Note 4 - Loans Held for Investment, Net - Allowance for Loan Losses and Recorded Investment in Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Ending balance: individually evaluated for impairment, allowance for loan losses			$ 0	$ 0
Ending balance: collectively evaluated for impairment, allowance for loan losses			3,117,190	2,506,033
Total, allowance for loan losses	$ 3,117,190	$ 2,506,033	3,117,190	2,506,033
Gross loans
Ending balance: individually evaluated for impairment, gross loans			5,436,972	6,181,082
Ending balance: collectively evaluated for impairment, gross loans			256,585,536	238,677,017
Total gross loans			262,022,508	244,858,099
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			3,117,190	2,506,033
Total, allowance for loan losses	3,117,190	2,506,033	3,117,190	2,506,033
Balance	2,506,033	1,894,196
Provision for loan losses	575,000	1,019,000
Charge-offs	(20,845)	(525,288)
Recoveries	57,002	118,125
Net recoveries (charge-offs)	36,157	(407,163)
Balance	3,117,190	2,506,033
Receivables Acquired with Deteriorated Credit Quality [Member]
Gross loans
Total gross loans			0	0
Commercial 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			2,055,911	1,688,448
Total, allowance for loan losses	2,055,911	1,688,448	2,055,911	1,688,448
Gross loans
Ending balance: individually evaluated for impairment, gross loans			3,483,078	3,441,874
Ending balance: collectively evaluated for impairment, gross loans			211,388,710	192,372,331
Total gross loans			214,871,788	195,814,205
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			2,055,911	1,688,448
Total, allowance for loan losses	2,055,911	1,688,448	2,055,911	1,688,448
Balance	1,688,448	1,136,458
Provision for loan losses	366,263	435,865
Recoveries	1,200	116,125
Net recoveries (charge-offs)	1,200	116,125
Balance	2,055,911	1,688,448
Commercial Real Estate Portfolio Segment [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Gross loans
Total gross loans			0	0
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			567,290	617,912
Total, allowance for loan losses	567,290	617,912	567,290	617,912
Gross loans
Ending balance: individually evaluated for impairment, gross loans			679,184	1,744,062
Ending balance: collectively evaluated for impairment, gross loans			28,434,876	28,232,563
Total gross loans			29,114,060	29,976,625
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			567,290	617,912
Total, allowance for loan losses	567,290	617,912	567,290	617,912
Balance	617,912	656,089
Provision for loan losses	(54,777)	100,548
Charge-offs	(20,845)	(140,725)
Recoveries	25,000	2,000
Net recoveries (charge-offs)	4,155	(138,725)
Balance	567,290	617,912
One-to-four Family Residential Real Estate Portfolio Segment [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Gross loans
Total gross loans			0	0
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			462,406	147,371
Total, allowance for loan losses	462,406	147,371	462,406	147,371
Gross loans
Ending balance: individually evaluated for impairment, gross loans			1,274,710	801,078
Ending balance: collectively evaluated for impairment, gross loans			11,021,598	9,074,942
Total gross loans			12,296,308	9,876,020
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			462,406	147,371
Total, allowance for loan losses	462,406	147,371	462,406	147,371
Balance	147,371	63,527
Provision for loan losses	284,233	468,407
Charge-offs		(384,563)
Recoveries	30,802
Net recoveries (charge-offs)	30,802	(384,563)
Balance	462,406	147,371
Commercial and Industrial Portfolio Segment [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Gross loans
Total gross loans			0	0
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			31,583	52,302
Total, allowance for loan losses	31,583	52,302	31,583	52,302
Gross loans
Ending balance: individually evaluated for impairment, gross loans				194,068
Ending balance: collectively evaluated for impairment, gross loans			5,740,352	8,997,181
Total gross loans			5,740,352	9,191,249
Ending balance: individually evaluated for impairment, allowance for loan losses			0	0
Ending balance: collectively evaluated for impairment, allowance for loan losses			31,583	52,302
Total, allowance for loan losses	31,583	52,302	31,583	52,302
Balance	52,302	38,122
Provision for loan losses	(20,719)	14,180
Balance	$ 31,583	$ 52,302
Consumer and Other Portfolio Segment [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Gross loans
Total gross loans			$ 0	$ 0