Note 7 - Loans Receivable and Allowance for Loan Losses - Outstanding Commitments and Unused Lines of Credit (Details) - USD ($)	Mar. 31, 2018	Mar. 31, 2017
Unused Commercial Lines of Credit [Member]
Outstanding commitments and unused lines of credit	$ 9,187,810	$ 10,733,345
Unused Home Equity Lines of Credit [Member]
Outstanding commitments and unused lines of credit	22,560,376	22,993,289
Unused Consumer Lines of Credit [Member]
Outstanding commitments and unused lines of credit	29,331	1,110,155
Residential Construction Loan Commitments [Member]
Outstanding commitments and unused lines of credit	4,234,076	8,047,156
Commercial Construction Loan Commitments [Member]
Outstanding commitments and unused lines of credit	8,968,416	7,091,564
Home Equity Loan Commitments [Member]
Outstanding commitments and unused lines of credit	389,600	84,000
Commercial loan commitments [Member]
Outstanding commitments and unused lines of credit	5,125,000	1,089,218
Standby Letters of Credit [Member]
Outstanding commitments and unused lines of credit	$ 250,224	$ 472,354