Note 4 - Investments - Securities Measured and Carried at Fair Value on Recurring Basis With Significant Unobservable Inputs (Details) $ in Thousands		Jun. 30, 2023 USD ($)		Jun. 30, 2022 USD ($)
Investments in debt securities	[1]	$ 7,008	[2]	$ 10,625
Valuation Technique, Option Pricing Model [Member] | Measurement Input, Price Volatility [Member]
Investments in debt securities		$ 290
Investments in equity securities, unobservable inputs		1
Valuation Technique, Option Pricing Model [Member] | Measurement Input, Risk Free Interest Rate [Member]
Investments in equity securities, unobservable inputs		0.05
Valuation Technique, Binomial Lattice Model [Member]
Investments in debt securities		$ 7,008
Valuation Technique, Binomial Lattice Model [Member] | Measurement Input, Price Volatility [Member]
Investments in debt securities, unobservable inputs		1
Valuation Technique, Binomial Lattice Model [Member] | Measurement Input, Risk Free Interest Rate [Member]
Investments in debt securities, unobservable inputs		0.042
Valuation Technique, Binomial Lattice Model [Member] | Measurement Input, Credit Spread [Member]
Investments in debt securities, unobservable inputs		0.115

[1] Changes in unrealized gains and losses are included in the statement of comprehensive income (loss), except for embedded derivatives. Changes in unrealized and realized gains and losses for embedded derivatives are included in earnings in the statement of operations.

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