CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (114,021)	$ (44,585)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	95	55
Non-cash lease expense	468
Amortization and accretion of discounts on short-term investments	1,130	92
Stock compensation expense	28,115	4,998
Changes in operating assets and liabilities:
Unbilled grant receivables		129
Accrued interest	299	(160)
Prepaid expenses and other current assets	(1,943)	(4,542)
Other assets	(1,206)
Accounts payable, accrued expenses and amount due to related party	8,812	4,295
Net cash used in operating activities	(78,251)	(39,718)
Cash flows from investing activities
Purchase of property and equipment	(396)
Purchase of short-term investments	(30,098)	(242,419)
Maturities of short-term investments	230,000	71,000
Net cash provided by (used in) investing activities	199,506	(171,419)
Cash flows from financing activities
Payment of initial public offering costs		(3,120)
Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts of $22,238		295,449
Proceeds from exercise of stock options	167
Net cash provided by financing activities	167	292,329
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(44)	(26)
Net increase in cash, cash equivalents, and restricted cash	121,378	81,166
Cash, cash equivalents, and restricted cash at beginning of period	122,661	61,084
Cash, cash equivalents, and restricted cash at end of period	244,039	142,250
Non-cash investing and financing activities
Unrealized gain on available-for-sale securities	23	(83)
Right-of-use assets obtained in exchange for operating lease liability	26,386
Deferred offering costs included in accounts payable and accrued expenses		356
Conversion of preferred stock to common stock upon initial public offering		173,127
Cash and cash equivalents	243,187	142,250
Restricted cash	852
Total cash, cash equivalents, and restricted cash	$ 244,039	$ 142,250