Note 2 - Investments - Schedule of Carrying Value and Fair Value of Equity Securities (Details) - USD ($)	Jan. 31, 2025	Apr. 30, 2024
Equity securities, cost	$ 15,509,000	$ 11,663,000
Equity securities, fair value	21,808,000	16,344,000
Exchange Traded Funds [Member]
Equity securities, cost	15,509,000	11,663,000
Equity securities, gross unrealized gains	6,319,000	4,685,000
Equity securities, gross unrealized losses	(20,000)	(4,000)
Equity securities, fair value	$ 21,808,000	$ 16,344,000