Consolidated Statements of Stockholders' Equity - 6 months ended Jun. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2014	$ 121,789	$ 63	$ 257,642	$ (135,916)
Balance, Shares at Dec. 31, 2014		63,182,806
Stock-based compensation	1,667		1,667
Issuance of common stock, net of issuance costs	52,533	$ 19	52,514
Issuance of common stock, net of issuance costs, Shares		18,681,000
Exercise of stock options	250		250
Exercise of stock options, Shares		618,000
Net loss	(19,468)			(19,468)
Balance at Jun. 30, 2015	$ 156,771	$ 82	$ 312,073	$ (155,384)
Balance, Shares at Jun. 30, 2015		82,481,722