Note 3 - Loans Held for Investment, Net - Allowance for Loan Losses and Recorded Investment in Loans (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Ending balance: individually evaluated for impairment			$ 215,000	$ 0
Ending balance: collectively evaluated for impairment			2,907,170	3,117,190
Total, allowance for loan losses	$ 3,122,170	$ 2,506,033	3,122,170	3,117,190
Ending balance: individually evaluated for impairment, gross loans			5,694,627	5,436,972
Ending balance: collectively evaluated for impairment, gross loans			256,807,298	256,585,536
Total, gross loans			262,501,925	262,022,508
Balance	3,117,190	2,506,033
Provision for loan losses	22,000	250,000
Charge-offs	(23,269)
Recoveries	6,249	7,450
Net recoveries	(17,020)	7,450
Balance	3,122,170	2,763,483
Commercial Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment			215,000	0
Ending balance: collectively evaluated for impairment			1,851,285	2,055,911
Total, allowance for loan losses	2,066,285	1,688,448	2,066,285	2,055,911
Ending balance: individually evaluated for impairment, gross loans			3,709,122	3,483,078
Ending balance: collectively evaluated for impairment, gross loans			208,891,446	211,388,710
Total, gross loans			212,600,568	214,871,788
Balance	2,055,911	1,688,448
Provision for loan losses	10,374	120,158
Recoveries		1,200
Net recoveries		1,200
Balance	2,066,285	1,809,806
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			503,295	567,290
Total, allowance for loan losses	503,295	617,912	503,295	567,290
Ending balance: individually evaluated for impairment, gross loans			710,795	679,184
Ending balance: collectively evaluated for impairment, gross loans			29,230,099	28,434,876
Total, gross loans			29,940,894	29,114,060
Balance	567,290	617,912
Provision for loan losses	(46,975)	3,488
Charge-offs	(23,269)
Recoveries	6,249	6,250
Net recoveries	(17,020)	6,250
Balance	503,295	627,650
Commercial and Industrial Portfolio Segment [Member]
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			514,307	462,406
Total, allowance for loan losses	514,307	147,371	514,307	462,406
Ending balance: individually evaluated for impairment, gross loans			1,274,710	1,274,710
Ending balance: collectively evaluated for impairment, gross loans			12,268,835	11,021,598
Total, gross loans			13,543,545	12,296,308
Balance	462,406	147,371
Provision for loan losses	51,901	152,397
Charge-offs
Recoveries
Net recoveries
Balance	514,307	299,768
Consumer and Other Portfolio Segment [Member]
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			38,283	31,583
Total, allowance for loan losses	38,283	52,302	38,283	31,583
Ending balance: individually evaluated for impairment, gross loans			0
Ending balance: collectively evaluated for impairment, gross loans			6,416,918	5,740,352
Total, gross loans			$ 6,416,918	$ 5,740,352
Balance	31,583	52,302
Provision for loan losses	6,700	(26,043)
Balance	$ 38,283	$ 26,259