Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenue		$ 34	$ 71
Operating expenses:
Research and development expenses	[1]	6,925	5,680
General and administrative expenses	[1]	3,346	3,217
Total operating expenses		10,271	8,897
Operating loss		(10,237)	(8,826)
Other income:
Interest income, net		16	17
Other income (expense), net		(2)	9
Total other income		14	26
Loss before income taxes		(10,223)	(8,800)
Provision for income taxes		0	0
Net loss		(10,223)	(8,800)
Series A and A-1 convertible preferred stock dividends		(209)	(4,130)
Net loss applicable to common stockholders		$ (10,432)	$ (12,930)
Net loss per common share applicable to common stockholders:
Basic and diluted		$ (0.21)	$ (0.79)
Weighted average common shares: basic and diluted		49,703,822	16,362,905

[1] Non-cash stock-based compensation expenses included in operating expenses are as follows: Research and development $ 632 $ 836 General and administrative $ 903 $ 1,010