Note 11 - Comprehensive Income - Components of Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2025	Apr. 30, 2024	Apr. 30, 2023
Change in unrealized gains on available-for-sale fixed income securities	$ 237	$ (793)	$ 503
Change in unrealized gains on available-for-sale fixed income securities	(50)	166	(105)
Change in unrealized gains on available-for-sale fixed income securities	187	(627)	398
Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, before Tax, Portion Attributable to Parent	237	(793)	503
Other Comprehensive Income (Loss), Available-for-Sale Securities, Tax, Portion Attributable to Parent	(50)	166	(105)
Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	$ 187	$ (627)	$ 398

Amount, before tax and after reclassification adjustment, of gain (loss) in value of unsold investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), attributable to parent.

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