CONDENSED STATEMENTS OF OPERATIONS (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Grant revenues	$ 411		$ 411
Type of Revenue [Extensible List]	us-gaap:GrantMember	us-gaap:GrantMember	us-gaap:GrantMember	us-gaap:GrantMember
Operating expenses:
Research and development	$ 4,354	$ 1,330	$ 9,779	$ 4,387
General and administrative	1,056	565	2,616	1,700
Total operating expenses	5,410	1,895	12,395	6,087
Loss from operations	(4,999)	(1,895)	(11,984)	(6,087)
Other income (expense):
Interest income	60	14	132	29
Interest expense	(890)	(618)	(3,741)	(1,605)
Change in fair value of warrant liability	(1,713)	5	(2,709)	130
Change in fair value of derivative liability	(359)	(66)	(676)	(179)
Total other income (expense)	(2,902)	(665)	(6,994)	(1,625)
Net loss	$ (7,901)	$ (2,560)	$ (18,978)	$ (7,712)
Net loss per common share, basic and diluted	$ (10.45)	$ (3.44)	$ (25.33)	$ (10.38)
Weighted average common shares outstanding, basic and diluted	755,908	743,241	749,198	743,241