Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating expenses:
Research and development	$ 3,384	$ 2,568
General and administrative	3,285	2,999
Total operating expenses	6,669	5,567
Operating loss	(6,669)	(5,567)
Other income (expense):
Interest income	57	54
Interest expense	(20)	(63)
Derivatives gain (loss)	241	(1,047)
Other income (expense), net	278	(1,056)
Net loss	$ (6,391)	$ (6,623)
Net loss per share, basic and diluted (in dollars per share)	$ (0.20)	$ (0.24)
Weighted average number of common shares outstanding, basic and diluted	32,080,141	28,171,606
Other comprehensive loss:
Net loss	$ (6,391)	$ (6,623)
Other comprehensive loss:
Unrealized loss on marketable securities	(2)
Comprehensive loss	$ (6,393)	$ (6,623)