Note 4 - Loans Held for Investment, Net - Impaired Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Impaired loans, with no related allowance recorded, recorded investment	$ 5,436,972	$ 5,968,221
Impaired loans, with no related allowance recorded, principal net of charge-offs,	5,436,972	5,968,221
Impaired loans, with no related allowance recorded, average recorded investment	5,503,793	3,117,308
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	5,436,972	5,968,221
Impaired loans, principal net of charge-offs	5,436,972	5,968,221
Impaired loans, average recorded investment	5,503,793	3,117,308
Impaired loans, recorded investment	5,436,972	5,968,221
Commercial Real Estate Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	3,483,078	3,718,686
Impaired loans, with no related allowance recorded, principal net of charge-offs,	3,483,078	3,718,686
Impaired loans, with no related allowance recorded, average recorded investment	3,521,421	1,385,277
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	3,483,078	3,718,686
Impaired loans, principal net of charge-offs	3,483,078	3,718,686
Impaired loans, average recorded investment	3,521,421	1,385,277
Impaired loans, recorded investment	3,483,078	3,718,686
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	679,184	648,880
Impaired loans, with no related allowance recorded, principal net of charge-offs,	679,184	648,880
Impaired loans, with no related allowance recorded, average recorded investment	684,632	656,495
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	679,184	648,880
Impaired loans, principal net of charge-offs	679,184	648,880
Impaired loans, average recorded investment	684,632	656,495
Impaired loans, recorded investment	679,184	648,880
Commercial and Industrial Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	1,274,710	1,600,655
Impaired loans, with no related allowance recorded, principal net of charge-offs,	1,274,710	1,600,655
Impaired loans, with no related allowance recorded, average recorded investment	1,297,740	1,075,536
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	1,274,710	1,600,655
Impaired loans, principal net of charge-offs	1,274,710	1,600,655
Impaired loans, average recorded investment	1,297,740	1,075,536
Impaired loans, recorded investment	1,274,710	1,600,655
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
Impaired loans, recorded investment	$ 0	$ 0