CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (168,710)	$ (171,962)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	723	189
Non-cash lease expense	1,842	928
(Accretion) amortization of short-term investment (premiums) discounts	(1,076)	1,197
Stock-based compensation expense	41,315	43,975
Changes in operating assets and liabilities:
Interest receivable	(107)	400
Prepaid expenses and other current assets and prepaid expenses to related party	(3,028)	(1,241)
Other assets	490	(1,102)
Income tax payable	(879)	1,007
Accounts payable, accrued expenses and amount due to related party	(12,622)	20,290
Net cash used in operating activities	(142,052)	(106,319)
Cash flows from investing activities
Purchase of property and equipment		(26)
Purchase of short-term investments	(228,806)	(76,591)
Maturities of short-term investments	148,328	262,600
Net cash (used in) provided by investing activities	(80,478)	185,983
Cash flows from financing activities
Proceeds from issuance of common stock in registered direct offering, net of issuance costs	126,425
Proceeds from issuance of stock under the 2020 Employee Stock Purchase Plan	536
Proceeds from exercise of stock options		232
Net cash provided by financing activities	126,961	232
Effect of exchange rate changes on cash, cash equivalents, and restricted cash		(44)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(95,569)	79,852
Cash, cash equivalents, and restricted cash at beginning of period	202,513	122,661
Cash, cash equivalents, and restricted cash at end of period	106,944	202,513
Non-cash investing and financing activities
Unrealized (loss) gain on available-for-sale securities	(313)	1
Right-of-use assets obtained in exchange for operating lease liability	14,717	26,386
Reduction of right-of-use asset due to modification	(5,506)
Purchase of property and equipment included in AP and accrued expenses	104	899
Supplemental disclosure of cash flows
Income taxes paid, net of refunds	613
Cash and cash equivalents	106,092	201,661
Restricted Cash	852	852
Total cash, cash equivalents, and restricted cash	$ 106,944	$ 202,513