Note 4 - Loans Held for Investment, Net - Allowance for Loan Losses and Recorded Investment in Loans (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018
Ending balance: individually evaluated for impairment								$ 0
Ending balance: collectively evaluated for impairment							3,068,291	2,901,091
Total, allowance for loan losses	$ 3,068,291	$ 2,901,091	$ 3,122,170	$ 3,117,190	$ 3,068,291	$ 3,117,190	3,068,291	2,901,091
Ending balance: individually evaluated for impairment, gross loans							3,590,539	3,643,608
Ending balance: collectively evaluated for impairment, gross loans							290,045,405	283,197,281
Total, gross loans							293,635,944	286,840,889
Balance	2,981,412	2,901,091	3,122,170	3,117,190	2,901,091	3,117,190
Provision for loan losses	85,000	87,500	71,000	22,000	172,500	93,000
Charge-offs		(8,686)		(23,269)
Recoveries	1,879	1,507	6,250	6,249
Net recoveries (charge-offs)	1,879	(7,179)	6,250	(17,020)
Balance	3,068,291	2,981,412	3,199,420	3,122,170	3,068,291	3,199,420
Provision for loan losses	(85,000)	(87,500)	(71,000)	(22,000)	(172,500)	(93,000)
Commercial Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment								0
Ending balance: collectively evaluated for impairment							2,426,902	2,130,124
Total, allowance for loan losses	2,426,902	2,130,124	2,066,285	2,055,911	2,426,902	2,055,911	2,426,902	2,130,124
Ending balance: individually evaluated for impairment, gross loans							2,982,136	2,993,923
Ending balance: collectively evaluated for impairment, gross loans							237,486,146	230,108,714
Total, gross loans							240,468,282	233,102,637
Balance	2,341,297	2,130,124	2,066,285	2,055,911	2,130,124	2,055,911
Provision for loan losses	85,605	211,173	77,026	10,374
Charge-offs
Recoveries
Net recoveries (charge-offs)
Balance	2,426,902	2,341,297	2,143,311	2,066,285	2,426,902	2,143,311
Provision for loan losses	(85,605)	(211,173)	(77,026)	(10,374)
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment							0	0
Ending balance: collectively evaluated for impairment							219,630	359,705
Total, allowance for loan losses	219,630	359,705	503,295	567,290	219,630	567,290	219,630	359,705
Ending balance: individually evaluated for impairment, gross loans							608,403	649,685
Ending balance: collectively evaluated for impairment, gross loans							29,062,613	29,205,777
Total, gross loans							29,671,016	29,855,462
Balance	220,139	359,705	503,295	567,290	359,705	567,290
Provision for loan losses	(2,388)	(130,880)	(22,165)	(46,975)
Charge-offs		(8,686)		(23,269)
Recoveries	1,879		6,250	6,249
Net recoveries (charge-offs)	1,879	(8,686)	6,250	(17,020)
Balance	219,630	220,139	487,380	503,295	219,630	487,380
Provision for loan losses	2,388	130,880	22,165	46,975
Commercial and Industrial Portfolio Segment [Member]
Ending balance: individually evaluated for impairment							0	0
Ending balance: collectively evaluated for impairment							398,339	377,180
Total, allowance for loan losses	398,339	377,180	514,307	462,406	398,339	462,406	398,339	377,180
Ending balance: individually evaluated for impairment, gross loans
Ending balance: collectively evaluated for impairment, gross loans							19,105,548	17,508,258
Total, gross loans							19,105,548	17,508,258
Balance	388,425	377,180	514,307	462,406	377,180	462,406
Provision for loan losses	9,914	9,738	13,138	51,901
Charge-offs
Recoveries		1,507
Net recoveries (charge-offs)		1,507
Balance	398,339	388,425	527,445	514,307	398,339	527,445
Provision for loan losses	(9,914)	(9,738)	(13,138)	(51,901)
Consumer and Other Portfolio Segment [Member]
Ending balance: individually evaluated for impairment							0	0
Ending balance: collectively evaluated for impairment							23,420	34,082
Total, allowance for loan losses	23,420	34,082	38,283	31,583	23,420	31,583	23,420	34,082
Ending balance: individually evaluated for impairment, gross loans							0
Ending balance: collectively evaluated for impairment, gross loans							4,391,098	6,374,532
Total, gross loans							$ 4,391,098	$ 6,374,532
Balance	31,551	34,082	38,283	31,583	34,082	31,583
Provision for loan losses	(8,131)	(2,531)	3,001	6,700
Charge-offs
Recoveries
Net recoveries (charge-offs)
Balance	23,420	31,551	41,284	38,283	$ 23,420	$ 41,284
Provision for loan losses	$ 8,131	$ 2,531	$ (3,001)	$ (6,700)