Fair Value of Financial Instruments (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	May 03, 2013
Assumptions used to calculate fair value of common stock warrant liability using Monte-Carlo simulation with a Black-Scholes lattice model
Interest rate (as a percent)	7.50%
Warrant to purchase common stock
Assumptions used to calculate fair value of common stock warrant liability using Monte-Carlo simulation with a Black-Scholes lattice model
Volatility (as a percent)	65.00%
Stock Price (in dollars per share)	$ 8.30
Dividend Yield (as a percent)	0.00%
Warrant to purchase common stock | Minimum
Assumptions used to calculate fair value of common stock warrant liability using Monte-Carlo simulation with a Black-Scholes lattice model
Exercise Price (in dollars per share)	$ 4.00
Term	6 years 1 month 6 days
Risk-Free Rate (as a percent)	1.80%
Warrant to purchase common stock | Maximum
Assumptions used to calculate fair value of common stock warrant liability using Monte-Carlo simulation with a Black-Scholes lattice model
Exercise Price (in dollars per share)	$ 5.00
Term	7 years
Risk-Free Rate (as a percent)	2.00%
Interest make-whole liability
Assumptions used to calculate fair value of common stock warrant liability using Monte-Carlo simulation with a Black-Scholes lattice model
Volatility (as a percent)	45.00%
Stock Price (in dollars per share)	$ 8.30
Credit Spread (as a percent)	14.63%
Term	2 years 3 months 18 days
Dividend Yield (as a percent)	0.00%
7.50% Convertible Senior Secured Notes due 2019
Assumptions used to calculate fair value of common stock warrant liability using Monte-Carlo simulation with a Black-Scholes lattice model
Interest rate (as a percent)	7.50%	7.50%