Note 4 - Investments - Fair Value Measurement on Recurring Basis (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Total investments	$ 1,250
Purchases	0	$ 1,250
Total investments	1,250	1,250
Total investments	1,250	1,250
Common Stock [Member]
Total investments	250
Purchases	0	250
Total investments	250	250
Total investments	250	250
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Total investments	1,000
Purchases	0	1,000
Total investments	1,000	1,000
Total investments	$ 1,000	$ 1,000