Annual report pursuant to Section 13 and 15(d)

STOCKHOLDERS??? EQUITY (Details) - Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range

v3.20.2
STOCKHOLDERS’ EQUITY (Details) - Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range - $ / shares
 12 Months Ended
May 31, 2018
May 31, 2020
May 31, 2019
Jul. 19, 2019
Jul. 08, 2019
Nov. 14, 2018
Sep. 06, 2018
Aug. 14, 2018
May 30, 2018
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]                  
Exercise Price       $ 1.10 $ 1.10 $ 0.75 $ 0.75 $ 0.75  
Number of warrants outstanding (in Shares)   54,835,145 54,818,985           4,495,750
Weighted average remaining contractual life   1 year 6 months              
Weighted average exercise price of outstanding warrants $ 0.61 $ 0.53 $ 0.53            
Number of warrants exercisable (in Shares)   54,835,145              
Weighted average exercise price of exercisable warrants   $ 0.53              
Warrant Exercisable at $0.49 [Member]                  
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]                  
Exercise Price   $ 0.49              
Number of warrants outstanding (in Shares)   33,465,110              
Weighted average remaining contractual life   1 year 6 months              
Weighted average exercise price of outstanding warrants   $ 0.49              
Number of warrants exercisable (in Shares)   33,465,110              
Weighted average exercise price of exercisable warrants   $ 0.49              
Warrants Exercisable at $0.50 [Member]                  
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]                  
Exercise Price   $ 0.50              
Number of warrants outstanding (in Shares)   2,736,500              
Weighted average remaining contractual life   1 year 266 days              
Weighted average exercise price of outstanding warrants   $ 0.50              
Number of warrants exercisable (in Shares)   2,736,500              
Weighted average exercise price of exercisable warrants   $ 0.50              
Warrant Exercisable at $0.60 [Member]                  
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]                  
Exercise Price   $ 0.60              
Number of warrants outstanding (in Shares)   17,500,000              
Weighted average remaining contractual life   1 year 6 months              
Weighted average exercise price of outstanding warrants   $ 0.60              
Number of warrants exercisable (in Shares)   17,500,000              
Weighted average exercise price of exercisable warrants   $ 0.60              
Warrant Exercisable at $0.75 [Member]                  
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]                  
Exercise Price   $ 0.75              
Number of warrants outstanding (in Shares)   837,500              
Weighted average remaining contractual life   262 days              
Weighted average exercise price of outstanding warrants   $ 0.75              
Number of warrants exercisable (in Shares)   837,500              
Weighted average exercise price of exercisable warrants   $ 0.75              
Warrant Exercisable at $1.10 [Member]                  
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]                  
Exercise Price   $ 1.10              
Number of warrants outstanding (in Shares)   296,035              
Weighted average remaining contractual life   1 year 204 days              
Weighted average exercise price of outstanding warrants   $ 1.10              
Number of warrants exercisable (in Shares)   296,035              
Weighted average exercise price of exercisable warrants   $ 1.10