Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Grant revenue	$ 2,425	$ 2,521
Operating expenses:
Research and development	10,159	8,287
In-process research and development	18,088
General and administrative	7,286	1,820
Total operating expenses	35,533	10,107
Loss from operations	(33,108)	(7,586)
Other income (expense):
Change in fair value of warrant liability	(1,268)	713
Other income		216
Interest expense		(1)
Interest income	188	79
Total other income (expense)	(1,080)	1,007
Net loss	$ (34,188)	$ (6,579)
Net loss per share, basic and diluted	$ (3.31)	$ (1.83)
Weighted-average shares outstanding, basic and diluted	10,329	3,591