Revenue - Deferred Revenue Balance (Details) - USD ($) $ in Thousands		Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Revenue from Contract with Customer [Abstract]
Deferred revenue, current	[1]	$ 72,263	$ 53,537
Deferred revenue, non-current		2,964	6,758
Total deferred revenue		$ 75,227	$ 60,295	$ 91,225

[1] Including amounts from a related party of $7,697 and $1,499 as of April 30, 2021 and 2020, respectively.