Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities:
Net loss	$ (91,420)	$ (75,155)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization, net of amortization of deferred grants	36,186	29,948
Deferred income taxes	8,203	5,399
Stock-based compensation expense	10,694	5,874
Interest on pass-through financing obligations	3,099	3,118
Reduction in pass-through financing obligations	(5,028)	(4,552)
Other noncash losses and expenses	5,667	5,580
Changes in operating assets and liabilities:
Accounts receivable	(360)	3,465
Inventories	6,525	7,723
Prepaid and other assets	(6,746)	(9,819)
Accounts payable	(12,982)	(4,357)
Accrued expenses and other liabilities	(7,048)	(11,297)
Deferred revenue	7,456	6,593
Net cash used in operating activities	(45,754)	(37,480)
Investing activities:
Payments for the costs of solar energy systems	(163,190)	(159,754)
Purchases of property and equipment	(1,521)	(2,610)
Net cash used in investing activities	(164,711)	(162,364)
Financing activities:
Proceeds from state tax credits, net of recapture	(49)	13,388
Payment of debt fees	(3,880)	0
Proceeds from pass-through financing obligations	1,502	1,448
Contributions received from noncontrolling interests and redeemable noncontrolling interests	143,604	162,565
Distributions paid to noncontrolling interests and redeemable noncontrolling interests	(15,263)	(12,887)
Proceeds from exercises of stock options, net of withholding taxes paid on restricted stock units	(576)	(1,067)
Payment of finance lease obligations	(2,113)	(2,749)
Net cash provided by financing activities	212,003	197,419
Net change in cash and restricted cash	1,538	(2,425)
Cash and restricted cash, beginning of period	241,790	224,363
Cash and restricted cash, end of period	243,328	221,938
Supplemental disclosures of cash flow information
Cash paid for interest	16,446	9,347
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	17,233	22,468
Purchases of solar energy systems included in non-recourse debt	0	12,873
Distributions payable to noncontrolling interests and redeemable noncontrolling interests	15,134	11,157
Right-of-use assets obtained in exchange for new finance lease liabilities	99	76
Recourse debt
Financing activities:
Proceeds from issuance of debt	2,000	57,400
Repayment of debt	(2,000)	(54,000)
Non recourse debt
Financing activities:
Proceeds from issuance of debt	95,900	38,225
Repayment of debt	$ (7,122)	$ (4,904)