Stockholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Shareholders Equity [Line Items]
Beginning Balance	$ 1,065,466	$ 936,890	$ 689,524
Ending Balance	1,329,675	1,065,466	936,890
Foreign Currency Translation Gains (Losses)
Shareholders Equity [Line Items]
Beginning Balance	(16,860)	(15,028)	(3,597)
Other comprehensive (loss) income	2,142	(1,832)	(11,431)
Ending Balance	(14,718)	(16,860)	(15,028)
Unrealized Gains (Losses) on Investments
Shareholders Equity [Line Items]
Beginning Balance	1,672	339	(607)
Other comprehensive (loss) income	(303)	1,333	946
Ending Balance	1,369	1,672	339
Unrealized Gains (Losses) on Derivative Instruments
Shareholders Equity [Line Items]
Beginning Balance	3,999
Other comprehensive (loss) income	(2,095)	3,999
Ending Balance	1,904	3,999
Accumulated Other Comprehensive Income (Loss)
Shareholders Equity [Line Items]
Beginning Balance	(11,189)	(14,689)	(4,204)
Other comprehensive (loss) income	(256)	3,500	(10,485)
Ending Balance	$ (11,445)	$ (11,189)	$ (14,689)