Note 4 - Investments - Details of Marketable Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Fair value	$ 18	$ 22
Basis	34	34
Cumulative unrealized (loss) gain	(16)	(12)
Equity Securities [Member]
Fair value	18	22
Basis	34	34
Cumulative unrealized (loss) gain	$ (16)	$ (12)