Note 7 - Fair Value - Assets Measured at Fair Value on a Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Total	$ 171,000	$ 88,000
Other real estate owned	0	88,000
Fair Value, Inputs, Level 1 [Member]
Total
Other real estate owned
Fair Value, Inputs, Level 2 [Member]
Total
Other real estate owned
Fair Value, Inputs, Level 3 [Member]
Total	171,000	88,000
Other real estate owned		$ 88,000
Commercial Real Estate Portfolio Segment [Member]
Impaired loans	131,000
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Impaired loans
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Impaired loans
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans	131,000
Commercial Portfolio Segment [Member]
Impaired loans	40,000
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Impaired loans
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Impaired loans
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans	$ 40,000