Debt (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Dec. 31, 2014 USD ($) item	Apr. 30, 2013 USD ($) item	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($)	Dec. 31, 2007 $ / shares
Line of Credit Facility [Line Items]
Royalty and interest expense			$ 1,203	$ 936	$ 2,213	$ 1,745
Exercise price of warrants (in dollars per share) | $ / shares							$ 0.0978
Long-term Debt, Fiscal Year Maturity [Abstract]
2015 (six months)			1,170		1,170
2016			2,340		2,340
2017			1,170		1,170
2019			20,000		20,000
Total			$ 24,680		24,680
Credit Agreement
Line of Credit Facility [Line Items]
Borrowing capacity		$ 40,000
Borrowings		$ 20,000
Base interest rate (as a percent)		1.00%
Spread on base interest rate (as a percent)		8.00%
Interest rate floor (as a percent)		9.00%
Royalty payment percentage owed on fiscal year revenues up to threshold		1.00%
Revenue threshold amount for determination of royalty payment percentage		$ 50,000
Royalty payment percentage owed on fiscal year revenues in excess of threshold		1.50%
Interest expense					900	900
Royalty expenses					$ 1,100	$ 700
Effective interest and royalty yield (as a percent)					20.50%
Number of shares of common stock that may be called by warrants | shares			376,691		376,691
Exercise price of warrants (in dollars per share) | $ / shares			$ 2.3229		$ 2.3229
Prepayment premium (as a percent)			10.00%		10.00%
Minimum liquidity required under debt covenants			$ 5,000		$ 5,000
Equipment Financing Facility
Line of Credit Facility [Line Items]
Borrowing capacity		$ 5,000
Borrowings	$ 5,900
Prepayment premium (as a percent)	1.00%
Spread on variable rate (as a percent)		4.10%
Effective interest rate upon closing (as a percent)	6.35%	7.35%
Number of payment installments | item	30	27
Minimum cash balance required under debt covenants		$ 5,000
Equipment Financing Facility | 30-day LIBOR
Line of Credit Facility [Line Items]
Spread on reference rate (as a percent)		2.50%
Equipment Financing Facility | Prime
Line of Credit Facility [Line Items]
Spread on variable rate (as a percent)	3.10%