Quarterly report pursuant to Section 13 or 15(d)

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

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Equity Awards and Warrants - Options, RSUs, PSUs (Details)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Jun. 01, 2021
shares
May 31, 2021
USD ($)
shares
Feb. 28, 2022
USD ($)
plan
$ / shares
shares
Feb. 28, 2021
USD ($)
May 31, 2021
shares
Feb. 21, 2022
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Number of active plans | plan     1      
Number of inactive plans | plan     1      
Issuance of common stock upon vesting of stock based compensation awards, shares   400        
Proceeds from stock option exercises | $     $ 390 $ 1,829    
Stock Options            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock option granted, Shares     11,200      
Award vesting period     3 years      
Options term     10 years      
Exercise of stock option, shares     500      
Proceeds from stock option exercises | $     $ 400      
Stock Options | Maximum            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock option granted, exercise price | $ / shares     $ 2.23      
Stock options grant date fair value | $ / shares     1.71      
Stock options exercised, exercise price | $ / shares     1.06      
Stock Options | Minimum            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock option granted, exercise price | $ / shares     0.58      
Stock options grant date fair value | $ / shares     0.45      
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   200  
Issuance of common stock upon vesting of stock based compensation awards, value | $     $ 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, value | $   $ 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      
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     50,000  
Increase in number of shares authorized 6,300          
Shares reallocated to be used for general purposes           15,000
Annual increase in shares authorized, as a percent of outstanding shares 1.00%          
Shares available for future stock-based grants     10,300