Note 8 - Marketable Securities - Maturity of Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Due within one year, Amortized cost	$ 562	$ 1,506
Due within one year, Fair Value	586	1,556
Due after one year through three years, Amortized cost	4,591	3,607
Due after one year through three years, Fair Value	4,671	3,674
Amortized Cost	5,153	5,113
Estimated Fair Value	$ 5,257	$ 5,230