Income Taxes - Summary of Activity Related to Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Balance, beginning of fiscal year	$ 80,591	$ 68,156	$ 55,474
Decrease related to prior year tax positions	(828)	(949)	(1,183)
Increases related to current year tax positions	13,199	13,384	13,865
Balance, end of fiscal year	$ 92,962	$ 80,591	$ 68,156