Note 4 - Loans - Loans by Credit Grade (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Loans	$ 338,190,781	$ 343,940,842
Excellent [Member]
Loans	945,661	1,016,648
Above Average [Member]
Loans	5,038,870	4,915,980
Average [Member]
Loans	138,129,802	149,320,353
Acceptable [Member]
Loans	148,980,319	149,689,041
Pass [Member]
Loans	33,770,704	27,472,332
Special Mention [Member]
Loans
Substandard [Member]
Loans	11,305,012	11,448,021
Doubtful [Member]
Loans	20,413	78,467
Commercial Real Estate Portfolio Segment [Member]
Loans	236,794,302	238,834,149
Commercial Real Estate Portfolio Segment [Member] | Excellent [Member]
Loans
Commercial Real Estate Portfolio Segment [Member] | Above Average [Member]
Loans	3,491,312	3,632,231
Commercial Real Estate Portfolio Segment [Member] | Average [Member]
Loans	97,290,160	101,633,803
Commercial Real Estate Portfolio Segment [Member] | Acceptable [Member]
Loans	104,534,189	104,454,812
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Loans	22,775,714	20,356,642
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Loans
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Loans	8,702,927	8,756,661
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member]
Loans
Construction and Land Development [Member]
Loans	15,914,131	18,265,505
Construction and Land Development [Member] | Excellent [Member]
Loans
Construction and Land Development [Member] | Above Average [Member]
Loans
Construction and Land Development [Member] | Average [Member]
Loans	5,865,774	8,190,212
Construction and Land Development [Member] | Acceptable [Member]
Loans	7,733,236	7,871,642
Construction and Land Development [Member] | Pass [Member]
Loans	2,315,121	2,203,651
Construction and Land Development [Member] | Special Mention [Member]
Loans
Construction and Land Development [Member] | Substandard [Member]
Loans
Construction and Land Development [Member] | Doubtful [Member]
Loans
Residential Portfolio Segment [Member]
Loans	63,019,749	63,024,106
Residential Portfolio Segment [Member] | Excellent [Member]
Loans	20,490	35,926
Residential Portfolio Segment [Member] | Above Average [Member]
Loans	1,416,824	1,178,899
Residential Portfolio Segment [Member] | Average [Member]
Loans	24,815,266	26,856,131
Residential Portfolio Segment [Member] | Acceptable [Member]
Loans	28,517,090	30,169,305
Residential Portfolio Segment [Member] | Pass [Member]
Loans	5,653,182	2,093,825
Residential Portfolio Segment [Member] | Special Mention [Member]
Loans
Residential Portfolio Segment [Member] | Substandard [Member]
Loans	2,596,897	2,690,020
Residential Portfolio Segment [Member] | Doubtful [Member]
Loans
Commercial Portfolio Segment [Member]
Loans	22,095,306	23,323,073
Commercial Portfolio Segment [Member] | Excellent [Member]
Loans	912,227	977,054
Commercial Portfolio Segment [Member] | Above Average [Member]
Loans	22,200	24,180
Commercial Portfolio Segment [Member] | Average [Member]
Loans	9,998,931	12,373,503
Commercial Portfolio Segment [Member] | Acceptable [Member]
Loans	8,135,261	7,130,122
Commercial Portfolio Segment [Member] | Pass [Member]
Loans	3,026,687	2,818,214
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans
Consumer Portfolio Segment [Member]
Loans	367,293	494,009
Consumer Portfolio Segment [Member] | Excellent [Member]
Loans	12,944	3,668
Consumer Portfolio Segment [Member] | Above Average [Member]
Loans	108,534	80,670
Consumer Portfolio Segment [Member] | Average [Member]
Loans	159,671	266,704
Consumer Portfolio Segment [Member] | Acceptable [Member]
Loans	60,543	63,160
Consumer Portfolio Segment [Member] | Pass [Member]
Loans
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans	5,188	1,340
Consumer Portfolio Segment [Member] | Doubtful [Member]
Loans	$ 20,413	$ 78,467