STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Grant revenues	$ 668
Type of Revenue [Extensible List]	us-gaap:GrantMember	us-gaap:GrantMember
Operating expenses:
Research and development	$ 15,455	$ 6,210
General and administrative	4,857	2,328
Total operating expenses	20,312	8,538
Loss from operations	(19,644)	(8,538)
Other income (expense):
Interest income	387	52
Interest expense	(3,924)	(2,723)
Change in fair value of warrant liability	11	1,019
Change in fair value of derivative liability	(676)	(57)
Total other income (expense)	(4,202)	(1,709)
Net loss	$ (23,846)	$ (10,247)
Net loss per common share, basic and diluted	$ (4.49)	$ (13.78)
Weighted average common shares outstanding, basic and diluted	5,305,062	743,470