Revenue - Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Change In Contract With Customer, Liability [Roll Forward]
Beginning Balance	$ 75,227	$ 60,295
Performance obligations satisfied during the period that were included in the deferred revenue balance at the beginning of the year	(38,319)	(24,337)
Increases due to invoicing prior to satisfaction of performance obligations	62,989	71,286
Ending Balance	$ 99,897	$ 107,244