Fair Value of Financial Instruments (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2015
Fair Value of Financial Instruments
Interest rate (as a percent)	7.50%
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)	$ 12.09
Credit Spread (as a percent)	13.88%
Term	2 years 1 month 6 days
Dividend Yield (as a percent)	0.00%
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)	$ 12.09
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	5 years 9 months 18 days
Risk-Free Rate (as a percent)	1.50%
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	6 years 9 months 18 days
Risk-Free Rate (as a percent)	1.70%