands): March 31, 2018 Level 1 Level 2 Level 3 Total Financial Assets Interest rate swaps $ — $ 19,772 $ — $ 19,772 December 31, 2017 Level 1 Level 2 Level 3 Total Financial Assets Interest rate swaps $ — $ 14,028 $ — $ 14,028 Financial Liabilities Interest rate swaps $ — $ 1,280 $ — $ 1,280
Schedule of Carrying Values and Fair Values of Company's Long-term Debt	The carrying values and fair values of the Company’s long-term debt were as follows (in thousands): March 31, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value Floating-rate long-term debt $ 792,191 $ 792,191 $ 757,044 $ 757,044 Fixed-rate long-term debt 196,168 225,629 199,063 238,618 Total $ 988,359 $ 1,017,820 $ 956,107 $ 995,662

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consisted of the following (in thousands): March 31, December 31, 2018 2017 Solar energy systems held for sale $ 14,982 $ 21,971 Photovoltaic installation products 808 626 Total inventories $ 15,790 $ 22,597

Solar Energy Systems (Tables)

Solar Energy Systems (Tables)	3 Months Ended
	Mar. 31, 2018
Solar Energy Systems Disclosure [Abstract]
Solar Energy Systems	Solar energy systems, net consisted of the following (in thousands): March 31, December 31, 2018 2017 System equipment costs $ 1,484,019 $ 1,437,419 Initial direct costs related to solar energy systems 355,164 336,136 1,839,183 1,773,555 Less: Accumulated depreciation and amortization (145,016 ) (129,640 ) 1,694,167 1,643,915 Solar energy system inventory 33,312 29,617 Solar energy systems, net $ 1,727,479 $ 1,673,532

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2018
Property Plant And Equipment [Abstract]
Summary of Property and Equipment Net	Property and equipment, net consisted of the following (in thousands): Estimated March 31, December 31, Useful Lives 2018 2017 Vehicles acquired under capital leases 3-5 years $ 13,729 $ 15,113 Leasehold improvements 1-12 years 12,284 15,071 Furniture and computer and other equipment 3 years 4,166 6,492 30,179 36,676 Less: Accumulated depreciation and amortization (16,864 ) (21,598 ) Property and equipment, net $ 13,315 $ 15,078

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets, Net	Intangible assets, net consisted of the following (in thousands): March 31, December 31, 2018 2017 Cost: Internal-use software $ 1,199 $ 1,314 Developed technology 522 522 Trademarks/trade names 201 201 Customer relationships 164 164 Total carrying value 2,086 2,201 Accumulated amortization: Internal-use software (863 ) (872 ) Developed technology (274 ) (258 ) Trademarks/trade names (85 ) (79 ) Customer relationships (139 ) (130 ) Total accumulated amortization (1,361 ) (1,339 ) Total intangible assets, net $ 725 $ 862

Accrued Compensation (Tables)

Accrued Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Accrued Compensation Disclosure [Abstract]
Summary of Accrued Compensation	Accrued compensation consisted of the following (in thousands): March 31, December 31, 2018 2017 Accrued payroll $ 10,985 $ 13,064 Accrued commissions 8,905 7,928 Total accrued compensation $ 19,890 $ 20,992

Accrued and Other Current Lia35

Accrued and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Payables And Accruals [Abstract]
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following (in thousands): March 31, December 31, 2018 2017 Accrued unused commitment fees and interest $ 7,816 $ 7,445 Current portion of lease pass-through financing obligation 4,953 4,931 Accrued professional fees 4,012 3,977 Sales, use and property taxes payable 2,732 3,046 Accrued workers' compensation 1,887 1,446 Workmanship accrual 1,404 1,359 Current portion of deferred rent 934 937 Accrued inventory 496 4,122 Other accrued expenses 1,755 2,412 Total accrued and other current liabilities $ 25,989 $ 29,675

Debt Obligations (Tables)

Debt Obligations (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Debt	Debt obligations consisted of the following as of March 31, 2018 (in thousands, except interest rates): Principal Unamortized Debt Unused Borrowings Issuance Costs Net Carrying Value Borrowing Interest Maturity Outstanding Current Long-term Current Long-term Capacity Rate Date 2017 Term loan facility $ 194,873 $ (172 ) $ (4,901 ) $ 6,733 $ 183,067 $ — 6.0 % January 2035 2016 Term loan facility (1) 283,566 (125 ) (7,149 ) 4,850 271,442 — 4.6 August 2021 Subordinated HoldCo facility 197,125 (32 ) (3,090 ) 1,968 192,035 — 9.7 March 2020 Credit agreement 1,295 (2 ) (135 ) 15 1,143 — 6.5 February 2023 Revolving lines of credit (2) Aggregation facility 175,000 — — — 175,000 200,000 4.8 September 2020 Working capital facility (3) 136,500 — — — 136,500 — 5.1 March 2020 Total debt $ 988,359 $ (331 ) $ (15,275 ) $ 13,566 $ 959,187 $ 200,000 Debt obligations consisted of the following as of December 31, 2017 (in thousands, except interest rates): Principal Unamortized Debt Unused Borrowings Issuance Costs Net Carrying Value Borrowing Interest Maturity Outstanding Current Long-term Current Long-term Capacity Rate Date 2017 Term loan facility $ 197,764 $ (176 ) $ (4,990 ) $ 6,644 $ 185,954 $ — 6.0 % January 2035 2016 Term loan facility (1) 287,919 (141 ) (7,623 ) 4,962 275,193 — 4.3 August 2021 Subordinated HoldCo facility 197,625 (35 ) (3,451 ) 1,965 192,174 — 9.3 March 2020 Credit agreement 1,299 (2 ) (140 ) 14 1,143 — 6.5 February 2023 Revolving lines of credit (2) Aggregation facility 135,000 — — — 135,000 240,000 4.7 September 2020 Working capital facility (3) 136,500 — — — 136,500 — 4.8 March 2020 Total debt $ 956,107 $ (354 ) $ (16,204 ) $ 13,585 $ 925,964 $ 240,000 (1) The interest rate of this facility is partially hedged to an effective interest rate of 4.0% for $260.1 million of the principal borrowings. See Note 11—Derivative Financial Instruments. (2) Revolving lines of credit are not presented net of unamortized debt issuance costs. (3) Facility is recourse debt, which refers to debt that is collateralized by the Company’s general assets. All of the Company’s other debt obligations are non-recourse, which refers to debt that is only collateralized by specified assets or subsidiaries of the Company.

