Long-Term Debt and Other Financings - Interest Expense and Amortization of Debt Issuance Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Interest expense and amortization of debt issuance costs [Abstract]
Interest expense	$ 922	$ 1,238
Hercules Loan [Member]
Interest expense and amortization of debt issuance costs [Abstract]
Interest expense		311
SVB Loan [Member]
Interest expense and amortization of debt issuance costs [Abstract]
Interest expense	258
Servier Loan [Member]
Interest expense and amortization of debt issuance costs [Abstract]
Interest expense		431
Novartis Note [Member]
Interest expense and amortization of debt issuance costs [Abstract]
Interest expense	627	490
Other [Member]
Interest expense and amortization of debt issuance costs [Abstract]
Interest expense	$ 37	$ 6