Accrued Expenses and Deferred Revenue - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands		Apr. 30, 2021	Apr. 30, 2020
Payables And Accruals [Abstract]
Accrued taxes other than income	[1]	$ 12,210	$ 21,256
Accrued employee benefits		4,780	4,407
Accrued other		3,451	5,456
Deferred revenue	[2]	2,907	14,744
Accrued professional fees		2,804	3,675
Accrued distributor incentives		2,414	2,253
Accrued rebates and promotions		2,174	3,335
Current portion of operating lease obligation		1,309	1,506
Current portion of finance lease obligation		1,087	1,046
Total accrued expenses and deferred revenue		$ 33,136	$ 57,678

[1] Decrease in accrued taxes other than income is due to the deferral of federal excise tax payments allowed by the Tax and Trade Bureau as a result of the COVID-19 pandemic as of April 30, 2020

[2] Decrease in deferred revenue due to the fulfillment of performance obligations related to promotional activity.