Derivative Financial Instrume37

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Schedule of Derivative Financial Instruments at Fair Value	Derivative financial instruments consisted of the following at fair value (in thousands): March 31, 2018 Fair Value Balance Sheet Location Derivatives designated as hedging instruments: Interest rate swaps $ 18,790 Other non-current assets, net Derivatives not designated as hedging instruments: Interest rate swaps $ 982 Other non-current assets, net December 31, 2017 Fair Value Balance Sheet Location Derivatives designated as hedging instruments: Interest rate swaps $ 14,028 Other non-current assets, net Derivatives not designated as hedging instruments: Interest rate swaps $ 1,280 Other non-current liabilities
Schedule of (Gains) Losses on Derivative Financial Instruments Recognized in OCI and Condensed Consolidated Statements of Operations Before Tax Effect	The (gains) losses on derivatives designated as cash flow hedges recognized in OCI, before tax effect, consisted of the following (in thousands): Three Months Ended March 31, 2018 2017 Derivatives designated as cash flow hedges: Interest rate swaps $ (5,143 ) $ 46 The (gains) losses on derivative financial instruments recognized in the condensed consolidated statements of operations, before tax effect, consisted of the following (in thousands): Three Months Ended March 31, 2018 2017 Interest expense Other (income) expense, net Interest expense Other (income) expense, net Total amounts presented in the income statement line items $ 16,922 $ (2,261 ) $ 14,721 $ 276 Derivatives designated as cash flow hedges: Interest rate swaps (Gains) losses reclassified from AOCI into income $ (381 ) $ — $ 150 $ — (Gains) recognized in income - ineffective portion: — — — (676 ) Derivatives not designated as hedging instruments: Interest rate swaps (Gains) losses recognized in income — (2,262 ) — 952 Total (gains) losses $ (381 ) $ (2,262 ) $ 150 $ 276

Investment Funds (Tables)

Investment Funds (Tables)	3 Months Ended
	Mar. 31, 2018
Schedule Of Investments [Abstract]
Aggregate Carrying Value of Funds Assets and Liabilities	As of March 31, 2018 and December 31, 2017, the Company had formed investment funds for the purpose of funding the purchase of solar energy systems under long-term customer contracts. The aggregate carrying value of these funds’ assets and liabilities (after elimination of intercompany transactions and balances) in the Company’s condensed consolidated balance sheets were as follows (in thousands): March 31, December 31, 2018 2017 Assets Current assets: Cash and cash equivalents $ 12,937 $ 17,280 Accounts receivable, net 9,350 5,143 Prepaid expenses and other current assets 774 952 Total current assets 23,061 23,375 Solar energy systems, net 1,532,897 1,486,023 Other non-current assets, net 7,560 6,792 Total assets $ 1,563,518 $ 1,516,190 Liabilities Current liabilities: Distributions payable to non-controlling interests and redeemable non-controlling interests $ 7,501 $ 16,437 Current portion of deferred revenue 1,950 9,176 Accrued and other current liabilities 4,457 4,478 Total current liabilities 13,908 30,091 Deferred revenue, net of current portion 8,527 26,847 Other non-current liabilities 1,458 1,444 Total liabilities $ 23,893 $ 58,382

Redeemable Non-Controlling In39

Redeemable Non-Controlling Interests and Equity (Tables)	3 Months Ended
	Mar. 31, 2018
Noncontrolling Interest [Abstract]
Schedule of Reserved Shares of Common Stock for Issuance	The Company had reserved shares of common stock for issuance as follows (in thousands): March 31, December 31, 2018 2017 Shares available for grant under equity incentive plans 16,333 12,774 Restricted stock units issued and outstanding 7,142 6,688 Stock options issued and outstanding 4,199 3,837 Long-term incentive plan 2,706 2,706 Total 30,380 26,005
Schedule of Changes in Redeemable Non-Controlling Interests	The changes in redeemable non-controlling interests were as follows (in thousands): Balance as of December 31, 2017 $ 122,444 Contributions from redeemable non-controlling interests 42,771 Distributions to redeemable non-controlling interests (2,093 ) Net loss (33,015 ) Balance as of March 31, 2018 $ 130,107
Schedule of Changes in Total Stockholders' Equity and Non-Controlling Interests	The changes in stockholders’ equity and non-controlling interests were as follows (in thousands): Total Stockholders' Non-Controlling Equity Interests Total Equity Balance as of December 31, 2017 $ 780,951 $ 80,115 $ 861,066 Cumulative-effect adjustment from adoption of new ASUs (473,828 ) — (473,828 ) Stock-based compensation expense 2,969 — 2,969 Issuance of common stock 207 — 207 Distributions to non-controlling interests — (7,093 ) (7,093 ) Total other comprehensive income 3,471 — 3,471 Net loss (12,976 ) (15,393 ) (28,369 ) Balance as of March 31, 2018 $ 300,794 $ 57,629 $ 358,423
Schedule Changes in Accumulated Other Comprehensive Income Related to Cash Flow Hedges	The changes in AOCI are related to the Company’s cash flow hedges. The changes in AOCI, net of tax, were as follows (in thousands): Accumulated Other Comprehensive Income Balance as of December 31, 2017 $ 6,905 Cumulative-effect adjustment from adoption of new ASUs 3,318 Other comprehensive income before reclassifications 3,749 Less: Amounts reclassified from AOCI 278 Balance as of March 31, 2018 $ 13,694

