Commitments and Contingencies (Details) - USD ($) $ in Millions		12 Months Ended
	May 30, 2018	Mar. 31, 2022	Mar. 31, 2021
Takeda License Agreement
Supply Commitment [Line Items]
Royalty expense		$ 6.9	$ 0.3
Accrued royalties		$ 2.5	$ 0.3
Takeda Commercial Supply Agreement
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