Note 5 - Loans Held for Investment, Net - Allowance for Loan Losses and Recorded Investment in Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Ending balance: individually evaluated for impairment, allowance for loan losses				$ 0
Ending balance: collectively evaluated for impairment, allowance for loan losses			2,921,931	2,901,091
Total, allowance for loan losses	$ 2,901,091	$ 3,117,190	2,921,931	2,901,091
Ending balance: individually evaluated for impairment, gross loans			3,505,288	3,643,608
Ending balance: collectively evaluated for impairment, gross loans			291,963,300	283,197,281
Total, gross loans			295,468,588	286,840,889
Balance	2,901,091	3,117,190
Provision for loan losses	22,500	318,000
Charge-offs	(8,686)	(596,418)
Recoveries	7,026	62,319
Net recoveries (charge-offs)	(1,660)	(534,099)
Commercial Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment, allowance for loan losses				0
Ending balance: collectively evaluated for impairment, allowance for loan losses			2,588,714	2,130,124
Total, allowance for loan losses	2,130,124	2,055,911	2,588,714	2,130,124
Ending balance: individually evaluated for impairment, gross loans			2,718,731	2,993,923
Ending balance: collectively evaluated for impairment, gross loans			239,963,990	230,108,714
Total, gross loans			242,682,721	233,102,637
Balance	2,130,124	2,055,911
Provision for loan losses	458,590	624,213
Charge-offs		(550,000)
Recoveries
Net recoveries (charge-offs)		(550,000)
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			187,345	359,705
Total, allowance for loan losses	359,705	567,290	187,345	359,705
Ending balance: individually evaluated for impairment, gross loans			786,557	649,685
Ending balance: collectively evaluated for impairment, gross loans			28,063,083	29,205,777
Total, gross loans			28,849,640	29,855,462
Balance	359,705	567,290
Provision for loan losses	(169,193)	(183,988)
Charge-offs	(8,686)	(36,096)
Recoveries	5,519	12,499
Net recoveries (charge-offs)	(3,167)	(23,597)
Commercial and Industrial Portfolio Segment [Member]
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			115,502	377,180
Total, allowance for loan losses	377,180	462,406	115,502	377,180
Ending balance: individually evaluated for impairment, gross loans
Ending balance: collectively evaluated for impairment, gross loans			20,075,236	17,508,258
Total, gross loans			20,075,236	17,508,258
Balance	377,180	462,406
Provision for loan losses	(263,185)	(124,724)
Charge-offs		(10,322)
Recoveries	1,507	49,820
Net recoveries (charge-offs)	1,507	39,498
Consumer and Other Portfolio Segment [Member]
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			30,370	34,082
Total, allowance for loan losses	34,082	31,583	30,370	34,082
Ending balance: individually evaluated for impairment, gross loans
Ending balance: collectively evaluated for impairment, gross loans			3,860,991	6,374,532
Total, gross loans			$ 3,860,991	$ 6,374,532
Balance	34,082	31,583
Provision for loan losses	$ (3,712)	2,499
Net recoveries (charge-offs)