Sunrun (RUN) 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 06, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	RUN
Entity Registrant Name	Sunrun Inc.
Entity Central Index Key	0001469367
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		115,130,399

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash		$ 245,604	$ 226,625
Restricted cash		64,182	77,626
Accounts receivable (net of allowances for doubtful accounts of $2,282 and $2,228 as of March 31, 2019 and December 31, 2018, respectively)		67,522	66,435
State tax credits receivable		0	2,697
Inventories		76,184	79,467
Prepaid expenses and other current assets		9,568	8,563
Total current assets		463,060	461,413
Restricted cash		148	148
Solar energy systems, net		3,976,504	3,820,017
Property and equipment, net		35,281	34,893
Intangible assets, net		9,195	10,088
Goodwill		87,543	87,543
Other assets		367,951	335,685
Total assets	[1]	4,939,682	4,749,787
Current liabilities:
Accounts payable		105,977	131,278
Distributions payable to noncontrolling interests and redeemable noncontrolling interests		15,628	15,847
Accrued expenses and other liabilities		103,764	98,636
Deferred revenue, current portion		55,795	47,407
Deferred grants, current portion		7,961	7,885
Finance lease obligations, current portion		9,459	9,193
Non-recourse debt, current portion		26,937	35,484
Pass-through financing obligation, current portion		11,281	26,461
Total current liabilities		336,802	372,191
Deferred revenue, net of current portion		637,666	544,218
Deferred grants, net of current portion		219,583	221,739
Finance lease obligations, net of current portion		10,246	9,992
Recourse debt		239,035	247,000
Non-recourse debt, net of current portion		1,558,250	1,466,438
Pass-through financing obligation, net of current portion		329,501	337,282
Other liabilities		84,068	48,210
Deferred tax liabilities		84,804	93,633
Total liabilities (1)	[1]	3,499,955	3,340,703
Commitments and contingencies (Note 15)
Redeemable noncontrolling interests		137,616	126,302
Stockholders’ equity:
Preferred stock, $0.0001 par value—authorized, 200,000 shares as of March 31, 2019 and December 31, 2018; no shares issued and outstanding as of March 31, 2019 and December 31, 2018		0	0
Common stock, $0.0001 par value—authorized, 2,000,000 shares as of March 31, 2019 and December 31, 2018; issued and outstanding, 114,739 and 113,149 shares as of March 31, 2019 and December 31, 2018, respectively		11	11
Additional paid-in capital		730,126	722,429
Accumulated other comprehensive loss		(21,866)	(3,124)
Retained earnings		216,269	229,391
Total stockholders’ equity		924,540	948,707
Noncontrolling interests		377,571	334,075
Total equity		1,302,111	1,282,782
Total liabilities, redeemable noncontrolling interests and total equity		$ 4,939,682	$ 4,749,787
[1]	The Company’s consolidated assets as of March 31, 2019 and December 31, 2018 include $2,981,910 and $2,905,295, respectively, in assets of variable interest entities (“VIEs”) that can only be used to settle obligations of the VIEs. These assets include solar energy systems, net, as of March 31, 2019 and December 31, 2018 of $2,761,312 and $2,712,377, respectively; cash as of March 31, 2019 and December 31, 2018 of $135,548 and $105,494, respectively; restricted cash as of March 31, 2019 and December 31, 2018 of $969 and $2,071, respectively; accounts receivable, net as of March 31, 2019 and December 31, 2018 of $16,988 and $18,539, respectively; prepaid expenses and other current assets as of March 31, 2019 and December 31, 2018 of $386 and $387, respectively; and other assets as of March 31, 2019 and December 31, 2018 of $66,707 and $66,427, respectively. The Company’s consolidated liabilities as of March 31, 2019 and December 31, 2018 include $701,595 and $660,758, respectively, in liabilities of VIEs whose creditors have no recourse to the Company. These liabilities include accounts payable as of March 31, 2019 and December 31, 2018 of $10,979 and $12,136, respectively; distributions payable to noncontrolling interests and redeemable noncontrolling interests as of March 31, 2019 and December 31, 2018 of $15,545 and $15,797, respectively; accrued expenses and other current liabilities as of March 31, 2019 and December 31, 2018 of $7,315 and $7,122, respectively; deferred revenue as of March 31, 2019 and December 31, 2018 of $438,765 and $396,920, respectively; deferred grants as of March 31, 2019 and December 31, 2018 of $28,964 and $29,229, respectively; non-recourse debt as of March 31, 2019 and December 31, 2018 of $189,294 and $190,711, respectively; and other liabilities as of March 31, 2019 and December 31, 2018 of $10,733 and $8,843, respectively.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts		$ 2,282	$ 2,228
Preferred stock, par value (in dollars per share)		$ 0.0001	$ 0.0001
Preferred stock, shares authorized		200,000	200,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, par value (in dollars per share)		$ 0.0001	$ 0.0001
Common stock, shares authorized		2,000,000	2,000,000
Common stock, shares issued		114,739	113,149
Common stock, shares outstanding		114,739	113,149
Total assets	[1]	$ 4,939,682	$ 4,749,787
Solar energy systems, net		3,976,504	3,820,017
Cash		245,604	226,625
Restricted cash		64,182	77,626
Accounts receivable, net		67,522	66,435
Prepaid expenses and other current assets		9,568	8,563
Other assets		367,951	335,685
Total liabilities	[1]	3,499,955	3,340,703
Accounts payable		105,977	131,278
Distributions payable to noncontrolling interests and redeemable noncontrolling interests		15,628	15,847
Accrued expenses and other liabilities		103,764	98,636
Deferred revenue		693,461	591,625
Non-recourse debt		1,824,222	1,748,922
Other liabilities		84,068	48,210
Variable Interest Entities
Total assets		2,981,910	2,905,295
Solar energy systems, net		2,761,312	2,712,377
Cash		135,548	105,494
Restricted cash		969	2,071
Accounts receivable, net		16,988	18,539
Prepaid expenses and other current assets		386	387
Other assets		66,707	66,427
Total liabilities		701,595	660,758
Accounts payable		10,979	12,136
Distributions payable to noncontrolling interests and redeemable noncontrolling interests		15,545	15,797
Accrued expenses and other liabilities		7,315	7,122
Deferred revenue		438,765	396,920
Deferred grants		28,964	29,229
Non-recourse debt		189,294	190,711
Other liabilities		$ 10,733	$ 8,843
[1]	The Company’s consolidated assets as of March 31, 2019 and December 31, 2018 include $2,981,910 and $2,905,295, respectively, in assets of variable interest entities (“VIEs”) that can only be used to settle obligations of the VIEs. These assets include solar energy systems, net, as of March 31, 2019 and December 31, 2018 of $2,761,312 and $2,712,377, respectively; cash as of March 31, 2019 and December 31, 2018 of $135,548 and $105,494, respectively; restricted cash as of March 31, 2019 and December 31, 2018 of $969 and $2,071, respectively; accounts receivable, net as of March 31, 2019 and December 31, 2018 of $16,988 and $18,539, respectively; prepaid expenses and other current assets as of March 31, 2019 and December 31, 2018 of $386 and $387, respectively; and other assets as of March 31, 2019 and December 31, 2018 of $66,707 and $66,427, respectively. The Company’s consolidated liabilities as of March 31, 2019 and December 31, 2018 include $701,595 and $660,758, respectively, in liabilities of VIEs whose creditors have no recourse to the Company. These liabilities include accounts payable as of March 31, 2019 and December 31, 2018 of $10,979 and $12,136, respectively; distributions payable to noncontrolling interests and redeemable noncontrolling interests as of March 31, 2019 and December 31, 2018 of $15,545 and $15,797, respectively; accrued expenses and other current liabilities as of March 31, 2019 and December 31, 2018 of $7,315 and $7,122, respectively; deferred revenue as of March 31, 2019 and December 31, 2018 of $438,765 and $396,920, respectively; deferred grants as of March 31, 2019 and December 31, 2018 of $28,964 and $29,229, respectively; non-recourse debt as of March 31, 2019 and December 31, 2018 of $189,294 and $190,711, respectively; and other liabilities as of March 31, 2019 and December 31, 2018 of $10,733 and $8,843, respectively.

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue:
Revenue	$ 194,504	$ 144,363
Operating expenses:
Sales and marketing	55,953	44,079
Research and development	5,474	3,896
General and administrative	29,063	32,893
Amortization of intangible assets	893	1,051
Total operating expenses	238,675	201,074
Loss from operations	(44,171)	(56,711)
Interest expense, net	41,340	28,198
Other expenses (income), net	4,756	(1,692)
Loss before income taxes	(90,267)	(83,217)
Income tax (benefit) expense	(3,361)	8,203
Net loss	(86,906)	(91,420)
Net loss attributable to noncontrolling interests and redeemable noncontrolling interests	(73,044)	(119,452)
Net (loss) income attributable to common stockholders	$ (13,862)	$ 28,032
Net (loss) income per share attributable to common stockholders
Basic (in dollars per share)	$ (0.12)	$ 0.26
Diluted (in dollars per share)	$ (0.12)	$ 0.25
Weighted average shares used to compute net (loss) income per share attributable to common stockholders
Basic (in shares)	113,912	107,449
Diluted (in shares)	113,912	110,781
Customer agreements and incentives
Revenue:
Customer agreements and incentives	$ 99,850	$ 66,990
Operating expenses:
Costs	69,493	54,576
Solar energy systems and product sales
Revenue:
Revenue	94,654	77,373
Operating expenses:
Costs	$ 77,799	$ 64,579

Consolidated Statements of Comp

Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net (loss) income attributable to common stockholders	$ (13,862)	$ 28,032
Other comprehensive (loss) income:
Unrealized (loss) gain on derivatives, net of income taxes	(17,013)	16,171
Interest expense on derivatives recognized into earnings, net of income taxes	(989)	(1,233)
Other comprehensive (loss) income	(18,002)	14,938
Comprehensive (loss) income	$ (31,864)	$ 42,970

Consolidated Statements of Rede

Consolidated Statements of Redeemable Noncontrolling Interests and Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Redeemable Noncontrolling Interests	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Total Stockholders' Equity	Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, (in shares)			0	107,350
Beginning Balance at Dec. 31, 2017		$ 123,801
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, (in shares)			0	108,681
Beginning balance at Dec. 31, 2017	$ 1,240,516		$ 0	$ 11	$ 682,950	$ (4,113)	$ 202,734	$ 881,582	$ 358,934
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)				443
Exercise of stock options	1,908				1,908			1,908
Issuance of restricted stock units, net of tax withholdings (in shares)				888
Issuance of restricted stock units, net of tax withholdings	(2,484)				(2,484)			(2,484)
Stock-based compensation	10,703				10,703			10,703
Contributions from noncontrolling interests and redeemable noncontrolling interests	112,501	31,103							112,501
Distributions to noncontrolling interests and redeemable noncontrolling interests	(14,206)	(2,608)							(14,206)
Net (loss) income	(72,648)	(18,772)					28,032	28,032	(100,680)
Other comprehensive loss, net of taxes	14,938					14,938		14,938
Ending Balance at Mar. 31, 2018		133,524
Ending balance, (in shares) at Mar. 31, 2018			0	108,681
Ending balance at Mar. 31, 2018	1,291,228		$ 0	$ 11	693,077	10,825	230,766	934,679	356,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, (in shares)			0	108,681
Beginning balance, (in shares)			0	113,149
Beginning Balance at Dec. 31, 2018	126,302	126,302
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, (in shares)			0	114,739
Beginning balance at Dec. 31, 2018	$ 1,282,782		$ 0	$ 11	722,429	(3,124)	229,391	948,707	334,075
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	1,139			1,139
Exercise of stock options	$ 4,279				4,279			4,279
Issuance of restricted stock units, net of tax withholdings (in shares)				451
Issuance of restricted stock units, net of tax withholdings	(3,442)				(3,442)			(3,442)
Stock-based compensation	5,783				5,783			5,783
Contributions from noncontrolling interests and redeemable noncontrolling interests	120,539	31,610							120,539
Distributions to noncontrolling interests and redeemable noncontrolling interests	(15,103)	(3,126)							(15,103)
Net (loss) income	(69,736)	(17,170)					(13,862)	(13,862)	(55,874)
Acquisition of noncontrolling interest	(4,989)				1,077			1,077	(6,066)
Other comprehensive loss, net of taxes	(18,002)					(18,002)		(18,002)
Ending Balance at Mar. 31, 2019	137,616	$ 137,616
Ending balance, (in shares) at Mar. 31, 2019			0	114,739
Ending balance at Mar. 31, 2019	$ 1,302,111		$ 0	$ 11	$ 730,126	$ (21,866)	$ 216,269	$ 924,540	$ 377,571
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, (in shares)			0	114,739

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net loss	$ (86,906)	$ (91,420)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization, net of amortization of deferred grants	43,661	36,186
Deferred income taxes	(3,361)	8,203
Stock-based compensation expense	5,783	10,694
Interest on pass-through financing obligations	6,472	3,099
Reduction in pass-through financing obligations	(9,986)	(5,028)
Other noncash losses and expenses	1,489	5,667
Changes in operating assets and liabilities:
Accounts receivable	(147)	6,217
Inventories	3,283	6,525
Prepaid and other assets	(35,868)	(13,323)
Accounts payable	(22,577)	(12,982)
Accrued expenses and other liabilities	7,724	(7,048)
Deferred revenue	101,848	7,456
Net cash provided by (used in) operating activities	11,415	(45,754)
Investing activities:
Payments for the costs of solar energy systems	(198,880)	(163,190)
Purchases of property and equipment	(2,517)	(1,521)
Net cash used in investing activities	(201,397)	(164,711)
Financing activities:
Proceeds from state tax credits, net of recapture	2,604	(49)
Payment of debt fees	(2,654)	(3,880)
Proceeds from pass-through financing and other obligations	1,785	1,502
Early repayment of pass-through financing obligation	(7,597)	0
Payment of finance lease obligations	(3,001)	(2,113)
Contributions received from noncontrolling interests and redeemable noncontrolling interests	152,149	143,604
Distributions paid to noncontrolling interests and redeemable noncontrolling interests	(18,447)	(15,263)
Acquisition of noncontrolling interest	(4,600)	0
Proceeds from exercises of stock options, net of withholding taxes paid on restricted stock units	839	(576)
Net cash provided by financing activities	195,517	212,003
Net change in cash and restricted cash	5,535	1,538
Cash and restricted cash, beginning of period	304,399	241,790
Cash and restricted cash, end of period	309,934	243,328
Supplemental disclosures of cash flow information
Cash paid for interest	20,058	16,446
Cash paid for taxes	0	0
Supplemental disclosures of noncash investing and financing activities
Purchases of solar energy systems and property and equipment included in accounts payable and accrued expenses	24,303	17,233
Right-of-use assets obtained in exchange for new finance lease liabilities	3,543	99
Recourse debt
Financing activities:
Proceeds from issuance of debt	40,000	2,000
Repayment of debt	(47,965)	(2,000)
Non-recourse debt
Financing activities:
Proceeds from issuance of debt	181,652	95,900
Repayment of debt	$ (99,248)	$ (7,122)