Equity Compensation Plans (Tabl

Equity Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity	Stock option activity for the three months ended March 31, 2018 was as follows (in thousands, except term and per share amounts): Weighted- Weighted- Average Shares Average Remaining Aggregate Underlying Exercise Contractual Intrinsic Options Price Term (in years) Value Outstanding—December 31, 2017 3,837 $ 2.01 $ 8,522 Granted 517 3.15 Exercised (155 ) 1.34 Cancelled — — Outstanding—March 31, 2018 4,199 $ 2.17 7.1 $ 6,938 Options vested and exercisable—March 31, 2018 1,902 $ 1.71 5.9 $ 4,235
RSU Activity	RSU activity for the three months ended March 31, 2018 was as follows (awards in thousands): Weighted- Average Number of Grant Date Awards Fair Value Outstanding at December 31, 2017 6,688 $ 3.20 Granted 613 3.26 Vested (75 ) 6.35 Forfeited (84 ) 3.23 Outstanding at March 31, 2018 7,142 $ 3.17
Summary of Stock-Based Compensation Expense	Stock-based compensation was included in operating expenses as follows (in thousands): Three Months Ended March 31, 2018 2017 Cost of revenue $ 274 $ 281 Sales and marketing 831 992 General and administrative 1,820 2,514 Research and development 44 135 Total stock-based compensation $ 2,969 $ 3,922
Summary of Unrecognized Stock-Based Compensation Expense	Unrecognized stock-based compensation expense for time-based stock options and RSUs as of March 31, 2018 was as follows (in thousands, except years): Unrecognized Weighted- Stock-Based Average Period Compensation of Recognition Expense (in years) RSUs $ 10,756 1.7 Time-based stock options 2,547 1.8 Total unrecognized stock-based compensation expense $ 13,303

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Components of Related Party Transactions	The Company’s condensed consolidated statements of operations included the following related party transactions (in thousands): Three Months Ended March 31, 2018 2017 Cost of revenue—operating leases and incentives $ — $ 398 Sales and marketing 701 698 General and administrative — 75

Basic and Diluted Net (Loss) 42

Basic and Diluted Net (Loss) Income Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net (Loss) Income Per Share to Common Stockholders	The following table sets forth the computation of the Company’s basic and diluted net (loss attributable) income available per share to common stockholders for the three months ended March 31, 2018 and 2017 (in thousands, except per share amounts): Three Months Ended March 31, 2018 2017 Numerator: Net (loss attributable) income available to common stockholders $ (12,976 ) $ 13,292 Denominator: Shares used in computing net (loss attributable) income available per share to common stockholders, basic 115,155 110,765 Weighted-average effect of potentially dilutive shares to purchase common stock — 5,633 Shares used in computing net (loss attributable) income available per share to common stockholders, diluted 115,155 116,398 Net (loss attributable) income available per share to common stockholders: Basic $ (0.11 ) $ 0.12 Diluted $ (0.11 ) $ 0.11

Organization - Additional Infor

Organization - Additional Information (Details)	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Contractual term of customers	20 years

Summary of Significant Accoun44

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	Jan. 02, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Investment tax credit percentage of qualified assets		30.00%
Recapture period of revenue recognition		5 years
Effect of adopting new accounting pronouncements		$ 473,828,000
ASU 2014-09
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect adjustment, retained earnings	$ 19,200,000
ASU 2016-16
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect adjustment, retained earnings	493,100,000
Cumulative effect adjustment, deferred tax liability, net	12,800,000
ASU 2018-02
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect adjustment, retained earnings	1,500,000
ASU 2017-12
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect adjustment, retained earnings	$ 1,800,000
Calculated under Revenue Guidance in Effect before Topic 606
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue		0		$ 0
Effect of adopting new accounting pronouncements		2,400,000	$ 2,400,000
Monitoring Services
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue		$ 2,500,000		$ 2,100,000

Summary of Significant Accoun45

Summary of Significant Accounting Policies - Adjustments made to Condensed Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	$ 68,250	$ 53,114
Income tax expense	18,643	9,401
Net (loss attributable) income available to common stockholders	$ (12,976)	$ 13,292
Diluted	$ (0.11)	$ 0.11
Revenue Adjustment | ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue		$ (2,364)
Income tax expense		(946)
Net (loss attributable) income available to common stockholders		$ (1,418)
Diluted		$ (0.01)
As Adjusted | ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue		$ 50,750
Income tax expense		8,455
Net (loss attributable) income available to common stockholders		$ 11,874
Diluted		$ 0.10

Summary of Significant Accoun46

Summary of Significant Accounting Policies - Adjustments made to Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Current portion of deferred revenue	$ 24,255	$ 41,846
Deferred revenue, net of current portion	11,311	29,200
Deferred tax liability, net	356,984	342,382
Retained earnings	$ (277,015)	213,107
Revenue Adjustment | ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Current portion of deferred revenue		(7,707)
Deferred revenue, net of current portion		(18,690)
Deferred tax liability, net		7,160
Retained earnings		(19,237)
As Adjusted | ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Current portion of deferred revenue		34,139
Deferred revenue, net of current portion		10,510
Deferred tax liability, net		349,542
Retained earnings		$ 193,870

Summary of Significant Accoun47

Summary of Significant Accounting Policies - Adoption of ASU 2016-16 Effect on Condensed Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax expense	$ 18,643	$ 9,401
Net loss	(61,384)	(55,452)
Net (loss attributable) income available to common stockholders	$ (12,976)	$ 13,292
Basic earnings per share	$ (0.11)	$ 0.12
Diluted earnings per share	$ (0.11)	$ 0.11
Pre-Adoption Accounting | ASU 2016-16
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax expense	$ 5,781
Net loss	(48,522)
Net (loss attributable) income available to common stockholders	$ (114)
Basic earnings per share	$ 0
Diluted earnings per share	$ 0
Effect of Adoption | ASU 2016-16
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax expense	$ 12,862
Net loss	(12,862)
Net (loss attributable) income available to common stockholders	$ (12,862)
Basic earnings per share	$ (0.11)
Diluted earnings per share	$ (0.11)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Details) - Interest Rate Swaps - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	$ 19,772	$ 14,028
Financial Liabilities		1,280
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	$ 19,772	14,028
Financial Liabilities		$ 1,280

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Realized gains or losses on financial assets	$ 0	$ 0

