Fair Value Measurements (Level III) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)
Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	$ 2,232
Change in fair value	3,925
Balance at the end of the period	6,157
Senior Secured Term Loan | Non‑operating expense
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	20,964
Change in fair value	2,122
Balance at the end of the period	$ 23,086