Note 3 - Investments - Securities Measured and Carried at Fair Value on Recurring Basis With Significant Unobservable Inputs (Details) $ in Thousands		Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)
Investments in equity securities		$ 11,297	$ 13,205
Investments in debt securities	[1]	5,784
Convertible Debt Securities [Member]
Investments in debt securities		5,784	$ 7,008
Valuation Technique, Option Pricing Model [Member]
Investments in equity securities		$ 2
Valuation Technique, Option Pricing Model [Member] | Measurement Input, Price Volatility [Member]
Investments in debt securities, unobservable input		1.85
Valuation Technique, Option Pricing Model [Member] | Measurement Input, Risk Free Interest Rate [Member]
Investments in debt securities, unobservable input		0.0466
Valuation Technique, Binomial Lattice Model [Member] | Convertible Debt Securities [Member]
Investments in debt securities		$ 5,784
Valuation Technique, Binomial Lattice Model [Member] | Measurement Input, Price Volatility [Member] | Convertible Debt Securities [Member]
Investments in debt securities, unobservable input		1
Valuation Technique, Binomial Lattice Model [Member] | Measurement Input, Risk Free Interest Rate [Member]
Investments in debt securities, unobservable input		0.0378
Valuation Technique, Binomial Lattice Model [Member] | Measurement Input, Credit Spread [Member]
Investments in debt securities, unobservable input		0.099

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