Note 3 - Investments - Schedule of Allowance for Credit Loss on Held to Maturity Investments (Details) - USD ($)		3 Months Ended
		Sep. 30, 2023		Sep. 30, 2022
Balance	[1]	$ 0
Provision for credit losses - reversal (1)		(27,000)	[2]	$ 0
Balance	[1]	205,000
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance		$ 232,000

[1] Held-to-maturity debt investments are carried at amortized cost, and the fair value is classified as Level 2 according to the fair value hierarchy.

[2] Represents the change in present value attributable to the passage of time included in interest income.