CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (93,079)	$ (87,404)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	960	804
Loss on disposal of property and equipment	87	0
Interest on non-recourse debt	13,482	9,962
Amortization of debt issuance costs	8	13
Non-cash lease expense	70	64
Non-cash expense related to stock-based compensation	3,848	1,743
Changes in other operating assets and liabilities	2,751	20,141
Net cash used in operating activities	(71,873)	(54,677)
Cash flows from investing activities
Purchases of property and equipment	(473)	(2,064)
Net cash used in investing activities	(473)	(2,064)
Cash flows from financing activities:
Exercise of stock options, net	32	1,825
Net cash provided by financing activities	32	1,825
Effect of changes in exchange rates on cash, cash equivalents and restricted cash	(19)	(9)
Net decrease in cash, cash equivalents and restricted cash	(72,333)	(54,925)
Cash, cash equivalents and restricted cash beginning of period	612,041	494,173
Cash, cash equivalents and restricted cash end of period	539,708	439,248
Supplemental disclosure of cash flow information:
Interest paid	169	169
Schedule for non-cash investing and financing activities:
Accrued capital expenditures	132	3,140
Shares received in cashless exercise	0	1,271
Issuance of common stock due to debt conversion	7,114	0
Non-cash lease expense	70	64
Change in operating lease liabilities	81	37
Total cash, cash equivalents and restricted cash	$ 539,708	$ 439,248