CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (157,749)	$ (357,319)	$ (273,887)	$ (153,266)
Adjustments to reconcile net loss to net cash used in operating activities:
Changes in fair value of warrant liabilities	(1,404)	0	108,636	61,074
Warrant related expense	0	0	0	7,649
Depreciation and amortization	2,099	3,822	1,297	923
Loss on disposal of property and equipment	0	1,003	0	0
Interest on non-recourse debt	19,288	39,929	19,791	0
Loss on induced exchanges of debt	897	0	13,005	0
Amortization of deferred revenue	(94)	0	(77)	(64)
Amortization of bond premiums	3	0	31	218
Amortization of debt issuance costs	179	50	1,679	730
Amortization of deferred rent	132	0	279	10
Non-cash lease expense	0	264	0	0
Loss on sale of marketable securities	0	0	0	16
Decrease in allowance for doubtful accounts	0	0	(9)	(62)
Non-cash expense related to stock-based compensation	886	11,736	4,024	4,333
Non-cash financing expenses	0	0	0	347
Changes in operating assets and liabilities
Accounts receivable, net	46	(295)	452	103
Inventories, net	0	0	580	(196)
Other receivables	0	0	(30)	223
Prepaid expenses and other current assets	3,617	(16,423)	(7,679)	(97)
Accounts payable and accrued expenses	1,436	29,977	(1,518)	15,809
Other liabilities	0	(186)	0	0
Deferred revenue	0	65,000	0	0
Net cash used in operating activities	(130,664)	(222,442)	(133,426)	(62,250)
Cash flows from investing activities:
Purchases of marketable securities	0	0	(10,380)	(131,610)
Proceeds from sales/maturities of marketable securities	21,818	0	95,112	57,183
Purchases of property and equipment	(11,213)	(6,849)	(9,975)	(1,837)
Net cash (used in) provided by investing activities	10,605	(6,849)	74,757	(76,264)
Cash flows from financing activities:
Exercise of stock options, net	176	2,553	2,261	4,290
Exercise of warrants	1,688	0	78,226	0
Sale of preferred stock, net of related expenses	0	0	0	121,782
Proceeds from public offering of common stock	0	273,031	299,467	28,578
Proceeds from the issuance of non-recourse debt	0	0	182,216	0
Debt conversion fees	0	0	(530)	0
Tax withholding payments for stock-based compensation	(192)	0	(1,521)	(546)
Net cash provided by financing activities	1,672	347,181	627,903	168,804
Effect of changes in exchange rates on cash, cash equivalents and restricted cash	(22)	(22)	(46)	(100)
Net increase (decrease) in cash, cash equivalents and restricted cash	(118,409)	117,868	569,188	30,190
Cash, cash equivalents, and restricted cash beginning of period	612,582	494,173	43,394	13,204
Cash, cash equivalents, and restricted cash end of period	494,173	612,041	612,582	43,394
Supplemental disclosure of cash flow information:
Interest paid	475	338	2,850	4,750
Income taxes paid	0	0	0	24
Schedule of non-cash investing and financing activities:
Issuance of common shares for debt conversion	13,757	0	92,307	0
Accrued capital expenditures	795	101	2,173	0
Non-cash component of warrant exercise	7,569	0	0	0
Shares received in cashless exercise	2,450	1,271	0	0
Total cash, cash equivalents and restricted cash	612,582	494,173	612,582	13,204
Market Offering
Cash flows from financing activities:
Proceeds from private offering of common stock	0	71,597	0	0
Private placement
Cash flows from financing activities:
Proceeds from private offering of common stock	$ 0	$ 0	$ 67,784	$ 14,700