Note 4 - Investments - Fair Value of Financial Instruments Measured on a Recurring Basis (Details) - Fair Value, Recurring [Member] $ in Thousands	Mar. 31, 2023 USD ($)
Total Investments	$ 5,366
Fair Value, Inputs, Level 1 [Member]
Total Investments	0
Fair Value, Inputs, Level 2 [Member]
Total Investments	0
Fair Value, Inputs, Level 3 [Member]
Total Investments	250
Common Stock [Member]
Total Investments	250
Common Stock [Member] | Fair Value, Inputs, Level 1 [Member]
Total Investments	0
Common Stock [Member] | Fair Value, Inputs, Level 2 [Member]
Total Investments	0
Common Stock [Member] | Fair Value, Inputs, Level 3 [Member]
Total Investments	250
Investments, at Fair Value [Member]
Total Investments	250
Investments, at Fair Value [Member] | Fair Value, Inputs, Level 1 [Member]
Total Investments	0
Investments, at Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
Total Investments	0
Investments, at Fair Value [Member] | Fair Value, Inputs, Level 3 [Member]
Total Investments	250
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Total Investments	1,000
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] | Fair Value, Inputs, Level 1 [Member]
Total Investments	0
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] | Fair Value, Inputs, Level 2 [Member]
Total Investments	0
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] | Fair Value, Inputs, Level 3 [Member]
Total Investments	0
US Government Agencies Debt Securities [Member]
Total Investments	4,116
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Total Investments	0
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Total Investments	0
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Total Investments	$ 0