Note 3 - Loans Held for Investment, Net - Credit Quality Indicators (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Total, gross loans	$ 290,978,673	$ 286,840,889
Pass [Member]
Total, gross loans	280,416,746	278,113,442
Special Mention [Member]
Total, gross loans	4,155,844	2,250,559
Substandard [Member]
Total, gross loans	6,406,083	6,476,888
Doubtful [Member]
Total, gross loans
Loss [Member]
Total, gross loans	0	0
Commercial Real Estate Portfolio Segment [Member]
Total, gross loans	238,120,124	233,102,637
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	229,465,218	226,510,803
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	4,060,029	1,981,667
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	4,594,877	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	29,170,381	29,855,462
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Pass [Member]
Total, gross loans	27,616,139	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	1,554,242	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	17,602,539	17,508,258
Commercial and Industrial Portfolio Segment [Member] | Pass [Member]
Total, gross loans	17,249,760	17,237,690
Commercial and Industrial Portfolio Segment [Member] | Special Mention [Member]
Total, gross loans	95,815
Commercial and Industrial Portfolio Segment [Member] | Substandard [Member]
Total, gross loans	256,964	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	6,085,629	6,374,532
Consumer and Other Portfolio Segment [Member] | Pass [Member]
Total, gross loans	6,085,629	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