Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating expenses:
Research and development	$ 7,467	$ 6,471
General and administrative	5,971	7,131
Total operating expenses	13,438	13,602
Total operating loss	(13,438)	(13,602)
Other income (expense):
Interest income	231	38
Interest expense	(87)	(336)
Total other income (expense)	144	(298)
Net loss	(13,294)	(13,900)
Preferred stock dividends	(263)	(1,147)
Warrant modification (Note 5)	(6,622)
Net loss applicable to common stockholders	$ (20,179)	$ (15,047)
Basic and diluted net loss per share	$ (0.39)	$ (0.38)
Shares used in computing basic and diluted net loss per share	52,238	39,414