Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

Summary of financial assets and liabilities measured on recurring basis

	June 30, 2015								December 31, 2014
	Level I		Level II		Level III		Total		Level I		Level II		Level III		Total
	(in thousands)
Current Liabilities:
Warrants	$	—	$	—	$	6,157	$	6,157	$	—	$	—	$	2,232	$	2,232
Long‑term Liabilities:
Senior secured term loan	$	—	$	—	$	23,086	$	23,086	$	—	$	—	$	20,964	$	20,964

Summary of quantitative information about inputs and valuation methodologies

					Weighted Average
					Interest on
	Fair Value at			Significant	Discount Rate
	June 30, 2015		Valuation Methodology	Unobservable Input	(range, if applicable)
	(in thousands)				(in thousands)
Senior secured term loan	$	23,086
—Term loan			Discounted Cash Flows	Discount rate on CCC bond plus premium					15.0	%
					CCC Bond range
					(3.7%‑ 25.3%)
—Royalty interest			Royalty interest in future revenues	Revenues Volatility	$	191,503	-	$	439,655
									33.3	%
—Loan commitment			Discounted Cash Flows	Discount rate on CCC bond plus premium					15.0	%
					CCC Bond range
					(3.7% ‑ 25.3%)
—Warrants	$	6,157	PWERM with 100% weight of the IPO price of $18.00 per share	Discount for lack of marketability					4.3	%
				Volatility					26.5	%

Warrants

Rollforward of fair value determined by Level 3 inputs

	Warrants
	(in thousands)
Balance at December 31, 2014	$	2,232
Change in fair value		3,925
Balance at June 30, 2015	$	6,157

Senior Secured Term Loan

Rollforward of fair value determined by Level 3 inputs

	Term Loan
	(in thousands)
Balance at December 31, 2014	$	20,964
Change in fair value recognized in non‑operating expense		2,122
Balance at June 30, 2015	$	23,086