Note 18 - Major Customer (Details Textual) - Customer Concentration Risk [Member] - FedEx Corporation [Member]	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Revenue Benchmark [Member]
Concentration Risk, Percentage	29.00%	38.00%
Accounts Receivable [Member]
Concentration Risk, Percentage	20.00%	15.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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