Organization

Organization	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Sunrun Inc. (“Sunrun” or the “Company”) was originally formed in 2007 as a California limited liability company and was converted into a Delaware corporation in 2008. The Company is engaged in the design, development, installation, sale, ownership and maintenance of residential solar energy systems (“Projects”) in the United States. Sunrun acquires customers directly and through relationships with various solar and strategic partners (“Partners”). The Projects are constructed either by Sunrun or by Sunrun’s Partners and are owned by the Company. Sunrun’s customers enter into an agreement to utilize the solar system (“Customer Agreement”) which typically has an initial term of 20 or 25 years. Sunrun monitors, maintains and insures the Projects. The Company also sells solar energy systems and products, such as panels and racking and solar leads generated to customers. The Company has formed various subsidiaries (“Funds”) to finance the development of Projects. These Funds, structured as limited liability companies, obtain financing from outside investors and purchase or lease Projects from Sunrun under master purchase or master lease agreements. The Company currently utilizes three legal structures in its investment Funds, which are referred to as: (i) pass-through financing obligations, (ii) partnership-flips and (iii) joint venture (“JV”) inverted leases.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the "SEC") 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 for the year ended December 31, 2018 . The results of the three months ended March 31, 2019 are not necessarily indicative of the results to be expected for the fiscal year ending December 31, 2019 or other future periods. The consolidated financial statements reflect the accounts and operations of the Company and those of its subsidiaries, including Funds, in which the Company has a controlling financial interest. The typical condition for a controlling financial interest ownership is holding a majority of the voting interests of an entity. However, a controlling financial interest may also exist in entities, such as variable interest entities (“VIEs”), through arrangements that do not involve controlling voting interests. In accordance with the provisions of Financial Accounting Standards Board (“FASB”), Accounting Standards Codification Topic 810 (“Topic 810”) Consolidation , the Company consolidates any VIE of which it is the primary beneficiary. The primary beneficiary, as defined in Topic 810, is the party that has (1) the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb the losses of the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether it continues to be the primary beneficiary. The consolidated financial statements reflect the assets and liabilities of VIEs that are consolidated. All intercompany transactions and balances have been eliminated in consolidation. Reclassifications Certain prior period amounts have been reclassified to conform to current period presentation. Use of Estimates The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company regularly makes estimates and assumptions, including, but not limited to, revenue recognition constraints that result in variable consideration, the discount rate used to adjust the promised amount of consideration for the effects of a significant financing component, the estimates that affect the collectability of accounts receivable, the valuation of inventories, the useful lives of solar energy systems, the useful lives of property and equipment, the valuation and useful lives of intangible assets, the effective interest rate used to amortize pass-through financing obligations, the discount rate uses for operating and financing leases, the valuation of stock-based compensation, the determination of valuation allowances associated with deferred tax assets, the fair value of debt instruments disclosed and the redemption value of redeemable noncontrolling interests. The Company bases its estimates on historical experience and on various other assumptions believed to be reasonable. Actual results may differ from such estimates. Segment Information The Company has one operating segment with one business activity, providing solar energy services and products to customers. The Company’s chief operating decision maker (“CODM”) is its Chief Executive Officer, who manages operations on a consolidated basis for purposes of allocating resources. When evaluating performance and allocating resources, the CODM reviews financial information presented on a consolidated basis. Revenue from external customers for each group of similar products and services is as follows (in thousands): Three Months Ended March 31, 2019 2018 Customer agreements $ 78,528 $ 61,649 Incentives 21,322 5,341 Customer agreements and incentives 99,850 66,990 Solar energy systems 58,436 33,998 Products 36,218 43,375 Solar energy systems and product sales 94,654 77,373 Total revenue $ 194,504 $ 144,363 Revenue from Customer Agreements includes payments by customers for the use of the solar system as well as utility and other rebates assigned by the customer to the Company in the Customer Agreement. Revenue from incentives includes revenue from the sale of investment tax credits ("ITCs") and renewable energy credits (“SRECs”). Cash and Restricted Cash Restricted cash represents amounts related to replacement of solar energy system components and obligations under certain financing transactions. The following table provides a reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statement of cash flows. Cash and restricted cash consists of the following (in thousands): March 31, 2019 December 31, 2018 Cash $ 245,604 $ 226,625 Restricted cash, current and long-term 64,330 77,774 Total $ 309,934 $ 304,399 Accounts Receivable Accounts receivable consist of amounts due from customers, as well as state and utility rebates due from government agencies and utility companies. Under Customer Agreements, the customers typically assign incentive rebates to the Company. The opening balance of Accounts receivable, net was $66.4 million as of December 31, 2017. Accounts receivable, net consists of the following (in thousands): March 31, 2019 December 31, 2018 Customer receivables $ 64,598 $ 64,180 Other receivables 2,179 1,466 Rebates receivable 3,027 3,017 Allowance for doubtful accounts (2,282 ) (2,228 ) Total $ 67,522 $ 66,435 Deferred Revenue When the Company receives consideration, or when such consideration is unconditionally due, from a customer prior to delivering goods or services to the customer under the terms of a Customer Agreement, the Company records deferred revenue. Such deferred revenue consists of amounts for which the criteria for revenue recognition have not yet been met and includes amounts that are collected or assigned from customers, including upfront deposits and prepayments, and rebates. Deferred revenue relating to financing components represents the cumulative excess of interest expense recorded on financing component elements over the related revenue recognized to date and will eventually net to zero by the end of the initial term. Amounts received related to the sales of SRECs which have not yet been delivered to the counterparty are recorded as deferred revenue. The opening balance of deferred revenue was $564.9 million as of December 31, 2017 . Deferred revenue consists of the following (in thousands): March 31, 2019 December 31, 2018 Under Customer Agreements: Payments received $ 543,945 $ 538,926 Financing component balance 39,577 37,801 583,522 576,727 Under SREC contracts: Payments received 108,002 12,977 Financing component balance 1,937 1,921 109,939 14,898 Total $ 693,461 $ 591,625 In the three months ended March 31, 2019 and 2018 , the Company recognized revenue of $14.0 million and $12.8 million , respectively, from amounts included in deferred revenue at the beginning of the respective periods. Revenue allocated to remaining performance obligations represents contracted revenue that has not yet been recognized and includes deferred revenue as well as amounts that will be invoiced and recognized as revenue in future periods. Contracted but not yet recognized revenue was approximately $5.6 billion as of March 31, 2019 , of which the Company expects to recognize approximately 6% over the next 12 months. The annual recognition is not expected to vary significantly over the next 10 years as the vast majority of existing Customer Agreements have at least 10 years remaining, given that the average age of the Company's fleet of residential solar energy systems under Customer Agreements is less than four years due to the Company being formed in 2007 and having experienced significant growth in the last few years. The annual recognition on these existing contracts will gradually decline over the midpoint of the Customer Agreements over the following 10 years as the typical 20 or 25 -year initial term expires on individual Customer Agreements. During the three months ended March 31, 2019, deferred revenue increased by $95.5 million arising from a sale of the right to SRECs to be generated over the next 10 - 15 years by a group of solar energy systems. In connection with the sale, the Company repaid debt previously drawn against the rights to these SRECs. Fair Value of Financial Instruments The Company defines fair value as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company uses valuation approaches to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. The FASB establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: • Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; • Level 2—Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and • Level 3—Inputs that are unobservable, significant to the measurement of the fair value of the assets or liabilities and are supported by little or no market data. Revenue Recognition The Company recognizes revenue when control of goods or services is transferred to its customers, in an amount that reflects the consideration it expected to be entitled to in exchange for those goods or services. Customer agreements and incentives Customer agreements and incentives revenue is primarily comprised of revenue from Customer Agreements in which the Company provides continuous access to a functioning solar system and revenue from the sales of ITCs and SRECs generated by the Company’s solar energy systems to third parties. The Company begins to recognize revenue on Customer Agreements when permission to operate ("PTO") is given by the local utility company or on the date daily operation commences if utility approval is not required. Revenue recognition does not necessarily follow the receipt of cash. The Company recognizes revenue evenly over the time that it satisfies its performance obligations over the initial term of the Customer Agreements. Customer Agreements typically have an initial term of 20 or 25 years. After the initial contract term, the Company's Customer Agreements typically automatically renew on an annual basis and the rate is initially set at up to a 10% discount to then-prevailing power prices. SREC revenue arises from the sale of environmental credits generated by solar energy systems and is generally recognized upon delivery of the SRECs to the counterparty. For pass-through financing obligation Funds, the value attributable to the monetization of ITCs is recognized in the period a solar system is granted PTO - see Note 10 , Pass-through Financing Obligations . In determining the transaction price, the Company adjusts the promised amount of consideration for the effects of the time value of money when the timing of payments provides it with a significant benefit of financing the transfer of goods or services to the customer. In those circumstances, the contract contains a significant financing component. When adjusting the promised amount of consideration for a significant financing component, the Company uses the discount rate that would be reflected in a separate financing transaction between the entity and its customer at contract inception and recognizes the revenue amount on a straight-line basis over the term of the Customer Agreement, and interest expense using the effective interest rate method. Consideration from customers is considered variable due to the performance guarantee under Customer Agreements and liquidated damage provisions under SREC contracts in the event minimum deliveries are not achieved. Performance guarantees provide a credit to the customer if the system's cumulative production, as measured on various PTO anniversary dates, is below the Company's guarantee of a specified minimum. Revenue is recognized to the extent it is probable that a significant reversal of such revenue will not occur. The Company capitalizes incremental costs incurred to obtain a contract in Other Assets in the consolidated balance sheets. These amounts are amortized on a straight-line basis over the term of the Customer Agreements, and are included in Sales and marketing in the consolidated statements of operations. Solar energy systems and product sales For solar energy systems sold to customers, the Company recognizes revenue when the solar energy system passes inspection by the authority having jurisdiction. The Company’s installation projects are typically completed in less than 12 months. Product sales consist of solar panels, racking systems, inverters, other solar energy products sold to resellers and customer leads. Product sales revenue is recognized upon shipment, which is at the time control is transferred. Customer lead revenue is recognized at the time the lead is delivered. Taxes assessed by government authorities that are directly imposed on revenue producing transactions are excluded from solar energy systems and product sales. Cost of Revenue Customer agreements and incentives Cost of revenue for customer agreements and incentives is primarily comprised of (1) the depreciation of the cost of the solar energy systems, as reduced by amortization of deferred grants, (2) solar energy system operations, monitoring and maintenance costs including associated personnel costs, and (3) allocated corporate overhead costs. Solar energy systems and product sales Cost of revenue for solar energy systems and non-lead generation product sales consist of direct and indirect material and labor costs for solar energy systems installations and product sales. Also included are engineering and design costs, estimated warranty costs, freight costs, allocated corporate overhead costs, vehicle depreciation costs and personnel costs associated with supply chain, logistics, operations management, safety and quality control. Cost of revenue for lead generations consists of costs related to direct-response advertising activities associated with generating customer leads. Recently Issued and Adopted Accounting Standards Accounting standards adopted January 1, 2019: In February 2018, the FASB issued Accounting Standards Update ("ASU") No. 2018-02, Income Statement -- Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , which allows companies to reclassify stranded tax effects resulting from the Tax Cuts and Jobs Act from accumulated other comprehensive income to retained earnings. The Company adopted ASU No. 2018-02 effective January 1, 2019, resulting in a current period adjustment of $0.7 million for the reclassification, as reflected in its consolidated statement of redeemable noncontrolling interests and stockholders' equity. The Company uses the aggregate portfolio approach when reclassing stranded tax effects from accumulated other comprehensive income. In June 2018, the FASB issued ASU No. 2018-07, Compensation -- Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting , which aligns the accounting for share-based payment awards issued to employees and nonemployees; however, this amendment does not apply to instruments issued in a financing transaction nor to equity instruments granted to a customer under a contract in the scope of Topic 606. Under this new amendment, equity-classified nonemployee share-based payments are measured at the grant-date fair value and recognized based on the probable outcome of the performance conditions. The Company adopted ASU No. 2018-07 effective January 1, 2019, and there was no material impact to its consolidated financial statements. In July 2018, the FASB issued ASU No. 2018-09, Codification Improvements . This amendment makes changes to a variety of topics to clarify, correct errors in, or make minor improvements to the Accounting Standards Codification. The Company adopted ASU No. 2018-09 effective January 1, 2019, and there was no material impact to its consolidated financial statements. In August 2018, the SEC adopted a Disclosure Update and Simplification release, which outlines Regulation S-X amendments to eliminate outdated or duplicative disclosure requirements. The final rule also amends the interim financial statement requirements to require a reconciliation of changes in stockholders’ equity in the notes or as a separate statement. These amendments are effective for all filings made 30 days after the amendments are published in the Federal Register, which was on October 4, 2018. The SEC announced that it would not object if the first presentation of the changes in stockholders’ equity for a calendar year end filer were made in the Company’s March 31, 2019 Form 10-Q. Effective with this interim report on Form 10-Q, the Company is now presenting consolidated statements of redeemable noncontrolling interests and stockholders' equity. Accounting standards to be adopted: In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments , which replaces the current incurred loss impairment methodology with a current expected credit losses model. The amendment applies to entities which hold financial assets and net investment in leases that are not accounted for at fair value through net income as well as loans, debt securities, trade receivables, net investments in leases, off-balance sheet credit exposures, reinsurance receivables and any other financial assets not excluded from the scope that have the contractual right to receive cash. This ASU is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted. Adoption of this ASU is applied using a modified retrospective approach, with certain aspects requiring a prospective approach. The Company is currently evaluating this guidance and the impact it may have on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework--Changes to the Disclosure Requirements for Fair Value Measurement , which modifies the disclosure requirements on fair value measurements as part of its disclosure framework project. Under this amendment, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. However, for Level 3 fair value measurements, disclosures around the range and weighted average used to develop significant unobservable inputs will be required. This ASU is effective for fiscal periods beginning after December 15, 2019. The Company is currently evaluating this guidance and the impact it may have on the Company's consolidated financial statements and disclosures. In August 2018, the FASB issued ASU No. 2018-15, Intangibles--Goodwill and Other--Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract , which requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance in Topic 350, Intangibles--Goodwill and Other , to determine which implementation costs to capitalize as assets or expense as incurred. This ASU is effective for annual reporting periods, and interim periods within those years, beginning after December 15, 2019, and can be applied either prospectively to implementation costs incurred after the date of adoption or retrospectively to all arrangements. The Company is currently evaluating this guidance and the impact it may have on the Company's consolidated financial statements. In October 2018, the FASB issued ASU No. 2018-17, Consolidation (Topic 810) , Targeted Improvements to Related Party Guidance for Variable Interest Entities, which aligns the evaluation of decision-making fees under the variable interest entity guidance. Under this new guidance, in order to determine whether decision-making fees represent a variable interest, an entity considers indirect interests held through related parties under common control on a proportionate basis. This ASU is effective for annual reporting periods, and interim periods within those years, beginning after December 15, 2019, and must be applied retrospectively with a cumulative-effect adjustment to retained earnings at the beginning of the earliest period presented. The Company is currently evaluating this guidance and the impact it may have on the Company's consolidated financial statements.

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement At March 31, 2019 and December 31, 2018 , the carrying value of receivables, accounts payable, accrued expenses and distributions payable to noncontrolling interests approximates fair value due to their short-term nature and falls under the Level 2 hierarchy. The carrying values and fair values of debt instruments are as follows (in thousands): March 31, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value Bank line of credit $ 239,035 $ 239,035 $ 247,000 $ 247,000 Senior debt 913,787 913,710 828,517 828,309 Subordinated debt 278,910 284,887 273,337 272,937 Securitization debt 392,490 406,818 400,068 394,756 Total $ 1,824,222 $ 1,844,450 $ 1,748,922 $ 1,743,002 At March 31, 2019 and December 31, 2018 , the fair value of the Company’s lines of credit, and certain senior, subordinated and SREC loans approximate their carrying values because their interest rates are variable rates that approximate rates currently available to the Company. At March 31, 2019 and December 31, 2018 , the fair value of the Company’s other debt instruments are based on rates currently offered for debt with similar maturities and terms. The Company’s fair value of the debt instruments fell under the Level 2 hierarchy. These valuation approaches involve some level of management estimation and judgment, the degree of which is dependent on the price transparency for the instruments or market. The Company determines the fair value of its interest rate swaps using a discounted cash flow model that incorporates an assessment of the risk of non-performance by the interest rate swap counterparty and an evaluation of the Company’s credit risk in valuing derivative instruments. The valuation model uses various inputs including contractual terms, interest rate curves, credit spreads and measures of volatility. At March 31, 2019 and December 31, 2018 , financial instruments measured at fair value on a recurring basis, based upon the fair value hierarchy, are as follows (in thousands): March 31, 2019 Level 1 Level 2 Level 3 Total Derivative assets: Interest rate swaps $ — $ 590 $ — $ 590 Total $ — $ 590 $ — $ 590 Derivative liabilities: Interest rate swaps $ — $ 28,314 $ — $ 28,314 Total $ — $ 28,314 $ — $ 28,314 December 31, 2018 Level 1 Level 2 Level 3 Total Derivative assets: Interest rate swaps $ — $ 6,958 $ — $ 6,958 Total $ — $ 6,958 $ — $ 6,958 Derivative liabilities: Interest rate swaps $ — $ 11,910 $ — $ 11,910 Total $ — $ 11,910 $ — $ 11,910

Inventories

Inventories	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following (in thousands): March 31, 2019 December 31, 2018 Raw materials $ 65,598 $ 64,256 Work-in-process 10,586 15,211 Total $ 76,184 $ 79,467

Solar Energy Systems, net

Solar Energy Systems, net	3 Months Ended
	Mar. 31, 2019
Solar Energy Systems Disclosure [Abstract]
Solar Energy Systems, net	Solar Energy Systems, net Solar energy systems, net consists of the following (in thousands): March 31, 2019 December 31, 2018 Solar energy system equipment costs $ 4,012,116 $ 3,823,853 Inverters 416,088 396,054 Total solar energy systems 4,428,204 4,219,907 Accumulated depreciation and amortization (575,094 ) (535,891 ) Construction-in-progress 123,394 136,001 Total solar energy systems, net $ 3,976,504 $ 3,820,017 All solar energy systems, including construction-in-progress, have been leased to or are subject to signed Customer Agreements with customers. The Company recorded depreciation expense related to solar energy systems of $39.4 million and $32.4 million for the three months ended March 31, 2019 and 2018 , respectively. The depreciation expense was reduced by the amortization of deferred grants of $2.0 million and $1.9 million for the three months ended March 31, 2019 and 2018 , respectively.

Other Assets

Other Assets	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets Other assets consist of the following (in thousands): March 31, 2019 December 31, 2018 Costs to obtain contracts- customer agreements $ 232,567 $ 219,307 Costs to obtain contracts- incentives 2,481 — Accumulated amortization of costs to obtain contracts (27,641 ) (24,992 ) Unbilled receivables 90,578 81,703 Operating lease right-of-use assets 38,051 20,257 Other assets 31,915 39,410 Total $ 367,951 $ 335,685 The Company recorded amortization of costs to obtain contracts of $2.7 million and $1.9 million for the three months ended March 31, 2019 and 2018 , respectively, in Sales and marketing in the consolidated statements of operations. The majority of unbilled receivables arise from fixed price escalators included in the Company's long-term Customer Agreements. The escalator is included in calculating the total estimated transaction value for an individual Customer Agreement. The total estimated transaction value is then recognized evenly over the term of the Customer Agreement. The amount of unbilled receivables increases while current period billings for an individual Customer Agreement are less than the current period revenue recognized for that Customer Agreement. Conversely, the amount of unbilled receivables decreases when the actual current period billings become higher than the current period revenue recognized. At the end of the initial term of a Customer Agreement, the cumulative amounts recognized as revenue and billed to date are the same, therefore the unbilled receivable balance for an individual Customer Agreement will be zero.

