Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities:
Net loss	$ (73,084)	$ (77,803)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization, net of amortization of deferred grants	31,710	21,596
Deferred income taxes	7,337
Stock-based compensation expense	5,874	3,809
Noncash interest expense	5,931	3,502
Interest on lease pass-through financing obligations	2,961	3,002
Reduction in lease pass-through financing obligations	(4,546)	(4,236)
Other noncash losses and expenses	2,898	1,657
Changes in operating assets and liabilities:
Accounts receivable	6,362	3,595
Inventories	7,723	(23,314)
Prepaid and other assets	(1,441)	(4,355)
Accounts payable	(4,357)	(10,103)
Accrued expenses and other liabilities	(15,445)	(317)
Deferred revenue	(1,030)	5,572
Net cash used in operating activities	(29,107)	(77,395)
Investing activities:
Payments for the costs of solar energy systems, leased and to be leased	(168,149)	(164,629)
Purchases of property and equipment	(2,610)	(5,023)
Net cash used in investing activities	(170,759)	(169,652)
Financing activities:
Proceeds from state tax credits, net of recapture	13,388	9,202
Proceeds from issuance of recourse debt	57,400	141,000
Repayment of recourse debt	(54,000)	(147,000)
Proceeds from issuance of non-recourse debt	38,225	106,400
Repayment of non-recourse debt	(4,904)	(2,160)
Payment of debt fees		(9,369)
Proceeds from lease pass-through financing obligations	1,448	9,746
Contributions received from noncontrolling interests and redeemable noncontrolling interests	162,565	154,944
Distributions paid to noncontrolling interests and redeemable noncontrolling interests	(12,887)	(9,986)
(Payments) proceeds from exercises of stock options, net of withholding taxes on restricted stock units	(1,067)	452
Offering costs paid related to initial public offering		(437)
Payment of capital lease obligations	(2,749)	(3,115)
Change in restricted cash	(126)	1,819
Net cash provided by financing activities	197,293	251,496
Net change in cash	(2,573)	4,449
Cash, beginning of period	206,364	203,864
Cash, end of period	203,791	208,313
Supplemental disclosures of cash flow information
Cash paid for interest	9,347	4,681
Supplemental disclosures of noncash investing and financing activities
Purchases of solar energy systems and property and equipment included in accounts payable and accrued expenses	22,468	15,769
Purchases of solar energy systems included in non-recourse debt	12,873
Distributions payable to noncontrolling interests and redeemable noncontrolling interests	11,157	7,368
Vehicles acquired under capital leases	$ 76	$ 7,318