CONDENSED STATEMENTS OF OPERATIONS (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Grant revenue	$ 653
Type of Revenue [Extensible List]	us-gaap:GrantMember	us-gaap:GrantMember
Operating expenses:
Research and development	$ 5,721	$ 2,235
General and administrative	2,316	643
Total operating expenses	8,037	2,878
Loss from operations	(7,384)	(2,878)
Other income (expense):
Interest income	317	36
Interest expense	(226)	(1,404)
Change in fair value of warrant liability		5
Change in fair value of derivative liability		(162)
Total other income (expense)	91	(1,525)
Net loss	$ (7,293)	$ (4,403)
Net loss per common share, basic and diluted	$ (0.30)	$ (5.90)
Weighted average common shares outstanding, basic and diluted	24,498,388	745,812