Note 7 - Loans Receivable and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Related allowance	[1]	$ 266,256	$ 285,359
Unpaid contractual principal balance	[1]	12,423,053	8,914,260
Recorded investment	[1]	8,720,339	5,657,048
Total recorded investment	[1]	9,644,505	6,684,630
Interest income recognized	[1]	250,008	251,819
Legacy Loans [Member]
Related allowance		266,256	284,177
Unpaid contractual principal balance		10,273,127	6,679,789
Recorded investment		7,094,524	4,091,563
Total recorded investment		7,774,125	5,149,890
Interest income recognized		171,476	174,329
Legacy Loans [Member] | Real Estate Loans [Member] | Residential [Member]
Unpaid contractual principal balance, with no related allowance recorded		665,051	491,249
Recorded investment with no related allowance recorded		517,600	360,590
Total recorded investment, with no related allowance recorded		548,636	373,618
Interest income recognized, with no related allowance recorded		9,257	11,901
Recorded investment with allowance		1,309,440	1,401,827
Unpaid contractual principal balance, with an allowance recorded		1,336,078	1,432,212
Recorded investment with an allowance recorded		1,309,440	1,401,827
Related allowance		266,256	284,177
Total recorded investment, with an allowance recorded		1,328,919	1,428,128
Interest income recognized, with an allowance recorded		51,928	54,121
Legacy Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member]
Unpaid contractual principal balance, with no related allowance recorded		126,389	107,710
Recorded investment with no related allowance recorded		60,949	16,919
Total recorded investment, with no related allowance recorded		118,175	16,306
Interest income recognized, with no related allowance recorded		3,772
Recorded investment with allowance
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial [Member]
Unpaid contractual principal balance, with no related allowance recorded		6,487,088	3,433,621
Recorded investment with no related allowance recorded		4,356,264	1,546,812
Total recorded investment, with no related allowance recorded		4,634,504	2,485,299
Interest income recognized, with no related allowance recorded		1,077	987
Recorded investment with allowance
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member]
Unpaid contractual principal balance, with no related allowance recorded
Recorded investment with no related allowance recorded
Total recorded investment, with no related allowance recorded
Interest income recognized, with no related allowance recorded
Recorded investment with allowance
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Legacy Loans [Member] | Commercial Portfolio Segment [Member]
Unpaid contractual principal balance, with no related allowance recorded		1,562,756	1,177,632
Recorded investment with no related allowance recorded		795,410	753,375
Total recorded investment, with no related allowance recorded		1,082,773	832,437
Interest income recognized, with no related allowance recorded		103,474	107,063
Recorded investment with allowance
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Legacy Loans [Member] | Home equity loans [Member]
Unpaid contractual principal balance, with no related allowance recorded		47,650	37,365
Recorded investment with no related allowance recorded		20,595	12,040
Total recorded investment, with no related allowance recorded		22,604	14,102
Interest income recognized, with no related allowance recorded		392	257
Recorded investment with allowance
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Legacy Loans [Member] | Consumer Portfolio Segment [Member]
Unpaid contractual principal balance, with no related allowance recorded		48,115
Recorded investment with no related allowance recorded		34,266
Total recorded investment, with no related allowance recorded		38,514
Interest income recognized, with no related allowance recorded		1,576
Recorded investment with allowance
Unpaid contractual principal balance, with an allowance recorded
Recorded investment with an allowance recorded
Related allowance
Total recorded investment, with an allowance recorded
Interest income recognized, with an allowance recorded
Acquired Loans [Member]
Related allowance	[1]		1,182
Unpaid contractual principal balance	[1]	2,149,926	2,234,471
Recorded investment	[1]	1,625,815	1,565,485
Total recorded investment	[1]	1,870,380	1,534,740
Interest income recognized	[1]	78,532	77,490
Acquired Loans [Member] | Real Estate Loans [Member] | Residential [Member]
Unpaid contractual principal balance, with no related allowance recorded	[1]	1,082,484	1,320,985
Recorded investment with no related allowance recorded	[1]	922,252	1,133,646
Total recorded investment, with no related allowance recorded	[1]	945,602	1,017,399
Interest income recognized, with no related allowance recorded	[1]	26,437	51,442
