Stockholders’ Equity (Deficit) (Details) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Shareholders Deficit [Line Items]
Number of Warrants, Outstanding as of December 31, 2014	29,385
Number of Warrants, Warrants exercised for cash	(888)
Number of Warrants, Warrants exercised on a cashless basis	(117)	[1]
Number of Warrants, Warrant adjustment due to Cognate price reset	62
Number of Warrants, Expired in first quarter of 2015	(128)
Number of Warrants, Adjustment related to prior issued warrants	16
Number of Warrants, Outstanding as of March 31, 2015	28,330	[2]
Weighted Average Exercise Price - Outstanding as of December 31, 2014	4.72
Weighted Average Exercise Price - Warrants exercised for cash	4.11
Weighted average exercise Price - Warrants exercised on a cashless basis	3.35	[1]
Weighted Average Exercise Price - Warrant adjustment due to Cognate price reset	3.35
Weighted Average Exercise Price - Expired in first quarter of 2015	9.42
Weighted Average Exercise Price - Adjustment related to prior issued warrants	5.73
Weighted Average Exercise Price - Outstanding as of March 31, 2015	4.72	[2]

[1] The warrants contain “down round protection” and the Company classifies these warrant instruments as liabilities measured at fair value and re-measures these instruments at fair value each reporting period.

[2] Approximately 14,323,003 warrants issued to Cognate, during the eight year period from 2008 through 2015, with a weighted average exercise price and remaining contractual term of $3.3 and 4.4 years, respectively. The weighted average exercise price gives effect to adjustments related to the most favored nation clause that occurred during the period.