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	3 Months Ended
	Mar. 31, 2019
Payables and Accruals [Abstract]
Accrued Expenses and Other Liabilities	Accrued Expenses and Other Liabilities Accrued expenses and other liabilities consist of the following (in thousands): March 31, 2019 December 31, 2018 Accrued employee compensation $ 35,393 $ 39,738 Operating lease obligations 9,462 7,857 Accrued interest 12,942 8,436 Accrued professional fees 12,185 9,199 Other accrued expenses 33,782 33,406 Total $ 103,764 $ 98,636

Indebtedness

Indebtedness	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Indebtedness	Indebtedness As of March 31, 2019 , debt consisted of the following (in thousands, except percentages): Carrying Values, net of debt discount Unused Borrowing Capacity Interest Rate (1) Maturity Date Current Long Term Total Recourse debt: Bank line of credit $ — $ 239,035 $ 239,035 $ — 5.59% - 5.90% April 2020 Total recourse debt — 239,035 239,035 — Non-recourse debt: Senior 12,679 901,108 913,787 — 4.50% - 5.49% September 2020 - October 2024 Subordinated 5,715 273,195 278,910 — 7.03% - 10.00% September 2020 - January 2030 Securitization Class A 8,072 374,875 382,947 — 4.40% - 5.31% July 2024 - April 2049 Securitization Class B 471 9,072 9,543 — 5.38 % July 2024 Total non-recourse debt 26,937 1,558,250 1,585,187 — Total debt $ 26,937 $ 1,797,285 $ 1,824,222 $ — (1) Reflects contractual, unhedged rates. See Note 9 , Derivatives for hedge rates. As of December 31, 2018 , debt consisted of the following (in thousands, except percentages): Carrying Values, net of debt discount Unused Borrowing Capacity Interest Rate (1) Maturity Date Current Long Term Total Recourse debt: Bank line of credit $ — $ 247,000 $ 247,000 $ 406 5.45% - 5.77% April 2020 Total recourse debt — 247,000 247,000 406 Non-recourse debt: Senior 19,070 809,447 828,517 — 4.50% - 5.54% September 2020 - October 2024 Subordinated 5,824 267,513 273,337 — 7.03% - 10.00% September 2020 - January 2030 Securitization Class A 10,125 380,299 390,424 — 4.40% - 5.31% July 2024 - April 2049 Securitization Class B 465 9,179 9,644 — 5.38 % July 2024 Total non-recourse debt 35,484 1,466,438 1,501,922 — Total debt $ 35,484 $ 1,713,438 $ 1,748,922 $ 406 (1) Reflects contractual, unhedged rates. See Note 9 , Derivatives for hedge rates. Bank Line of Credit The Company has outstanding borrowings under a syndicated working capital facility with banks for a total commitment of up to $250.0 million . The working capital facility is secured by substantially all of the unencumbered assets of the Company, as well as ownership interests in certain subsidiaries of the Company. Loans under the facility bear interest at LIBOR + 3.25% per annum or the Base Rate + 2.25% per annum. The Base Rate is the highest of the Federal Funds Rate + 0.50% , the Prime Rate, or LIBOR + 1.00% . Under the terms of the working capital facility, the Company is required to meet various restrictive covenants, such as the completion and presentation of audited consolidated financial statements, maintaining a minimum unencumbered liquidity of at least $25 million at the end of each calendar month, maintaining quarter end liquidity of at least $30 million , and maintaining a minimum interest coverage ratio of 3.00 or greater, measured quarterly as of the last day of each quarter. The Company was in compliance with all debt covenants as of March 31, 2019 . As of March 31, 2019 , the balance under this facility was $239.0 million with a maturity date in April 2020. Although there is no assurance that the Company will be able to do so, the Company believes that it is probable that it will be able to extend or otherwise refinance the facility prior to maturity. Senior and Subordinated Each of the Company's senior and subordinated debt facilities contains customary covenants including the requirement to maintain certain financial measurements and provide lender reporting. Each of the senior and subordinated debt facilities also contain certain provisions in the event of default that entitle lenders to take certain actions including acceleration of amounts due under the facilities and acquisition of membership interests and assets that are pledged to the lenders under the terms of the senior and subordinated debt facilities. The facilities are non-recourse to the Company and are secured by net cash flows from Customer Agreements less certain operating, maintenance and other expenses that are available to the borrower after distributions to tax equity investors, where applicable. The Company was in compliance with all debt covenants as of March 31, 2019 . As of March 31, 2019 , certain subsidiaries of the Company have an outstanding balance of $281.8 million on secured credit facilities that were syndicated with various lenders due in October 2024 . The credit facilities totaled $303.0 million and consisted of $293.0 million in term loans, and a $10.0 million revolving debt service reserve letter of credit facility. Term Loan A ("TLA") is a senior delayed draw term loan that bears interest at LIBOR + 2.75% per annum for LIBOR loans or the Base Rate + 1.75% per annum on Base Rate loans. Term Loan B ("TLB") is subordinated debt and consists of a Class A portion which accrues interest at a fixed interest rate of 7.03% per annum and a Class B portion which accrues interest at LIBOR + 5.00% per annum or the Base Rate + 4.00% per annum. The Base Rate is the highest of the Federal Funds Rate + 0.50% , the Prime Rate, or LIBOR + 1.00% . Under TLA, prepayments are permitted with no penalties. Under TLB, prepayments are permitted with associated penalties ranging from 0% - 5% depending on the timing of prepayments. As of March 31, 2019 , certain subsidiaries of the Company have an outstanding balance of $183.8 million on senior secured credit facilities that were syndicated with various lenders due in April 2024 . These facilities are subject to the National Grid project equity transaction. The credit facilities totaled $202.0 million and consisted of a $195.0 million senior delayed draw term loan facility and a $7.0 million revolving debt service reserve letter of credit facility. Loans under the facility bear interest at LIBOR + 2.25% per annum, for the initial four -year period for LIBOR loans or the Base Rate + 1.25% per annum for Base Rate Loans. The Base Rate is the highest of the Federal Funds Rate + 0.50% , the Prime Rate, or LIBOR + 1.00% . The facilities are non-recourse to the Company and are secured by net cash flows from Customer Agreements and SRECs, less certain operating, maintenance and other expenses that are available to the borrower after distributions to tax equity investors. Prepayments are permitted under the delayed draw term loan facility. As of March 31, 2019 , certain subsidiaries of the Company have an outstanding balance of $362.6 million on secured credit facilities agreements, as amended, with a syndicate of banks due in March 2023 . The facilities totaled $595.0 million and consisted of a revolving aggregation facility (“Aggregation Facility”), a term loan ("Term Loan") and a revolving debt service reserve letter of credit facility. Senior loans under the Aggregation Facility bear interest at LIBOR + 2.50% per annum for the initial three -year revolving availability period, stepping up to LIBOR + 2.75% per annum in the following two -year period. The subordinated Term Loan bears interest at LIBOR + 5.00% per annum for the first three -year period, stepping up to LIBOR + 6.50% per annum thereafter. Term Loan prepayment penalties range from 0% - 1% depending on the timing of prepayments. As of March 31, 2019 , a subsidiary of the Company has an outstanding balance of $210.2 million on a revolving loan facility due in September 2020 .The facility is secured by the assets and related net cash flow of this subsidiary and is non-recourse to the Company's other assets. Loans under the facility bear interest at LIBOR + 2.75% per annum for the senior secured loan, and LIBOR + 5.50% per annum for the subordinated loan. As of March 31, 2019 , a subsidiary of the Company has an outstanding balance of $20.0 million on a term loan due in April 2022 . The loan is secured by the assets and related net cash flow of this subsidiary and is non-recourse to the Company’s other assets. Loans under this facility bear interest at 4.50% per annum. As of March 31, 2019 , a subsidiary of the Company has an outstanding balance of $16.1 million on a secured, non-recourse loan agreement due in September 2022 . The loan will be repaid through cash flows from a pass-through financing obligation arrangement previously entered into by the Company. The loan agreement contains customary covenants including the requirement to maintain certain financial measurements and provide lender reporting. The loan also contains certain provisions in the event of default that entitles the lender to take certain actions including acceleration of amounts due under the loan. Loans under this facility bear interest at LIBOR + 2.25% per annum. As of March 31, 2019 , a subsidiary of the Company has an outstanding balance of $118.2 million on a term loan due in January 2030. The loan is secured by the assets and related net cash flow of this subsidiary and is non-recourse to the Company’s other assets. Loans under this facility bear interest at 10.00% per annum. Securitization Loans Each of the Company's securitized loans contains customary covenants including the requirement to provide reporting to the indenture trustee and ratings agencies. Each of the securitized loans also contain certain provisions in the event of default which entitle the indenture trustee to take certain actions including acceleration of amounts due under the facilities and acquisition of membership interests and assets that are pledged to the lenders under the terms of the securitized loans. The facilities are non-recourse to the Company and are secured by net cash flows from Customer Agreements less certain operating, maintenance and other expenses that are available to the borrower after distributions to tax equity investors, where applicable. The Company was in compliance with all debt covenants as of March 31, 2019 . As of March 31, 2019 , a subsidiary of the Company has an outstanding balance of $89.1 million on solar asset-backed notes ("Notes") secured by associated customer contracts (“Solar Assets”) held by a special purpose entity (“Issuer”). As of March 31, 2019 and December 31, 2018 , these Solar Assets had a carrying value of $162.7 million and $164.7 million , respectively, and are included under solar energy systems, net, in the consolidated balance sheets. The Notes were issued at a discount of 0.08% As of March 31, 2019 , a subsidiary of the Company has an outstanding balance of $303.4 million on solar asset-backed notes secured by net cash flows from Customer Agreements less certain operating, maintenance and other expenses that are available to the issuer after distributions to tax equity investors. The Notes were issued at a discount of 1.47% . The assets and cash flows generated by the Solar Assets are not available to the other creditors of the Company, and the creditors of the Issuer, including the Note holders, have no recourse to the Company's other assets.

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives Interest Rate Swaps The Company uses interest rate swaps to hedge variable interest payments due on certain of its term loans and aggregation facility. These swaps allow the Company to incur fixed interest rates on these loans and receive payments based on variable interest rates with the swap counterparty based on the one or three month LIBOR on the notional amounts over the life of the swaps. The interest rate swaps have been designated as cash flow hedges. The credit risk adjustment associated with these swaps is the risk of non-performance by the counterparties to the contracts. In the three months ended March 31, 2019 , the hedge relationships on the Company’s interest rate swaps have been assessed as highly effective as the critical terms of the interest rate swaps match the critical terms of the underlying forecasted hedged transactions. Accordingly, changes in the fair value of these derivatives are recorded as a component of accumulated other comprehensive income, net of income taxes. Changes in the fair value of these derivatives are subsequently reclassified into earnings, and are included in interest expense, net in the Company’s statements of operations, in the period that the hedged forecasted transactions affects earnings. The following table summarizes the post-tax amount of unrealized gain or loss recognized in Accumulated other comprehensive income (loss) ("OCI") in the consolidated statements of redeemable noncontrolling interests and stockholders' equity (in thousands): Three Months Ended March 31, 2019 2018 Derivatives designated as cash flow hedges: Loss in OCI at the beginning of the period $ (3,124 ) $ (4,113 ) Unrealized (loss) gain recognized in OCI (17,013 ) 16,171 Amount reclassified from OCI to earnings (989 ) (1,233 ) Net (loss) gain on derivatives (net of tax effect of $6,093 and $5,134) (18,002 ) 14,938 Cumulative effect of adoption of new ASU (No. 2018-02) (740 ) — (Loss) gain in OCI at the end of the period (21,866 ) 10,825 During the next 12 months, the Company expects to reclassify $0.1 million of net gains on derivative instruments from accumulated other comprehensive income to earnings. There were no undesignated derivative instruments recorded by the Company as of March 31, 2019 . The Company’s master netting and other similar arrangements allow net settlements under certain conditions. When those conditions are met, the Company presents derivatives at net fair value. As of March 31, 2019 the information related to these offsetting arrangements were as follows (in thousands): Instrument Description Gross Amounts of Recognized Assets / Liabilities Gross Amounts Offset in the Consolidated Balance Sheet Net Amounts of Assets / Liabilities Included in the Consolidated Balance Sheet Assets: Derivatives $ 590 $ (276 ) $ 314 Liabilities: Derivatives (28,314 ) 276 (28,038 ) Total $ (27,724 ) $ — $ (27,724 ) As of December 31, 2018 the information related to these offsetting arrangements were as follows (in thousands): Instrument Description Gross Amounts of Recognized Assets / Liabilities Gross Amounts Offset in the Consolidated Balance Sheet Net Amounts of Assets / Liabilities Included in the Consolidated Balance Sheet Assets: Derivatives $ 6,958 $ (1,605 ) $ 5,353 Liabilities: Derivatives (11,910 ) 1,605 (10,305 ) Total $ (4,952 ) $ — $ (4,952 ) At March 31, 2019 , the Company had the following derivative instruments (dollars in thousands): Type Quantity Effective Dates Maturity Dates Hedge Interest Rates Notional Amount Adjusted Net Fair Market Value Interest rate swap 1 5/21/2018 9/20/2020 2.69% $ 80,500 $ (437 ) Interest rate swap 1 4/29/2016 8/31/2022 1.27%- 1.29% 13,179 314 Interest rate swaps 8 7/31/2017 - 1/31/2018 4/30/2024 - 10/20/2024 2.16%- 2.39% 283,160 (384 ) Interest rate swaps 3 4/30/2021 10/30/2026 - 10/31/2026 2.89% - 3.08% 102,720 (3,631 ) Interest rate swap 1 10/22/2018 9/20/2027 2.97% 30,023 (1,011 ) Interest rate swaps 2 4/22/2019 - 9/20/2020 3/20/2030 - 6/20/2030 2.22% - 2.57% 160,401 (1,177 ) Interest rate swap 1 9/20/2020 1/20/2031 2.61% 9,899 (332 ) Interest rate swaps 3 1/31/2020 4/30/2034 2.78% 200,000 (6,545 ) Interest rate swaps 5 7/31/2017 - 4/30/2024 7/31/2035 2.56% - 2.95% 151,610 (2,197 ) Interest rate swaps 5 1/31/2018 - 10/18/2024 10/31/2036 2.62% - 2.95% 183,398 (2,710 ) Interest rate swaps 3 1/31/2019 - 4/30/2021 4/30/2037 3.28% - 3.30% 100,000 (7,099 ) Interest rate swaps 3 10/30/2026 - 10/31/2026 1/31/2038 3.01% - 3.16% 101,135 (2,515 ) Total $ 1,416,025 $ (27,724 )

Pass-through Financing Obligati

Pass-through Financing Obligations	3 Months Ended
	Mar. 31, 2019
Property Subject to or Available for Operating Lease, Net [Abstract]
Pass-Through Financing Obligations	Pass-through Financing Obligations The Company's pass-through financing obligations ("financing obligations") arise when the Company leases solar energy systems to Fund investors who are considered commercial customers under a master lease agreement, and these investors in turn are assigned the Customer Agreements with customers. The Company receives all of the value attributable to the accelerated tax depreciation and some or all of the value attributable to the other incentives. Given the assignment of operating cash flows, these arrangements are accounted for as financing obligations. The Company also sells the rights and related value attributable to the ITC to these investors. Under these financing obligation arrangements, wholly owned subsidiaries of the Company finance the cost of solar energy systems with investors for an initial term of typically 20 or 22 years. The solar energy systems are subject to Customer Agreements with an initial term of typically 20 or 25 years that automatically renew on an annual basis. These solar energy systems are reported under the line item solar energy systems, net in the consolidated balance sheets. As of March 31, 2019 and December 31, 2018 , the cost of the solar energy systems placed in service under the financing obligation arrangements was $656.5 million and $664.1 million , respectively. The accumulated depreciation related to these assets as of March 31, 2019 and December 31, 2018 was $79.8 million and $82.1 million , respectively. The investors make a series of large up-front payments and, in certain cases, subsequent smaller quarterly payments (lease payments) to the subsidiaries of the Company. The Company accounts for the payments received from the investors under the financing obligation arrangements as borrowings by recording the proceeds received as financing obligations on its consolidated balance sheets, and cash provided by financing activities in its consolidated statement of cash flows. These financing obligations are reduced over a period of approximately 22 years by customer payments under the Customer Agreements, U.S. Treasury grants (where applicable), incentive rebates (where applicable) and proceeds from the contracted resale of SRECs as they are received by the investor. In addition, funds paid for the ITC value upfront are initially recorded as a refund liability and recognized as revenue as the associated solar system reaches PTO. The ITC value is reflected in the cash provided by operations on the consolidated statement of cash flows. The Company accounts for the Customer Agreements and any related U.S. Treasury grants or incentive rebates as well as the resale of SRECs consistent with the Company’s revenue recognition accounting policies as described in Note 2, Summary of Significant Accounting Policies. Interest is calculated on the financing obligations using the effective interest rate method. The effective interest rate, which is adjusted on a prospective basis, is the interest rate that equates the present value of the estimated cash amounts to be received by the investor over the lease term with the present value of the cash amounts paid by the investor to the Company, adjusted for amounts received by the investor. The financing obligations are nonrecourse once the associated assets have been placed in service and all the contractual arrangements have been assigned to the investor. Under the majority of the financing obligations, the investor has a right to extend its right to receive cash flows from the customers beyond the initial term in certain circumstances. Depending on the arrangement, the Company has the option to settle the outstanding financing obligation on the ninth or eleventh anniversary of the Fund inception at a price equal to the higher of (a) the fair value of future remaining cash flows or (b) the amount that would result in the investor earning their targeted return. In several of these financing obligations, the investor has an option to require repayment of the entire outstanding balance on the tenth anniversary of the Fund inception at a price equal to the fair value of the future remaining cash flows. Under all financing obligations, the Company is responsible for services such as warranty support, accounting, lease servicing and performance reporting to customers. As part of the warranty and performance guarantee with the customers, the Company guarantees certain specified minimum annual solar energy production output for the solar energy systems leased to the customers, which the Company accounts for as disclosed in Note 2, Summary of Significant Accounting Policies. During the three months ended March 31, 2019, the Company made an early repayment of one of its financing obligations for $11.7 million , which resulted in a debt extinguishment expense of $4.4 million .

