Commitments and Contingencies - Narrative (Details) - Takeda Commercial Supply Agreement		12 Months Ended
	May 30, 2018	Mar. 31, 2021
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