Note 3 - Investments - Schedule of Allowance for Credit Loss on Held to Maturity Investments (Details) - USD ($)		3 Months Ended	6 Months Ended
		Dec. 31, 2023	Dec. 31, 2023		Dec. 31, 2022
Balance			$ 0
Provision for credit losses - reversal (1)		$ 28,000	55,000	[1]	$ 0
Balance	[2]	$ 177,000	177,000
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance			$ 232,000

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

[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.