Collaborations (Detail)		1 Months Ended		3 Months Ended			9 Months Ended
	Jul. 18, 2018	Oct. 31, 2023 program	Oct. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2023 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue				$ 44,747,000		$ 66,940,000	$ 155,610,000	$ 207,112,000
Deferred revenue, current				80,468,000			80,468,000		$ 62,521,000
G S K
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement, period	4 years
Aggregate cash consideration for collaboration arrangement			$ 50,000,000
Revenue						13,100,000	11,800,000	36,300,000
Deferred revenue, current									11,800,000
Research and development expense				2,800,000		$ 3,300,000	11,000,000	$ 9,500,000
Accounts payable, accrued expenses and other current liabilities				15,800,000			$ 15,800,000		$ 11,900,000
Voting interest percentage					20.10%		19.90%
G S K 2023 Amendment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue				20,000,000			$ 20,000,000
License for data access, expiration period		1 year
Programs, opted-out of cost sharing and other research and development | program		3
Revenue				$ 0			$ 0