Fair Value Measurements - Sch50

Fair Value Measurements - Schedule of Carrying Values and Fair Values of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, Carrying Value	$ 988,359	$ 956,107
Long-term debt, Fair Value	1,017,820	995,662
Floating-rate Long-term Debt
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, Carrying Value	792,191	757,044
Long-term debt, Fair Value	792,191	757,044
Fixed-rate Long-term Debt
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, Carrying Value	196,168	199,063
Long-term debt, Fair Value	$ 225,629	$ 238,618

Inventories - Summary of Invent

Inventories - Summary of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Solar energy systems held for sale	$ 14,982	$ 21,971
Photovoltaic installation products	808	626
Total inventories	$ 15,790	$ 22,597

Solar Energy Systems (Details)

Solar Energy Systems (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property Subject To Or Available For Operating Lease [Line Items]
Solar energy systems, gross	$ 1,839,183	$ 1,773,555
Less: Accumulated depreciation and amortization	(145,016)	(129,640)
Solar energy systems, net excluding inventory	1,694,167	1,643,915
Solar energy system inventory	33,312	29,617
Solar energy systems, net	1,727,479	1,673,532
System Equipment Costs
Property Subject To Or Available For Operating Lease [Line Items]
Solar energy systems, gross	1,484,019	1,437,419
Initial Direct Costs Related to Solar Energy Systems
Property Subject To Or Available For Operating Lease [Line Items]
Solar energy systems, gross	$ 355,164	$ 336,136

Solar Energy Systems - Addition

Solar Energy Systems - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Property Subject To Or Available For Operating Lease [Line Items]
Depreciation and amortization expense	$ 16,307,000	$ 14,162,000
Solar Energy System Inventory
Property Subject To Or Available For Operating Lease [Line Items]
Depreciation	0
Solar Energy Systems
Property Subject To Or Available For Operating Lease [Line Items]
Depreciation and amortization expense	$ 15,400,000	$ 12,800,000

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property, gross	$ 30,179	$ 36,676
Less: Accumulated depreciation and amortization	(16,864)	(21,598)
Property and equipment, net	13,315	15,078
Vehicles Acquired Under Capital Leases
Property Plant And Equipment [Line Items]
Property, gross	13,729	15,113
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, gross	$ 12,284	15,071
Furniture and Computer and Other Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Estimated Useful Lives	3 years
Property, gross	$ 4,166	$ 6,492
Minimum | Vehicles Acquired Under Capital Leases
Property Plant And Equipment [Line Items]
Property and Equipment, Estimated Useful Lives	3 years
Minimum | Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and Equipment, Estimated Useful Lives	1 year
Maximum | Vehicles Acquired Under Capital Leases
Property Plant And Equipment [Line Items]
Property and Equipment, Estimated Useful Lives	5 years
Maximum | Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and Equipment, Estimated Useful Lives	12 years

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 16,307	$ 14,162
Solar Energy Systems
Property Plant And Equipment [Line Items]
Depreciation and amortization	15,400	12,800
Property and equipment
Property Plant And Equipment [Line Items]
Depreciation and amortization	1,700	2,400
Vehicles Acquired Under Capital Leases | Solar Energy Systems
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 700	$ 1,100

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Intangible assets, carrying value	$ 2,086	$ 2,201
Intangible assets, accumulated amortization	(1,361)	(1,339)
Total intangible assets, net	725	862
Internal-use software
Finite Lived Intangible Assets [Line Items]
Intangible assets, carrying value	1,199	1,314
Intangible assets, accumulated amortization	(863)	(872)
Developed Technology
Finite Lived Intangible Assets [Line Items]
Intangible assets, carrying value	522	522
Intangible assets, accumulated amortization	(274)	(258)
Trademarks/Trade Names
Finite Lived Intangible Assets [Line Items]
Intangible assets, carrying value	201	201
Intangible assets, accumulated amortization	(85)	(79)
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Intangible assets, carrying value	164	164
Intangible assets, accumulated amortization	$ (139)	$ (130)

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 136	$ 140

Accrued Compensation - Summary

Accrued Compensation - Summary of Accrued Compensation (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accrued Compensation Disclosure [Abstract]
Accrued payroll	$ 10,985	$ 13,064
Accrued commissions	8,905	7,928
Total accrued compensation	$ 19,890	$ 20,992

Accrued and Other Current Lia59

Accrued and Other Current Liabilities - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued unused commitment fees and interest	$ 7,816	$ 7,445
Current portion of lease pass-through financing obligation	4,953	4,931
Accrued professional fees	4,012	3,977
Sales, use and property taxes payable	2,732	3,046
Accrued workers' compensation	1,887	1,446
Workmanship accrual	1,404	1,359
Current portion of deferred rent	934	937
Accrued inventory	496	4,122
Other accrued expenses	1,755	2,412
Total accrued and other current liabilities	$ 25,989	$ 29,675

