Stockholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Shareholders Equity [Line Items]
Beginning Balance	$ 936,890	$ 689,524	$ 452,071
Ending Balance	1,065,466	936,890	689,524
Foreign Currency Translation Gains (Losses)
Shareholders Equity [Line Items]
Beginning Balance	(15,028)	(3,597)	(20,459)
Other comprehensive income (loss)	(1,832)	(11,431)	16,862
Ending Balance	(16,860)	(15,028)	(3,597)
Unrealized Gains (Losses) on Investments
Shareholders Equity [Line Items]
Beginning Balance	339	(607)	(147)
Other comprehensive income (loss)	1,333	946	(461)
Ending Balance	1,672	339	(607)
Unrealized Gains (Losses) on Derivative Instruments
Shareholders Equity [Line Items]
Other comprehensive income (loss)	3,999
Ending Balance	3,999
Accumulated Other Comprehensive Income (Loss)
Shareholders Equity [Line Items]
Beginning Balance	(14,689)	(4,204)	(20,606)
Other comprehensive income (loss)	3,500	(10,485)	16,401
Ending Balance	$ (11,189)	$ (14,689)	$ (4,204)