CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Federal contract revenue	$ 1,905		$ 3,711
Expenses:
Research and development	18,562	$ 11,752	37,153	$ 26,756
General and administrative	6,828	4,130	17,204	7,980
Loss from operations	(23,485)	(15,882)	(50,646)	(34,736)
Interest income	16	212	40	398
Interest expense	(351)		(351)
Other expense, net	(3)	(5)	(7)	(9)
Net loss and comprehensive loss	(23,823)	(15,675)	(50,964)	(34,347)
Deemed dividends on convertible preferred stock				(8,880)
Net loss applicable to common shareholders	$ (23,823)	$ (15,675)	$ (50,964)	$ (43,227)
Per share information:
Net loss per share of common stock-basic and diluted	$ (0.65)	$ (0.63)	$ (1.39)	$ (1.86)
Basic and diluted weighted average shares outstanding	36,659,615	24,942,624	36,629,823	23,295,199
Net loss	$ (23,823)	$ (15,675)	$ (50,964)	$ (34,347)
Other comprehensive income:
Unrealized gain on available-for-sale securities				27
Total comprehensive loss	$ (23,823)	$ (15,675)	$ (50,964)	$ (34,320)