Commitments and Contingencies - Narrative (Details) - Takeda Commercial Supply Agreement	3 Months Ended
	Jun. 30, 2020
Supply Commitment [Line Items]
Agreement term after first commercial sale	10 years
Agreement term	5 years
Automatic renewal term	1 year
Termination notice term	12 months
Termination notice term, uncured material breach	90 days
Termination notice term, open purchase orders filed	180 days