Product Revenue and Concentration of Credit Risks - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Net product sales	$ 12,349	$ 0
Geographic Concentration Risk [Member] | Accounts Receivable
Disaggregation of Revenue [Line Items]
Concentration of credit risk and major customers (percent)	90.00%
Geographic Concentration Risk [Member] | Product revenue
Disaggregation of Revenue [Line Items]
Concentration of credit risk and major customers (percent)	90.00%
United States
Disaggregation of Revenue [Line Items]
Net product sales	$ 11,300
Germany
Disaggregation of Revenue [Line Items]
Net product sales	$ 1,000