Note 3 - Loans Held for Investment, Net - Credit Quality Indicators (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Total, gross loans	$ 284,557,764	$ 262,022,508
Pass [Member]
Total, gross loans	274,301,150	251,988,999
Special Mention [Member]
Total, gross loans	1,845,517	954,953
Substandard [Member]
Total, gross loans	7,861,097	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	231,303,130	214,871,788
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	224,370,286	208,395,458
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	1,845,517	911,571
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	4,537,327	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	30,138,258	29,114,060
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	28,519,214	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	1,619,044	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	16,560,992	12,296,308
Commercial and Industrial Portfolio Segment [Member] | Pass [Member]
Total, gross loans	15,012,206	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	1,548,786	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	6,555,384	5,740,352
Consumer and Other Portfolio Segment [Member] | Pass [Member]
Total, gross loans	6,399,444	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	155,940	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