Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share, Basic [Abstract]
Numerator for basic loss per share									$ (34,453)	$ (25,650)	$ (31,554)
Denominator for basic income (loss) per share (in shares)									42,178,397	40,789,445	29,830,207
Basic income (loss) per common share (in dollars per share)	$ (0.40)	$ (0.04)	$ (0.17)	$ (0.21)	$ (0.08)	$ (0.15)	$ (0.06)	$ (0.35)	$ (0.82)	$ (0.63)	$ (1.06)
Earnings Per Share, Diluted [Abstract]
Numerator for basic loss per share									$ (34,453)	$ (25,650)	$ (31,554)
Warrant revaluation income (expense) for dilutive warrants									1,529	2,840	2,270
Numerator for diluted loss per share									$ (35,982)	$ (28,490)	$ (33,824)
Denominator for basic income (loss) per share (in shares)									42,178,397	40,789,445	29,830,207
Incremental shares underlying in the money warrants outstanding (in shares)									172,949	179,954	366,409
Weighted average number of common shares outstanding - diluted (in shares)									42,351,346	40,969,399	30,196,616
Diluted net income (loss) per share (in dollars per share)	$ (0.40)	$ (0.07)	$ (0.17)	$ (0.21)	$ (0.09)	$ (0.17)	$ (0.09)	$ (0.35)	$ (0.85)	$ (0.70)	$ (1.12)