Employee Stock Purchase Plan - Summary of Employee Stock Purchase Plan (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Employee Stock Purchase Plan [Line Items]
Employee contributions	$ 564,000	$ 534,000	$ 505,000
Shares acquired	2,495,935
Employee Stock Purchase Plan [Member]
Employee Stock Purchase Plan [Line Items]
Shares acquired	3,363	6,007	8,451
Average purchase price	$ 167.71	$ 88.85	$ 59.70