Note 4 - Loans (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums, Total	$ 680		$ 680		$ 879
Financing Receivable, Number of Payment Deferrals	16		16		82
Financing Receivable, Deferred Payments	$ 4,100		$ 4,100		$ 9,500
Mortgage Loans in Process of Foreclosure, Amount	106		106		80
Financing Receivable, Troubled Debt Restructuring	$ 5,800		$ 5,800		$ 6,100
Troubled Debt Restructurings Percentage of Gross Portfolio Loans	0.53%		0.53%		0.53%
Financing Receivable, Number of Contracts Qualified as Troubled Debt Restructuring	89		89
Impaired Financing Receivable, Recorded Investment, Total	$ 7,729		$ 7,729		$ 11,103
Percentage of Collateral Coverage to Loan Balance to Consider Restructured Loan to Performing and Accrual Status			100.00%
Financing Receivable, Modifications, Number of Contracts		1	0	1
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	0	0	0	0
Percentage of Unallocated Allowance Amount out of Allowance for Loan and Lease Losses			5.00%		4.00%
Loans and Leases Receivable, Allowance, Ending Balance	$ 17,194		$ 17,194		$ 16,910
Percentage of Allowance for Loan and Lease Losses out of Net Loans	1.58%		1.58%		1.48%
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Asset	$ 301,800		$ 301,800		$ 267,800
Reserve for Unfunded Commitments Included in Other Liabilities	800		800		800
Loans and Leases Receivable, Gross, Total	$ 1,090,745		$ 1,090,745		1,139,732
Maximum Loan to Value, Percentage			80.00%
Percentage of Loan Portfolio Secured by Real Estate	84.00%		84.00%
Percentage of Loan Portfolio Secured by Real Estate, Excluding PPP Loans	89.00%		89.00%
Residential Portfolio Segment [Member]
Impaired Financing Receivable, Recorded Investment, Total	$ 5,082		$ 5,082		5,318
Loans and Leases Receivable, Gross, Total	94,998		94,998		103,854
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Financing Receivable, Troubled Debt Restructuring	$ 4,600		$ 4,600
Financing Receivable, Number of Contracts Qualified as Troubled Debt Restructuring	81		81
Loans and Leases Receivable, Gross, Total	$ 26,912		$ 26,912		29,035
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Troubled Debt Restructuring		$ 654		$ 654
Impaired Financing Receivable, Recorded Investment, Total	695		695		3,734
Financing Receivable, Modifications, Number of Contracts		1		1
Loans and Leases Receivable, Gross, Total	$ 825,609		$ 825,609		767,536
SBA CARES Act Paycheck Protection Program [Member]
Number of Customers Participated in PPP	281		281
Loans and Leases Receivable, Gross, Total	$ 59,058		$ 59,058		130,814
Performing Financial Instruments [Member]
Financing Receivable, Number of Contracts Qualified as Troubled Debt Restructuring	88		88
Impaired Financing Receivable, Recorded Investment, Total	$ 3,900		$ 3,900		4,100
Loans and Leases Receivable, Gross, Total	1,086,932		1,086,932		1,132,719
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Loans and Leases Receivable, Gross, Total	25,449		25,449		27,450
Performing Financial Instruments [Member] | SBA CARES Act Paycheck Protection Program [Member]
Loans and Leases Receivable, Gross, Total	59,058		59,058		130,814
Federal Home Loan Bank of San Francisco [Member]
Loans Pledged as Collateral	616,800		616,800		523,500
Merchants Holding Company [Member]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums, Total	694		694		$ 920
Accretion (Amortization) of Discounts and Premiums, Acquired Loans	$ 115	$ 216	$ 225	$ 379