Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net loss	$ (138,326)	$ (142,530)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization, net of amortization of deferred grants	65,282	46,564
Deferred income taxes	22,788	3,210
Stock-based compensation expense	11,389	8,647
Noncash interest expense	9,481	5,335
Interest on lease pass-through financing obligations	5,949	6,019
Reduction in lease pass-through financing obligations	(9,162)	(9,491)
Other noncash losses and expenses	4,590	2,924
Changes in operating assets and liabilities:
Accounts receivable	(4,215)	3,884
Inventories	14,582	(16,839)
Prepaid and other assets	(2,854)	(2,760)
Accounts payable	2,636	(9,889)
Accrued expenses and other liabilities	(11,283)	3,218
Deferred revenue	(4,314)	3,295
Net cash used in operating activities	(33,457)	(98,413)
Investing activities:
Payments for the costs of solar energy systems, leased and to be leased	(356,726)	(332,472)
Purchases of property and equipment	(4,464)	(8,208)
Business acquisition, net of cash acquired	0	(5,000)
Net cash used in investing activities	(361,190)	(345,680)
Financing activities:
Proceeds from state tax credits, net of recapture	13,171	9,123
Payment of debt fees	(4,955)	(12,277)
Proceeds from lease pass-through financing obligations	3,062	12,805
Contributions received from noncontrolling interests and redeemable noncontrolling interests	303,545	239,621
Distributions paid to noncontrolling interests and redeemable noncontrolling interests	(24,635)	(18,257)
(Payments) proceeds from exercises of stock options, net of withholding taxes on restricted stock units and issuance of shares in connection with the Employee Stock Purchase Plan	(425)	3,616
Offering costs paid related to initial public offering	0	(437)
Payment of capital lease obligations	(5,262)	(6,416)
Change in restricted cash	(2,592)	1,068
Net cash provided by financing activities	399,604	447,449
Net change in cash	4,957	3,356
Cash, beginning of period	206,364	203,864
Cash, end of period	211,321	207,220
Supplemental disclosures of cash flow information
Cash paid for interest	17,434	10,676
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	25,284	15,586
Purchases of solar energy systems included in non-recourse debt	12,873	0
Distributions payable to noncontrolling interests and redeemable noncontrolling interests	13,212	8,515
Vehicles acquired under capital leases	94	10,914
Recourse debt
Financing activities:
Proceeds from issuance of debt	91,400	257,400
Repayment of debt	(88,400)	(212,000)
Non recourse debt
Financing activities:
Proceeds from issuance of debt	199,525	189,746
Repayment of debt	$ (84,830)	$ (16,543)