Note 4 - Loans Held for Investment, Net - Allowance for Loan Losses and Recorded Investment in Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Ending balance: individually evaluated for impairment				$ 0
Ending balance: collectively evaluated for impairment			2,901,091	3,117,190
Total, allowance for loan losses	$ 3,117,190	$ 2,506,033	2,901,091	3,117,190
Ending balance: individually evaluated for impairment, gross loans			3,643,608	5,436,972
Ending balance: collectively evaluated for impairment, gross loans			283,197,281	256,585,536
Total, gross loans			286,840,889	262,022,508
Balance	3,117,190	2,506,033
Provision for loan losses	318,000	575,000
Charge-offs	(596,418)	(20,845)
Recoveries	62,319	57,002
Net recoveries (charge-offs)	(534,099)	36,157
Commercial Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment				0
Ending balance: collectively evaluated for impairment			2,130,124	2,055,911
Total, allowance for loan losses	2,055,911	1,688,448	2,130,124	2,055,911
Ending balance: individually evaluated for impairment, gross loans			2,993,923	3,483,078
Ending balance: collectively evaluated for impairment, gross loans			230,108,714	211,388,710
Total, gross loans			233,102,637	214,871,788
Balance	2,055,911	1,688,448
Provision for loan losses	624,213	366,263
Charge-offs	(550,000)
Recoveries		1,200
Net recoveries (charge-offs)	(550,000)	1,200
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			359,705	567,290
Total, allowance for loan losses	567,290	617,912	359,705	567,290
Ending balance: individually evaluated for impairment, gross loans			649,685	679,184
Ending balance: collectively evaluated for impairment, gross loans			29,205,777	28,434,876
Total, gross loans			29,855,462	29,114,060
Balance	567,290	617,912
Provision for loan losses	(183,988)	(54,777)
Charge-offs	(36,096)	(20,845)
Recoveries	12,499	25,000
Net recoveries (charge-offs)	(23,597)	4,155
Commercial and Industrial Portfolio Segment [Member]
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			377,180	462,406
Total, allowance for loan losses	462,406	147,371	377,180	462,406
Ending balance: individually evaluated for impairment, gross loans				1,274,710
Ending balance: collectively evaluated for impairment, gross loans			17,508,258	11,021,598
Total, gross loans			17,508,258	12,296,308
Balance	462,406	147,371
Provision for loan losses	(124,724)	284,233
Charge-offs	(10,322)
Recoveries	49,820	30,802
Net recoveries (charge-offs)	39,498	30,802
Consumer and Other Portfolio Segment [Member]
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			34,082	31,583
Total, allowance for loan losses	31,583	52,302	34,082	31,583
Ending balance: individually evaluated for impairment, gross loans			0
Ending balance: collectively evaluated for impairment, gross loans			6,374,532	5,740,352
Total, gross loans			$ 6,374,532	$ 5,740,352
Balance	31,583	52,302
Provision for loan losses	2,499	$ (20,719)
Net recoveries (charge-offs)