Note 7 - Fair Value (Details Textual)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	$ 147,000	$ 78,000	$ 147,000	$ 78,000	$ 76,000
Impaired Financing Receivable, Related Allowance	12,000	6,000	12,000	6,000	5,000
Provision for Loan and Lease Losses, Total	$ 1,100,000	270,000	$ 1,892,000	450,000
Measurement Input, Discount Rate [Member]
Other Real Estate Owned, Measurement Input	0.1		0.1
Fair Value, Nonrecurring [Member]
Provision for Loan and Lease Losses, Total	$ 32,000	14,000	$ 32,000	35,000
Other Real Estate, Ending Balance	9,000		9,000		88,000
Other Real Estate, Gross Amount	18,000		18,000		91,000
Other Real Estate, Disposals			9,000		3,000
Impaired Loans [Member]
Provision for Loan and Lease Losses, Total	7,000	63,000	31,000	63,000
Real Estate Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	70,000		70,000		67,000
Home Equity Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	4,000		4,000		4,000
Commercial Portfolio Segment [Member]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	72,000		72,000
Impaired Financing Receivable, Related Allowance	11,000		11,000
Provision for Loan and Lease Losses, Total	268,000	$ 43,000	313,000	$ 249,000
Collateral Pledged [Member]
Impaired Financing Receivable, with Related Allowance, Fair Value					$ 0
Collateral Pledged [Member] | Commercial Portfolio Segment [Member]
Impaired Financing Receivable, with Related Allowance, Fair Value	60,000		60,000
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	67,000		67,000
Impaired Financing Receivable, Related Allowance	$ 7,000		$ 7,000