Note 15 - Fair Values Measurements and Disclosures - Assets Measured at Fair Value on a Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Foreclosed assets	$ 12,926	$ 78,926
Impaired loans, net	351,236	841,522
Fair Value, Inputs, Level 1 [Member]
Foreclosed assets	0
Impaired loans, net	0	0
Fair Value, Inputs, Level 2 [Member]
Foreclosed assets	0
Impaired loans, net	0	0
Fair Value, Inputs, Level 3 [Member]
Foreclosed assets	12,926	78,926
Impaired loans, net	$ 351,236	$ 841,522