Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Collaboration revenue	$ 1,023	$ 3,532
Operating expenses:
Research and development	4,896	6,779
General and administrative	4,825	6,052
Impairment loss	3,901	0
Total operating expenses	13,622	12,831
Loss from operations	(12,599)	(9,299)
Other income (expense):
Interest Expense	(210)	(488)
Interest income and other income (expense), net	(372)	(29)
(Loss) gain on debt extinguishment	(200)	1,134
Total other income (expense), net	(782)	617
Net loss	(13,381)	(8,682)
Net loss applicable to common shareholders	$ (13,381)	$ (8,682)
Net loss per share, basic and diluted	$ (1.24)	$ (0.85)
Weighted average common shares outstanding, basic and diluted	10,752,686	10,193,328