Note 3 - Investment Securities - Gross Unrealized Losses on Continuous Basis for Investment Securities (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Less than 12 months Fair value	$ 10,895,242	$ 4,474,342
Less than 12 months Unrealized losses	58,543	55,418
12 months or more Fair value	9,447,585	23,787,341
12 months or more Unrealized losses	143,509	982,580
Total Fair value	20,342,827	28,261,683
Total Unrealized losses	202,052	1,037,998
US States and Political Subdivisions Debt Securities [Member]
Less than 12 months Fair value	251,618	3,435,052
Less than 12 months Unrealized losses	480	42,080
12 months or more Fair value		3,740,467
12 months or more Unrealized losses		177,781
Total Fair value	251,618	7,175,519
Total Unrealized losses	480	219,861
SBA Pools [Member]
Less than 12 months Fair value		443,288
Less than 12 months Unrealized losses		6,707
12 months or more Fair value	2,151,797	2,276,084
12 months or more Unrealized losses	52,037	53,332
Total Fair value	2,151,797	2,719,372
Total Unrealized losses	52,037	60,039
Collateralized Mortgage Backed Securities [Member]
Less than 12 months Fair value	10,643,624	596,002
Less than 12 months Unrealized losses	58,063	6,631
12 months or more Fair value	7,295,788	17,770,790
12 months or more Unrealized losses	91,472	751,467
Total Fair value	17,939,412	18,366,792
Total Unrealized losses	$ 149,535	$ 758,098