Deerfield Loan (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Disbursement	Dec. 31, 2013	Dec. 31, 2012
Line of Credit Facility [Line Items]
Date facility agreement entered	Feb. 13, 2013
Loan facility, maximum amount	$ 30,000,000
Number of disbursements	2
Loan facility payment terms	The principal amount of the loan is payable in three $10 million annual installments beginning in February 2017, provided that the amount payable in February 2017 shall be deferred for one year if either (i) our “Net Sales” (defined below) for the immediately preceding 12-month period are at least $20 million, or (ii) our “Equity Value” (defined below) is at least $200 million; and provided further, that the amount payable in February 2018 (together with any amount deferred in February 2017) shall be deferred until February 2019 if either (i) our “Net Sales” for the immediately preceding 12-month period are at least $30 million, or (ii) our “Equity Value” is at least $250 million.
Transaction fee, percentage (in hundredths)	1.50%
Cash interest rate under loan facility (in hundredths)	8.75%
Percentage sale of assets (in hundredths)	50.00%
Number of shares under issued warrants (in shares)	7.0
Exercise price of warrants (in dollars per share)	$ 2.81
Percentage of common stock, maximum (in hundredths)	9.985%
Fair value of warrants issued under both the first and second disbursement	11,700,000
Transaction fee	450,000
Carrying value of Facility Agreement [Abstract]
Note Payable	30,000,000	30,000,000
Unamortized discount	(9,698,000)	(11,646,000)
Long-term debt, net of discount	20,302,000	18,354,000
Interest expense [Abstract]
Cash interest expense	2,625,000	911,000	0
Non-cash amortization of debt discounts	1,948,000	534,000	0
Amortization of debt costs	19,000	18,000	0
Total Deerfield Loan interest expenses	4,592,000	1,463,000	0
Deerfield Warrants [Member]
Significant unobservable input assumptions of Level 3 valuations [Abstract]
Historical Volatility (in hundredths)	101.00%
Minimum [Member] | Deerfield Warrants [Member]
Significant unobservable input assumptions of Level 3 valuations [Abstract]
Expected Term (in years)	5 years 2 months 12 days
Risk-free interest rate (in hundredths)	1.20%
Maximum [Member] | Deerfield Warrants [Member]
Significant unobservable input assumptions of Level 3 valuations [Abstract]
Expected Term (in years)	6 years
Risk-free interest rate (in hundredths)	1.50%
First Disbursement [Member]
Line of Credit Facility [Line Items]
Number of shares under issued warrants (in shares)	2.3
Second Disbursement [Member]
Line of Credit Facility [Line Items]
Number of shares under issued warrants (in shares)	4.7
Fourth anniversary [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Net sales for 12-month period immediately preceding repayment date	20,000,000
Equity Value at repayment date	200,000,000
Sixth anniversary [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Net sales for 12-month period immediately preceding repayment date	30,000,000
Equity Value at repayment date	$ 250,000,000