Retirement Savings Plan - Additional Information (Detail) - USD ($)	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Employer contribution	$ 829,000	$ 777,000	$ 557,000

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration