CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues:
Grant revenue	$ 7,300	$ 1,532
Collaboration revenue		$ 169
Type of Revenue [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember
Total revenues	$ 7,300	$ 1,701
Operating expenses:
Research and development	18,404	20,436
General and administrative	8,299	4,086
Total operating expenses	26,703	24,522
Loss from operations	(19,403)	(22,821)
Other income (expense):
Interest income	98	237
Other income (expense), net	(118)	(674)
Total other income (expense), net	(20)	(437)
Net loss	$ (19,423)	$ (23,258)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.66)	$ (1.22)
Weighted average common shares outstanding, basic and diluted:	29,414,148	19,557,418
Comprehensive loss:
Net loss	$ (19,423)	$ (23,258)
Other comprehensive gain (loss):
Unrealized gain (loss) on marketable securities	4	(35)
Net unrealized gains (losses) on securities	4	(35)
Total comprehensive loss	$ (19,419)	$ (23,293)