Note 3 - Investment Securities - Schedule of Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Amortized cost, as adjusted	$ 134,308	$ 124,575
Gross unrealized holding gains	0	30
Gross unrealized holding losses	28	53
Estimated fair value	134,280	124,552
US Government Agencies Debt Securities [Member]
Amortized cost, as adjusted	134,308	124,575
Gross unrealized holding gains	0	30
Gross unrealized holding losses	28	53
Estimated fair value	$ 134,280	$ 124,552

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

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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