CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net loss	$ (68,511)	$ (20,971)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	51	37
Non-cash lease expense	210
Amortization and accretion of discounts on short-term investments	897	7
Stock compensation expense	17,829	1,138
Changes in operating assets and liabilities:
Unbilled grant receivables		(56)
Accrued interest	41	204
Prepaid expenses and other current assets	1,638	(1,749)
Other assets	(692)
Accounts payable, accrued expenses and amount due to related party	6,723	(271)
Net cash used in operating activities	(41,814)	(21,661)
Cash flows from investing activities
Purchase of property and equipment	(363)
Purchase of short-term investments	(30,098)	(26,156)
Maturities of short-term investments	175,000	65,000
Net cash provided by investing activities	144,539	38,844
Cash flows from financing activities
Effect of exchange rate changes on cash and cash equivalents	61
Net increase in cash and cash equivalents	102,786	17,183
Cash and cash equivalents at beginning of period	122,661	61,084
Cash and cash equivalents at end of period	225,447	78,627
Non-cash investing and financing activities
Unrealized gain on available-for-sale securities	26	$ 42
Right-of-use assets obtained in exchange for operating lease liability	3,089
Purchase of property and equipment included in accounts payable and accrued expenses	$ 91