CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (43,863)	$ (30,923)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	466	18
Non-cash lease expense	380	54
Amortization and accretion of discounts on short-term investments	76	456
Stock compensation expense	10,467	8,103
Changes in operating assets and liabilities:
Interest receivable	(122)	(19)
Prepaid expenses and other current assets	284	1,735
Other assets	122
Income tax payable	(500)
Accounts payable, accrued expenses and amount due to related party	(13,786)	1,650
Net cash used in operating activities	(46,476)	(18,926)
Cash flows from investing activities
Purchase of property and equipment		(75)
Purchase of short-term investments	(60,979)	(30,098)
Maturities of short-term investments	6,000	95,000
Net cash (used in) provided by investing activities	(54,979)	64,827
Cash flows from financing activities
Effect of exchange rate changes on cash, cash equivalents, and restricted cash		83
Net (decrease) increase in cash, cash equivalents, and restricted cash	(101,455)	45,984
Cash, cash equivalents, and restricted cash at beginning of period	202,513	122,661
Cash, cash equivalents, and restricted cash at end of period	101,058	168,645
Non-cash investing and financing activities
Unrealized (loss) gain on available-for-sale securities	(195)	42
Right-of-use assets obtained in exchange for operating lease liability		3,099
Reduction of right-of-use asset due to modification	(5,506)
Supplemental disclosure of cash flows
Cash paid for income taxes	500
Cash and cash equivalents	100,206	168,645
Restricted cash	852
Total cash, cash equivalents, and restricted cash	$ 101,058	$ 168,645