Note 4 - Supplementary Cash Flows Information - Supplementary Cash Flow Elements (Details) - USD ($) $ in Thousands	9 Months Ended
Jan. 31, 2025	Jan. 31, 2024	Apr. 30, 2024
Cash and cash equivalents (including short term investments of $26,005 and $4,136, respectively)	$ 26,816	$ 5,780	$ 4,390
State and local income tax payments	966	656
Restricted cash	305	305
Federal income tax payments	3,958	4,000
Total cash, cash equivalents, and restricted cash shown in the Consolidated Condensed Statement of Cash Flows	$ 27,121	$ 6,085

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including, but not limited to, disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-8

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 24
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-24

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-4

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Balance Type:	debit
Period Type:	instant