Note 2 - Summary of Significant Accounting Policies - Weighted Average Number of Shares (Details) - shares	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Basic (in shares)	4,844,010	4,841,347
Dilutive effect of stock options (in shares)	6,557	4,865
Shares used in computing net income per share – diluted (in shares)	4,850,567	4,846,212

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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