Note 3 - Investments - Components of Investments (Details) - USD ($)		12 Months Ended
		Jun. 30, 2025		Jun. 30, 2024		Jun. 30, 2023
Cost		$ 12,748,000		$ 11,605,000
Unrealized gains (losses)		(622,000)		(720,000)
Fair value		12,126,000		10,885,000
Corporate debt securities, Unrealized gains (losses)		(146,000)		(7,000)
Total trading securities at fair value, cost		12,963,000		11,820,000
Total trading securities at fair value, Unrealized gains (losses)		(775,000)		(727,000)
Total trading securities at fair value		12,188,000		11,093,000
Amortized cost		3,993,000	[1]	6,204,000
Debt Securities, Available-for-Sale, Total	[1]	1,576,000
Allowance for credit losses		0		0
Corporate debt securities, amortized cost	[2]	1,000,000		1,000,000
Corporate debt securities, allowance for credit losses		(52,000)	[2]	(132,000)	[2]	$ 0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	[2]	948,000		868,000
Corporate debt securities, gross unrecognized holding gains	[2]	0		0
Corporate debt securities, gross unrecognized holding losses	[2]	0		0
Corporate debt securities, fair value	[2]	948,000		868,000
Convertible Debt Securities [Member]
Amortized cost		3,993,000		6,204,000
Gross unrealized gains in other comprehensive income (loss)		125,000		740,000
Gross unrealized losses in other comprehensive income (loss)		0		0
Gross unrealized losses in net investment income (loss)	[3]	(2,542,000)		(2,530,000)
Debt Securities, Available-for-Sale, Total		1,576,000		4,414,000
Allowance for credit losses		0		0
Corporate Debt Securities [Member]
Corporate debt securities, cost		215,000		215,000
Corporate debt securities, Unrealized gains (losses)		(153,000)		(7,000)
Corporate debt securities, fair value		62,000		208,000
Equity Securities Domestic [Member]
Cost		87,000		45,000
Unrealized gains (losses)		(60,000)		(45,000)
Fair value		27,000		0
Equity Securities International [Member]
Cost		761,000		762,000
Unrealized gains (losses)		(335,000)		(327,000)
Fair value		426,000		435,000
Exchange Traded Funds Crypto and Digital Asset [Member]
Cost		967,000		0
Unrealized gains (losses)		30,000		0
Fair value		997,000		0
Exchange Traded Funds Global Equity [Member]
Cost		30,000		0
Unrealized gains (losses)		2,000		0
Fair value		32,000		0
Exchange Traded Funds Option Strategy and Income [Member]
Cost		105,000		0
Unrealized gains (losses)		6,000		0
Fair value		111,000		0
Mutual Funds Fixed Income [Member]
Cost		9,869,000		9,869,000
Unrealized gains (losses)		(177,000)		(225,000)
Fair value		9,692,000		9,644,000
Mutual Funds Global Equity [Member]
Cost		929,000		929,000
Unrealized gains (losses)		(88,000)		(123,000)
Fair value		$ 841,000		$ 806,000

[1] Principal payments of $750,000 are due quarterly with a final maturity in January 2026.

[2] Held-to-maturity debt investments are carried at amortized cost, net of allowance for credit losses, and the fair value is classified as Level 2 according to the fair value hierarchy.

[3] Represents changes in unrealized gains and losses related to embedded derivatives included in net investment income (loss) in the Consolidated Statements of Operations.