Common Stock and Stockholders' Equity - Schedule of Stock-based Compensation Expense Attributed to Cost of Revenue, Research and Development, Sales and Marketing and General and Administrative Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 23,358	$ 13,833	$ 44,546	$ 24,860
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,300	895	2,522	1,588
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	7,434	3,858	14,462	7,121
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	10,533	6,028	19,592	10,818
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 4,091	$ 3,052	$ 7,970	$ 5,333