Debt Obligations - Schedule of

Debt Obligations - Schedule of Debt Obligations (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Principal Borrowings Outstanding		$ 988,359	$ 956,107
Unamortized Debt Issuance Costs, Current		(331)	(354)
Unamortized Debt Issuance Costs, Long-term		(15,275)	(16,204)
Current portion of long-term debt		13,566	13,585
Long-term debt, net of current portion		959,187	925,964
Unused Borrowing Capacity		200,000	240,000
2017 Term Loan Facility
Debt Instrument [Line Items]
Principal Borrowings Outstanding		194,873	197,764
Unamortized Debt Issuance Costs, Current		(172)	(176)
Unamortized Debt Issuance Costs, Long-term		(4,901)	(4,990)
Current portion of long-term debt		6,733	6,644
Long-term debt, net of current portion		$ 183,067	$ 185,954
Interest Rate		6.00%	6.00%
Maturity Date		Jan. 31, 2035	Jan. 31, 2035
2016 Term Loan Facility
Debt Instrument [Line Items]
Principal Borrowings Outstanding	[1]	$ 283,566	$ 287,919
Unamortized Debt Issuance Costs, Current	[1]	(125)	(141)
Unamortized Debt Issuance Costs, Long-term	[1]	(7,149)	(7,623)
Current portion of long-term debt	[1]	4,850	4,962
Long-term debt, net of current portion	[1]	$ 271,442	$ 275,193
Interest Rate	[1]	4.60%	4.30%
Maturity Date	[1]	Aug. 31, 2021	Aug. 31, 2021
Subordinated HoldCo Facility
Debt Instrument [Line Items]
Principal Borrowings Outstanding		$ 197,125	$ 197,625
Unamortized Debt Issuance Costs, Current		(32)	(35)
Unamortized Debt Issuance Costs, Long-term		(3,090)	(3,451)
Current portion of long-term debt		1,968	1,965
Long-term debt, net of current portion		$ 192,035	$ 192,174
Interest Rate		9.70%	9.30%
Maturity Date		Mar. 31, 2020	Mar. 31, 2020
Credit Agreement
Debt Instrument [Line Items]
Principal Borrowings Outstanding		$ 1,295	$ 1,299
Unamortized Debt Issuance Costs, Current		(2)	(2)
Unamortized Debt Issuance Costs, Long-term		(135)	(140)
Current portion of long-term debt		15	14
Long-term debt, net of current portion		$ 1,143	$ 1,143
Interest Rate		6.50%	6.50%
Maturity Date		Feb. 28, 2023	Feb. 28, 2023
Aggregation Facility
Debt Instrument [Line Items]
Principal Borrowings Outstanding	[2]	$ 175,000	$ 135,000
Long-term debt, net of current portion	[2]	175,000	135,000
Unused Borrowing Capacity	[2]	$ 200,000	$ 240,000
Interest Rate	[2]	4.80%	4.70%
Maturity Date	[2]	Sep. 30, 2020	Sep. 30, 2020
Working Capital Facility
Debt Instrument [Line Items]
Principal Borrowings Outstanding	[2],[3]	$ 136,500	$ 136,500
Long-term debt, net of current portion	[2],[3]	$ 136,500	$ 136,500
Interest Rate	[2],[3]	5.10%	4.80%
Maturity Date	[2],[3]	Mar. 31, 2020	Mar. 31, 2020
[1]	The interest rate of this facility is partially hedged to an effective interest rate of 4.0% for $260.1 million of the principal borrowings. See Note 11—Derivative Financial Instruments.
[2]	Revolving lines of credit are not presented net of unamortized debt issuance costs.
[3]	Facility is recourse debt, which refers to debt that is collateralized by the Company’s general assets. All of the Company’s other debt obligations are non-recourse, which refers to debt that is only collateralized by specified assets or subsidiaries of the Company.

Debt Obligations - Schedule o61

Debt Obligations - Schedule of Debt Obligations (Parenthetical) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Principal borrowings outstanding	$ 988,359	$ 956,107
Interest Rate Swaps
Debt Instrument [Line Items]
Effective interest rate of principal borrowings	4.00%
Principal borrowings outstanding	$ 260,100

Debt Obligations - Additional I

Debt Obligations - Additional Information (Details) - USD ($)	1 Months Ended			3 Months Ended
	Jan. 31, 2017	Aug. 31, 2016	Mar. 31, 2016	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2015	Sep. 30, 2014
Debt Instrument [Line Items]
Restricted cash and cash equivalents				$ 47,773,000	$ 46,486,000
Letter of credit related to insurance contracts				13,500,000
Minimum
Debt Instrument [Line Items]
Restricted cash and cash equivalents				$ 10,000,000	$ 10,000,000
2017 Term Loan Facility
Debt Instrument [Line Items]
Interest on borrowings accrue at an annual fixed rate and payable in arrears	6.00%
Debt instrument, frequency of periodic payment	Quarterly basis
2016 Term Loan Facility
Debt Instrument [Line Items]
Debt instrument basis spread on variable rate for first four years		3.00%
Debt instrument basis spread on variable rate thereafter		3.25%
Subordinated HoldCo Facility
Debt Instrument [Line Items]
Debt instrument interest rate			8.00%
Percentage of principal prepayments fee			3.00%
Aggregation Facility
Debt Instrument [Line Items]
Maximum borrowing amount under credit agreement							$ 375,000,000
Additional borrowing capacity							$ 175,000,000
Aggregation Facility | Minimum
Debt Instrument [Line Items]
Debt instrument interest rate				3.25%
Aggregation Facility | Maximum
Debt Instrument [Line Items]
Debt instrument interest rate				3.75%
Aggregation Facility | Federal Funds Rate Plus
Debt Instrument [Line Items]
Debt instrument interest rate				0.50%
Aggregation Facility | L I B O R Plus
Debt Instrument [Line Items]
Debt instrument interest rate				1.00%
Working Capital Facility
Debt Instrument [Line Items]
Debt instrument interest rate				2.25%
Maximum borrowing amount under credit agreement						$ 150,000,000
Letter of credit related to insurance contracts				$ 13,500,000
Debt Instrument interest rate description				(1) a rate equal to the Eurodollar Rate for the interest period divided by one minus the Eurodollar Reserve Percentage, plus a margin of 3.25%; or (2) the highest of (a) the Federal Funds Rate plus 0.50%, (b) the Citibank prime rate and (c) the one-month interest period Eurodollar rate plus 1.00%, plus a margin of 2.25%. Interest is payable depending on the type of borrowing at the end of (1) the interest period that the Company may elect as a term, not to exceed three months, (2) quarterly or (3) at maturity of the Working Capital Facility.
Minimum cash balance requirement				$ 30,000,000
Working Capital Facility | Federal Funds Rate Plus
Debt Instrument [Line Items]
Debt instrument interest rate				0.50%
Working Capital Facility | Eurodollar Reserve Percentage Plus
Debt Instrument [Line Items]
Debt instrument interest rate				3.25%
Working Capital Facility | Euro Dollar Rate Plus
Debt Instrument [Line Items]
Debt instrument interest rate				1.00%
Required Reserves | 2017 Term Loan Facility
Debt Instrument [Line Items]
Restricted cash and cash equivalents				$ 19,300,000
Required Reserves | 2016 Term Loan Facility
Debt Instrument [Line Items]
Restricted cash and cash equivalents		$ 2,600
Required Reserves | Subordinated HoldCo Facility
Debt Instrument [Line Items]
Restricted cash and cash equivalents				10,500,000
Required Reserves | Aggregation Facility
Debt Instrument [Line Items]
Restricted cash and cash equivalents				$ 5,300,000

