Extinguishment of Debt (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 30, 2019	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Proceeds from related party debt financing		$ 0	$ 245,000	$ 113,700
Loss on extinguishment of debt		$ 0	$ 0	4,851
Term Loan | Letter Agreement with Sumitomo Dainippon Pharma, Co., Ltd.
Debt Instrument [Line Items]
Proceeds from related party debt financing	$ 113,700
Loss on extinguishment of debt				$ 4,900
Line of Credit | NovaQuest
Debt Instrument [Line Items]
Principal repayment of debt	60,000
Accrued interest repayment of debt	7,600
Prepayment penalty	2,400
Line of Credit | Hercules
Debt Instrument [Line Items]
Principal repayment of debt	40,000
Accrued interest repayment of debt	300
Prepayment penalty	400
End-of-term charge	$ 2,600