Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue:
Grant revenue	$ 62	$ 177
Operating expenses:
Research and development	6,227	4,222
Selling, general and administrative	10,333	1,780
Total operating expenses	16,560	6,002
Loss from operations	(16,498)	(5,825)
Other income (expense):
Interest income	69	332
Total other income (expense)	69	332
Net loss	(16,429)	(5,493)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities	(26)	533
Comprehensive loss	$ (16,455)	$ (4,960)
Net loss per share available to common shareholders, diluted (in usd per share)	$ (0.27)	$ (0.61)
Net loss per share available to common shareholders, basic (in usd per share)	$ (0.27)	$ (0.61)
Weighted average number of shares outstanding, diluted (in shares)	59,887,842	8,944,284
Weighted-average common shares outstanding, basic (in shares)	59,887,842	8,944,284
Revenue, Product and Service [Extensible List]	Grant revenue	Grant revenue