Derivative Financial Instrume63

Derivative Financial Instruments - Schedule of Derivative Financial Instruments at Fair Value (Details) - Interest Rate Swaps - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives Designated as Hedging Instruments | Other Noncurrent Assets, Net
Derivatives Fair Value [Line Items]
Fair Value	$ 18,790	$ 14,028
Derivatives Not Designated as Hedging Instruments | Other Noncurrent Assets, Net
Derivatives Fair Value [Line Items]
Fair Value	$ 982
Derivatives Not Designated as Hedging Instruments | Other Noncurrent Liabilities
Derivatives Fair Value [Line Items]
Fair Value		$ 1,280

Derivative Financial Instrume64

Derivative Financial Instruments - Additional Information (Details) - USD ($)		3 Months Ended	12 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
2016 Term Loan Facility
Derivatives Fair Value [Line Items]
Revolving credit facility maturity date	[1]	Aug. 31, 2021	Aug. 31, 2021
Interest Rate Swaps
Derivatives Fair Value [Line Items]
Accumulated other comprehensive income, expected amount of cash flow hedge to be reclassified to interest expense within the next 12 months		$ 2,900,000
Interest Rate Swaps | 2016 Term Loan Facility
Derivatives Fair Value [Line Items]
Notional amount		260,100,000
Interest Rate Swaps | Amended Bank Of America Aggregation Credit Facility
Derivatives Fair Value [Line Items]
Notional amount		$ 150,000,000
Percentage of outstanding term loans in interest rate hedged		75.00%
Revolving credit facility maturity date		Sep. 30, 2020
Threshold period		15 days
[1]	The interest rate of this facility is partially hedged to an effective interest rate of 4.0% for $260.1 million of the principal borrowings. See Note 11—Derivative Financial Instruments.

Derivative Financial Instrume65

Derivative Financial Instruments - Schedule of (Gains) Losses on Derivative Financial Instruments Recognized in OCI and Condensed Consolidated Statements of Operations Before Tax Effect (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Total amounts presented in the income statement line items, Interest expense	$ 16,922	$ 14,721
(Gains) losses on interest rate swaps	(2,262)	276
Total amounts presented in the income statement line items, Other (income) expense, net	(2,261)	276
Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
(Gains) losses on interest rate swaps	(381)	150
Other (Income) Expense, Net
Derivative Instruments, Gain (Loss) [Line Items]
(Gains) losses on interest rate swaps	(2,262)	276
Derivatives Designated | Cash Flow Hedging | Interest Rate Swaps | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
(Gains) losses reclassified from AOCI into income	(381)	150
Derivatives Designated | Cash Flow Hedging | Interest Rate Swaps | Other (Income) Expense, Net
Derivative Instruments, Gain (Loss) [Line Items]
(Gains) recognized in income - ineffective portion:		(676)
Derivatives Designated | Cash Flow Hedging | Interest Rate Swaps | Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
(Gains) losses recognized in OCI	(5,143)	46
Derivatives Not Designated as Hedging Instruments | Interest Rate Swaps | Other (Income) Expense, Net
Derivative Instruments, Gain (Loss) [Line Items]
(Gains) recognized in income - ineffective portion:	$ (2,262)	$ 952

Investment Funds - Additional I

Investment Funds - Additional Information (Details) - USD ($)	Mar. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Investment Holdings [Line Items]
Summary of investment fund		As of March 31, 2018 and December 31, 2017, the Company had formed investment funds for the purpose of funding the purchase of solar energy systems under long-term customer contracts.
Investors cash contribution to variable interest equity	$ 1,307,400,000	$ 1,307,400,000	$ 1,264,600,000
Solar energy systems, net	1,727,479,000	$ 1,727,479,000	1,673,532,000
Recapture period of revenue recognition		5 years
Distributions paid to reimburse fund investors		$ 10,000,000
Accrued distribution	1,900,000	1,900,000
Restricted cash	47,773,000	47,773,000	46,486,000
Minimum
Investment Holdings [Line Items]
Restricted cash	10,000,000	10,000,000	10,000,000
Variable Interest Entities
Investment Holdings [Line Items]
Solar energy systems, net	1,532,897,000	1,532,897,000	1,486,023,000
Deferred revenue	10,500,000	10,500,000	36,000,000
Investment tax credit repayment	0
Calculated under Revenue Guidance in Effect before Topic 606
Investment Holdings [Line Items]
Deferred revenue	0	0	0
Financing Obligation
Investment Holdings [Line Items]
Solar energy systems, net	57,600,000	$ 57,600,000	58,200,000
Investment tax credit rate		30.00%
Deferred revenue	0	$ 0	26,400,000
Financing liabilities	5,800,000	5,800,000	32,100,000
Financing Obligation | Other Liabilities
Investment Holdings [Line Items]
Lease pass-through financing obligation	5,800,000	$ 5,800,000	$ 5,800,000
Financing Obligation | Calculated under Revenue Guidance in Effect before Topic 606
Investment Holdings [Line Items]
Recapture period of revenue recognition		5 years
Investor
Investment Holdings [Line Items]
Investors cash contribution to variable interest equity	$ 110,000,000	$ 110,000,000

