Note 1 - Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Net income available to common stockholders	$ 814,024	$ 1,261,098
Basic potential common shares:
Weighted average shares outstanding (in shares)	3,467,208	3,019,749
Weighted average unallocated ESOP shares (in shares)	(187,545)	(59,149)
Weighted average unvested MRP shares (in shares)		(938)
Basic weighted average shares outstanding (in shares)	3,279,663	2,959,662
Dilutive potential common shares:
Dilutive weighted average shares outstanding (in shares)	3,295,863	2,975,713
Basic earnings per share (in dollars per share)	$ 0.25	$ 0.43
Diluted earnings per share (in dollars per share)	$ 0.25	$ 0.42
Management Recognition Plan [Member]
Dilutive potential common shares:
Dilutive weighted average shares outstanding (in shares)		1,099
Recognition and Retention Plan - DO NOT USE[Member]
Dilutive potential common shares:
Dilutive weighted average shares outstanding (in shares)	16,200	14,952