Note 4 - Loans Held for Investment, Net - Credit Quality Indicators (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Total, gross loans	$ 286,840,889	$ 262,022,508
Pass [Member]
Total, gross loans	278,113,442	251,988,999
Special Mention [Member]
Total, gross loans	2,250,559	954,953
Substandard [Member]
Total, gross loans	6,476,888	8,528,556
Doubtful [Member]
Total, gross loans		550,000
Loss [Member]
Total, gross loans	0	0
Commercial Real Estate Portfolio Segment [Member]
Total, gross loans	233,102,637	214,871,788
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	226,510,803	208,395,458
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	1,981,667	911,571
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	4,610,167	5,014,759
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member]
Total, gross loans		550,000
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	29,855,462	29,114,060
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	27,990,417	27,400,698
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	268,892	43,382
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	1,596,153	1,669,980
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	17,508,258	12,296,308
Commercial and Industrial Portfolio Segment [Member] | Pass [Member]
Total, gross loans	17,237,690	10,624,210
Commercial and Industrial Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	0
Commercial and Industrial Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	270,568	1,672,098
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	6,374,532	5,740,352
Consumer and Other Portfolio Segment [Member] | Pass [Member]
Total, gross loans	6,374,532	5,568,633
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		171,719
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