Note 19 - Fair Value Measurements - Securities Available for Sale Measured On a Recurring Basis (Details) - USD ($)	Mar. 31, 2018	Mar. 31, 2017
Investment securities available-for-sale	$ 75,404,136	$ 102,429,128
Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale	73,450,044	100,498,342
Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale	1,954,092	1,930,786
US Government Agencies Debt Securities [Member]
Investment securities available-for-sale	2,718,649	3,512,303
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale	2,718,649	3,512,303
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale
Municipal Bonds [Member]
Investment securities available-for-sale	11,705,991	16,167,839
Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale	11,705,991	14,239,526
Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale		1,928,313
Corporate Bond Securities [Member]
Investment securities available-for-sale	1,954,076	1,916,522
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale		1,916,522
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale	1,954,076
Collateralized Mortgage Backed Securities [Member]
Investment securities available-for-sale	59,025,420	80,832,464
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale	59,025,404	80,829,991
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale	$ 16	$ 2,473