Lease Commitments - Additional Information (Detail) £ in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2022 USD ($) ft² Sublease	Mar. 31, 2021 USD ($)	Mar. 31, 2022 GBP (£) ft²
Lessee Lease Description [Line Items]
Number of sublease agreements | Sublease	0
Area of conventional reagents manufacturing facility | ft²	87,200		87,200
Lease commencement period		2018-03
Lease expiration period	2052-09
Lease term	5 years		5 years
Lessee, operating lease, extended term	8 years		8 years
Lessee, operating lease, option to extend, description	This lease was extended for a further five-year period to March 14, 2025 and allows for the option to extend this lease through March 14, 2030.
Lessee, operating lease, existence of option to extend		true
Lessee, operating lease, expiration date	Mar. 14, 2030
Operating lease right-of-use assets	$ 29,411	$ 22,011
Operating lease liability	32,288	24,354
Operating lease liability, current	$ 3,535	$ 3,446
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent	Other Assets, Noncurrent
Finance lease right of use asset	$ 908	$ 1,384
Finance lease liability	925	1,280
Finance lease liability, current	537	835
Other Non-current Assets [Member]
Lessee Lease Description [Line Items]
Rent deposit	$ 4,700	$ 5,000	£ 3,600
Minimum [Member]
Lessee Lease Description [Line Items]
Lease term	1 year		1 year