Recorded investment with allowance	[1]
Unpaid contractual principal balance, with an allowance recorded	[1]
Recorded investment with an allowance recorded	[1]
Related allowance	[1]
Total recorded investment, with an allowance recorded	[1]
Interest income recognized, with an allowance recorded	[1]
Acquired Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member]
Unpaid contractual principal balance, with no related allowance recorded	[1]	682,045	503,920
Recorded investment with no related allowance recorded	[1]	444,254	148,506
Total recorded investment, with no related allowance recorded	[1]	659,246	230,757
Interest income recognized, with no related allowance recorded	[1]	37,368	12,229
Recorded investment with allowance	[1]		38,382
Unpaid contractual principal balance, with an allowance recorded	[1]		66,446
Recorded investment with an allowance recorded	[1]		38,382
Related allowance	[1]		1,182
Total recorded investment, with an allowance recorded	[1]		34,448
Interest income recognized, with an allowance recorded	[1]
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial [Member]
Unpaid contractual principal balance, with no related allowance recorded	[1]	248,938	254,844
Recorded investment with no related allowance recorded	[1]	198,938	204,844
Total recorded investment, with no related allowance recorded	[1]	201,519	208,057
Interest income recognized, with no related allowance recorded	[1]	7,336	7,770
Recorded investment with allowance	[1]
Unpaid contractual principal balance, with an allowance recorded	[1]
Recorded investment with an allowance recorded	[1]
Related allowance	[1]
Total recorded investment, with an allowance recorded	[1]
Interest income recognized, with an allowance recorded	[1]
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member]
Unpaid contractual principal balance, with no related allowance recorded	[1]
Recorded investment with no related allowance recorded	[1]
Total recorded investment, with no related allowance recorded	[1]
Interest income recognized, with no related allowance recorded	[1]
Recorded investment with allowance	[1]
Unpaid contractual principal balance, with an allowance recorded	[1]
Recorded investment with an allowance recorded	[1]
Related allowance	[1]
Total recorded investment, with an allowance recorded	[1]
Interest income recognized, with an allowance recorded	[1]
Acquired Loans [Member] | Commercial Portfolio Segment [Member]
Unpaid contractual principal balance, with no related allowance recorded	[1]
Recorded investment with no related allowance recorded	[1]
Total recorded investment, with no related allowance recorded	[1]
Interest income recognized, with no related allowance recorded	[1]
Recorded investment with allowance	[1]
Unpaid contractual principal balance, with an allowance recorded	[1]
Recorded investment with an allowance recorded	[1]
Related allowance	[1]
Total recorded investment, with an allowance recorded	[1]
Interest income recognized, with an allowance recorded	[1]
Acquired Loans [Member] | Home equity loans [Member]
Unpaid contractual principal balance, with no related allowance recorded	[1]	40,473
Recorded investment with no related allowance recorded	[1]
Total recorded investment, with no related allowance recorded	[1]
Interest income recognized, with no related allowance recorded	[1]	1,329
Recorded investment with allowance	[1]
Unpaid contractual principal balance, with an allowance recorded	[1]
Recorded investment with an allowance recorded	[1]
Related allowance	[1]
Total recorded investment, with an allowance recorded	[1]
Interest income recognized, with an allowance recorded	[1]
Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Unpaid contractual principal balance, with no related allowance recorded	[1]	95,986	88,276
Recorded investment with no related allowance recorded	[1]	60,371	40,107
Total recorded investment, with no related allowance recorded	[1]	64,013	44,079
Interest income recognized, with no related allowance recorded	[1]	6,062	6,049
Recorded investment with allowance	[1]
Unpaid contractual principal balance, with an allowance recorded	[1]
Recorded investment with an allowance recorded	[1]
Related allowance	[1]
Total recorded investment, with an allowance recorded	[1]
Interest income recognized, with an allowance recorded	[1]

[1] Generally accepted accounting principles require that we record acquired loans at fair value at acquisition, which includes a discount for loans with credit impairment. These purchased credit impaired loans are not performing according to their contractual terms and meet the definition of an impaired loan. Although we do not accrue interest income at the contractual rate on these loans, we do recognize an accretable yield as interest income to the extent such yield is supported by cash flow analysis of the underlying loans.