Note 3 - Investments in Debt Securities - Maturities of Debt Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
One year or less, amortized cost	$ 2,589	$ 2,671
One year or less, fair value	2,589	2,671
Greater than one year through five years, amortized cost	587	464
Greater than one year through five years, fair value	588	468
Amortized cost	3,176	3,135
Fair value	$ 3,177	$ 3,139

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

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