CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities
Net loss	$ (44,585)	$ (15,096)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	55
Accretion of discounts on short-term investments	92	(450)
Stock compensation expense	4,998	2,268
Changes in operating assets and liabilities:
Subscription receivable and unbilled grants receivable	129	(273)
Accrued interest	(160)	(305)
Prepaid expenses and other current assets	(4,542)	(301)
Accounts payable, accrued expenses and amount due to related party	4,295	3,028
Deferred grant revenue		(158)
Net cash used in operating activities	(39,718)	(11,287)
Cash flows from investing activities
Purchase of property and equipment		(218)
Purchase of short-term investments	(242,419)	(119,305)
Maturities of short-term investments	71,000	20,000
Net cash used in investing activities	(171,419)	(99,523)
Cash flows from financing activities
Proceeds from issuance of Preferred Stock		121,253
Issuance costs related to the issuance of preferred stock		(330)
Payment of initial public offering costs	(3,120)
Proceeds from issuance of commons stock upon initial public offering, net of underwriting discounts of $22,238	295,449
Net cash provided by financing activities	292,329	120,923
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(26)
Net increase in cash, cash equivalents and restricted cash	81,166	10,113
Cash, cash equivalents and restricted cash at beginning of period	61,084	24,960
Cash, cash equivalents and restricted cash at end of period	142,250	35,073
Non-cash investing and financing activities
Unrealized gain on short-term investments	(83)	102
Right-of-use assets obtained in exchange for operating lease liability		$ 13,213
Deferred offering costs included in accounts payable and accrued expenses	356
Conversion of preferred stock to common stock upon initial public offering	$ 173,127