VIE Arrangements

VIE Arrangements	3 Months Ended
	Mar. 31, 2019
Variable Interest Entity Disclosure [Abstract]
VIE Arrangements	VIE Arrangements The Company consolidated various VIEs at March 31, 2019 and December 31, 2018 . The carrying amounts and classification of the VIEs’ assets and liabilities included in the consolidated balance sheets are as follows (in thousands): March 31, 2019 December 31, 2018 Assets Current assets Cash $ 135,548 $ 105,494 Restricted cash 969 2,071 Accounts receivable, net 16,988 18,539 Prepaid expenses and other current assets 386 387 Total current assets 153,891 126,491 Solar energy systems, net 2,761,312 2,712,377 Other assets 66,707 66,427 Total assets $ 2,981,910 $ 2,905,295 Liabilities Current liabilities Accounts payable $ 10,979 $ 12,136 Distributions payable to noncontrolling interests and redeemable noncontrolling interests 15,545 15,797 Accrued expenses and other liabilities 7,315 7,122 Deferred revenue, current portion 33,504 29,102 Deferred grants, current portion 982 982 Non-recourse debt, current portion 4,336 4,217 Total current liabilities 72,661 69,356 Deferred revenue, net of current portion 405,261 367,818 Deferred grants, net of current portion 27,982 28,247 Non-recourse debt, net of current portion 184,958 186,494 Other liabilities 10,733 8,843 Total liabilities $ 701,595 $ 660,758 The Company holds a variable interest in an entity that provides the noncontrolling interest with a right to terminate the leasehold interests in all of the leased projects on the tenth anniversary of the effective date of the master lease. In this circumstance, the Company would be required to pay the noncontrolling interest an amount equal to the fair market value, as defined in the governing agreement of all leased projects as of that date. The Company holds certain variable interests in nonconsolidated VIEs established as a result of six pass-through Fund arrangements as further explained in Note 10 , Pass-through Financing Obligations . The Company does not have material exposure to losses as a result of its involvement with the VIEs in excess of the amount of the pass-through financing obligation recorded in the Company’s consolidated financial statements. The Company is not considered the primary beneficiary of these VIEs. During the three months ended March 31, 2019, the Company acquired an investor's interest in a consolidated VIE for total cash consideration of $4.6 million . This transaction increased the Company's additional paid-in-capital, net of the related tax impact, by $1.1 million .

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests and Equity	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Redeemable Noncontrolling Interests and Equity	Redeemable Noncontrolling Interests and Equity During certain specified periods of time (the “Early Exit Periods”), noncontrolling interests in certain funding arrangements have the right to put all of their membership interests to the Company (the “Put Provisions”). During a specific period of time (the “Call Periods”), the Company has the right to call all membership units of the related redeemable noncontrolling interests. The carrying value of redeemable noncontrolling interests was greater than the redemption value except for seven and six Funds at March 31, 2019 and December 31, 2018 , respectively, where the carrying value has been adjusted to the redemption value.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock Options The following table summarizes the activity for all stock options under all of the Company’s equity incentive plans for the three months ended March 31, 2019 (shares and aggregate intrinsic value in thousands): Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2018 13,590 $ 6.07 6.63 $ 66,462 Granted 1,064 14.57 Exercised (1,139 ) 3.86 Cancelled (17 ) 10.30 Outstanding at March 31, 2019 13,498 $ 6.92 6.71 $ 97,127 Options vested and exercisable at March 31, 2019 8,154 $ 6.21 5.67 $ 64,261 Restricted Stock Units The following table summarizes the activity for all restricted stock units (“RSUs”) under all of the Company’s equity incentive plans for the three months ended March 31, 2019 (shares in thousands): Number of Awards Weighted Average Grant Date Fair Value Unvested balance at December 31, 2018 4,182 $ 7.05 Granted 1,524 14.42 Issued (451 ) 6.75 Cancelled / forfeited (295 ) 7.20 Unvested balance at March 31, 2019 4,960 $ 9.33 Employee Stock Purchase Plan Under the Company's 2015 Employee Stock Purchase Plan ("ESPP"), as amended in May 2017, eligible employees are offered shares bi-annually through a 24 -month offering period that encompasses four six-month purchase periods. Each purchase period begins on the first trading day on or after May 15 and November 15 of each year. Employees may purchase a limited number of shares of the Company’s common stock via regular payroll deductions at a discount of 15% of the lower of the fair market value of the Company’s common stock on the first trading date of each offering period or on the exercise date. Employees may deduct up to 15% of payroll, with a cap of $25,000 of fair market value of shares in any calendar year and 10,000 shares per employee per purchase period. Stock-Based Compensation Expense The Company recognized stock-based compensation expense, including ESPP expenses, in the consolidated statements of operations as follows (in thousands): Three Months Ended March 31, 2019 2018 Cost of customer agreements and incentives $ 632 $ 611 Cost of solar energy systems and product sales 167 170 Sales and marketing 1,128 4,150 Research and development 336 295 General and administration 3,520 5,468 Total $ 5,783 $ 10,694 In August 2017, the Company entered into an agreement with an affiliate ("Contractor") of Comcast Corporation ("Comcast") whereby Contractor will receive lead or sales fees for new customers it brings to the Company over a 40 -month term. Comcast may also earn a warrant to purchase up to 11,793,355 shares of the Company's outstanding common stock, at an exercise price of $0.01 per warrant share. The warrant initially vests 50.05% when both (i) Contractor has earned a lead or sales fee with respect to 30,000 of installed solar energy systems, and (ii) Contractor or its affiliates have spent at least $10.0 million in marketing and sales in connection with the agreement. Thereafter, the warrant will vest in five additional increments for each additional 6,000 installed solar energy systems. On November 7, 2018 the warrant vesting schedule was modified so that it will initially vest either (i) as to 10.0% if Contractor has earned a lead or sales fee with respect to 6,000 of installed solar energy systems by September 30, 2019 or (ii) as to 13.3% if Contractor has earned a lead or sales fee with respect to 8,000 of installed solar energy systems by December 31, 2019, provided that, in either case, Contractor or its affiliates have spent at least $ 25.0 million in marketing and sales in connection with the agreement. Thereafter, the warrant will vest in additional 8.3% increments for each additional 5,000 installed solar energy systems. If the initial vesting conditions have not been met by December 31, 2019, the Warrant will expire. As of May 8, 2019 , none of the shares under this amended warrant have vested and, therefore, no expense has been recognized to date.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The income tax expense rate for the three months ended March 31, 2019 and 2018 was 3.7% and (9.9)% , respectively. The differences between the actual consolidated effective income tax rate and the U.S. federal statutory rate were primarily attributable to an increase in valuation allowance on deferred tax assets and the allocation of losses on noncontrolling interests and redeemable noncontrolling interests. The Company sells solar energy systems to investment Funds. As the investment Funds are consolidated by the Company, the gain on the sale of the assets has been eliminated in the consolidated financial statements, however gains on sale are recognized for tax purposes. Tax Cuts and Jobs Act On December 22, 2017, the U.S, government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Tax Act”). While the Company has fully accounted for the impact of the Tax Act, it will continue to monitor additional clarification and guidance from the IRS, including guidance related to Section 451(c) income recognition that could lead to the Company utilizing a portion of its net operating losses. Uncertain Tax Positions As of March 31, 2019 and December 31, 2018 , the Company had $0.6 million of unrecognized tax benefits related to an acquisition in 2015. In addition, there was $0.2 million of interest and penalties for uncertain tax positions as of March 31, 2019 and December 31, 2018 . Due to the expiration of federal and California statute of limitations, the Company expects the total amount of gross unrecognized tax benefits will decrease by $0.5 million within 12 months of March 31, 2019 . Net Operating Loss Carryforwards As a result of the Company’s net operating loss carryforwards as of March 31, 2019 and December 31, 2018 , the Company does not expect to pay income tax, including in connection with its income tax provision for the three months ended March 31, 2019 . As of December 31, 2018 , the Company had net operating loss carryforwards for federal, California, and other state income tax purposes of approximately $1.1 billion , $572.2 million , 535.8 million , respectively, which will begin to expire in the year 2028 , 2028 , and 2024 , respectively, if not utilized. The Company does not expect to pay any income taxes until the Company's net operating losses are fully utilized. Federal and certain state net operating loss carryforwards generated in tax years beginning after December 31, 2017 have indefinite carryover periods and do not expire, but are limited to the amount that can be utilized in any one year.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Letters of Credit As of March 31, 2019 and December 31, 2018 , the Company had $14.4 million and $9.7 million , respectively, of unused letters of credit outstanding, which carry fees of 2.75% - 3.25% per annum and 2.50% - 3.25% per annum, respectively. Operating and Finance Leases The Company leases real estate under non-cancellable-operating leases and equipment under finance leases. The components of lease expense were as follows (in thousands): Three Months Ended March 31, 2019 2018 Finance lease cost: Amortization of right-of-use assets $ 3,484 $ 2,634 Interest on lease liabilities 239 119 Operating lease cost 2,879 2,629 Short-term lease cost 524 201 Variable lease cost 877 777 Sublease income (156 ) (106 ) Total lease cost $ 7,847 $ 6,254 Other information related to leases was as follows (in thousands): Three Months Ended March 31, 2019 2018 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 2,567 $ 2,600 Operating cash flows from finance leases 201 109 Financing cash flows from finance leases 3,060 2,159 Right-of-use assets obtained in exchange for lease obligations: Operating leases 20,395 1,117 Finance leases 3,566 99 Weighted average remaining lease term (years): Operating leases 5.55 3.89 Finance leases 2.90 1.87 Weighted average discount rate: Operating leases 5.2 % 4.1 % Finance leases 4.3 % 3.1 % Future minimum lease payments under non-cancellable leases as of March 31, 2019 were as follows (in thousands): Operating Leases Sublease Income Net Operating Leases Finance Leases 2019 $ 11,952 $ 777 $ 11,175 $ 10,060 2020 11,878 791 11,087 5,453 2021 10,538 439 10,099 3,587 2022 9,101 — 9,101 1,568 2023 8,189 — 8,189 60 Thereafter 10,677 — 10,677 49 Total future lease payments 62,335 2,007 60,328 20,777 Less: Amount representing interest 6,200 — 6,200 1,072 Present value of future payments 56,135 2,007 54,128 19,705 Less: Short term leases not recorded as a liability 11,761 — 11,761 — Less: Tenant incentives 3,186 — 3,186 — Revised Present value of future payments 41,188 2,007 39,181 19,705 Less: Current portion 9,462 — 9,462 9,459 Long-term portion $ 31,726 $ 2,007 $ 29,719 $ 10,246 During the three months ended March 31, 2019, the Company entered into two non-cancellable operating lease agreements over the next five to seven years for corporate office space in San Francisco, California, and Denver, Colorado, to replace existing office space whose lease terms expire in 2019. Purchase Commitment The Company entered into purchase commitments, which have the ability to be canceled without significant penalties, with multiple suppliers to purchase $60.6 million of photovoltaic modules and inverters by the end of 2019. Warranty Accrual The Company accrues warranty costs when revenue is recognized for solar energy systems sales, based on the estimated future costs of meeting its warranty obligations. Warranty costs primarily consist of replacement costs for supplies and labor costs for service personnel since warranties for equipment and materials are covered by the original manufacturer’s warranty (other than a small deductible in certain cases). As such, the warranty reserve is immaterial in all periods presented. The Company makes and revises these estimates based on the number of solar energy systems under warranty, the Company’s historical experience with warranty claims, assumptions on warranty claims to occur over a systems’ warranty period and the Company’s estimated replacement costs. ITC and Cash Grant Indemnification The Company is contractually committed to compensate certain investors for any losses that they may suffer in certain limited circumstances resulting from reductions in ITCs or U.S. Treasury grants. Generally, such obligations would arise as a result of reductions to the value of the underlying solar energy systems as assessed by the Internal Revenue Service (the “IRS”). At each balance sheet date, the Company assesses and recognizes, when applicable, the potential exposure from this obligation based on all the information available at that time, including any audits undertaken by the IRS. The Company believes that this obligation is not probable based on the facts known as of the filing date of this Quarterly Report on Form 10-Q. The maximum potential future payments that the Company could have to make under this obligation would depend largely on the difference between the prices at which the solar energy systems were sold or transferred to the Funds (or, in certain structures, the fair market value claimed in respect of such systems (referred to as "claimed values")) and the eligible basis determined by the IRS. The Company set the purchase prices and claimed values based on fair market values determined with the assistance of an independent third-party appraisal with respect to the systems that generate ITCs that are passed-through to and claimed by the Fund investors. Since the Company cannot determine how the IRS may evaluate system values used in claiming ITCs, the Company is unable to reliably estimate the maximum potential future payments that it could have to make under this obligation as of each balance sheet date, though any potential future payments are mitigated by the insurance policy described below. In April 2018, the Company purchased an insurance policy providing for certain payments by the insurers in the event there is any final determination (including a judicial determination) that reduced the ITCs claimed in respect of solar energy systems sold or transferred to most Funds through April 2018, or later, in the case of Funds added to the policy after such date. In general, the policy indemnifies the Company and related parties for additional taxes (including penalties and interest) owed in respect of lost ITCs, gross-up costs and expenses incurred in defending such claim, subject to negotiated exclusions from, and limitations to, coverage. Litigation The Company is subject to certain legal proceedings, claims, investigations and administrative proceedings in the ordinary course of its business. The Company records a provision for a liability when it is both probable that the liability has been incurred and the amount of the liability can be reasonably estimated. These provisions, if any, are reviewed at least quarterly and adjusted to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case. Depending on the nature and timing of any such proceedings that may arise, an unfavorable resolution of a matter could materially affect the Company’s future consolidated results of operations, cash flows or financial position in a particular period. On November 20, 2015, a putative class action captioned Slovin et al. v. Sunrun Inc. and Clean Energy Experts, LLC , Case No. 4:15-cv-05340, was filed in the United States District Court, Northern District of California. The complaint generally alleged violations of the Telephone Consumer Protection Act (the “TCPA”) on behalf of an individual and putative classes of persons alleged to be similarly situated. Plaintiffs filed a First Amended Complaint on December 2, 2015, and a Second Amended Complaint on March 25, 2016, also asserting individual and putative class claims under the TCPA. By Order entered on April 28, 2016, the Court granted the Company’s motion to strike the class allegations set forth in the Second Amended Complaint, and granted leave to amend. Plaintiffs filed a Third Amended Complaint on July 12, 2016 asserting individual and putative class claims under the TCPA. On October 12, 2016, the Court denied the Company’s motion to again strike the class allegations set forth in the Third Amended Complaint. On October 3, 2017, plaintiffs filed a motion for leave to file a Fourth Amended Complaint, seeking to, among other things, revise the definitions of the classes that plaintiffs seek to represent. In each iteration of their complaint, plaintiffs seek statutory damages, equitable and injunctive relief, and attorneys’ fees and costs, on behalf of themselves and the absent classes. On April 12, 2018, the Company and plaintiffs advised the Court that they reached a settlement in principle, and the Court vacated all deadlines relating to the motion for class certification. On September 27, 2018, Plaintiffs filed a motion for preliminary approval to settle all claims against the Company for $ 5.5 million , which was accrued as of March 31, 2018. On November 27, 2018, a hearing was held on Plaintiff's motion for preliminary approval. The Court requested certain clarifications be made to the proposed settlement agreement and notice documents. On January 11, 2019, Plaintiffs filed revised settlement documents reflecting the changes requested by the Court, and on January 29, 2019, the Court granted preliminary approval of the settlement. Most, if not all, of the claims asserted in the lawsuit relate to activities allegedly engaged in by third-party vendors, for which the Company denies any responsibility. The vendors are contractually obligated to indemnify the Company for losses related to the conduct alleged. The Company has denied, and continues to deny, the claims alleged and the settlement does not reflect any admission of fault, wrongdoing or liability. The settlement is subject to definitive documentation, class notice and court approval. On May 3, 2017, a purported shareholder class action captioned Fink, et al. v. Sunrun Inc., et al. , Case No. 3:17-cv-02537, was filed in the United States District Court, Northern District of California, against the Company and certain of the Company’s directors and officers. The complaint generally alleges that the defendants violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act") and SEC Rule 10b-5, by making false or misleading statements in connection with public filings made between September 15, 2015 and March 8, 2017 regarding the number of customers who canceled contracts after signing up for the Company’s home-solar energy system. The plaintiff seeks compensatory damages, including interest, attorney's fees, and costs, on behalf of all persons other than the defendants who purchased the Company's securities between September 16, 2015 and May 2, 2017. On May 4, 2017, a purported shareholder class action captioned Hall, et al. v. Sunrun Inc., et al. , Case No. 3:17-cv-02571, was filed in the United States District Court, Northern District of California. On May 18, 2017, a purported shareholder class action captioned Sanogo, et al. v. Sunrun Inc., et al. , Case No. 3:17-cv-02865, was filed in the United States District Court, Northern California District of California. The Hall and Sanogo complaints are substantially similar to the Fink complaint, and seek similar relief against similar defendants on behalf of a substantially similar class. On August 23, 2017, the Fink , Hall , and Sanogo actions were consolidated, and on September 25, 2017, plaintiffs filed a consolidated amended complaint which alleges the same underlying violations as the original Fink , Hall and Sanogo complaints (such consolidated action referred to as the "federal court litigation"). On April 5, 2018, the court granted the Company’s motion to dismiss without prejudice. Plaintiffs filed a second amended complaint on May 3, 2018. On July 19, 2018, the court again granted defendants' motion to dismiss without prejudice. On August 8, 2018, the Company reached an agreement in principle with plaintiffs to settle all claims asserted in the federal court litigation against all defendants for $2.5 million , all of which will be funded by the Company's insurers. The Company and all defendants have denied, and continue to deny, the claims alleged in the federal court litigation and the settlement does not reflect any admission of fault, wrongdoing or liability as to any defendant. On November 20, 2018, the Court granted preliminary approval of the settlement. On March 4, 2019, the court granted final approval of the settlement and judgment. On June 29, 2017, a shareholder derivative complaint captioned Barbara Sue Sklar Living Trust v. Sunrun Inc. et al. , was filed in the United States District Court, Northern District of California, against the Company and certain of the Company’s directors and officers. The complaint generally alleges that the defendants violated Section 14(a) of the Exchange Act by making false or misleading statements in connection with public filings, including proxy statements, made between September 10, 2015 and May 3, 2017 regarding the number of customers who cancelled contracts after signing up for the Company’s home solar energy system. The Plaintiff seeks, among other things, damages in favor of the Company, certain corporate actions to purportedly improve the Company’s corporate governance, and an award of costs and expenses to the putative plaintiff stockholder, including attorneys’ fees. On April 5, 2018, a stockholder derivative complaint captioned Leonard Olsen v. Sunrun Inc. et al. , was filed in the United States District Court, District of Delaware, against the Company and certain of the Company’s directors and officers. The Olsen complaint is substantially similar to the Sklar complaint, alleges that the defendants breached their fiduciary duties and violated Section 14(a) of the Exchange Act in connection with public statements made between September 16, 2015 and May 21, 2017, and seeks similar relief. On January 28, 2019, the Company reached an agreement in principle to settle all claims asserted in the Sklar and Olsen derivative actions against all defendants. Under the terms of the proposed settlement, the Company agreed to adopt certain corporate governance measures in the future. The Company and all defendants have denied, and continue to deny, the claims alleged in the derivative actions and the settlement does not reflect any admission of fault, wrongdoing or liability as to any defendant. The settlement is subject to definitive documentation and court approval.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The computation of the Company’s basic and diluted net (loss) income per share is as follows (in thousands, except per share amounts): Three Months Ended March 31, 2019 2018 Numerator: Net (loss) income attributable to common stockholders $ (13,862 ) $ 28,032 Denominator: Weighted average shares used to compute net (loss) income per share attributable to common stockholders, basic 113,912 107,449 Weighted average effect of potentially dilutive shares to purchase common stock — 3,332 Weighted average shares used to compute net (loss) income per share attributable to common stockholders, diluted 113,912 110,781 Net (loss) income per share attributable to common stockholders Basic $ (0.12 ) $ 0.26 Diluted $ (0.12 ) $ 0.25 The following shares were excluded from the computation of diluted net (loss) income per share as the impact of including those shares would be anti-dilutive (in thousands): Three Months Ended March 31, 2019 2018 Warrants — 1,251 Outstanding stock options 1,313 9,917 Unvested restricted stock units 1,480 1,779 Total 2,793 12,947

