Note 13 - Fair Value Measurements - Assets Measured on a Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Impaired loans, net of valuation allowance	$ 144	$ 268
Other real estate owned, net	443	958
Fair Value, Inputs, Level 1 [Member]
Impaired loans, net of valuation allowance	0	0
Other real estate owned, net		0
Fair Value, Inputs, Level 2 [Member]
Impaired loans, net of valuation allowance	0	0
Other real estate owned, net	0	0
Fair Value, Inputs, Level 3 [Member]
Impaired loans, net of valuation allowance	144	268
Other real estate owned, net	$ 443	$ 958