Note 3 - Loans Held for Investment, Net - Credit Quality Indicators (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Total, gross loans	$ 280,860,839	$ 262,022,508
Pass [Member]
Total, gross loans	270,035,385	251,988,999
Special Mention [Member]
Total, gross loans	1,855,712	954,953
Substandard [Member]
Total, gross loans	8,419,742	8,528,556
Doubtful [Member]
Total, gross loans	550,000	550,000
Loss [Member]
Total, gross loans	0	0
Commercial Real Estate Portfolio Segment [Member]
Total, gross loans	231,983,432	214,871,788
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	224,546,530	208,395,458
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	1,855,712	911,571
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	5,031,190	5,014,759
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member]
Total, gross loans	550,000	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	28,932,957	29,114,060
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	27,280,221	27,400,698
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	0	43,382
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	1,652,736	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	12,897,863	12,296,308
Commercial and Industrial Portfolio Segment [Member] | Pass [Member]
Total, gross loans	11,321,992	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	1,575,871	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	7,046,587	5,740,352
Consumer and Other Portfolio Segment [Member] | Pass [Member]
Total, gross loans	6,886,642	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	159,945	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