Note 14 - Income Taxes - Summary of Tax Effects of Temporary Differences that Gave Rise to Deferred Tax Assets and Liabilities (Details) - USD ($)	Mar. 31, 2018	Mar. 31, 2017
Allowance for loan losses	$ 627,297	$ 887,510
Nonaccrual interest	219,172	197,363
Deferred compensation	547,968	822,939
Foreclosed real estate write down and holding costs	162,973	221,010
Deferred loan costs	34,870	42,285
Capital loss carryforward		48,872
Charitable contribution carryforward	28,272	42,098
Net operating loss carryforward	3,227,274	4,414,529
Stock based payment awards	66,968	80,833
Unrealized loss on investment securities available for sale	728,266	862,673
AMT credit carryover	245,260	225,294
Acquisition activity	510,506	1,078,763
Other	39,692
Total deferred tax assets	6,438,518	8,924,169
Valuation allowance on deferred tax asset	(5,790,102)	(42,364)
Total deferred tax asset, net	648,416	8,881,805
FHLB stock dividends	63,486	91,004
Goodwill and other intangible assets	522,993	717,933
Accumulated depreciation	61,937	65,193
Other		30,825
Total deferred tax liabilities	648,416	904,955
Net deferred tax asset		$ 7,976,850