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Note 10 - Stock-based Compensation - Summary of Unvested Options (Details) - $ / shares | 12 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Mar. 31, 2016
Unvested, Shares (in shares) | 373,766 | 358,263 | 274,038
Granted, Numbers of Shares (in shares) | 96,330 | 134,955 | 184,030
Options forfeited, Shares (in shares) | (72,166) | (35,015) | (16,334)
Options vested, Shares (in shares) | (83,408) | (84,437) | (83,471)
Unvested, Shares (in shares) | 314,522 | 373,766 | 358,263
Unvested, Weighted-average grant-date fair value (in dollars per share) | $ 22.49 | $ 19.46 | $ 18.42
Options granted, Weighted-average grant-date fair value (in dollars per share) | 39.06 | 31.27 | 18.78
Options forfeited, Weighted-average grant-date fair value (in dollars per share) | 28.43 | 22.64 | 19.07
Options vested, Weighted-average grant-date fair value (in dollars per share) | 21.84 | 16.96 | 14.65
Unvested, Weighted-average grant-date fair value (in dollars per share) | $ 29.01 | $ 22.49 | $ 19.46

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- Definition Gross number of share options (or share units) granted during the period. + References No definition available. + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Number of non-vested options outstanding. + References No definition available. + Details
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- Definition Number of non-vested options forfeited. + References No definition available. + Details
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- Definition Weighted average grant-date fair value of non-vested options forfeited. + References No definition available. + Details
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