Note 3 - Acquisition - Merger Related Expenses (Details) - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Merger related expenses		$ 219,417
Fraternity Community Bancorp, Inc. and Fairmount Bancorp, Inc. [Member]
Merger related expenses	219,417
Legal [Member] | Fraternity Community Bancorp, Inc. and Fairmount Bancorp, Inc. [Member]
Merger related expenses	55,500
Professional Services [Member] | Fraternity Community Bancorp, Inc. and Fairmount Bancorp, Inc. [Member]
Merger related expenses	157,567
Other [Member] | Fraternity Community Bancorp, Inc. and Fairmount Bancorp, Inc. [Member]
Merger related expenses	$ 6,350