Note 4 - Loans Held for Investment, Net - Allowance for Loan Losses and Recorded Investment in Loans (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018
Ending balance: individually evaluated for impairment										$ 0
Ending balance: collectively evaluated for impairment									3,071,322	2,901,091
Total, allowance for loan losses	$ 3,071,322	$ 2,981,412	$ 2,901,091	$ 3,199,420	$ 3,122,170	$ 3,117,190	$ 3,071,322	$ 3,117,190	3,071,322	2,901,091
Ending balance: individually evaluated for impairment, gross loans									3,562,937	3,643,608
Ending balance: collectively evaluated for impairment, gross loans									299,691,027	283,197,281
Total, gross loans									303,253,964	286,840,889
Balance	3,068,291	2,981,412	2,901,091	3,199,420	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)	(12,827)		(23,269)
Recoveries	3,031	1,879	1,507	47,220	6,250	6,249
Net recoveries (charge-offs)	3,031	1,879	(7,179)	34,393	6,250	(17,020)
Balance	3,071,322	3,068,291	2,981,412	3,233,813	3,199,420	3,122,170	3,071,322	3,233,813
Commercial Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment										0
Ending balance: collectively evaluated for impairment									2,400,458	2,130,124
Total, allowance for loan losses	2,400,458	2,341,297	2,130,124	2,143,311	2,066,285	2,055,911	2,400,458	2,055,911	2,400,458	2,130,124
Ending balance: individually evaluated for impairment, gross loans									2,976,737	2,993,923
Ending balance: collectively evaluated for impairment, gross loans									245,977,277	230,108,714
Total, gross loans									248,954,014	233,102,637
Balance	2,426,902	2,341,297	2,130,124	2,143,311	2,066,285	2,055,911	2,130,124	2,055,911
Provision for loan losses	(26,444)	85,605	211,173	108,118	77,026	10,374
Charge-offs
Recoveries
Net recoveries (charge-offs)
Balance	2,400,458	2,426,902	2,341,297	2,251,429	2,143,311	2,066,285	2,400,458	2,251,429
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment									0	0
Ending balance: collectively evaluated for impairment									178,708	359,705
Total, allowance for loan losses	178,708	220,139	359,705	487,380	503,295	567,290	178,708	567,290	178,708	359,705
Ending balance: individually evaluated for impairment, gross loans									586,200	649,685
Ending balance: collectively evaluated for impairment, gross loans									28,469,611	29,205,777
Total, gross loans									29,055,811	29,855,462
Balance	219,630	220,139	359,705	487,380	503,295	567,290	359,705	567,290
Provision for loan losses	(43,953)	(2,388)	(130,880)	(94,439)	(22,165)	(46,975)
Charge-offs			(8,686)	(12,827)		(23,269)
Recoveries	3,031	1,879			6,250	6,249
Net recoveries (charge-offs)	3,031	1,879	(8,686)	(12,827)	6,250	(17,020)
Balance	178,708	219,630	220,139	380,114	487,380	503,295	178,708	380,114
Commercial and Industrial Portfolio Segment [Member]
Ending balance: individually evaluated for impairment									0	0
Ending balance: collectively evaluated for impairment									463,141	377,180
Total, allowance for loan losses	463,141	388,425	377,180	527,445	514,307	462,406	463,141	462,406	463,141	377,180
Ending balance: individually evaluated for impairment, gross loans
Ending balance: collectively evaluated for impairment, gross loans									20,131,619	17,508,258
Total, gross loans									20,131,619	17,508,258
Balance	398,339	388,425	377,180	527,445	514,307	462,406	377,180	462,406
Provision for loan losses	64,802	9,914	9,738	(15,171)	13,138	51,901
Charge-offs
Recoveries			1,507	47,220
Net recoveries (charge-offs)			1,507	47,220
Balance	463,141	398,339	388,425	559,494	527,445	514,307	463,141	559,494
Consumer and Other Portfolio Segment [Member]
Ending balance: individually evaluated for impairment									0	0
Ending balance: collectively evaluated for impairment									29,015	34,082
Total, allowance for loan losses	29,015	31,551	34,082	41,284	38,283	31,583	29,015	31,583	29,015	34,082
Ending balance: individually evaluated for impairment, gross loans									0
Ending balance: collectively evaluated for impairment, gross loans									5,112,520	6,374,532
Total, gross loans									$ 5,112,520	$ 6,374,532
Balance	23,420	31,551	34,082	41,284	38,283	31,583	34,082	31,583
Provision for loan losses	5,595	(8,131)	(2,531)	1,492	3,001	6,700
Charge-offs
Recoveries
Net recoveries (charge-offs)
Balance	$ 29,015	$ 23,420	$ 31,551	$ 42,776	$ 41,284	$ 38,283	$ 29,015	$ 42,776