Collaboration and License Agreements - Narrative (Details)					1 Months Ended		3 Months Ended	12 Months Ended
	Jul. 16, 2021 USD ($)	Dec. 26, 2020 USD ($)	Mar. 31, 2020 USD ($)	Mar. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Apr. 30, 2020 USD ($)	Mar. 31, 2022 USD ($) milestone	Dec. 31, 2022 USD ($)	Mar. 31, 2022 USD ($) milestone	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Jul. 31, 2021 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from collaborators									$ 0		$ (146,384,000)
Amounts due to Pfizer							$ 32,563,000		32,563,000		1,954,000
Contract assets							0		0		0
Increase (decrease) in deferred revenue									(21,663,000)		457,933,000	$ 40,000,000
Pfizer collaboration revenue									104,996,000		22,354,000	0
Cost share advance from Pfizer									(90,457,000)		121,227,000	$ 0
Shared costs									90,457,000		25,157,000
Richter
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment received				$ 40,000,000
License Agreement, Regulatory Milestones, Upfront Payment Received			$ 40,000,000
Regulatory milestone payments received	$ 15,000,000			25,000,000					15,000,000
Maximum payment from sales-related milestones achieved				107,500,000
Remaining transaction price				$ 50,000,000
Additions						$ 10,000,000
Additions											10,000,000
Deferred revenue recognized											(33,300,000)
Richter | Revenue Recognized Upon Completion of Delivery
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues							$ 16,700,000		$ 16,700,000		33,300,000
Pfizer
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum payment from sales-related milestones achieved		$ 3,500,000,000
Percentage of revenue recognized		100.00%
Upfront payment received					$ 650,000,000
Maximum payment from milestones achieved		$ 3,800,000,000
Number of regulatory milestones | milestone							2		2
Maximum payment from regulatory milestones achieved		100,000,000											$ 100,000,000
Maximum aggregate payment from milestones achieved		200,000,000
Costs covered by company										$ 100,000,000
Proceeds from collaborators		$ (150,000,000)
Repayment period		2 years
Reduction in cost share advance from implied financing costs		$ 3,600,000
Deferred revenue, recognition period		6 years
Amounts due to Pfizer							$ 32,600,000		$ 32,600,000		1,900,000
Amounts due to collaboration partner, share of profits							$ 14,100,000		$ 14,100,000		1,800,000
Percentage of revenue recognized by counterparty							50.00%		50.00%
Amounts due to collaboration partner, reimbursement of allowable expenses							$ 18,500,000		$ 18,500,000		100,000
Additions											503,600,000
Pfizer collaboration revenue									(105,000,000)		(22,400,000)
Cost share advance from Pfizer									88,000,000		121,900,000
Shared costs									90,400,000		25,200,000
Amortized deferred financing costs									$ 2,400,000		600,000
Present value of cost share advance											$ 146,400,000
Reimbursement of total expenses (as a percent)									100.00%
Reimbursement of allowable expenses (as a percent)									50.00%		50.00%
Pfizer | R&D expense
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shared costs									$ 30,700,000		$ 14,100,000
Pfizer | SG&A expense
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shared costs									$ 59,700,000		$ 11,100,000
Pfizer | Forecast
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Costs covered by company								$ 50,000,000