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the "SEC") 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 for the year ended December 31, 2018 . The results of the three months ended March 31, 2019 are not necessarily indicative of the results to be expected for the fiscal year ending December 31, 2019 or other future periods. The consolidated financial statements reflect the accounts and operations of the Company and those of its subsidiaries, including Funds, in which the Company has a controlling financial interest. The typical condition for a controlling financial interest ownership is holding a majority of the voting interests of an entity. However, a controlling financial interest may also exist in entities, such as variable interest entities (“VIEs”), through arrangements that do not involve controlling voting interests. In accordance with the provisions of Financial Accounting Standards Board (“FASB”), Accounting Standards Codification Topic 810 (“Topic 810”) Consolidation , the Company consolidates any VIE of which it is the primary beneficiary. The primary beneficiary, as defined in Topic 810, is the party that has (1) the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb the losses of the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether it continues to be the primary beneficiary. The consolidated financial statements reflect the assets and liabilities of VIEs that are consolidated. All intercompany transactions and balances have been eliminated in consolidation.
Reclassifications	Reclassifications Certain prior period amounts have been reclassified to conform to current period presentation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company regularly makes estimates and assumptions, including, but not limited to, revenue recognition constraints that result in variable consideration, the discount rate used to adjust the promised amount of consideration for the effects of a significant financing component, the estimates that affect the collectability of accounts receivable, the valuation of inventories, the useful lives of solar energy systems, the useful lives of property and equipment, the valuation and useful lives of intangible assets, the effective interest rate used to amortize pass-through financing obligations, the discount rate uses for operating and financing leases, the valuation of stock-based compensation, the determination of valuation allowances associated with deferred tax assets, the fair value of debt instruments disclosed and the redemption value of redeemable noncontrolling interests. The Company bases its estimates on historical experience and on various other assumptions believed to be reasonable. Actual results may differ from such estimates.
Segment Information	Segment Information The Company has one operating segment with one business activity, providing solar energy services and products to customers. The Company’s chief operating decision maker (“CODM”) is its Chief Executive Officer, who manages operations on a consolidated basis for purposes of allocating resources. When evaluating performance and allocating resources, the CODM reviews financial information presented on a consolidated basis. Revenue from external customers for each group of similar products and services is as follows (in thousands): Three Months Ended March 31, 2019 2018 Customer agreements $ 78,528 $ 61,649 Incentives 21,322 5,341 Customer agreements and incentives 99,850 66,990 Solar energy systems 58,436 33,998 Products 36,218 43,375 Solar energy systems and product sales 94,654 77,373 Total revenue $ 194,504 $ 144,363 Revenue from Customer Agreements includes payments by customers for the use of the solar system as well as utility and other rebates assigned by the customer to the Company in the Customer Agreement. Revenue from incentives includes revenue from the sale of investment tax credits ("ITCs") and renewable energy credits (“SRECs”).
Cash and Restricted Cash	Cash and Restricted Cash Restricted cash represents amounts related to replacement of solar energy system components and obligations under certain financing transactions. The following table provides a reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statement of cash flows. Cash and restricted cash consists of the following (in thousands): March 31, 2019 December 31, 2018 Cash $ 245,604 $ 226,625 Restricted cash, current and long-term 64,330 77,774 Total $ 309,934 $ 304,399
Accounts Receivable	Accounts Receivable Accounts receivable consist of amounts due from customers, as well as state and utility rebates due from government agencies and utility companies. Under Customer Agreements, the customers typically assign incentive rebates to the Company. The opening balance of Accounts receivable, net was $66.4 million as of December 31, 2017. Accounts receivable, net consists of the following (in thousands): March 31, 2019 December 31, 2018 Customer receivables $ 64,598 $ 64,180 Other receivables 2,179 1,466 Rebates receivable 3,027 3,017 Allowance for doubtful accounts (2,282 ) (2,228 ) Total $ 67,522 $ 66,435
Deferred Revenue	Deferred Revenue When the Company receives consideration, or when such consideration is unconditionally due, from a customer prior to delivering goods or services to the customer under the terms of a Customer Agreement, the Company records deferred revenue. Such deferred revenue consists of amounts for which the criteria for revenue recognition have not yet been met and includes amounts that are collected or assigned from customers, including upfront deposits and prepayments, and rebates. Deferred revenue relating to financing components represents the cumulative excess of interest expense recorded on financing component elements over the related revenue recognized to date and will eventually net to zero by the end of the initial term. Amounts received related to the sales of SRECs which have not yet been delivered to the counterparty are recorded as deferred revenue.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company defines fair value as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company uses valuation approaches to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. The FASB establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: • Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; • Level 2—Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and • Level 3—Inputs that are unobservable, significant to the measurement of the fair value of the assets or liabilities and are supported by little or no market data.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when control of goods or services is transferred to its customers, in an amount that reflects the consideration it expected to be entitled to in exchange for those goods or services. Customer agreements and incentives Customer agreements and incentives revenue is primarily comprised of revenue from Customer Agreements in which the Company provides continuous access to a functioning solar system and revenue from the sales of ITCs and SRECs generated by the Company’s solar energy systems to third parties. The Company begins to recognize revenue on Customer Agreements when permission to operate ("PTO") is given by the local utility company or on the date daily operation commences if utility approval is not required. Revenue recognition does not necessarily follow the receipt of cash. The Company recognizes revenue evenly over the time that it satisfies its performance obligations over the initial term of the Customer Agreements. Customer Agreements typically have an initial term of 20 or 25 years. After the initial contract term, the Company's Customer Agreements typically automatically renew on an annual basis and the rate is initially set at up to a 10% discount to then-prevailing power prices. SREC revenue arises from the sale of environmental credits generated by solar energy systems and is generally recognized upon delivery of the SRECs to the counterparty. For pass-through financing obligation Funds, the value attributable to the monetization of ITCs is recognized in the period a solar system is granted PTO - see Note 10 , Pass-through Financing Obligations . In determining the transaction price, the Company adjusts the promised amount of consideration for the effects of the time value of money when the timing of payments provides it with a significant benefit of financing the transfer of goods or services to the customer. In those circumstances, the contract contains a significant financing component. When adjusting the promised amount of consideration for a significant financing component, the Company uses the discount rate that would be reflected in a separate financing transaction between the entity and its customer at contract inception and recognizes the revenue amount on a straight-line basis over the term of the Customer Agreement, and interest expense using the effective interest rate method. Consideration from customers is considered variable due to the performance guarantee under Customer Agreements and liquidated damage provisions under SREC contracts in the event minimum deliveries are not achieved. Performance guarantees provide a credit to the customer if the system's cumulative production, as measured on various PTO anniversary dates, is below the Company's guarantee of a specified minimum. Revenue is recognized to the extent it is probable that a significant reversal of such revenue will not occur. The Company capitalizes incremental costs incurred to obtain a contract in Other Assets in the consolidated balance sheets. These amounts are amortized on a straight-line basis over the term of the Customer Agreements, and are included in Sales and marketing in the consolidated statements of operations. Solar energy systems and product sales For solar energy systems sold to customers, the Company recognizes revenue when the solar energy system passes inspection by the authority having jurisdiction. The Company’s installation projects are typically completed in less than 12 months. Product sales consist of solar panels, racking systems, inverters, other solar energy products sold to resellers and customer leads. Product sales revenue is recognized upon shipment, which is at the time control is transferred. Customer lead revenue is recognized at the time the lead is delivered. Taxes assessed by government authorities that are directly imposed on revenue producing transactions are excluded from solar energy systems and product sales. Cost of Revenue Customer agreements and incentives Cost of revenue for customer agreements and incentives is primarily comprised of (1) the depreciation of the cost of the solar energy systems, as reduced by amortization of deferred grants, (2) solar energy system operations, monitoring and maintenance costs including associated personnel costs, and (3) allocated corporate overhead costs. Solar energy systems and product sales Cost of revenue for solar energy systems and non-lead generation product sales consist of direct and indirect material and labor costs for solar energy systems installations and product sales. Also included are engineering and design costs, estimated warranty costs, freight costs, allocated corporate overhead costs, vehicle depreciation costs and personnel costs associated with supply chain, logistics, operations management, safety and quality control. Cost of revenue for lead generations consists of costs related to direct-response advertising activities associated with generating customer leads.
Recently Issued and Adopted Accounting Standards	Recently Issued and Adopted Accounting Standards Accounting standards adopted January 1, 2019: In February 2018, the FASB issued Accounting Standards Update ("ASU") No. 2018-02, Income Statement -- Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , which allows companies to reclassify stranded tax effects resulting from the Tax Cuts and Jobs Act from accumulated other comprehensive income to retained earnings. The Company adopted ASU No. 2018-02 effective January 1, 2019, resulting in a current period adjustment of $0.7 million for the reclassification, as reflected in its consolidated statement of redeemable noncontrolling interests and stockholders' equity. The Company uses the aggregate portfolio approach when reclassing stranded tax effects from accumulated other comprehensive income. In June 2018, the FASB issued ASU No. 2018-07, Compensation -- Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting , which aligns the accounting for share-based payment awards issued to employees and nonemployees; however, this amendment does not apply to instruments issued in a financing transaction nor to equity instruments granted to a customer under a contract in the scope of Topic 606. Under this new amendment, equity-classified nonemployee share-based payments are measured at the grant-date fair value and recognized based on the probable outcome of the performance conditions. The Company adopted ASU No. 2018-07 effective January 1, 2019, and there was no material impact to its consolidated financial statements. In July 2018, the FASB issued ASU No. 2018-09, Codification Improvements . This amendment makes changes to a variety of topics to clarify, correct errors in, or make minor improvements to the Accounting Standards Codification. The Company adopted ASU No. 2018-09 effective January 1, 2019, and there was no material impact to its consolidated financial statements. In August 2018, the SEC adopted a Disclosure Update and Simplification release, which outlines Regulation S-X amendments to eliminate outdated or duplicative disclosure requirements. The final rule also amends the interim financial statement requirements to require a reconciliation of changes in stockholders’ equity in the notes or as a separate statement. These amendments are effective for all filings made 30 days after the amendments are published in the Federal Register, which was on October 4, 2018. The SEC announced that it would not object if the first presentation of the changes in stockholders’ equity for a calendar year end filer were made in the Company’s March 31, 2019 Form 10-Q. Effective with this interim report on Form 10-Q, the Company is now presenting consolidated statements of redeemable noncontrolling interests and stockholders' equity. Accounting standards to be adopted: In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments , which replaces the current incurred loss impairment methodology with a current expected credit losses model. The amendment applies to entities which hold financial assets and net investment in leases that are not accounted for at fair value through net income as well as loans, debt securities, trade receivables, net investments in leases, off-balance sheet credit exposures, reinsurance receivables and any other financial assets not excluded from the scope that have the contractual right to receive cash. This ASU is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted. Adoption of this ASU is applied using a modified retrospective approach, with certain aspects requiring a prospective approach. The Company is currently evaluating this guidance and the impact it may have on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework--Changes to the Disclosure Requirements for Fair Value Measurement , which modifies the disclosure requirements on fair value measurements as part of its disclosure framework project. Under this amendment, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. However, for Level 3 fair value measurements, disclosures around the range and weighted average used to develop significant unobservable inputs will be required. This ASU is effective for fiscal periods beginning after December 15, 2019. The Company is currently evaluating this guidance and the impact it may have on the Company's consolidated financial statements and disclosures. In August 2018, the FASB issued ASU No. 2018-15, Intangibles--Goodwill and Other--Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract , which requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance in Topic 350, Intangibles--Goodwill and Other , to determine which implementation costs to capitalize as assets or expense as incurred. This ASU is effective for annual reporting periods, and interim periods within those years, beginning after December 15, 2019, and can be applied either prospectively to implementation costs incurred after the date of adoption or retrospectively to all arrangements. The Company is currently evaluating this guidance and the impact it may have on the Company's consolidated financial statements. In October 2018, the FASB issued ASU No. 2018-17, Consolidation (Topic 810) , Targeted Improvements to Related Party Guidance for Variable Interest Entities, which aligns the evaluation of decision-making fees under the variable interest entity guidance. Under this new guidance, in order to determine whether decision-making fees represent a variable interest, an entity considers indirect interests held through related parties under common control on a proportionate basis. This ASU is effective for annual reporting periods, and interim periods within those years, beginning after December 15, 2019, and must be applied retrospectively with a cumulative-effect adjustment to retained earnings at the beginning of the earliest period presented. The Company is currently evaluating this guidance and the impact it may have on the Company's consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Schedule of revenue from external customers	Revenue from external customers for each group of similar products and services is as follows (in thousands): Three Months Ended March 31, 2019 2018 Customer agreements $ 78,528 $ 61,649 Incentives 21,322 5,341 Customer agreements and incentives 99,850 66,990 Solar energy systems 58,436 33,998 Products 36,218 43,375 Solar energy systems and product sales 94,654 77,373 Total revenue $ 194,504 $ 144,363
Cash and restricted cash	Cash and restricted cash consists of the following (in thousands): March 31, 2019 December 31, 2018 Cash $ 245,604 $ 226,625 Restricted cash, current and long-term 64,330 77,774 Total $ 309,934 $ 304,399
Cash and restricted cash	Cash and restricted cash consists of the following (in thousands): March 31, 2019 December 31, 2018 Cash $ 245,604 $ 226,625 Restricted cash, current and long-term 64,330 77,774 Total $ 309,934 $ 304,399
Accounts receivable, net	Accounts receivable, net consists of the following (in thousands): March 31, 2019 December 31, 2018 Customer receivables $ 64,598 $ 64,180 Other receivables 2,179 1,466 Rebates receivable 3,027 3,017 Allowance for doubtful accounts (2,282 ) (2,228 ) Total $ 67,522 $ 66,435
Deferred revenue	The opening balance of deferred revenue was $564.9 million as of December 31, 2017 . Deferred revenue consists of the following (in thousands): March 31, 2019 December 31, 2018 Under Customer Agreements: Payments received $ 543,945 $ 538,926 Financing component balance 39,577 37,801 583,522 576,727 Under SREC contracts: Payments received 108,002 12,977 Financing component balance 1,937 1,921 109,939 14,898 Total $ 693,461 $ 591,625

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of carrying values and fair values of debt instruments	The carrying values and fair values of debt instruments are as follows (in thousands): March 31, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value Bank line of credit $ 239,035 $ 239,035 $ 247,000 $ 247,000 Senior debt 913,787 913,710 828,517 828,309 Subordinated debt 278,910 284,887 273,337 272,937 Securitization debt 392,490 406,818 400,068 394,756 Total $ 1,824,222 $ 1,844,450 $ 1,748,922 $ 1,743,002
Schedule of fair value, financial instruments measured on recurring basis	At March 31, 2019 and December 31, 2018 , financial instruments measured at fair value on a recurring basis, based upon the fair value hierarchy, are as follows (in thousands): March 31, 2019 Level 1 Level 2 Level 3 Total Derivative assets: Interest rate swaps $ — $ 590 $ — $ 590 Total $ — $ 590 $ — $ 590 Derivative liabilities: Interest rate swaps $ — $ 28,314 $ — $ 28,314 Total $ — $ 28,314 $ — $ 28,314 December 31, 2018 Level 1 Level 2 Level 3 Total Derivative assets: Interest rate swaps $ — $ 6,958 $ — $ 6,958 Total $ — $ 6,958 $ — $ 6,958 Derivative liabilities: Interest rate swaps $ — $ 11,910 $ — $ 11,910 Total $ — $ 11,910 $ — $ 11,910

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Schedule of inventories	Inventories consist of the following (in thousands): March 31, 2019 December 31, 2018 Raw materials $ 65,598 $ 64,256 Work-in-process 10,586 15,211 Total $ 76,184 $ 79,467

Solar Energy Systems, net (Tabl

Solar Energy Systems, net (Tables)	3 Months Ended
	Mar. 31, 2019
Solar Energy Systems Disclosure [Abstract]
Solar energy systems, net	Solar energy systems, net consists of the following (in thousands): March 31, 2019 December 31, 2018 Solar energy system equipment costs $ 4,012,116 $ 3,823,853 Inverters 416,088 396,054 Total solar energy systems 4,428,204 4,219,907 Accumulated depreciation and amortization (575,094 ) (535,891 ) Construction-in-progress 123,394 136,001 Total solar energy systems, net $ 3,976,504 $ 3,820,017

