Balance Sheet Components - Schedule of Information About Contracts with Customers (Details)) - USD ($) $ in Thousands	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Contract Balances [Line Items]
Unbilled accounts receivable, included in accounts receivable, net	$ 2,622	$ 1,710	$ 1,139	$ 1,114
Deferred revenue	259,702	170,666	$ 102,561	$ 54,152
Contracts with Customers
Contract Balances [Line Items]
Unbilled accounts receivable, included in accounts receivable, net	2,622	1,710
Deferred contract acquisition costs	43,549	26,150
Deferred revenue	$ 259,702	$ 170,666