Note 7 - Fair Value Measurements - Fair Value of Financial Instruments Measured on a Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020
Reported Value Measurement [Member]
Other real estate owned		$ 183	$ 0
Impaired loans, net	[1]	2,584	2,635
Total assets		2,767	2,635
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Other real estate owned		0	0
Impaired loans, net	[1]	0	0
Total assets		0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Other real estate owned		0	0
Impaired loans, net	[1]	0	0
Total assets		0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Other real estate owned		183	0
Impaired loans, net	[1]	2,584	2,635
Total assets		$ 2,767	$ 2,635

[1] Amount is net of a valuation allowance of $699,000 at March 31, 2021 and $742,000 at December 31, 2020 as required by ASC 310, "Receivables."