Note 10 - Goodwill and Other Intangible Assets - Activity in Goodwill and Intangible Assets (Details) - USD ($)		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Goodwill, balance		$ 8,563,530	$ 6,767,811
Goodwill, additions	[1]		1,877,243
Goodwill, post acquisition adjustments			(81,524)
Goodwill, Amortization		0
Goodwill, balance		8,563,530	8,563,530
Core deposit intangible, Amortization		(126,064)	(121,022)
Core deposit intangible, balance		613,234
Core Deposits [Member]
Core deposit intangible, balance		739,298	618,300
Core deposit intangible, additions	[1]		242,020
Core deposit intangible, post acquisition adjustments
Core deposit intangible, Amortization		(126,064)	(121,022)
Core deposit intangible, balance		$ 613,234	$ 739,298

[1] Additions to intangible assets are related to the acquisition of Fraternity Community Bancorp, Inc.