Note 2 - Summary of Significant Accounting Policies - Debt Securities by Maturity (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Within one year, amortized cost	$ 2,469
Within one year, fair value	2,460
After one year through two years, amortized cost	3,937
After one year through two years, fair value	3,866
After two years through three years, amortized cost	3,402
After two years through three years, fair value	3,321
Amortized cost	9,808
Fair value	$ 9,647