CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (69,784)	$ (23,839)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	73	19
Amortization and accretion of discounts on short-term investments	502	(620)
Stock compensation expense	9,429	2,890
Changes in operating assets and liabilities:
Unbilled grant receivables	298	4
Accrued interest	(188)	(262)
Prepaid expenses and other current assets	(3,867)	(620)
Accounts payable, accrued expenses and amount due to related party	2,726	4,936
Deferred grant revenue		(2,663)
Net cash used in operating activities	(60,811)	(20,155)
Cash flows from investing activities
Purchase of property and equipment	(235)	(339)
Purchase of short-term investments	(300,262)	(119,305)
Maturities of short-term investments	131,000	55,000
Net cash used in investing activities	(169,497)	(64,644)
Cash flows from financing activities
Proceeds from issuance of Series B Preferred Stock		121,253
Issuance costs related to the issuance of preferred stock		(330)
Payment of initial public offering costs	(3,474)
Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts of $22,238	295,449
Net cash provided by financing activities	291,975	120,923
Effect of exchange rate changes on cash and cash equivalents	(90)
Net increase in cash and cash equivalents	61,577	36,124
Cash and cash equivalents at beginning of period	61,084	24,960
Cash and cash equivalents at end of period	122,661	61,084
Non-cash investing and financing activities
Unrealized (loss) gain on available-for-sale securities	(90)	68
Right-of-use assets obtained in exchange for operating lease liability		13,213
Purchase of property and equipment included in AP and accrued expenses	300	30
Issuance of Series A3 Preferred Stock related to anti-dilution rights		3,681
Conversion of preferred stock to common stock upon initial public offering	$ 173,127
Supplemental disclosure of cash flows
Cash paid for interest		$ 125