Note 2 - Available-for-sale Securities - Gross Unrealized Losses in a Continuous Loss Position (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 11,818,974	$ 19,923,126
Available-for-sale Securities, Less than 12 Months, Gross Unrealized Losses	(125,234)	(400,360)
Available-for-sale Securities, 12 Months or More, Fair Value	11,025,113	5,351,384
Available-for-sale Securities, 12 Months or More, Gross Unrealized Losses	(236,123)	(105,211)
Available-for-sale Securities, Fair Value	22,844,087	25,274,510
Available-for-sale Securities, Gross Unrealized Losses	(361,357)	(505,571)
Collateralized Mortgage Backed Securities [Member]
Available-for-sale Securities, Less than 12 Months, Fair Value	11,168,062	17,377,335
Available-for-sale Securities, Less than 12 Months, Gross Unrealized Losses	(108,806)	(337,092)
Available-for-sale Securities, 12 Months or More, Fair Value	10,059,582	5,351,384
Available-for-sale Securities, 12 Months or More, Gross Unrealized Losses	(198,736)	(105,211)
Available-for-sale Securities, Fair Value	21,227,644	22,728,719
Available-for-sale Securities, Gross Unrealized Losses	(307,542)	(442,303)
US Government Agencies Debt Securities [Member]
Available-for-sale Securities, Less than 12 Months, Fair Value	650,912	2,525,737
Available-for-sale Securities, Less than 12 Months, Gross Unrealized Losses	(16,428)	(63,107)
Available-for-sale Securities, 12 Months or More, Fair Value	965,531	0
Available-for-sale Securities, 12 Months or More, Gross Unrealized Losses	(37,387)	0
Available-for-sale Securities, Fair Value	1,616,443	2,525,737
Available-for-sale Securities, Gross Unrealized Losses	$ (53,815)	(63,107)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities, Less than 12 Months, Fair Value		20,054
Available-for-sale Securities, Less than 12 Months, Gross Unrealized Losses		(161)
Available-for-sale Securities, 12 Months or More, Fair Value		0
Available-for-sale Securities, 12 Months or More, Gross Unrealized Losses		0
Available-for-sale Securities, Fair Value		20,054
Available-for-sale Securities, Gross Unrealized Losses		$ (161)