Note 3 - Securities - Available-for-sale Debt Securities (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Available-for-sale securities, amortized cost	$ 117,152,760	$ 88,102,659
Available-for-sale securities, gross unrealized gains	1,468,000	111,507
Available-for-sale securities, gross unrealized (losses)	(375,446)	(1,947,969)
Available-for-sale securities	118,245,314	86,266,197
US Government Agencies Debt Securities [Member]
Available-for-sale securities, amortized cost	2,499,755
Available-for-sale securities, gross unrealized gains
Available-for-sale securities, gross unrealized (losses)	(11,962)
Available-for-sale securities	2,487,793
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, amortized cost	35,625,038	34,470,648
Available-for-sale securities, gross unrealized gains	675,382	10,581
Available-for-sale securities, gross unrealized (losses)	(125,693)	(710,709)
Available-for-sale securities	36,174,727	33,770,520
Corporate Debt Securities [Member]
Available-for-sale securities, amortized cost	15,395,190	3,000,000
Available-for-sale securities, gross unrealized gains	154,942	18,927
Available-for-sale securities, gross unrealized (losses)	(14,945)
Available-for-sale securities	15,535,187	3,018,927
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities, amortized cost	49,844,049	50,632,011
Available-for-sale securities, gross unrealized gains	585,641	81,999
Available-for-sale securities, gross unrealized (losses)	(193,454)	(1,237,260)
Available-for-sale securities	50,236,236	$ 49,476,750
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-sale securities, amortized cost	13,788,728
Available-for-sale securities, gross unrealized gains	52,035
Available-for-sale securities, gross unrealized (losses)	(29,392)
Available-for-sale securities	$ 13,811,371

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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