Other Assets Other Assets (Tabl

Other Assets Other Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of other assets	Other assets consist of the following (in thousands): March 31, 2019 December 31, 2018 Costs to obtain contracts- customer agreements $ 232,567 $ 219,307 Costs to obtain contracts- incentives 2,481 — Accumulated amortization of costs to obtain contracts (27,641 ) (24,992 ) Unbilled receivables 90,578 81,703 Operating lease right-of-use assets 38,051 20,257 Other assets 31,915 39,410 Total $ 367,951 $ 335,685

Accrued Expenses and Other Li_2

Accrued Expenses and Other Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Payables and Accruals [Abstract]
Accrued expenses and other liabilities	Accrued expenses and other liabilities consist of the following (in thousands): March 31, 2019 December 31, 2018 Accrued employee compensation $ 35,393 $ 39,738 Operating lease obligations 9,462 7,857 Accrued interest 12,942 8,436 Accrued professional fees 12,185 9,199 Other accrued expenses 33,782 33,406 Total $ 103,764 $ 98,636

Indebtedness (Tables)

Indebtedness (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of debt	As of March 31, 2019 , debt consisted of the following (in thousands, except percentages): Carrying Values, net of debt discount Unused Borrowing Capacity Interest Rate (1) Maturity Date Current Long Term Total Recourse debt: Bank line of credit $ — $ 239,035 $ 239,035 $ — 5.59% - 5.90% April 2020 Total recourse debt — 239,035 239,035 — Non-recourse debt: Senior 12,679 901,108 913,787 — 4.50% - 5.49% September 2020 - October 2024 Subordinated 5,715 273,195 278,910 — 7.03% - 10.00% September 2020 - January 2030 Securitization Class A 8,072 374,875 382,947 — 4.40% - 5.31% July 2024 - April 2049 Securitization Class B 471 9,072 9,543 — 5.38 % July 2024 Total non-recourse debt 26,937 1,558,250 1,585,187 — Total debt $ 26,937 $ 1,797,285 $ 1,824,222 $ — (1) Reflects contractual, unhedged rates. See Note 9 , Derivatives for hedge rates. As of December 31, 2018 , debt consisted of the following (in thousands, except percentages): Carrying Values, net of debt discount Unused Borrowing Capacity Interest Rate (1) Maturity Date Current Long Term Total Recourse debt: Bank line of credit $ — $ 247,000 $ 247,000 $ 406 5.45% - 5.77% April 2020 Total recourse debt — 247,000 247,000 406 Non-recourse debt: Senior 19,070 809,447 828,517 — 4.50% - 5.54% September 2020 - October 2024 Subordinated 5,824 267,513 273,337 — 7.03% - 10.00% September 2020 - January 2030 Securitization Class A 10,125 380,299 390,424 — 4.40% - 5.31% July 2024 - April 2049 Securitization Class B 465 9,179 9,644 — 5.38 % July 2024 Total non-recourse debt 35,484 1,466,438 1,501,922 — Total debt $ 35,484 $ 1,713,438 $ 1,748,922 $ 406 (1) Reflects contractual, unhedged rates. See Note 9 , Derivatives for hedge rates.

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of unrealized gain or loss recognized in Accumulated other comprehensive income (loss)	The following table summarizes the post-tax amount of unrealized gain or loss recognized in Accumulated other comprehensive income (loss) ("OCI") in the consolidated statements of redeemable noncontrolling interests and stockholders' equity (in thousands): Three Months Ended March 31, 2019 2018 Derivatives designated as cash flow hedges: Loss in OCI at the beginning of the period $ (3,124 ) $ (4,113 ) Unrealized (loss) gain recognized in OCI (17,013 ) 16,171 Amount reclassified from OCI to earnings (989 ) (1,233 ) Net (loss) gain on derivatives (net of tax effect of $6,093 and $5,134) (18,002 ) 14,938 Cumulative effect of adoption of new ASU (No. 2018-02) (740 ) — (Loss) gain in OCI at the end of the period (21,866 ) 10,825
Offsetting assets	As of March 31, 2019 the information related to these offsetting arrangements were as follows (in thousands): Instrument Description Gross Amounts of Recognized Assets / Liabilities Gross Amounts Offset in the Consolidated Balance Sheet Net Amounts of Assets / Liabilities Included in the Consolidated Balance Sheet Assets: Derivatives $ 590 $ (276 ) $ 314 Liabilities: Derivatives (28,314 ) 276 (28,038 ) Total $ (27,724 ) $ — $ (27,724 )
Offsetting liabilities	As of March 31, 2019 the information related to these offsetting arrangements were as follows (in thousands): Instrument Description Gross Amounts of Recognized Assets / Liabilities Gross Amounts Offset in the Consolidated Balance Sheet Net Amounts of Assets / Liabilities Included in the Consolidated Balance Sheet Assets: Derivatives $ 590 $ (276 ) $ 314 Liabilities: Derivatives (28,314 ) 276 (28,038 ) Total $ (27,724 ) $ — $ (27,724 )
Summary of derivative instruments classified as derivative assets	At March 31, 2019 , the Company had the following derivative instruments (dollars in thousands): Type Quantity Effective Dates Maturity Dates Hedge Interest Rates Notional Amount Adjusted Net Fair Market Value Interest rate swap 1 5/21/2018 9/20/2020 2.69% $ 80,500 $ (437 ) Interest rate swap 1 4/29/2016 8/31/2022 1.27%- 1.29% 13,179 314 Interest rate swaps 8 7/31/2017 - 1/31/2018 4/30/2024 - 10/20/2024 2.16%- 2.39% 283,160 (384 ) Interest rate swaps 3 4/30/2021 10/30/2026 - 10/31/2026 2.89% - 3.08% 102,720 (3,631 ) Interest rate swap 1 10/22/2018 9/20/2027 2.97% 30,023 (1,011 ) Interest rate swaps 2 4/22/2019 - 9/20/2020 3/20/2030 - 6/20/2030 2.22% - 2.57% 160,401 (1,177 ) Interest rate swap 1 9/20/2020 1/20/2031 2.61% 9,899 (332 ) Interest rate swaps 3 1/31/2020 4/30/2034 2.78% 200,000 (6,545 ) Interest rate swaps 5 7/31/2017 - 4/30/2024 7/31/2035 2.56% - 2.95% 151,610 (2,197 ) Interest rate swaps 5 1/31/2018 - 10/18/2024 10/31/2036 2.62% - 2.95% 183,398 (2,710 ) Interest rate swaps 3 1/31/2019 - 4/30/2021 4/30/2037 3.28% - 3.30% 100,000 (7,099 ) Interest rate swaps 3 10/30/2026 - 10/31/2026 1/31/2038 3.01% - 3.16% 101,135 (2,515 ) Total $ 1,416,025 $ (27,724 )

VIE Arrangements (Tables)

VIE Arrangements (Tables)	3 Months Ended
	Mar. 31, 2019
Variable Interest Entity Disclosure [Abstract]
Carrying amounts and classification of the VIEs' assets and liabilities included in the consolidated balance sheets	The carrying amounts and classification of the VIEs’ assets and liabilities included in the consolidated balance sheets are as follows (in thousands): March 31, 2019 December 31, 2018 Assets Current assets Cash $ 135,548 $ 105,494 Restricted cash 969 2,071 Accounts receivable, net 16,988 18,539 Prepaid expenses and other current assets 386 387 Total current assets 153,891 126,491 Solar energy systems, net 2,761,312 2,712,377 Other assets 66,707 66,427 Total assets $ 2,981,910 $ 2,905,295 Liabilities Current liabilities Accounts payable $ 10,979 $ 12,136 Distributions payable to noncontrolling interests and redeemable noncontrolling interests 15,545 15,797 Accrued expenses and other liabilities 7,315 7,122 Deferred revenue, current portion 33,504 29,102 Deferred grants, current portion 982 982 Non-recourse debt, current portion 4,336 4,217 Total current liabilities 72,661 69,356 Deferred revenue, net of current portion 405,261 367,818 Deferred grants, net of current portion 27,982 28,247 Non-recourse debt, net of current portion 184,958 186,494 Other liabilities 10,733 8,843 Total liabilities $ 701,595 $ 660,758

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of stock option activity	The following table summarizes the activity for all stock options under all of the Company’s equity incentive plans for the three months ended March 31, 2019 (shares and aggregate intrinsic value in thousands): Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2018 13,590 $ 6.07 6.63 $ 66,462 Granted 1,064 14.57 Exercised (1,139 ) 3.86 Cancelled (17 ) 10.30 Outstanding at March 31, 2019 13,498 $ 6.92 6.71 $ 97,127 Options vested and exercisable at March 31, 2019 8,154 $ 6.21 5.67 $ 64,261
Summary of activity for all restricted stock units (RSUs)	The following table summarizes the activity for all restricted stock units (“RSUs”) under all of the Company’s equity incentive plans for the three months ended March 31, 2019 (shares in thousands): Number of Awards Weighted Average Grant Date Fair Value Unvested balance at December 31, 2018 4,182 $ 7.05 Granted 1,524 14.42 Issued (451 ) 6.75 Cancelled / forfeited (295 ) 7.20 Unvested balance at March 31, 2019 4,960 $ 9.33
Summary of stock-based compensation expense	The Company recognized stock-based compensation expense, including ESPP expenses, in the consolidated statements of operations as follows (in thousands): Three Months Ended March 31, 2019 2018 Cost of customer agreements and incentives $ 632 $ 611 Cost of solar energy systems and product sales 167 170 Sales and marketing 1,128 4,150 Research and development 336 295 General and administration 3,520 5,468 Total $ 5,783 $ 10,694

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Lease expense and other information related to leases	The components of lease expense were as follows (in thousands): Three Months Ended March 31, 2019 2018 Finance lease cost: Amortization of right-of-use assets $ 3,484 $ 2,634 Interest on lease liabilities 239 119 Operating lease cost 2,879 2,629 Short-term lease cost 524 201 Variable lease cost 877 777 Sublease income (156 ) (106 ) Total lease cost $ 7,847 $ 6,254 Other information related to leases was as follows (in thousands): Three Months Ended March 31, 2019 2018 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 2,567 $ 2,600 Operating cash flows from finance leases 201 109 Financing cash flows from finance leases 3,060 2,159 Right-of-use assets obtained in exchange for lease obligations: Operating leases 20,395 1,117 Finance leases 3,566 99 Weighted average remaining lease term (years): Operating leases 5.55 3.89 Finance leases 2.90 1.87 Weighted average discount rate: Operating leases 5.2 % 4.1 % Finance leases 4.3 % 3.1 %
Future minimum lease payments under non-cancellable leases	Future minimum lease payments under non-cancellable leases as of March 31, 2019 were as follows (in thousands): Operating Leases Sublease Income Net Operating Leases Finance Leases 2019 $ 11,952 $ 777 $ 11,175 $ 10,060 2020 11,878 791 11,087 5,453 2021 10,538 439 10,099 3,587 2022 9,101 — 9,101 1,568 2023 8,189 — 8,189 60 Thereafter 10,677 — 10,677 49 Total future lease payments 62,335 2,007 60,328 20,777 Less: Amount representing interest 6,200 — 6,200 1,072 Present value of future payments 56,135 2,007 54,128 19,705 Less: Short term leases not recorded as a liability 11,761 — 11,761 — Less: Tenant incentives 3,186 — 3,186 — Revised Present value of future payments 41,188 2,007 39,181 19,705 Less: Current portion 9,462 — 9,462 9,459 Long-term portion $ 31,726 $ 2,007 $ 29,719 $ 10,246
Future minimum lease payments under non-cancellable leases	Future minimum lease payments under non-cancellable leases as of March 31, 2019 were as follows (in thousands): Operating Leases Sublease Income Net Operating Leases Finance Leases 2019 $ 11,952 $ 777 $ 11,175 $ 10,060 2020 11,878 791 11,087 5,453 2021 10,538 439 10,099 3,587 2022 9,101 — 9,101 1,568 2023 8,189 — 8,189 60 Thereafter 10,677 — 10,677 49 Total future lease payments 62,335 2,007 60,328 20,777 Less: Amount representing interest 6,200 — 6,200 1,072 Present value of future payments 56,135 2,007 54,128 19,705 Less: Short term leases not recorded as a liability 11,761 — 11,761 — Less: Tenant incentives 3,186 — 3,186 — Revised Present value of future payments 41,188 2,007 39,181 19,705 Less: Current portion 9,462 — 9,462 9,459 Long-term portion $ 31,726 $ 2,007 $ 29,719 $ 10,246

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Computation of basic and diluted net income (loss) per share	The computation of the Company’s basic and diluted net (loss) income per share is as follows (in thousands, except per share amounts): Three Months Ended March 31, 2019 2018 Numerator: Net (loss) income attributable to common stockholders $ (13,862 ) $ 28,032 Denominator: Weighted average shares used to compute net (loss) income per share attributable to common stockholders, basic 113,912 107,449 Weighted average effect of potentially dilutive shares to purchase common stock — 3,332 Weighted average shares used to compute net (loss) income per share attributable to common stockholders, diluted 113,912 110,781 Net (loss) income per share attributable to common stockholders Basic $ (0.12 ) $ 0.26 Diluted $ (0.12 ) $ 0.25
Schedule of shares excluded from computation of diluted net income per share	The following shares were excluded from the computation of diluted net (loss) income per share as the impact of including those shares would be anti-dilutive (in thousands): Three Months Ended March 31, 2019 2018 Warrants — 1,251 Outstanding stock options 1,313 9,917 Unvested restricted stock units 1,480 1,779 Total 2,793 12,947

Organization - Additional Infor

Organization - Additional Information (Details)	3 Months Ended
	Mar. 31, 2019InvestmentFund
Operating Leased Assets [Line Items]
Power purchase or lease agreement term	22 years
Number of types of investment funds used by the company	3
Minimum
Operating Leased Assets [Line Items]
Power purchase or lease agreement term	20 years
Maximum
Operating Leased Assets [Line Items]
Power purchase or lease agreement term	25 years

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2019BusinessActivitySegment
Summary Of Significant Accounting Policies [Line Items]
Number of operating segments | Segment	1
Number of business activities | BusinessActivity	1
Customer Agreements, initial set up, discount percent	10.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Revenues from External Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue, Major Customer [Line Items]
Total Revenue	$ 194,504	$ 144,363
Customer agreements and incentives
Revenue, Major Customer [Line Items]
Customer agreements and incentives	99,850	66,990
Customer agreements
Revenue, Major Customer [Line Items]
Customer agreements and incentives	78,528	61,649
Incentives
Revenue, Major Customer [Line Items]
Customer agreements and incentives	21,322	5,341
Solar energy systems and product sales
Revenue, Major Customer [Line Items]
Total Revenue	94,654	77,373
Solar energy systems
Revenue, Major Customer [Line Items]
Total Revenue	58,436	33,998
Products
Revenue, Major Customer [Line Items]
Total Revenue	$ 36,218	$ 43,375

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash	$ 245,604	$ 226,625
Restricted cash, current and long-term	64,330	77,774
Total Cash and Restricted Cash	$ 309,934	$ 304,399	$ 243,328	$ 241,790

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Customer receivables	$ 64,598	$ 64,180
Other receivables	2,179	1,466
Rebates receivable	3,027	3,017
Allowance for doubtful accounts	(2,282)	(2,228)
Accounts receivable, net	$ 67,522	$ 66,435	$ 66,400

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 693,461		$ 591,625	$ 564,900
Deferred revenue, revenue recognized	14,000	$ 12,800
Contracted but not yet recognized	$ 5,600,000
Revenue expected to recognize over next twelve months, percent	6.00%
Revenue recognized, term, existing deferred revenue	10 years
Customer agreement, initial term	22 years
Deferred revenue, increase (decrease)	$ 101,848	$ 7,456
Under Customer Agreements
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 583,522		576,727
Under Customer Agreements | Solar energy systems
Deferred Revenue Arrangement [Line Items]
Average age	4 years
Under Customer Agreements | Payments received
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 543,945		538,926
Under Customer Agreements | Financing component balance
Deferred Revenue Arrangement [Line Items]
Deferred revenue	39,577		$ 37,801
Under SREC contracts
Deferred Revenue Arrangement [Line Items]
Deferred revenue, increase (decrease)	$ 95,500
Minimum
Deferred Revenue Arrangement [Line Items]
Customer agreement, initial term	20 years
Minimum | Under SREC contracts
Deferred Revenue Arrangement [Line Items]
Customer agreement, initial term	10 years
Maximum
Deferred Revenue Arrangement [Line Items]
Customer agreement, initial term	25 years
Maximum | Under SREC contracts
Deferred Revenue Arrangement [Line Items]
Customer agreement, initial term	15 years

Fair Value Measurement - Schedu

Fair Value Measurement - Schedule of Carrying Values and Fair Values of Debt Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 1,824,222	$ 1,748,922
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	1,844,450	1,743,002
Bank line of credit | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	239,035	247,000
Bank line of credit | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	239,035	247,000
Senior debt | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	913,787	828,517
Senior debt | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	913,710	828,309
Subordinated debt | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	278,910	273,337
Subordinated debt | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	284,887	272,937
Securitization debt | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	392,490	400,068
Securitization debt | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 406,818	$ 394,756

Fair Value Measurement - Sche_2

Fair Value Measurement - Schedule of Fair Value, Financial Instruments Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		$ 5,353	$ 314
Derivative liabilities		10,305	$ 28,038
Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 590	6,958
Derivative liabilities	28,314	11,910
Fair value, measurements, recurring | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	590	6,958
Derivative liabilities	28,314	11,910
Fair value, measurements, recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair value, measurements, recurring | Level 1 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair value, measurements, recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	590	6,958
Derivative liabilities	28,314	11,910
Fair value, measurements, recurring | Level 2 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	590	6,958
Derivative liabilities	28,314	11,910
Fair value, measurements, recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair value, measurements, recurring | Level 3 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	$ 0	$ 0

