SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding - $ / shares	12 Months Ended
May 31, 2022	May 31, 2021
Exercise Price Range Per Share $0.82 - $8.18 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options outstanding, number of stock options		1,789,251
Options outstanding, weighted average exercise price		$ 2.75
Exercise Price Range Per Share $5.14 - $8.70 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options granted, number of stock options		430,616
Options granted, weighted average exercise price		$ 6.73
Exercise Price Range Per Share $0.82 - $3.62 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options exercised, number of stock options		(86,750)
Options exercised, weighted average exercise price		$ 1.2
Exercise Price Range Per Share $2.35 - $8.18 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options canceled or expired, number of stock options		(51,751)
Options canceled or expired, weighted average exercise price		$ 4.77
Exercise Price Range Per Share $0.82 - $8.70 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options outstanding, number of stock options	2,081,366
Options outstanding, weighted average exercise price	$ 3.59
Options outstanding, number of stock options	2,321,616	2,081,366
Options outstanding, weighted average exercise price	$ 3.72	$ 3.59
Exercise Price Range Per Share $4.25 - $4.46 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options granted, number of stock options	344,000
Options granted, weighted average exercise price	$ 4.43
Exercise Price Range Per Share $1.20 - $3.62 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options exercised, number of stock options	(39,500)
Options exercised, weighted average exercise price	$ 1.99
Exercise Price Range Per Share $1.61 - $8.18 [Member]
SHAREHOLDERS' EQUITY (Details) - Activity as to aggregate stock options outstanding [Line Items]
Options canceled or expired, number of stock options	(64,250)
Options canceled or expired, weighted average exercise price	$ 4.41

No definition available.

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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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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Weighted average price of options that were either forfeited or expired.

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

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

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
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