Note 3 - Available-for-sale Securities - Carrying Amount of Securities and Fair Value (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Total, amortized cost	$ 59,863,049	$ 44,104,831
Available-for-sale securities, gross unrealized gains	1,555,489	671,824
Available-for-sale securities, gross unrealized losses	(43,738)	(259,477)
Available-for-sale securities, fair value	61,374,800	44,517,178
Asset-backed Securities [Member]
Total, amortized cost	33,484,461	30,722,958
Available-for-sale securities, gross unrealized gains	1,054,762	415,564
Available-for-sale securities, gross unrealized losses	(14,660)	(119,774)
Available-for-sale securities, fair value	34,524,563	31,018,748
US Government Agencies Debt Securities [Member]
Total, amortized cost	961,651	1,102,532
Available-for-sale securities, gross unrealized gains	4,123	1,739
Available-for-sale securities, gross unrealized losses	(12,652)	(24,824)
Available-for-sale securities, fair value	953,122	1,079,447
US States and Political Subdivisions Debt Securities [Member]
Total, amortized cost	25,416,937	12,279,341
Available-for-sale securities, gross unrealized gains	496,604	254,521
Available-for-sale securities, gross unrealized losses	(16,426)	(114,879)
Available-for-sale securities, fair value	$ 25,897,115	$ 12,418,983

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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