Note 1 - Organization and Significant Accounting Policies - Debt Securities by Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Within one year, amortized cost	$ 10,184
Within one year, fair value	10,200
After one year through two years, amortized cost	10,875
After one year through two years, fair value	10,876
Amortized cost	21,059	$ 15,800
Fair value	$ 21,076	$ 15,714