Note 4 - Investments - Maturities of Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
One year or less, amortized cost	$ 2,752	$ 2,432
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One	2,746	2,440
Greater than one year through five years, amortized cost	333	551
Greater than one year through five years, fair value	331	552
Amortized cost	3,085	2,983
Fair value	$ 3,077	$ 2,992

Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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