CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Grant revenue	$ 1,097	$ 3,042	$ 2,919	$ 10,342
Collaboration revenue	$ 896	$ 2,106	$ 1,143	$ 2,106
Type of Revenue [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember
Total revenues	$ 1,993	$ 5,148	$ 4,062	$ 12,448
Operating expenses:
Research and development	8,173	14,461	25,144	32,865
General and administrative	8,051	9,229	23,356	17,528
Restructuring	11,849	0	11,849	0
Total operating expenses	28,073	23,690	60,349	50,393
Loss from operations	(26,080)	(18,542)	(56,287)	(37,945)
Other income (expense):
Interest income	111	82	183	180
Other income (expense), net	(10)	(112)	(23)	(230)
Interest expense related to the sale of future royalties	(117)	0	(2,605)	0
Loss on extinguishment of liability related to the sale of future royalties	(3,581)	0	(3,581)	0
Change in fair value of derivative liability	995	0	802	0
Total other income (expense), net	(2,602)	(30)	(5,224)	(50)
Net loss	$ (28,682)	$ (18,572)	$ (61,511)	$ (37,995)
Net loss per share, basic and diluted	$ (0.87)	$ (0.63)	$ (1.88)	$ (1.29)
Net loss per share, basic and diluted	$ (0.87)	$ (0.63)	$ (1.88)	$ (1.29)
Weighted average common shares outstanding, basic and diluted	32,977,807	29,675,399	32,793,288	29,545,496
Weighted average common shares outstanding, basic and diluted:	32,977,807	29,675,399	32,793,288	29,545,496
Comprehensive loss:
Net loss	$ (28,682)	$ (18,572)	$ (61,511)	$ (37,995)
Other comprehensive gain (loss):
Unrealized gain (loss) on marketable securities	6	1	2	5
Net unrealized gains (losses) on securities	6	1	2	5
Total comprehensive loss	$ (28,676)	$ (18,571)	$ (61,509)	$ (37,990)