Note 3 - Loans Held for Investment, Net - Nonperforming Receivables Past Due (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Past due loans	$ 3,564,298	$ 4,154,832
Current loans	287,414,375	282,686,057
Total, gross loans	290,978,673	286,840,889
Financial Asset, 30 to 59 Days Past Due [Member]
Past due loans	448,614	782,835
Financial Asset, 60 to 89 Days Past Due [Member]
Past due loans	47,905	2,978,929
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due loans	3,067,779	393,068
Commercial Real Estate Portfolio Segment [Member]
Past due loans	2,784,139	2,744,405
Current loans	235,335,985	230,358,232
Total, gross loans	238,120,124	233,102,637
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due loans	39,734
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	780,159	1,410,427
Current loans	28,390,222	28,445,035
Total, gross loans	29,170,381	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	408,880	782,835
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due loans	47,905	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	323,374	393,068
Commercial and Industrial Portfolio Segment [Member]
Past due loans
Current loans	17,602,539	17,508,258
Total, gross loans	17,602,539	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	6,085,629	6,374,532
Total, gross loans	6,085,629	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