Debt and Related Warrants - Summary of 2015 Credit Facility (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
2015 Credit Facility
Net carrying value of debt, Current Portion	$ 3,910	$ 3,884
Net carrying value of debt, Long-term debt	3,517	4,218
2015 Credit Facility
2015 Credit Facility
Debt, including end of term fee, Current Portion	4,054	4,054
Less: Discount attributable to warrants, end of term fee and debt issuance costs, Current Portion	(144)	(177)
Net carrying value of debt, Current Portion	3,910	3,877
Debt, including end of term fee, Long-term debt	3,574	4,301
Less: Discount attributable to warrants, end of term fee and debt issuance costs, Long-term debt	(57)	(83)
Net carrying value of debt, Long-term debt	3,517	4,218
Debt, including end of term fee, Total	7,628	8,355
Less: Discount attributable to warrants, end of term fee and debt issuance costs, Total	(201)	(260)
Net carrying value of debt, Total	$ 7,427	$ 8,095