Debt - Term Debt Narrative (Details)	1 Months Ended				12 Months Ended
	Dec. 31, 2014 USD ($) payment $ / shares shares	Jul. 31, 2012 shares	Jul. 31, 2011	Jun. 30, 2011 $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares	Dec. 31, 2013 USD ($)	Jul. 27, 2012 $ / shares	Dec. 31, 2011 USD ($)
Debt Instrument [Line Items]
Long-term debt interest expense					$ 3,060,000	$ 2,750,000	$ 5,672,000
Shares of common stock exercisable through warrants | shares		1,973,025
Warrants exercise price (in usd per share) | $ / shares								$ 20.00
Term of common stock warrant exercisable		5 years	10 years
Imputed interest on working capital advance					4,615,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility					4,000,000
Commitment fee amount	$ 32,000
Number of additional commitment fee payments | payment	2
Commitment fee due in one year	$ 32,000
Commitment fee due in year two	32,000
Commitment fee due In year three	32,000
Costs related to securing debt	$ 241,000
Loan And Security Agreement [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility					$ 4,000,000
Maximum borrowing capacity against eligible account receivable (percent)					85.00%
Default rate amount added to interest rate (percent)	5.00%
Oxford/SVB [Member]
Debt Instrument [Line Items]
Shares of common stock exercisable through warrants | shares	63,559			3,306
Warrants exercised | shares	31,779				31,779
Warrants exercise price (in usd per share) | $ / shares	$ 9.44			$ 30.24	$ 9.44	$ 9.44
Term of common stock warrant exercisable	10 years			7 years
Imputed interest on working capital advance	$ 558,000					$ 558,000			$ 76,000
Prime Rate [Member] | Loan And Security Agreement [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	4.75%
Term Loan [Member] | Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Revolving credit facility					$ 20,000,000
Interest rate (percent)					8.75%
Outstanding balance	$ 20,000,000				$ 20,000,000	20,000,000
Percent of principal amount of loan					5.00%
Facility fee					$ 200,000
Term Loan [Member] | Prime Rate [Member] | Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	5.25%
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding balance	$ 1,450,000				$ 0	$ 1,450,000
Silicon Valley Bank [Member] | Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Deposit account percent of account balances	85.00%
Liquidity ratio					1.25