Quarterly report pursuant to Section 13 or 15(d)

Equity Awards and Warrants - Options, RSUs, PSUs (Details)

v3.21.2
Equity Awards and Warrants - Options, RSUs, PSUs (Details)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended
Aug. 31, 2021
USD ($)
item
$ / shares
shares
May 31, 2021
USD ($)
shares
Aug. 31, 2020
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of active plans | item 1    
Number of inactive plans | item 1    
Annual increase in shares authorized, as a percent of outstanding shares 1.00%    
Shares available for future stock-based grants 26,100    
Options outstanding, vested 10,700    
Options outstanding, nonvested 6,800    
Proceeds from stock option exercises | $ $ 189   $ 39
Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock option granted, Shares 3,000    
Options term 10 years    
Stock option exercises, shares 300    
Proceeds from stock option exercises | $ $ 200    
Stock Options | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock option granted, exercise price | $ / shares $ 1.32    
Stock options grant date fair value | $ / shares 1.00    
Stock options exercised, exercise price | $ / shares $ 0.63    
Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Issuance of common stock upon vesting of stock based compensation awards, shares 400    
Restricted Stock Units (RSUs) [Member] | One Particular Award To Management Or Employee [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Issuance of common stock upon vesting of stock based compensation awards, shares 200    
Issuance of common stock upon vesting of stock based compensation awards, value | $ $ 300 $ 300  
Performance Shares [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Issuance of common stock upon vesting of stock based compensation awards, shares 400 400  
Issuance of common stock upon vesting of stock based compensation awards, value | $   $ 1,300  
Stock units granted, shares 4,350    
Stock units forfeited 3,900    
2012 Equity Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares authorized for issuance 50,000    
Increase in number of shares authorized 6,300