Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating expenses:
Research and development	$ 1,505	$ 3,503	$ 5,279	$ 10,719
General and administrative	1,175	911	5,338	3,155
Total operating expenses	2,680	4,414	10,617	13,874
Total operating loss	(2,680)	(4,414)	(10,617)	(13,874)
Other income (expense):
Interest income	15	6	23	21
Interest expense	(87)		(256)
Total other income (expense)	(72)	6	(233)	21
Net loss	(2,752)	(4,408)	(10,850)	(13,853)
Preferred stock dividends	(294)	(254)	(848)	(827)
Net loss applicable to common stockholders	$ (3,046)	$ (4,662)	$ (11,698)	$ (14,680)
Net loss per common share - basic and diluted	$ (0.07)	$ (0.13)	$ (0.30)	$ (0.42)
Weighted average common shares outstanding - basic and diluted	40,921	35,165	38,822	34,600