Note 2 - Summary of Significant Accounting Policies - Debt Securities by Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Within one year, amortized cost	$ 12,183
Within one year, fair value	12,217
After one year through two years, amortized cost	6,985
After one year through two years, fair value	7,003
After two years through three years, amortized cost	984
After two years through three years, fair value	997
Amortized cost	20,152	$ 21,059
Fair value	$ 20,217	$ 21,076