Debt - Outstanding Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total debt, Outstanding Principal	$ 22,900	$ 18,000
Less: Current portion, Outstanding Principal	(20,000)	(18,000)
Long-term debt, Outstanding Principal	2,900
Total debt, Unamortized Discount	(2,784)	(75)
Less: Current portion, Unamortized Discount	1,100	75
Long-term debt, Unamortized Discount	(1,684)
Total debt, Net Carrying Amount	20,116	17,925
Less: Current portion, Net Carrying Amount	(18,900)	(17,925)
Long-term debt	1,216
GE Secured Lending Facility
Debt Instrument [Line Items]
Total debt, Outstanding Principal		18,000
Total debt, Unamortized Discount		(75)
Total debt, Net Carrying Amount		17,925
Less: Current portion, Net Carrying Amount	(14,300)
Hercules Term Loan
Debt Instrument [Line Items]
Total debt, Outstanding Principal	20,000
Total debt, Unamortized Discount	(1,100)
Total debt, Net Carrying Amount	18,900
Convertible Note
Debt Instrument [Line Items]
Total debt, Outstanding Principal	2,900
Total debt, Unamortized Discount	(1,684)
Total debt, Net Carrying Amount	$ 1,216