Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Operating expenses:
Research and development	$ 2,546	$ 3,051	$ 4,849	$ 6,293
General and administrative	3,214	1,688	6,422	3,517
Total operating expenses	5,760	4,739	11,271	9,810
Operating loss	(5,760)	(4,739)	(11,271)	(9,810)
Other income (expense):
Interest income	2	1	3	2
Interest expense	(32)	(35)	(66)	(68)
Derivatives gain (loss)	(4,653)	1,127	(14,940)	1,127
Other income (expense), net	(4,683)	1,093	(15,003)	1,061
Net loss	$ (10,443)	$ (3,646)	$ (26,273)	$ (8,749)
Net loss per share, basic (in dollars per share)	$ (0.39)	$ (0.17)	$ (1.02)	$ (0.45)
Net loss per share, diluted (in dollars per share)	$ (0.39)	$ (0.17)	$ (1.02)	$ (0.45)
Weighted average number of common shares outstanding, basic (in shares)	26,508,170	21,821,355	25,713,438	19,561,455
Weighted average number of common shares outstanding, diluted (in shares)	26,508,170	21,821,355	25,713,438	19,561,455