Note 3 - Investment Securities (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Accrued interest receivable	Accrued interest receivable
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss	$ 267,300	$ 302,500
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]		Accrued interest receivable
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss	121,300	$ 122,000
Available for sale	0	23,887,000
Debt Securities, Available-for-Sale, Realized Gain (Loss)		(18,000)
Debt Securities, Available-for-Sale, Realized Gain (Loss)		18,000
Derivative, Gain (Loss) on Derivative, Net	0	(260,000)
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale	13,259,000	18,071,000
Corporate Debt Securities [Member]
Available for sale		521,000
Debt Securities, Available-for-Sale, Realized Gain (Loss)		32,000
Debt Securities, Available-for-Sale, Realized Gain (Loss)		(32,000)
Collateralized Mortgage-Backed Securities [Member]
Available for sale	23,400,000
Debt Securities, Available-for-Sale, Realized Gain (Loss)	(605,000)
Debt Securities, Available-for-Sale, Realized Gain (Loss)	605,000
Derivative, Gain (Loss) on Derivative, Net	586,000
Securities Called at a Premium [Member]
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale	0	0
Asset Pledged as Collateral [Member] \| Government Deposits and Securities Sold Under Repurchase Agreement [Member]
Debt Securities	$ 21,000,000	$ 26,300,000

Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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