Note 4 - Loans Held for Investment, Net - Credit Quality Indicators (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Total, gross loans	$ 293,635,944	$ 286,840,889
Pass [Member]
Total, gross loans	286,742,078	278,113,442
Special Mention [Member]
Total, gross loans		2,250,559
Substandard [Member]
Total, gross loans	6,893,866	6,476,888
Doubtful [Member]
Total, gross loans
Loss [Member]
Total, gross loans	0	0
Commercial Real Estate Portfolio Segment [Member]
Total, gross loans	240,468,282	233,102,637
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	235,347,875	226,510,803
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans		1,981,667
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	5,120,407	4,610,167
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member]
Total, gross loans
Commercial Real Estate Portfolio Segment [Member] | Loss [Member]
Total, gross loans	0	0
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Total, gross loans	29,671,016	29,855,462
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	28,133,783	27,990,417
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans		268,892
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	1,537,233	1,596,153
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Doubtful [Member]
Total, gross loans	0	0
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Loss [Member]
Total, gross loans	0	0
Commercial and Industrial Portfolio Segment [Member]
Total, gross loans	19,105,548	17,508,258
Commercial and Industrial Portfolio Segment [Member] | Pass [Member]
Total, gross loans	18,869,322	17,237,690
Commercial and Industrial Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans
Commercial and Industrial Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	236,226	270,568
Commercial and Industrial Portfolio Segment [Member] | Doubtful [Member]
Total, gross loans	0
Commercial and Industrial Portfolio Segment [Member] | Loss [Member]
Total, gross loans	0	0
Consumer and Other Portfolio Segment [Member]
Total, gross loans	4,391,098	6,374,532
Consumer and Other Portfolio Segment [Member] | Pass [Member]
Total, gross loans	4,391,098	6,374,532
Consumer and Other Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	0	0
Consumer and Other Portfolio Segment [Member] | Substandard [Member]
Total, gross loans
Consumer and Other Portfolio Segment [Member] | Doubtful [Member]
Total, gross loans	0	0
Consumer and Other Portfolio Segment [Member] | Loss [Member]
Total, gross loans	$ 0	$ 0