Collaborative Arrangement (Details) - USD ($) $ in Thousands	3 Months Ended		13 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Collaboration revenue	$ 1,249	$ 0
Contract liability	12,100		$ 12,100
Fixed Consideration
Disaggregation of Revenue [Line Items]
Performance obligation at inception of arrangement	$ 20,000	20,000	20,000
Portion of fixed consideration received			$ 17,000
Variable Consideration | Achievement of Regulatory Milestones
Disaggregation of Revenue [Line Items]
Amount that can be earned upon achievement of milestone		66,000
Variable Consideration | Achievement of Net Sales Milestones
Disaggregation of Revenue [Line Items]
Amount that can be earned upon achievement of net sales milestone		$ 42,500