STOCKHOLDERS' EQUITY (Summary of Stock Option Activity) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		9 Months Ended
Feb. 28, 2019	Nov. 30, 2019
Number of Options
Outstanding, beginning balance		1,054
Granted		171
Exercised		(106)
Forfeited or expired
Outstanding, ending balance	1,054	1,119
Exercisable		681
Weighted Average Exercise Price
Outstanding, beginning balance		$ 13.44
Granted		11.11
Exercised		2.35
Forfeited or expired
Outstanding, ending balance	$ 13.44	14.14
Exercisable		$ 12.46
Weighted average remaining contractual life, Outstanding	5 years 9 months 18 days	6 years 2 months 12 days
Weighted average remaining contractual life, Exercisable		4 years 8 months 12 days
Aggregate intrinsic value, Outstanding		$ 1,380
Aggregate intrinsic value, Exercisable		$ 1,380

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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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For presentations that combine terminations, 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 or that expired.

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Weighted average price of options that were either forfeited or expired.

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

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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

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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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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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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