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 65,598	$ 64,256
Work-in-process	10,586	15,211
Total	$ 76,184	$ 79,467

Solar Energy Systems, net (Deta

Solar Energy Systems, net (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property Subject to or Available for Operating Lease [Line Items]
Solar energy systems	$ 4,428,204	$ 4,219,907
Accumulated depreciation and amortization	(575,094)	(535,891)
Construction-in-progress	123,394	136,001
Total solar energy systems, net	3,976,504	3,820,017
Solar energy system equipment costs
Property Subject to or Available for Operating Lease [Line Items]
Solar energy systems	4,012,116	3,823,853
Inverters
Property Subject to or Available for Operating Lease [Line Items]
Solar energy systems	$ 416,088	$ 396,054

Solar Energy Systems, net - Add

Solar Energy Systems, net - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Solar Energy Systems Disclosure [Abstract]
Depreciation expense	$ 39.4	$ 32.4
Amortization of deferred grants	$ 2	$ 1.9

Other Assets Other Assets - Sch

Other Assets Other Assets - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Other Assets [Line Items]
Accumulated amortization of costs to obtain contracts	$ (27,641)		$ (24,992)
Unbilled receivables	90,578		81,703
Operating lease right-of-use assets	38,051		20,257
Other assets	31,915		39,410
Other assets, total	367,951		335,685
Amortization cost	2,700	$ 1,900
Customer agreements
Other Assets [Line Items]
Costs to obtain contracts- customer agreements	232,567		219,307
Incentives
Other Assets [Line Items]
Costs to obtain contracts- customer agreements	$ 2,481		$ 0

Accrued Expenses and Other Li_3

Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued employee compensation	$ 35,393	$ 39,738
Operating lease obligations	9,462	7,857
Accrued interest	12,942	8,436
Accrued professional fees	12,185	9,199
Other accrued expenses	33,782	33,406
Total	$ 103,764	$ 98,636

Indebtedness - Schedule of Debt

Indebtedness - Schedule of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long term debt, current	$ 26,937	$ 35,484
Long term debt, noncurrent	1,797,285	1,713,438
Long term debt	1,824,222	1,748,922
Unused borrowing capacity	0	406
Subordinated
Debt Instrument [Line Items]
Unused borrowing capacity	0	0
Recourse debt
Debt Instrument [Line Items]
Long term debt, current	0	0
Long term debt, noncurrent	239,035	247,000
Long term debt	239,035	247,000
Unused borrowing capacity	0	406
Recourse debt | Bank line of credit
Debt Instrument [Line Items]
Long term debt, current	0	0
Long term debt, noncurrent	239,035	247,000
Long term debt	239,035	247,000
Unused borrowing capacity	$ 0	$ 406
Recourse debt | Bank line of credit | Minimum
Debt Instrument [Line Items]
Interest rate	5.59%	5.45%
Recourse debt | Bank line of credit | Maximum
Debt Instrument [Line Items]
Interest rate	5.90%	5.77%
Non-recourse debt
Debt Instrument [Line Items]
Long term debt, current	$ 26,937	$ 35,484
Long term debt, noncurrent	1,558,250	1,466,438
Long term debt	1,585,187	1,501,922
Unused borrowing capacity	0	0
Non-recourse debt | Senior
Debt Instrument [Line Items]
Long term debt, current	12,679	19,070
Long term debt, noncurrent	901,108	809,447
Long term debt	913,787	828,517
Unused borrowing capacity	$ 0	$ 0
Non-recourse debt | Senior | Minimum
Debt Instrument [Line Items]
Interest rate	4.50%	4.50%
Non-recourse debt | Senior | Maximum
Debt Instrument [Line Items]
Interest rate	5.49%	5.54%
Non-recourse debt | Subordinated
Debt Instrument [Line Items]
Long term debt, current	$ 5,715	$ 5,824
Long term debt, noncurrent	273,195	267,513
Long term debt	$ 278,910	$ 273,337
Non-recourse debt | Subordinated | Minimum
Debt Instrument [Line Items]
Interest rate	7.03%	7.03%
Non-recourse debt | Subordinated | Maximum
Debt Instrument [Line Items]
Interest rate	10.00%	10.00%
Non-recourse debt | Securitization Class A
Debt Instrument [Line Items]
Long term debt, current	$ 8,072	$ 10,125
Long term debt, noncurrent	374,875	380,299
Long term debt	382,947	390,424
Unused borrowing capacity	$ 0	$ 0
Non-recourse debt | Securitization Class A | Minimum
Debt Instrument [Line Items]
Interest rate	4.40%	4.40%
Non-recourse debt | Securitization Class A | Maximum
Debt Instrument [Line Items]
Interest rate	5.31%	5.41%
Non-recourse debt | Securitization Class B
Debt Instrument [Line Items]
Long term debt, current	$ 471	$ 465
Long term debt, noncurrent	9,072	9,179
Long term debt	9,543	9,644
Unused borrowing capacity	$ 0	$ 0
Interest rate	5.38%	5.38%

Indebtedness - Additional Infor

Indebtedness - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Loan outstanding balance	$ 1,824,222,000	$ 1,748,922,000
Recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	239,035,000	247,000,000
Non-recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	1,585,187,000	1,501,922,000
Non-recourse debt | Aggregation facility, March 2023
Debt Instrument [Line Items]
Loan outstanding balance	362,600,000
Non-recourse debt | Line of credit | Aggregation facility, March 2023
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 595,000,000
Non-recourse debt | London Interbank Offered Rate (LIBOR) | Line of credit | Aggregation facility, March 2023
Debt Instrument [Line Items]
Basis spread on variable rate	2.50%
Facility available period	3 years
Debt instrument basis spread on variable rate, periodic increase	2.75%
Revolving line of credit facility available period, period increase	2 years
Bank line of credit | Recourse debt
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 250,000,000
Minimum unencumbered liquid assets to be maintained	25,000,000
Debt covenant, liability maintenance	$ 30,000,000
Interest coverage ratio	300.00%
Loan outstanding balance	$ 239,035,000	$ 247,000,000
Bank line of credit | Recourse debt | Minimum
Debt Instrument [Line Items]
Interest rate	5.59%	5.45%
Bank line of credit | Recourse debt | Maximum
Debt Instrument [Line Items]
Interest rate	5.90%	5.77%
Bank line of credit | Recourse debt | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	3.25%
Bank line of credit | Recourse debt | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Bank line of credit | Recourse debt | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Bank line of credit | Recourse debt | LIBOR Floor Rate
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Term Loan Due in October 2024 | Non-recourse debt | Senior secured revolving letter of credit facility | Aggregation facility, October 2024
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 303,000,000
Loan outstanding balance	281,800,000
Term Loan Due in October 2024 | Non-recourse debt | Term Loan | Aggregation facility, October 2024
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	293,000,000
Term Loan Due in October 2024 | Non-recourse debt | Revolving debt | Aggregation facility, October 2024
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 10,000,000
Term Loan | Non-recourse debt | Minimum | Aggregation facility, March 2023
Debt Instrument [Line Items]
Term loan prepayment penalty, percent	0.00%
Term Loan | Non-recourse debt | Maximum | Aggregation facility, March 2023
Debt Instrument [Line Items]
Term loan prepayment penalty, percent	1.00%
Term Loan | Non-recourse debt | London Interbank Offered Rate (LIBOR) | Aggregation facility, March 2023
Debt Instrument [Line Items]
Basis spread on variable rate	5.00%
Facility available period	3 years
Debt instrument basis spread on variable rate, periodic increase	6.50%
Term Loan A | Non-recourse debt | London Interbank Offered Rate (LIBOR) | Aggregation facility, October 2024
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%
Term Loan A | Non-recourse debt | Base Rate | Aggregation facility, October 2024
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
Term Loan B | Non-recourse debt | Minimum | Aggregation facility, October 2024
Debt Instrument [Line Items]
Term loan prepayment penalty, percent	0.00%
Term Loan B | Non-recourse debt | Maximum | Aggregation facility, October 2024
Debt Instrument [Line Items]
Term loan prepayment penalty, percent	5.00%
Term Loan B, Class A | Non-recourse debt | London Interbank Offered Rate (LIBOR) | Aggregation facility, October 2024
Debt Instrument [Line Items]
Basis spread on variable rate	7.03%
Term Loan B, Class B | Non-recourse debt | London Interbank Offered Rate (LIBOR) | Aggregation facility, October 2024
Debt Instrument [Line Items]
Basis spread on variable rate	5.00%
Basis spread on Federal Funds Rate	1.00%
Term Loan B, Class B | Non-recourse debt | Base Rate | Aggregation facility, October 2024
Debt Instrument [Line Items]
Basis spread on variable rate	4.00%
Basis spread on Federal Funds Rate	0.50%
Term Loan due in April 2024 | Non-recourse debt | Senior secured revolving letter of credit facility | Aggregation facility, April 2024
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 202,000,000
Loan outstanding balance	183,800,000
Term Loan due in April 2024 | Non-recourse debt | Revolving debt | Aggregation facility, April 2024
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	7,000,000
Term Loan due in April 2024 | Non-recourse debt | Delayed draw term loan | Aggregation facility, April 2024
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 195,000,000
Term Loan due in April 2024 | Non-recourse debt | London Interbank Offered Rate (LIBOR) | Aggregation facility, April 2024
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Facility available period	4 years
Term Loan due in April 2024 | Non-recourse debt | Base Rate | Aggregation facility, April 2024
Debt Instrument [Line Items]
Basis spread on variable rate	1.25%
Term Loan due in April 2024 | Non-recourse debt | Federal Funds Rate | Aggregation facility, April 2024
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Term Loan due in April 2024 | Non-recourse debt | LIBOR Floor Rate | Aggregation facility, April 2024
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Bank Term Loan due September 2020 | Non-recourse debt | Revolving loan facility, September 2020
Debt Instrument [Line Items]
Loan outstanding balance	$ 210,200,000
Senior debt | Non-recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	$ 913,787,000	$ 828,517,000
Senior debt | Non-recourse debt | Minimum
Debt Instrument [Line Items]
Interest rate	4.50%	4.50%
Senior debt | Non-recourse debt | Maximum
Debt Instrument [Line Items]
Interest rate	5.49%	5.54%
Senior debt | Non-recourse debt | London Interbank Offered Rate (LIBOR) | Revolving loan facility, September 2020
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%
Subordinated debt | Non-recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	$ 278,910,000	$ 273,337,000
Subordinated debt | Non-recourse debt | Minimum
Debt Instrument [Line Items]
Interest rate	7.03%	7.03%
Subordinated debt | Non-recourse debt | Maximum
Debt Instrument [Line Items]
Interest rate	10.00%	10.00%
Subordinated debt | Non-recourse debt | London Interbank Offered Rate (LIBOR) | Revolving loan facility, September 2020
Debt Instrument [Line Items]
Basis spread on variable rate	5.50%
Bank Term Loan due April 2022 | Non-recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	$ 20,000,000
Interest rate	4.50%
Bank Term Loan due September 2022 | Non-recourse debt
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Loan outstanding balance	$ 16,100,000
Bank Term Loan due January 2030 | Non-recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	$ 118,200,000
Interest rate	10.00%
Subsidiary one | Securitization loans
Debt Instrument [Line Items]
Secured borrowings assets carrying amount	$ 162,700,000	$ 164,700,000
Subsidiary one | Securitization loans | Non-recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	$ 89,100,000
Subsidiary one | Solar Asset Backed Notes
Debt Instrument [Line Items]
Debt Instrument Discount Rate	0.08%
Subsidiary two | Securitization loans | Non-recourse debt
Debt Instrument [Line Items]
Loan outstanding balance	$ 303,400,000
Subsidiary two | Solar Asset Backed Notes
Debt Instrument [Line Items]
Debt Instrument Discount Rate	1.47%

Derivatives - Additional Inform

Derivatives - Additional Information (Details) $ in Millions	Mar. 31, 2019USD ($)derivative_instrument
Derivatives, Fair Value [Line Items]
Derivative, undesignated, number of instruments held | derivative_instrument	0
Interest rate swaps
Derivatives, Fair Value [Line Items]
Additional amount to be classified as an increase to interest expense during next 12 months | $	$ 0.1

Derivatives Derivatives - Accum

Derivatives Derivatives - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019
Derivatives designated as cash flow hedges:
Beginning balance	$ 1,282,782	$ 1,240,516
Unrealized (loss) gain recognized in OCI	(17,013)	16,171
Amount reclassified from OCI to earnings	(989)	(1,233)
Net (loss) gain on derivatives (net of tax effect of $6,093 and $5,134)	(18,002)	14,938
Ending balance	1,302,111	1,291,228
Net (loss) gain on derivatives, tax	6,093	5,134
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Derivatives designated as cash flow hedges:
Beginning balance	(3,124)	(4,113)
Cumulative effect of adoption of new ASU (No. 2018-02)			$ (740)
Ending balance	$ (21,866)	$ 10,825

Derivatives Derivatives - Offse

Derivatives Derivatives - Offsetting Arrangements (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Mar. 31, 2018
Derivative Asset [Abstract]
Fair Market Value	$ 6,958	$ 590
Derivative Asset, gross amounts offset	(1,605)	(276)
Derivative Assets, net amounts of assets	5,353	314
Derivative Liability [Abstract]
Derivative Liability, gross amounts of liabilities	(11,910)	(28,314)
Derivative Liability, gross amounts offset	1,605	276
Derivative Liabilities, net amounts of liabilities	(10,305)	(28,038)
Derivative, net, gross amounts of assets/liabilities	(4,952)	(27,724)
Derivative Assets, Net amounts of assets/liabilities	$ (4,952)	$ (27,724)

Derivatives - Summary of Design

Derivatives - Summary of Designated Derivative Instruments Classified as Derivative Assets (Details) $ in Thousands	Mar. 31, 2019USD ($)Instrument	Dec. 31, 2018USD ($)	Mar. 31, 2018USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Market Value		$ 6,958	$ 590
Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	$ 1,416,025
Fair Market Value	$ (27,724)
Interest rate swaps | Interest rate swap, 9/20/2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Hedge Interest Rates	2.69%
Notional Amount	$ 80,500
Fair Market Value	$ (437)
Interest rate swaps | Interest rate swap, 8/31/2022
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Notional Amount	$ 13,179
Fair Market Value	$ 314
Interest rate swaps | Interest rate swap, 8/31/2022 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	1.27%
Interest rate swaps | Interest rate swap, 8/31/2022 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	1.29%
Interest rate swaps | Interest rate swap, 4/30/2024 - 10/31/2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	8
Notional Amount	$ 283,160
Fair Market Value	$ (384)
Interest rate swaps | Interest rate swap, 4/30/2024 - 10/31/2024 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.16%
Interest rate swaps | Interest rate swap, 4/30/2024 - 10/31/2024 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.39%
Interest rate swaps | Interest rate swap, 10/30/2026 - 10/31/2026
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	3
Notional Amount	$ 102,720
Fair Market Value	$ (3,631)
Interest rate swaps | Interest rate swap, 10/30/2026 - 10/31/2026 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.89%
Interest rate swaps | Interest rate swap, 10/30/2026 - 10/31/2026 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	3.08%
Interest rate swaps | Interest rate swap, 9/20/2027
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Hedge Interest Rates	2.97%
Notional Amount	$ 30,023
Fair Market Value	$ (1,011)
Interest rate swaps | Interest rate swap, 3/20/2030 - 6/20/2030
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	2
Notional Amount	$ 160,401
Fair Market Value	$ 1,177
Interest rate swaps | Interest rate swap, 3/20/2030 - 6/20/2030 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.22%
Interest rate swaps | Interest rate swap, 3/20/2030 - 6/20/2030 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.57%
Interest rate swaps | Interest rate swap, 1/20/2031
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Hedge Interest Rates	2.61%
Notional Amount	$ 9,899
Fair Market Value	$ (332)
Interest rate swaps | Interest rate swap, 4/30/3034
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	3
Hedge Interest Rates	2.78%
Notional Amount	$ 200,000
Fair Market Value	$ (6,545)
Interest rate swaps | Interest rate swap, 7/31/2035
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	5
Notional Amount	$ 151,610
Fair Market Value	$ (2,197)
Interest rate swaps | Interest rate swap, 7/31/2035 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.56%
Interest rate swaps | Interest rate swap, 7/31/2035 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.95%
Interest rate swaps | Interest rate swap, 10/31/2036
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	5
Notional Amount	$ 183,398
Fair Market Value	$ (2,710)
Interest rate swaps | Interest rate swap, 10/31/2036 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.62%
Interest rate swaps | Interest rate swap, 10/31/2036 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	2.95%
Interest rate swaps | Interest rate swap, 4/30/2037
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	3
Notional Amount	$ 100,000
Fair Market Value	$ (7,099)
Interest rate swaps | Interest rate swap, 4/30/2037 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	3.28%
Interest rate swaps | Interest rate swap, 4/30/2037 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	3.30%
Interest rate swaps | Interest rate swap, 1/31/2038
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	3
Notional Amount	$ 101,135
Fair Market Value	$ (2,515)
Interest rate swaps | Interest rate swap, 1/31/2038 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	3.01%
Interest rate swaps | Interest rate swap, 1/31/2038 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Interest Rates	3.16%

