Note 4 - Loans Held for Investment, Net - Nonperforming Receivables Past Due (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Past due loans	$ 3,168,942	$ 4,154,832
Current loans	300,085,022	282,686,057
Total, gross loans	303,253,964	286,840,889
Financial Asset, 30 to 59 Days Past Due [Member]
Past due loans		782,835
Financial Asset, 60 to 89 Days Past Due [Member]
Past due loans		2,978,929
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due loans	3,168,942	393,068
Commercial Real Estate Portfolio Segment [Member]
Past due loans	2,744,405	2,744,405
Current loans	246,209,609	230,358,232
Total, gross loans	248,954,014	233,102,637
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due loans
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due loans		2,744,405
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due loans	2,744,405
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Past due loans	424,537	1,410,427
Current loans	28,631,274	28,445,035
Total, gross loans	29,055,811	29,855,462
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due loans		782,835
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due loans		234,524
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due loans	424,537	393,068
Commercial and Industrial Portfolio Segment [Member]
Past due loans
Current loans	20,131,619	17,508,258
Total, gross loans	20,131,619	17,508,258
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due loans	0	0
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due loans	0	0
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due loans
Consumer and Other Portfolio Segment [Member]
Past due loans	0	0
Current loans	5,112,520	6,374,532
Total, gross loans	5,112,520	6,374,532
Consumer and Other Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due loans	0	0
Consumer and Other Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due loans	0	0
Consumer and Other Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due loans	$ 0	$ 0