Note 2 - Investments - Components of Investments (Details) - USD ($)		3 Months Ended			6 Months Ended			12 Months Ended
		Dec. 31, 2024		Dec. 31, 2023	Dec. 31, 2024		Dec. 31, 2023	Jun. 30, 2024		Jun. 30, 2023
Cost		$ 11,610,000			$ 11,610,000			$ 11,605,000
Unrealized gains (losses)		(819,000)			(819,000)			(720,000)
Fair value		10,791,000			10,791,000			10,885,000
Corporate debt securities, Unrealized gains (losses)		(89,000)		$ 46,000	(49,000)		$ 46,000
Total trading securities at fair value, cost		11,825,000			11,825,000			11,820,000
Total trading securities at fair value, Unrealized gains (losses)		(875,000)			(875,000)			(727,000)
Total trading securities at fair value		10,950,000			10,950,000			11,093,000
Amortized cost		5,187,000	[1]		5,187,000	[1]		6,204,000
Debt Securities, Available-for-Sale, Total	[1]	3,037,000			3,037,000
Allowance for credit losses		0			0			0
Corporate debt securities, amortized cost	[2]	1,000,000			1,000,000			1,000,000
Corporate debt securities, allowance for credit losses		(74,000)	[2]	$ (177,000)	(74,000)	[2]	$ (177,000)	(132,000)	[2]	$ 0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	[2]	926,000			926,000			868,000
Corporate debt securities, gross unrecognized holding gains	[2]	0			0			0
Corporate debt securities, gross unrecognized holding losses	[2]	0			0			0
Corporate debt securities, fair value	[2]	926,000			926,000			868,000
Convertible Debt Securities [Member]
Amortized cost		5,187,000			5,187,000			6,204,000
Gross unrealized gains in other comprehensive income (loss)		391,000			391,000			740,000
Gross unrealized losses in other comprehensive income (loss)		0			0			0
Gross unrealized losses in net investment income (loss)	[3]	(2,541,000)			(2,541,000)			(2,530,000)
Debt Securities, Available-for-Sale, Total		3,037,000			3,037,000			4,414,000
Allowance for credit losses		0			0			0
Corporate Debt Securities [Member]
Corporate debt securities, cost		215,000			215,000			215,000
Corporate debt securities, Unrealized gains (losses)					(56,000)			(7,000)
Corporate debt securities, fair value		159,000			159,000			208,000
Equity Securities International [Member]
Cost		761,000			761,000			762,000
Unrealized gains (losses)		(435,000)			(435,000)			(327,000)
Fair value		326,000			326,000			435,000
Equity Securities Domestic [Member]
Cost		45,000			45,000			45,000
Unrealized gains (losses)		(45,000)			(45,000)			(45,000)
Fair value		0			0			0
Exchange Traded Funds Global Equity [Member]
Cost		5,000			5,000
Unrealized gains (losses)		0			0
Fair value		5,000			5,000
Mutual Funds Fixed Income [Member]
Cost		9,870,000			9,870,000			9,869,000
Unrealized gains (losses)		(199,000)			(199,000)			(225,000)
Fair value		9,671,000			9,671,000			9,644,000
Mutual Funds Global Equity [Member]
Cost		929,000			929,000			929,000
Unrealized gains (losses)		(140,000)			(140,000)			(123,000)
Fair value		$ 789,000			$ 789,000			$ 806,000

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

[2] Held-to-maturity debt instruments 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.