Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (145,341)	$ (254,763)
Adjustments to reconcile net loss to net cash used in operating activities:
Noncash stock compensation expense	8,134	46,918
Depreciation and amortization	230	202
Amortization of premium (discount) on investment securities	(172)	421
Amortization of debt issuance costs	1,383	694
Amortization of leasehold interest	159	159
Noncash change in lease liability and right of use asset	2,205	1,422
Change in fair value of notes payable	(241)	(315)
Changes in assets and liabilities:
Decrease (increase) in other current assets	7,842	(7,255)
Decrease (increase) in accounts receivable	1,389	(1,384)
(Decrease) increase in accounts payable and accrued expenses	(27,436)	12,090
Decrease in lease liabilities	(1,741)	(1,507)
Increase (decrease) in other current liabilities	1,403	(5,293)
Decrease in deferred revenue	(114)	(114)
Net cash used in operating activities	(152,300)	(208,725)
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from maturity of short-term securities	67,005	40,000
Investment in held-to-maturity securities	(103,276)	(43,299)
Purchases of PPE	(11)	(321)
Net cash used in investing activities	(36,282)	(3,620)
CASH FLOWS FROM FINANCING ACTIVITIES
Payment of loan payable	(975)	(14,590)
Proceeds from exercise of options	535	216
Offering costs paid		(204)
Net cash used in financing activities	(440)	(14,578)
NET DECREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(189,022)	(226,923)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF PERIOD	300,151	554,698
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	$ 111,129	$ 327,775