Investment Funds - Aggregate Ca

Investment Funds - Aggregate Carrying Value of Funds Assets and Liabilities (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 78,466	$ 108,452
Accounts receivable, net		18,236	19,665
Prepaid expenses and other current assets		22,234	34,049
Total current assets		134,726	184,763
Solar energy systems, net		1,727,479	1,673,532
Other non-current assets, net		41,763	37,325
TOTAL ASSETS	[1]	1,965,781	2,463,929
Current liabilities:
Distributions payable to non-controlling interests and redeemable non-controlling interests		7,501	16,437
Current portion of deferred revenue		24,255	41,846
Accrued and other current liabilities		25,989	29,675
Total current liabilities		135,920	167,600
Deferred revenue, net of current portion		11,311	29,200
Other non-current liabilities		12,623	13,674
Total liabilities	[1]	1,477,251	1,480,419
Variable Interest Entities
Current assets:
Cash and cash equivalents		12,937	17,280
Accounts receivable, net		9,350	5,143
Prepaid expenses and other current assets		774	952
Total current assets		23,061	23,375
Solar energy systems, net		1,532,897	1,486,023
Other non-current assets, net		7,560	6,792
TOTAL ASSETS		1,563,518	1,516,190
Current liabilities:
Distributions payable to non-controlling interests and redeemable non-controlling interests		7,501	16,437
Current portion of deferred revenue		1,950	9,176
Accrued and other current liabilities		4,457	4,478
Total current liabilities		13,908	30,091
Deferred revenue, net of current portion		8,527	26,847
Other non-current liabilities		1,458	1,444
Total liabilities		$ 23,893	$ 58,382
[1]	The Company’s assets as of March 31, 2018 and December 31, 2017 include $1,563.5 million and $1,516.2 million consisting of assets of variable interest entities, or VIEs, that can only be used to settle obligations of the VIEs. These assets include solar energy systems, net, of $1,532.9 million and $1,486.0 million as of March 31, 2018 and December 31, 2017; cash and cash equivalents of $12.9 million and $17.3 million as of March 31, 2018 and December 31, 2017; accounts receivable, net, of $9.4 million and $5.1 million as of March 31, 2018 and December 31, 2017; other non-current assets, net of $7.6 million and $6.8 million as of March 31, 2018 and December 31, 2017; and prepaid expenses and other current assets of $0.8 million and $1.0 million as of March 31, 2018 and December 31, 2017. The Company’s liabilities as of March 31, 2018 and December 31, 2017 included $23.9 million and $58.4 million of liabilities of VIEs whose creditors have no recourse to the Company. These liabilities include distributions payable to non-controlling interests and redeemable non-controlling interests of $7.5 million and $16.4 million as of March 31, 2018 and December 31, 2017; deferred revenue of $10.5 million and $36.0 million as of March 31, 2018 and December 31, 2017; accrued and other current liabilities of $4.5 million as of March 31, 2018 and December 31, 2017; and other non-current liabilities of $1.5 million and $1.4 million as of March 31, 2018 and December 31, 2017. For further information see Note 12—Investment Funds.

Redeemable Non-Controlling In68

Redeemable Non-Controlling Interests and Equity - Schedule of Reserved Shares of Common Stock for Issuance (Details) - shares	Mar. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Shares available for grant under equity incentive plans	16,333,000	12,774,000
Restricted stock units issued and outstanding	7,142,000	6,688,000
Stock options issued and outstanding	4,199,000	3,837,000
Long-term incentive plan	2,706,000	2,706,000
Total	30,380,000	26,005,000

Redeemable Non-Controlling In69

Redeemable Non-Controlling Interests and Equity - Schedule of Changes in Redeemable Non-Controlling Interests (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Redeemable Noncontrolling Interest [Line Items]
Balance at beginning of period	$ 122,444
Contributions from redeemable non-controlling interests	42,771
Distributions to redeemable non-controlling interests	(2,093)
Balance at end of period	130,107
Redeemable Non Controlling Interests
Redeemable Noncontrolling Interest [Line Items]
Net loss	$ (33,015)

Redeemable Non-Controlling In70

Redeemable Non-Controlling Interests and Equity - Schedule of Changes in Total Stockholders' Equity and Non-Controlling Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Balance at beginning of year	$ 861,066
Balance at beginning of year	780,951
Balance at beginning of year	80,115
Cumulative-effect adjustment from adoption of new ASUs	(473,828)
Stock-based compensation expense	2,969	$ 3,922
Issuance of common stock	207
Distributions to non-controlling interests	(7,093)
Total other comprehensive income	3,471	(118)
Net loss	(61,384)	(55,452)
Net income (loss)	(12,976)	13,292
Net income (loss)	(48,408)	$ (68,744)
Balance at end of year	358,423
Balance at end of year	300,794
Balance at end of year	57,629
Profit Loss Excluding Redeemable Noncontrolling Interest
Net loss	(28,369)
Total Stockholders' Equity
Balance at beginning of year	780,951
Cumulative-effect adjustment from adoption of new ASUs	(473,828)
Stock-based compensation expense	2,969
Issuance of common stock	207
Total other comprehensive income	3,471
Net income (loss)	(12,976)
Balance at end of year	300,794
Non-controlling Interests
Balance at beginning of year	80,115
Distributions to non-controlling interests	(7,093)
Net income (loss)	(15,393)
Balance at end of year	$ 57,629

Redeemable Non-Controlling In71

Redeemable Non-Controlling Interests and Equity - Changes in Accumulated Other Comprehensive Income Related to Cash Flow Hedges (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Equity [Abstract]
Balance as of December 31, 2017	$ 6,905
Cumulative-effect adjustment from adoption of new ASUs	3,318
Other comprehensive income before reclassifications	3,749	$ (28)
Less: Amounts reclassified from AOCI	278	$ (90)
Balance as of March 31, 2018	$ 13,694

Redeemable Non-Controlling In72

Redeemable Non-Controlling Interests, Equity and Preferred Stock - Additional Information (Details)	3 Months Ended
	Mar. 31, 2018USD ($)
Put Option
Redeemable Noncontrolling Interest [Line Items]
Fund options expected to exercise	$ 0
Put Option | Minimum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options	2,100,000
Put Option | Maximum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options	4,100,000
Call Option
Redeemable Noncontrolling Interest [Line Items]
Fund options expected to exercise	0
Call Option | Minimum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options	1,200,000
Call Option | Maximum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options	$ 7,000,000

Equity Compensation Plans - Add

Equity Compensation Plans - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended
	Jan. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant under equity incentive plans		16,333,000	12,774,000
Unrecognized Stock-Based Compensation Expense		$ 13,303
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized Stock-Based Compensation Expense		$ 1,300
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant under equity incentive plans		16,300,000
Number of additional shares available for issuance	4,600,000

