Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jul. 31, 2021	Apr. 30, 2021
Payables And Accruals [Abstract]
Accrued freight	$ 4,852	$ 2,466
Accrued sales allowances	3,222	2,931
Accrued commissions	1,254	1,578
Accrued taxes other than income	1,099	1,052
Accrued professional fees	787	701
Accrued warranty	701	717
Accrued employee benefits	272	153
Accrued other	135	245
Total accrued expenses	$ 12,322	$ 9,843