Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Postemployment Benefits [Abstract]
Contributions to employee benefit plan	$ 6.3	$ 3.2	$ 2.3

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