Revenue - Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
Change In Contract With Customer, Liability [Roll Forward]
Beginning Balance	$ 60,295	$ 91,225
Performance obligations satisfied during the period that were included in the deferred revenue balance at the beginning of the year	(57,542)	(83,093)
Increases due to invoicing prior to satisfaction of performance obligations	72,474	52,163
Ending Balance	$ 75,227	$ 60,295