Note 1 - Basis of Presentation (Details Textual) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 31, 2020 USD ($)	Aug. 01, 2020 USD ($)	Oct. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)
Number of Employees, Voluntary Retirement		60
Voluntary Retirement Cost		$ 931
Number of Employees, Reduction in Force	150	108
Severance Costs	$ 2,742	$ 1,426
Government Wage Subsidy			$ 280	$ 1,378
Payroll Tax, Employer, Deferral under the CARES Act			$ 5,122

Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Name:	us-gaap_SeveranceCosts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration