Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Mar. 31, 2024
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 110,012	$ 110,082
Less: accumulated depreciation and amortization	(85,198)	(81,731)
Property and equipment, net	24,814	28,351
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,392	7,485
Laboratory equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	51,363	51,635
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	8,937	8,929
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	41,467	41,180
Capitalized asset retirement obligations
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 853	$ 853