Derivatives - Summary of Deriva

Derivatives - Summary of Derivative Instruments (Details) $ in Thousands	Mar. 31, 2019USD ($)Instrument	Dec. 31, 2018USD ($)	Mar. 31, 2018USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative asset, fair market value		$ 6,958	$ 590
Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	$ 1,416,025
Derivative asset, fair market value	$ (27,724)
Interest rate swaps | Interest rate swap, 9/20/2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Hedge interest rates	2.69%
Notional amount	$ 80,500
Derivative asset, fair market value	$ (437)
Interest rate swaps | Interest rate swap, 8/31/2022
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Notional amount	$ 13,179
Derivative asset, fair market value	$ 314
Interest rate swaps | Interest rate swap, 8/31/2022 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	1.27%
Interest rate swaps | Interest rate swap, 8/31/2022 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	1.29%
Interest rate swaps | Interest rate swap, 4/30/2024 - 10/31/2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	8
Notional amount	$ 283,160
Derivative asset, fair market value	$ (384)
Interest rate swaps | Interest rate swap, 4/30/2024 - 10/31/2024 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.16%
Interest rate swaps | Interest rate swap, 4/30/2024 - 10/31/2024 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.39%
Interest rate swaps | Interest rate swap, 10/30/2026 - 10/31/2026
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	3
Notional amount	$ 102,720
Derivative asset, fair market value	$ (3,631)
Interest rate swaps | Interest rate swap, 10/30/2026 - 10/31/2026 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.89%
Interest rate swaps | Interest rate swap, 10/30/2026 - 10/31/2026 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	3.08%
Interest rate swaps | Interest rate swap, 9/20/2027
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Hedge interest rates	2.97%
Notional amount	$ 30,023
Derivative asset, fair market value	$ (1,011)
Interest rate swaps | Interest rate swap, 3/20/2030 - 6/20/2030
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	2
Notional amount	$ 160,401
Derivative asset, fair market value	$ 1,177
Interest rate swaps | Interest rate swap, 3/20/2030 - 6/20/2030 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.22%
Interest rate swaps | Interest rate swap, 3/20/2030 - 6/20/2030 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.57%
Interest rate swaps | Interest rate swap, 1/20/2031
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	1
Hedge interest rates	2.61%
Notional amount	$ 9,899
Derivative asset, fair market value	$ (332)
Interest rate swaps | Interest rate swap, 4/30/3034
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	3
Hedge interest rates	2.78%
Notional amount	$ 200,000
Derivative asset, fair market value	$ (6,545)
Interest rate swaps | Interest rate swap, 7/31/2035
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	5
Notional amount	$ 151,610
Derivative asset, fair market value	$ (2,197)
Interest rate swaps | Interest rate swap, 7/31/2035 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.56%
Interest rate swaps | Interest rate swap, 7/31/2035 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.95%
Interest rate swaps | Interest rate swap, 10/31/2036
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	5
Notional amount	$ 183,398
Derivative asset, fair market value	$ (2,710)
Interest rate swaps | Interest rate swap, 10/31/2036 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.62%
Interest rate swaps | Interest rate swap, 10/31/2036 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	2.95%
Interest rate swaps | Interest rate swap, 4/30/2037
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Quantity | Instrument	3
Notional amount	$ 100,000
Derivative asset, fair market value	$ (7,099)
Interest rate swaps | Interest rate swap, 4/30/2037 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	3.28%
Interest rate swaps | Interest rate swap, 4/30/2037 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge interest rates	3.30%

Pass-through Financing Obliga_2

Pass-through Financing Obligations - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Property Subject to or Available for Operating Lease [Line Items]
Customer agreement, initial term	22 years
Solar energy systems, gross	$ 4,428,204	$ 4,219,907
Depreciation on lease	$ 575,094	535,891
Minimum
Property Subject to or Available for Operating Lease [Line Items]
Customer agreement, initial term	20 years
Maximum
Property Subject to or Available for Operating Lease [Line Items]
Customer agreement, initial term	25 years
Solar energy systems under lease pass-through fund arrangements
Property Subject to or Available for Operating Lease [Line Items]
Customer agreement, initial term	20 years
Solar energy systems, gross	$ 656,500	664,100
Depreciation on lease	79,800	$ 82,100
Extinguishment of financing obligation	11,700
Debt extinguishment expense	$ 4,000
Solar energy systems under lease pass-through fund arrangements | Minimum
Property Subject to or Available for Operating Lease [Line Items]
Solar energy systems, initial term	20 years
Solar energy systems under lease pass-through fund arrangements | Maximum
Property Subject to or Available for Operating Lease [Line Items]
Solar energy systems, initial term	22 years

VIE Arrangements - Carrying Amo

VIE Arrangements - Carrying Amounts and Classification of the VIEs' Assets and Liabilities Included in the Consolidated Balance Sheets (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2019USD ($)InvestmentFundfund	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Current assets:
Cash		$ 245,604		$ 226,625
Restricted cash		64,182		77,626
Accounts receivable, net		67,522		66,435	$ 66,400
Prepaid expenses and other current assets		9,568		8,563
Total current assets		463,060		461,413
Solar energy systems, net		3,976,504		3,820,017
Other assets		367,951		335,685
Total assets	[1]	4,939,682		4,749,787
Current liabilities:
Accounts payable		105,977		131,278
Distributions payable to noncontrolling interests and redeemable noncontrolling interests		15,628		15,847
Accrued expenses and other liabilities		103,764		98,636
Deferred revenue, current portion		55,795		47,407
Deferred grants, current portion		7,961		7,885
Non-recourse debt, current portion		26,937		35,484
Total current liabilities		336,802		372,191
Deferred revenue, net of current portion		637,666		544,218
Deferred grants, net of current portion		219,583		221,739
Non-recourse debt, net of current portion		1,558,250		1,466,438
Other liabilities		84,068		48,210
Total liabilities (1)	[1]	$ 3,499,955		3,340,703
Number of pass-through Fund arrangements | InvestmentFund		3
Payments to acquire interest in VIEs		$ 4,600	$ 0
Acquisition of Variable Interest Entity		4,989
Additional Paid-In Capital
Current liabilities:
Acquisition of Variable Interest Entity		(1,077)
Variable Interest Entities
Current assets:
Cash		135,548		105,494
Restricted cash		969		2,071
Accounts receivable, net		16,988		18,539
Prepaid expenses and other current assets		386		387
Total current assets		153,891		126,491
Solar energy systems, net		2,761,312		2,712,377
Other assets		66,707		66,427
Total assets		2,981,910		2,905,295
Current liabilities:
Accounts payable		10,979		12,136
Distributions payable to noncontrolling interests and redeemable noncontrolling interests		15,545		15,797
Accrued expenses and other liabilities		7,315		7,122
Deferred revenue, current portion		33,504		29,102
Deferred grants, current portion		982		982
Non-recourse debt, current portion		4,336		4,217
Total current liabilities		72,661		69,356
Deferred revenue, net of current portion		405,261		367,818
Deferred grants, net of current portion		27,982		28,247
Non-recourse debt, net of current portion		184,958		186,494
Other liabilities		10,733		8,843
Total liabilities (1)		$ 701,595		$ 660,758
Number of pass-through Fund arrangements | fund		6
Payments to acquire interest in VIEs		$ 4,600
Variable Interest Entities | Additional Paid-In Capital
Current liabilities:
Acquisition of Variable Interest Entity		$ 1,100
[1]	The Company’s consolidated assets as of March 31, 2019 and December 31, 2018 include $2,981,910 and $2,905,295, respectively, in assets of variable interest entities (“VIEs”) that can only be used to settle obligations of the VIEs. These assets include solar energy systems, net, as of March 31, 2019 and December 31, 2018 of $2,761,312 and $2,712,377, respectively; cash as of March 31, 2019 and December 31, 2018 of $135,548 and $105,494, respectively; restricted cash as of March 31, 2019 and December 31, 2018 of $969 and $2,071, respectively; accounts receivable, net as of March 31, 2019 and December 31, 2018 of $16,988 and $18,539, respectively; prepaid expenses and other current assets as of March 31, 2019 and December 31, 2018 of $386 and $387, respectively; and other assets as of March 31, 2019 and December 31, 2018 of $66,707 and $66,427, respectively. The Company’s consolidated liabilities as of March 31, 2019 and December 31, 2018 include $701,595 and $660,758, respectively, in liabilities of VIEs whose creditors have no recourse to the Company. These liabilities include accounts payable as of March 31, 2019 and December 31, 2018 of $10,979 and $12,136, respectively; distributions payable to noncontrolling interests and redeemable noncontrolling interests as of March 31, 2019 and December 31, 2018 of $15,545 and $15,797, respectively; accrued expenses and other current liabilities as of March 31, 2019 and December 31, 2018 of $7,315 and $7,122, respectively; deferred revenue as of March 31, 2019 and December 31, 2018 of $438,765 and $396,920, respectively; deferred grants as of March 31, 2019 and December 31, 2018 of $28,964 and $29,229, respectively; non-recourse debt as of March 31, 2019 and December 31, 2018 of $189,294 and $190,711, respectively; and other liabilities as of March 31, 2019 and December 31, 2018 of $10,733 and $8,843, respectively.

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests and Equity - Schedule of Changes in Redeemable Noncontrolling Interest,Total Stockholders' Equity and Noncontrolling Interests (Details) - fund	Mar. 31, 2019	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Number of funds, carrying value adjusted to redemption value	7	6

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Number of Options
Outstanding, beginning balance (in shares)	13,590
Granted (in shares)	1,064
Exercised (in shares)	(1,139)
Cancelled (in shares)	(17)
Outstanding, ending balance (in shares)	13,498
Options vested and exercisable (in shares)	8,154
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 6.07
Granted (in dollars per share)	14.57
Exercised (in dollars per share)	3.86
Cancelled (in dollars per share)	10.30
Outstanding, ending balance (in dollars per share)	6.92
Options vested and exercisable (in dollars per share)	$ 6.21
Weighted Average Remaining Contractual Life
Weighted-average remaining contractual life, options outstanding	6 years 8 months 15 days	6 years 7 months 17 days
Weighted-average remaining contractual life, options vested and exercisable	5 years 8 months 1 day
Aggregate intrinsic value, options outstanding	$ 97,127		$ 66,462
Aggregate intrinsic value, options vested and exercisable	$ 64,261

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity for All Restricted Stock Units ("RSUs") (Details) - Restricted Stock Units (RSUs) shares in Thousands	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Number of Awards
Unvested, beginning balance (in shares) | shares	4,182
Granted (in shares) | shares	1,524
Issued (in shares) | shares	(451)
Cancelled / forfeited (in shares) | shares	(295)
Unvested, ending balance (in shares) | shares	4,960
Weighted Average Grant Date Fair Value
Unvested, beginning balance (in dollars per share) | $ / shares	$ 7.05
Granted (in dollars per share) | $ / shares	14.42
Issued (in dollars per share) | $ / shares	6.75
Cancelled / forfeited (in dollars per share) | $ / shares	7.20
Unvested, ending balance (in dollars per share) | $ / shares	$ 9.33

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details)	Nov. 07, 2018USD ($)solar_energy_system_install	Aug. 31, 2017USD ($)solar_energy_system_install$ / sharesshares	Jul. 31, 2015USD ($)shares	Mar. 31, 2019purchase_period
Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant, term		40 months
Warrant, number purchased | shares		11,793,355
Warrant, exercise price (in dollars per share) | $ / shares		$ 0.01
Warrant, vesting percentage		50.05%
Warrant, milestone one, solar energy systems | solar_energy_system_install	6,000	30,000
Warrant, milestone two, marketing and sales dollars | $		$ 10,000,000
Warrant, vesting term		5 years
Warrant, milestone two, solar energy systems | solar_energy_system_install	8,000	6,000
Warrant, vesting percentage, milestone one	10.00%
Warrant, vesting percentage, milestone two	13.30%
Warrant, milestone one and two, marketing and sales dollars | $	$ 25,000,000
Warrant, vesting percentage, milestone three	8.30%
Warrant, milestone three, solar energy systems | solar_energy_system_install	5,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP offering period				24 months
Number of purchase periods | purchase_period				4
Maximum percentage in payroll deductions to acquire shares of common stock			15.00%
Maximum deductible fair market value of shares available for employee to purchase per calendar year | $			$ 25,000
Maximum number of shares available for employee to purchase per offering period | shares			10,000

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	$ 5,783	$ 10,694
Cost of customer agreements and incentives
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	632	611
Cost of solar energy systems and product sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	167	170
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	1,128	4,150
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	336	295
General and administration
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	$ 3,520	$ 5,468

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Income Tax Contingency [Line Items]
Effective income tax rates	3.70%	(9.90%)
Unrecognized tax benefits			$ 0.6
Unrecognized tax benefits income tax penalties and interest accrued			0.2
Unrecognized tax benefits, reduction resulting from lapse of applicable statute of limitations	$ 0.5
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards			$ 1,100
Net operating loss carryforwards, Year of expiration			2028
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards			$ 572.2
Net operating loss carryforwards, Year of expiration			2024
Other state
Income Tax Contingency [Line Items]
Net operating loss carryforwards			$ 535.8

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	Aug. 08, 2018USD ($)	Mar. 31, 2019USD ($)contract	Dec. 31, 2018USD ($)	Mar. 31, 2018USD ($)
Other Commitments [Line Items]
Letters of credit outstanding, amount		$ 14.4	$ 9.7
Purchase commitment		$ 60.6
Corporate office space | San Francisco, California and Denver, Colorado
Other Commitments [Line Items]
Operating lease agreements | contract		2
Minimum | Corporate office space | San Francisco, California and Denver, Colorado
Other Commitments [Line Items]
Lease agreement terms		5 years
Maximum | Corporate office space | San Francisco, California and Denver, Colorado
Other Commitments [Line Items]
Lease agreement terms		7 years
Letter of Credit | Minimum
Other Commitments [Line Items]
Letter of credit, fee percentage		2.75%	2.50%
Letter of Credit | Maximum
Other Commitments [Line Items]
Letter of credit, fee percentage		3.25%	3.25%
Settled litigation | Slovin et al. v. Sunrun Inc. and Clean Energy Experts, LLC
Other Commitments [Line Items]
Settlement amount, accrual				$ 5.5
Settled litigation | Fink, et al. v. Sunrun Inc., et al.
Other Commitments [Line Items]
Settlement amount	$ 2.5

Commitments and Contingencies_2

Commitments and Contingencies - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Finance lease cost:
Finance lease cost, amortization of right-of-use assets	$ 3,484	$ 2,634
Finance lease cost, interest on lease liabilities	239	119
Operating lease cost	2,879	2,629
Short-term lease cost	524	201
Variable lease cost	877	777
Sublease income	(156)	(106)
Total lease cost	$ 7,847	$ 6,254

Commitments and Contingencies_3

Commitments and Contingencies - Other Information Related to Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash paid for amounts included in the measurement of lease liabilities
Cash paid for amounts included in the measurement of lease liabilities, operating cash flows from operating leases	$ 2,567	$ 2,600
Cash paid for amounts included in the measurement of lease liabilities, operating cash flows from finance leases	201	109
Cash paid for amounts included in the measurement of lease liabilities, financing cash flows from finance leases	3,060	2,159
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	20,395	1,117
Finance leases	$ 3,566	$ 99
Weighted average remaining lease term (years):
Weighted average remaining lease term (years), operating leases	5 years 6 months 18 days	3 years 10 months 20 days
Weighted average remaining lease term (years), finance leases	2 years 10 months 24 days	1 year 10 months 13 days
Weighted average discount rate:
Weighted average discount rate, operating leases	5.20%	4.10%
Weighted average discount rate, finance leases	4.30%	3.10%

Commitments and Contingencies_4

Commitments and Contingencies - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
Operating leases, 2019	$ 11,952
Operating leases, 2020	11,878
Operating leases, 2021	10,538
Operating leases, 2022	9,101
Operating leases, 2023	8,189
Operating leases, thereafter	10,677
Operating leases, future lease payments	62,335
Operating leases, amount representing interest	6,200
Operating leases, present value of future payments	56,135
Operating leases, short term leases not recorded as a liability	11,761
Operating leases, tenant incentives	3,186
Operating leases, revised present value of future payments	41,188
Operating leases, current portion	9,462
Operating lease, long-term portion	31,726
Sublease Income
Sublease Income, 2019	777
Sublease Income, 2020	791
Sublease Income, 2021	439
Sublease Income, 2022	0
Sublease Income, 2023	0
Sublease Income, thereafter	0
Sublease Income, future lease payments	2,007
Net Operating Leases
Net operating leases, 2019	11,175
Net operating leases, 2020	11,087
Net operating leases, 2021	10,099
Net operating leases, 2022	9,101
Net operating leases, 2023	8,189
Net operating leases, thereafter	10,677
Net operating leases, future lease payments	60,328
Operating leases, future lease payments	6,200
Net operating leases, present value of future payments	54,128
Net operating leases, short term leases not recorded as a liability	11,761
Net operating leases, tenant incentives	3,186
Net operating leases, revised present value of future payments	39,181
Net operating leases, revised, current portion	9,462
Net operating leases, revised, noncurrent portion	29,719
Finance Leases
Finance leases, 2019	10,060
Finance leases, 2020	5,453
Finance leases, 2021	3,587
Finance leases, 2022	1,568
Finance leases, 2023	60
Finance leases, thereafter	49
Finance leases, future lease payments	20,777
Finance leases, present value of future payments	1,072
Finance leases, present value of future payments	19,705
Finance lease obligations, current portion	9,459	$ 9,193
Finance lease obligations, net of current portion	$ 10,246	$ 9,992

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net (loss) income attributable to common stockholders	$ (13,862)	$ 28,032
Denominator:
Weighted average shares used to compute net income per share attributable to common stockholders, basic (in shares)	113,912	107,449
Weighted average effect of potentially dilutive shares to purchase common stock (in shares)	0	3,332
Weighted average shares used to compute net income per share attributable to common stockholders, diluted (in shares)	113,912	110,781
Net (loss) income per share attributable to common stockholders
Basic (in dollars per share)	$ (0.12)	$ 0.26
Diluted (in dollars per share)	$ (0.12)	$ 0.25

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Shares Excluded From Computation of Diluted Net Income Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net income per share (in shares)	2,793	12,947
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net income per share (in shares)	0	1,251
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net income per share (in shares)	1,313	9,917
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net income per share (in shares)	1,480	1,779

Uncategorized Items - run-20190

Label	Element	Value
AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (740,000)
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 740,000