Note 5 - Investment Securities Available for Sale - Securities In a Continuous Unrealized Loss Position (Details) - USD ($)	Dec. 31, 2016	Mar. 31, 2016
Less than 12 months, gross unrealized losses	$ 2,118,342	$ 39,972
Less than 12 months, fair value	89,285,987	7,092,287
12 months or longer, gross unrealized losses	377,743	368,517
12 months or longer, fair value	9,288,676	22,172,677
Total gross unrealized losses	2,496,085	408,489
Total fair value	98,574,663	29,264,964
US Government Agencies Debt Securities [Member]
Less than 12 months, gross unrealized losses	20,324	6,752
Less than 12 months, fair value	3,004,648	2,244,157
12 months or longer, gross unrealized losses
12 months or longer, fair value
Total gross unrealized losses	20,324	6,752
Total fair value	3,004,648	2,244,157
Municipal Bonds [Member]
Less than 12 months, gross unrealized losses	994,563	140
Less than 12 months, fair value	14,805,701	480,168
12 months or longer, gross unrealized losses
12 months or longer, fair value
Total gross unrealized losses	994,563	140
Total fair value	14,805,701	480,168
Corporate Bond Securities [Member]
Less than 12 months, gross unrealized losses
Less than 12 months, fair value
12 months or longer, gross unrealized losses	86,472	101,360
12 months or longer, fair value	1,913,528	1,898,640
Total gross unrealized losses	86,472	101,360
Total fair value	1,913,528	1,898,640
Collateralized Mortgage Backed Securities [Member]
Less than 12 months, gross unrealized losses	1,103,455	33,080
Less than 12 months, fair value	71,475,638	4,367,962
12 months or longer, gross unrealized losses	291,271	267,157
12 months or longer, fair value	7,375,148	20,274,037
Total gross unrealized losses	1,394,726	300,237
Total fair value	$ 78,850,786	$ 24,641,999