Note 3 - Investments - Securities Measured and Carried at Fair Value on Recurring Basis With Significant Unobservable Inputs (Details) $ in Thousands		Mar. 31, 2024 USD ($)	Jun. 30, 2023 USD ($)
Investments in debt securities	[1]	$ 5,190
Convertible Debt Securities [Member]
Investments in debt securities		$ 5,190	$ 7,008
Valuation Technique, Binomial Lattice Model [Member] | Measurement Input, Credit Spread [Member]
Corporate debt securities - Convertible debentures		0.0428
Valuation Technique, Binomial Lattice Model [Member] | Convertible Debt Securities [Member]
Investments in debt securities		$ 5,190
Valuation Technique, Binomial Lattice Model [Member] | Convertible Debt Securities [Member] | Measurement Input, Price Volatility [Member]
Corporate debt securities - Convertible debentures		1.10
Valuation Technique, Option Pricing Model [Member] | Measurement Input, Risk Free Interest Rate [Member]
Corporate debt securities - Convertible debentures		0.07

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