Note 3 - Investment Securities - Gross Unrealized Losses on Continuous Basis for Investment Securities (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Less than 12 months Fair value		$ 4,474,342
State and municipal		55,418
12 months or more Fair value	23,111,310	23,787,341
12 months or more Unrealized losses	532,438	982,580
Total Fair value	23,111,310	28,261,683
Total Unrealized losses	532,438	1,037,998
US States and Political Subdivisions Debt Securities [Member]
Less than 12 months Fair value		3,435,052
State and municipal		42,080
12 months or more Fair value	3,092,607	3,740,467
12 months or more Unrealized losses	55,266	177,781
Total Fair value	3,092,607	7,175,519
Total Unrealized losses	55,266	219,861
SBA Pools [Member]
Less than 12 months Fair value		443,288
State and municipal		6,707
12 months or more Fair value	2,604,110	2,276,084
12 months or more Unrealized losses	54,648	53,332
Total Fair value	2,604,110	2,719,372
Total Unrealized losses	54,648	60,039
Collateralized Mortgage Backed Securities [Member]
Less than 12 months Fair value		596,002
State and municipal		6,631
12 months or more Fair value	17,414,593	17,770,790
12 months or more Unrealized losses	422,524	751,467
Total Fair value	17,414,593	18,366,792
Total Unrealized losses	$ 422,524	$ 758,098