Note 4 - Loans Held for Investment, Net - Impaired Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Impaired loans, with no related allowance recorded, recorded investment	$ 3,643,608	$ 5,436,972
Impaired loans, with no related allowance recorded, principal net of charge-offs,	3,643,608	5,436,972
Impaired loans, with no related allowance recorded, average recorded investment	3,663,931	5,503,793
Impaired loans, with an allowance recorded, recorded investment	0	0
Impaired loans, with an allowance recorded, principal net of charge-offs	0	0
Impaired loans, related allowance	0	0
Impaired loans, with an allowance recorded, average recorded investment	0	0
Impaired loans, fair value disclosure	3,643,608	5,436,972
Impaired loans, principal net of charge-offs	3,643,608	5,436,972
Impaired loans, average recorded investment	3,663,931	5,503,793
Commercial Real Estate Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	2,993,923	3,483,078
Impaired loans, with no related allowance recorded, principal net of charge-offs,	2,993,923	3,483,078
Impaired loans, with no related allowance recorded, average recorded investment	3,007,495	3,521,421
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	2,993,923	3,483,078
Impaired loans, principal net of charge-offs	2,993,923	3,483,078
Impaired loans, average recorded investment	3,007,495	3,521,421
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	649,685	679,184
Impaired loans, with no related allowance recorded, principal net of charge-offs,	649,685	679,184
Impaired loans, with no related allowance recorded, average recorded investment	656,436	684,632
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	649,685	679,184
Impaired loans, principal net of charge-offs	649,685	679,184
Impaired loans, average recorded investment	656,436	684,632
Commercial and Industrial Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment		1,274,710
Impaired loans, with no related allowance recorded, principal net of charge-offs,		1,274,710
Impaired loans, with no related allowance recorded, average recorded investment		1,297,740
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure		1,274,710
Impaired loans, principal net of charge-offs		1,274,710
Impaired loans, average recorded investment		1,297,740
Consumer and Other Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	0	0
Impaired loans, with no related allowance recorded, principal net of charge-offs,	0	0
Impaired loans, with no related allowance recorded, average recorded investment	0	0
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	0	0
Impaired loans, principal net of charge-offs	0	0
Impaired loans, average recorded investment	$ 0	$ 0