Common Stock and Stockholders' Equity - Narrative (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2014	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Class of Stock [Line Items]
Stock-based compensation expense		$ 39,852	$ 37,571	$ 74,734	$ 79,758
Unrecognized stock-based compensation cost		5,600		$ 5,600
Stock-based compensation cost expected to be recognized over weighted-average period				1 year 3 months 18 days
PSUs
Class of Stock [Line Items]
Stock-based compensation cost expected to be recognized over weighted-average period				2 years
Unrecognized stock-based compensation cost related to outstanding unvested stock awards		20,000		$ 20,000
PSUs | Share-based Payment Arrangement, One-Year
Class of Stock [Line Items]
Measurement period				1 year
PSUs | Share-based Payment Arrangement, Two-Year
Class of Stock [Line Items]
Measurement period				2 years
PSUs | Share-based Payment Arrangement, Three-Year
Class of Stock [Line Items]
Measurement period				3 years
PSUs | Minimum
Class of Stock [Line Items]
Percentage of total shareholder return				0.00%
PSUs | Maximum
Class of Stock [Line Items]
Percentage of total shareholder return				200.00%
RSUs
Class of Stock [Line Items]
Stock-based compensation cost expected to be recognized over weighted-average period				2 years 4 months 24 days
Unrecognized stock-based compensation cost related to outstanding unvested stock awards		$ 268,000		$ 268,000
ESPP shares
Class of Stock [Line Items]
Shares reserved for issuance under plan (in shares)	1,000,000
Additional shares available for issuance under the plan (in shares)	500,000
Percentage of common stock shares increased under the plan	1.00%
Shares purchased under plan (in shares)		102,750			100,309
Stock-based compensation expense		$ 1,500	$ 1,000	$ 2,800	$ 1,900
Shares available for issuance (in shares)		3,384,792		3,384,792
2008 Equity Incentive Plan
Class of Stock [Line Items]
Shares available for issuance (in shares)		0		0
2014 Equity Incentive Plan
Class of Stock [Line Items]
Shares reserved for issuance under plan (in shares)	5,000,000
Shares available for issuance (in shares)		15,400,450		15,400,450
Shares available for grant under plan (in shares)	5,184,878
Increase in shares available under plan, percentage of outstanding common stock shares	5.00%