Note 13 - Fair Value Measurements - Investment Securities Available for Sale, Measurements On Recurring Basis (Details) - USD ($)	Jun. 30, 2017	Mar. 31, 2017
Investment securities available for sale, at fair value	$ 98,613,783	$ 102,429,128
Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	96,695,394	100,498,342
Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value	1,918,389	1,930,786
US Government Agencies Debt Securities [Member]
Investment securities available for sale, at fair value	3,508,628	3,512,303
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	3,508,628	3,512,303
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value
Municipal Bonds [Member]
Investment securities available for sale, at fair value	16,463,850	16,167,839
Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	14,547,888	14,239,526
Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value	1,915,962	1,928,313
Corporate Bond Securities [Member]
Investment securities available for sale, at fair value	1,919,496	1,916,522
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	1,919,496	1,916,522
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value
Collateralized Mortgage Backed Securities [Member]
Investment securities available for sale, at fair value	76,721,809	80,832,464
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	76,719,382	80,829,991
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value	$ 2,427	$ 2,473