Note 7 - Loans Receivable and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Unpaid contractual principal balance	$ 8,914,260	$ 10,295,038
Recorded investment	5,657,048	7,438,106
Related allowance	285,359	59,571
Total recorded investment	6,684,630	8,383,935
Interest income recognized	251,819	414,180
Legacy Loans [Member]
Unpaid contractual principal balance	6,679,789	7,517,439
Recorded investment	4,091,563	5,974,073
Related allowance	284,177	59,571
Total recorded investment	5,149,890	6,740,543
Interest income recognized	174,329	310,529
Legacy Loans [Member] | Real Estate Loans [Member] | Residential [Member]
Interest income recognized, with no related allowance recorded	11,901	7,857
Total recorded investment, with an allowance recorded	1,428,128	1,306,414
Interest income recognized, with an allowance recorded	54,121	53,204
Unpaid contractual principal balance, with an allowance recorded	1,432,212	1,306,083
Recorded investment with an allowance recorded	1,401,827	1,291,808
Related allowance	284,177	59,571
Unpaid contractual principal balance, with no related allowance recorded	491,249	690,915
Recorded investment with no related allowance recorded	360,590	599,794
Total recorded investment, with no related allowance recorded	373,618	544,000
Legacy Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member]
Interest income recognized, with no related allowance recorded		2,437
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded	107,710	119,822
Recorded investment with no related allowance recorded	16,919	26,925
Total recorded investment, with no related allowance recorded	16,306	14,586
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial [Member]
Interest income recognized, with no related allowance recorded	987	99,599
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded	3,433,621	3,433,621
Recorded investment with no related allowance recorded	1,546,812	2,717,144
Total recorded investment, with no related allowance recorded	2,485,299	3,298,855
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member]
Interest income recognized, with no related allowance recorded
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded
Recorded investment with no related allowance recorded
Total recorded investment, with no related allowance recorded
Legacy Loans [Member] | Commercial Portfolio Segment [Member]
Interest income recognized, with no related allowance recorded	107,063	147,101
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded	1,177,632	1,884,258
Recorded investment with no related allowance recorded	753,375	1,279,233
Total recorded investment, with no related allowance recorded	832,437	1,557,871
Legacy Loans [Member] | Home equity loans [Member]
Interest income recognized, with no related allowance recorded	257	331
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded	37,365	82,740
Recorded investment with no related allowance recorded	12,040	59,169
Total recorded investment, with no related allowance recorded	14,102	18,817
Legacy Loans [Member] | Consumer Portfolio Segment [Member]
Interest income recognized, with no related allowance recorded
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded
Recorded investment with no related allowance recorded
Total recorded investment, with no related allowance recorded
Acquired Loans [Member]
Unpaid contractual principal balance	2,234,471	2,777,599
Recorded investment	1,565,485	1,464,033
Related allowance	1,182
Total recorded investment	1,534,740	1,643,392
Interest income recognized	77,490	103,651
Acquired Loans [Member] | Real Estate Loans [Member] | Residential [Member]
Interest income recognized, with no related allowance recorded	51,442	15,891
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded	1,320,985	549,388
Recorded investment with no related allowance recorded	1,133,646	412,934
Total recorded investment, with no related allowance recorded	1,017,399	360,962
Acquired Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member]
Interest income recognized, with no related allowance recorded	12,229	70,696
Total recorded investment, with an allowance recorded	34,448
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded	66,446
Recorded investment with an allowance recorded	38,382
Related allowance	1,182
Unpaid contractual principal balance, with no related allowance recorded	503,920	1,894,614
Recorded investment with no related allowance recorded	148,506	797,372
Total recorded investment, with no related allowance recorded	230,757	1,026,391
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial [Member]
Interest income recognized, with no related allowance recorded	7,770	9,978
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded	254,844	261,239
Recorded investment with no related allowance recorded	204,844	211,239
Total recorded investment, with no related allowance recorded	208,057	212,806
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member]
Interest income recognized, with no related allowance recorded
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded
Recorded investment with no related allowance recorded
Total recorded investment, with no related allowance recorded
Acquired Loans [Member] | Commercial Portfolio Segment [Member]
Interest income recognized, with no related allowance recorded
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded
Recorded investment with no related allowance recorded
Total recorded investment, with no related allowance recorded
Acquired Loans [Member] | Home equity loans [Member]
Interest income recognized, with no related allowance recorded
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded
Recorded investment with no related allowance recorded
Total recorded investment, with no related allowance recorded
Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Interest income recognized, with no related allowance recorded	6,049	7,086
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Unpaid contractual principal balance, with no related allowance recorded	88,276	72,358
Recorded investment with no related allowance recorded	40,107	42,488
Total recorded investment, with no related allowance recorded	$ 44,079	$ 43,233