Note 7 - Loans Receivable and Allowance for Loan Losses - Summary of Troubled Debt Restructurings (Details)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Number of contracts	16	16
Troubled debt restructurings	$ 3,747,382	$ 4,923,799
Performing Financial Instruments [Member]
Troubled debt restructurings	1,905,602	2,105,206
Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 1,841,780	$ 2,818,593
Real Estate Loans [Member] | Residential [Member]
Number of contracts	13	12
Troubled debt restructurings	$ 1,556,571	$ 1,559,001
Real Estate Loans [Member] | Residential [Member] | Performing Financial Instruments [Member]
Troubled debt restructurings	1,261,603	1,457,552
Real Estate Loans [Member] | Residential [Member] | Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 294,968	$ 101,449
Real Estate Loans [Member] | Investor Loans [Member]
Number of contracts	0	0
Troubled debt restructurings	$ 0	$ 0
Real Estate Loans [Member] | Investor Loans [Member] | Performing Financial Instruments [Member]
Troubled debt restructurings	0	0
Real Estate Loans [Member] | Investor Loans [Member] | Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 0	$ 0
Real Estate Loans [Member] | Commercial [Member]
Number of contracts	2	2
Troubled debt restructurings	$ 1,546,812	$ 2,717,144
Real Estate Loans [Member] | Commercial [Member] | Performing Financial Instruments [Member]
Troubled debt restructurings	0	0
Real Estate Loans [Member] | Commercial [Member] | Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 1,546,812	$ 2,717,144
Real Estate Loans [Member] | Commercial construction [Member]
Number of contracts	0	0
Troubled debt restructurings	$ 0	$ 0
Real Estate Loans [Member] | Commercial construction [Member] | Performing Financial Instruments [Member]
Troubled debt restructurings	0	0
Real Estate Loans [Member] | Commercial construction [Member] | Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 0	$ 0
Commercial Portfolio Segment [Member]
Number of contracts	1	2
Troubled debt restructurings	$ 643,999	$ 647,654
Commercial Portfolio Segment [Member] | Performing Financial Instruments [Member]
Troubled debt restructurings	643,999	647,654
Commercial Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 0	$ 0
Home equity loans [Member]
Number of contracts	0	0
Troubled debt restructurings	$ 0	$ 0
Home equity loans [Member] | Performing Financial Instruments [Member]
Troubled debt restructurings	0	0
Home equity loans [Member] | Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 0	$ 0
Consumer Portfolio Segment [Member]
Number of contracts	0	0
Troubled debt restructurings	$ 0	$ 0
Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Troubled debt restructurings	0	0
Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Troubled debt restructurings	$ 0	$ 0