Note 7 - Leases (Details Textual) - USD ($)	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Stockholders' Equity Attributable to Parent, Ending Balance	$ 577,815,000	$ 394,364,000
Retained Earnings [Member]
Stockholders' Equity Attributable to Parent, Ending Balance	585,874,000	$ 459,797,000	$ 409,504,000
Accounting Standards Update 2016-02 [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member] \| Retained Earnings [Member]
Stockholders' Equity Attributable to Parent, Ending Balance	$ 2,019,000

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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+ Details