Note 6 - Investment Securities Available for Sale - Amortized Cost and Fair Value of Securities (Details) - USD ($)	Mar. 31, 2017	Mar. 31, 2016
Gross unrealized losses	$ 2,274,302	$ 408,489
Fair value	102,429,128	70,484,400
Amortized cost	104,616,155	70,520,431
Gross unrealized gains	87,275	372,458
Collateralized Mortgage Backed Securities [Member]
Gross unrealized losses	1,226,935	300,237
Fair value	80,832,464	53,940,200
Amortized cost	81,994,305	53,939,706
Gross unrealized gains	65,094	300,731
US Government Agencies Debt Securities [Member]
Gross unrealized losses	13,393	6,752
Fair value	3,512,303	10,532,996
Amortized cost	3,525,373	10,519,126
Gross unrealized gains	323	20,622
Municipal Bonds [Member]
Gross unrealized losses	950,496	140
Fair value	16,167,839	4,112,564
Amortized cost	17,096,477	4,061,599
Gross unrealized gains	21,858	51,105
Corporate Bond Securities [Member]
Gross unrealized losses	83,478	101,360
Fair value	1,916,522	1,898,640
Amortized cost	2,000,000	$ 2,000,000
Gross unrealized gains