Note 4 - Loans and Allowance for Loan Losses - Summary of Consumer Credit Exposure (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Total loans (Note 4)	$ 534,146	$ 518,716
Residential Portfolio Segment [Member]
Total loans (Note 4)	79,808	87,172
Consumer Portfolio Segment [Member]
Total loans (Note 4)	303,404	302,084
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Total loans (Note 4)	23,749	25,856
Consumer Portfolio Segment [Member] | Other Loan [Member]
Total loans (Note 4)	3,782	3,740
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member]
Total loans (Note 4)	79,316	86,703
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Total loans (Note 4)	23,614	25,709
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Loan [Member]
Total loans (Note 4)	3,782	3,740
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member]
Total loans (Note 4)	492	469
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Total loans (Note 4)	135	147
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Loan [Member]
Total loans (Note 4)	$ 0	$ 0