Equity Compensation Plans - Sum

Equity Compensation Plans - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Underlying Options, Outstanding, Balance	3,837,000
Shares Underlying Options, Granted	517,000
Shares Underlying Options, Exercised	(155,000)
Shares Underlying Options, Outstanding, Balance	4,199,000
Shares Underlying Options, Options vested and exercisable	1,902,000
Weighted-Average Exercise Price, Outstanding, Balance	$ 2.01
Weighted-Average Exercise Price, Granted	3.15
Weighted-Average Exercise Price, Exercised	1.34
Weighted-Average Exercise Price, Outstanding, Balance	2.17
Weighted-Average Exercise Price, Options vested and exercisable	$ 1.71
Weighted-Average Remaining Contractual Term, Outstanding, Balance	7 years 1 month 6 days
Weighted-Average Remaining Contractual Term, Options vested and exercisable	5 years 10 months 24 days
Aggregate Intrinsic Value	$ 6,938	$ 8,522
Aggregate Intrinsic Value, Options vested and exercisable	$ 4,235

Equity Compensation Plans - RSU

Equity Compensation Plans - RSU Activity (Details)	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Awards, Outstanding at December 31, 2017 | shares	6,688,000
Number of Awards, Granted | shares	613,000
Number of Awards, Vested | shares	(75,000)
Number of Awards, Forfeited | shares	(84,000)
Number of Awards, Outstanding at March 31, 2018 | shares	7,142,000
Weighted Average Grant Date Fair Value, Outstanding at December 31, 2017 | $ / shares	$ 3.20
Weighted Average Grant Date Fair Value, Granted | $ / shares	3.26
Weighted Average Grant Date Fair Value, Vested | $ / shares	6.35
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	3.23
Weighted Average Grant Date Fair Value, Outstanding at March 31, 2018 | $ / shares	$ 3.17

Equity Compensation Plans - S76

Equity Compensation Plans - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule Of Stock Options [Line Items]
Stock-based compensation expense	$ 2,969	$ 3,922
Cost of Revenue
Schedule Of Stock Options [Line Items]
Stock-based compensation expense	274	281
Sales and Marketing
Schedule Of Stock Options [Line Items]
Stock-based compensation expense	831	992
General and Administrative
Schedule Of Stock Options [Line Items]
Stock-based compensation expense	1,820	2,514
Research and Development
Schedule Of Stock Options [Line Items]
Stock-based compensation expense	$ 44	$ 135

Equity Compensation Plans - S77

Equity Compensation Plans - Summary of Unrecognized Stock-Based Compensation Expense (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Schedule Of Stock Options [Line Items]
Unrecognized Stock-Based Compensation Expense	$ 13,303
RSUs
Schedule Of Stock Options [Line Items]
Unrecognized Stock-Based Compensation Expense, other than stock options	$ 10,756
Weighted- Average Period of Recognition	1 year 8 months 12 days
Time Based Stock Options
Schedule Of Stock Options [Line Items]
Unrecognized Stock-Based Compensation Expense, stock options	$ 2,547
Weighted- Average Period of Recognition	1 year 9 months 18 days

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	(43.60%)	(20.40%)
Income tax benefit—statutory federal rate	21.00%		35.00%
Useful life of assets	30 years
Prepaid tax asset, net			$ 505,883,000
Net tax benefits related to remeasurement of deferred tax balances	$ 187,500,000
Unrecognized tax benefits	0		0
Unrecognized tax benefits, income tax penalties and interest accrued	$ 0		$ 0

Related Party Transactions - Co

Related Party Transactions - Components of Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Related Party Transaction [Line Items]
Cost of revenue—operating leases and incentives	$ 38,687	$ 35,070
Sales and marketing	11,125	8,818
General and administrative	19,851	20,579
Related Party
Related Party Transaction [Line Items]
Cost of revenue—operating leases and incentives		398
Sales and marketing	$ 701	698
General and administrative		$ 75

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Aug. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Accounts payable—related party		$ 529		$ 163
Accrued equity distributions		7,501		16,437
Related Party
Related Party Transaction [Line Items]
Amounts due from direct-sales personnel		4,700		6,600
Provision for advances to direct-sales personnel		1,100		1,000
Accrued equity distributions		1,100		$ 1,200
Vivint Services
Related Party Transaction [Line Items]
Fees incurred in conjunction with agreements entered		$ 1,000	$ 700
Initial term of agreement period	2 years

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Apr. 30, 2018	Sep. 30, 2016	Mar. 31, 2018	Mar. 31, 2017
Other Commitments [Line Items]
Aggregate operating lease expense			$ 3.9	$ 4.3
Standby letter of credit outstanding			13.5
Sun Edison Inc
Other Commitments [Line Items]
Unsecured claim initial amount		$ 1,000
Sun Edison Inc | Subsequent Event
Other Commitments [Line Items]
Claim amount received from other party	$ 590
Received initial distribution amount	$ 2.1
2016 Term Loan Facility
Other Commitments [Line Items]
Debt service reserve			$ 12.1

Basic and Diluted Net (Loss) 82

Basic and Diluted Net (Loss) Income Per Share - Computation of Basic and Diluted Net (Loss) Income Per Share to Common Stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net (loss attributable) income available to common stockholders	$ (12,976)	$ 13,292
Denominator:
Shares used in computing net (loss attributable) income available per share to common stockholders, basic	115,155	110,765
Weighted-average effect of potentially dilutive shares to purchase common stock		5,633
Shares used in computing net (loss attributable) income available per share to common stockholders, diluted	115,155	116,398
Net (loss attributable) income available per share to common stockholders:
Basic	$ (0.11)	$ 0.12
Diluted	$ (0.11)	$ 0.11

Basic and Diluted Net (Loss) 83

Basic and Diluted Net (Loss) Income Per Share - Additional Information (Details) shares in Millions	3 Months Ended
	Mar. 31, 2017shares
Earnings Per Share [Abstract]
Number of shares excluded from dilutive shares	0.8

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) $ in Millions	Apr. 30, 2018USD ($)
Subsequent Event | Investment Funds
Subsequent Event [Line Items]
Total commitment under investment fund arrangement	$ 101