Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net loss	$ (60,492)	$ (7,374)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,772	681
Depreciation and amortization	216	185
Non-cash lease expense	143	138
Changes in operating assets and liabilities:
Unbilled grants receivable	233	(328)
Grants receivable	238	1,735
Prepaid expenses and other current assets	(342)	(29)
Prepaid research and development	6,803	(99)
Other long term assets	(981)
Accounts payable	5,821	(160)
Accrued expenses and other liabilities	24,283	(138)
Lease liabilities	(179)	(193)
Net cash used in operating activities	(22,485)	(5,582)
Investing activities
Purchase of property and equipment	(698)	(119)
Net cash used in investing activities	(698)	(119)
Financing activities
Proceeds from initial public offering, net of issuance costs	233,348
Proceeds from stock option exercises	131	5
Net cash provided by financing activities	233,479	5
Net increase in cash and restricted cash	210,296	(5,696)
Cash and restricted cash at beginning of period	173,133	21,604
Cash and restricted cash at end of period	383,429	15,908
Supplemental disclosure of noncash investing and financing activities
Property and equipment purchases included in accounts payable and accrued expenses and other liabilities	117	$ 73
Deferred initial public offering costs included in accrued expenses and other liabilities	$ 802