Stock Option Plan and Stock Based Compensation - Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
May 31, 2018	May 31, 2017	Feb. 28, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Options Outstanding, Beginning Balance	172,496
Number of Shares, Granted	0	0
Number of Shares, Terminated	0
Number of Shares, Exercised	0	0
Number of Shares, Options Outstanding, Ending Balance	172,496		172,496
Number of Shares, Exercisable	172,496
Weighted Average Exercise Price, Beginning Balance	$ 15.95
Weighted Average Exercise Price, Granted	0
Weighted Average Exercise Price, Terminated	0
Weighted Average Exercise Price, Exercised	0
Weighted Average Exercise Price, Ending Balance	15.95		$ 15.95
Weighted Average Exercise Price, Exercisable	$ 15.95
Weighted Average Remaining Contractual Life (in years)	3 years		3 years 2 months 12 days
Weighted Average Remaining Contractual Life, Exercisable	3 years
Aggregate Intrinsic Value	$ 405		$ 612
Aggregate Intrinsic Value, Exercisable	$ 405

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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