Discontinued Operations (Details)				1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 16, 2021 USD ($)	Dec. 02, 2021 USD ($)	Feb. 22, 2019 USD ($)	Jun. 30, 2020 USD ($)	Oct. 31, 2021 USD ($)	Apr. 30, 2022 USD ($) contract	Apr. 30, 2021 USD ($)	Apr. 30, 2020 USD ($)	Jun. 29, 2018 USD ($)
Other expense
Discontinued operations
Litigation reserve expense						$ 9,300,000
Discontinued Operations
Discontinued operations
Amount of alleged damages			$ 6,500,000
EES Business
Discontinued operations
Litigation reserve expense					$ 10,000,000
Amount of existing claims settled	$ 20,000,000	$ 20,000,000
Settlement paid						5,000,000
Payment period	24 months
EES Business | Disposed of by sale
Discontinued operations
Cash consideration received									$ 31,994,000
Amounts recorded in the consolidated financial statements				$ 341,000
EES Business | Disposed of by sale | Other income, net
Discontinued operations
Net sales						0	$ 38,000	$ 551,000
Holdback | Disposed of by sale
Discontinued operations
Cash consideration received						$ 6,500,000
Number of remaining contracts | contract						2