Note 4 - Loans Held for Investment, Net - Credit Quality Indicators (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Total, gross loans	$ 303,253,964	$ 286,840,889
Pass [Member]
Total, gross loans	296,188,155	278,113,442
Special Mention [Member]
Total, gross loans	475,062	2,250,559
Substandard [Member]
Total, gross loans	6,590,747	6,476,888
Doubtful [Member]
Total, gross loans
Loss [Member]
Total, gross loans	0	0
Commercial Real Estate Portfolio Segment [Member]
Total, gross loans	248,954,014	233,102,637
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	243,963,223	226,510,803
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	41,491	1,981,667
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	4,949,300	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	29,055,811	29,855,462
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	27,309,481	27,990,417
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	433,571	268,892
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	1,312,759	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	20,131,619	17,508,258
Commercial and Industrial Portfolio Segment [Member] | Pass [Member]
Total, gross loans	19,802,931	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	328,688	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	5,112,520	6,374,532
Consumer and Other Portfolio Segment [Member] | Pass [Member]
Total, gross loans	5,112,520	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