Debt - Term Debt Narrative (Details) (USD $)	0 Months Ended		1 Months Ended	12 Months Ended	1 Months Ended
	Jul. 27, 2012	Jul. 18, 2011	Dec. 31, 2014 payment	Dec. 31, 2014	Jun. 30, 2011	Dec. 31, 2013	Dec. 31, 2009	Dec. 31, 2012
Debt Instrument [Line Items]
Warrant exercisable to Healthcare Royalty, shares		225,000
Warrants exercise price (in usd per share)	$ 2.50
Term of common stock warrant exercisable	5 years	10 years
Imputed interest on working capital advance			$ 5,297,000	$ 5,297,000
Fair value of warrant liabilities			4,978,000	4,978,000		30,849,000
Revolving credit facility							200,000
Shares of common stock exercisable through warrants	15,784,200
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility			4,000,000	4,000,000
Commitment fee amount			32,000
Number of additional commitment fee payments			3
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	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]
Warrants exercise price (in usd per share)			$ 1.18	$ 1.18	$ 3.78
Term of common stock warrant exercisable			10 years		7 years
Imputed interest on working capital advance			558,000	558,000				76,000
Shares of common stock exercisable through warrants			508,476		26,455
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	20,000,000
Interest rate (percent)			8.75%	8.75%
Consolidated revenue amount			50,000,000
Percent of principal amount of loan				5.00%
Facility fee			$ 200,000	$ 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%
Silicon Valley Bank [Member] | Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Deposit account percent of account balances			85.00%