Quarterly report pursuant to Section 13 or 15(d)

Convertible Instruments - Preferred stock (Detail)

v3.21.2
Convertible Instruments - Preferred stock (Detail) - USD ($)
 3 Months Ended 12 Months Ended
Aug. 31, 2021
May 31, 2021
Class of Stock [Line Items]    
Preferred stock, shares authorized 5,000,000 5,000,000
Preferred stock, par value $ 0.001 $ 0.001
Accrued dividends $ 3,067,000 $ 2,647,000
Common stock, shares authorized 800,000,000 800,000,000
Series D Convertible Preferred Stock    
Class of Stock [Line Items]    
Preferred stock, shares authorized 11,737 12,000
Preferred stock, par value $ 0.001 $ 0.001
Preferred stock, shares issued 9,000 9,000
Preferred stock, shares outstanding 8,452 9,000
Preferred stock dividend rate, as a percent 10.00%  
Preferred stock dividend, value per share $ 0.50  
Preferred stock, stated value per share 1,000  
Preferred stock conversion price, per share $ 0.80  
Accrued dividends $ 1,300,000 $ 1,100,000
Accrued dividend, in shares of common stock 2,600,000 2,200,000
Series C Convertible Preferred Stock    
Class of Stock [Line Items]    
Preferred stock, shares authorized 8,203 8,000
Preferred stock, par value $ 0.001 $ 0.001
Preferred stock, shares issued 8,000 8,000
Preferred stock, shares outstanding 8,203 8,000
Preferred stock dividend rate, as a percent 10.00%  
Preferred stock dividend, value per share $ 0.50  
Preferred stock, stated value per share 1,000  
Preferred stock conversion price, per share $ 0.50  
Accrued dividends $ 1,700,000 $ 1,500,000
Accrued dividend, in shares of common stock 3,400,000 3,000,000.0
Series B Convertible Preferred Stock    
Class of Stock [Line Items]    
Preferred stock, shares authorized 400,000 400,000
Preferred stock, par value $ 0.001 $ 0.001
Preferred stock, shares issued 79,000 79,000
Preferred stock, shares outstanding 79,000 79,000
Preferred stock dividend, value per share $ 0.25  
Preferred stock, stated value per share 5.00  
Preferred stock conversion price, per share $ 0.50  
Number of shares issued upon conversion 10  
Undeclared dividend $ 22,700 $ 17,800
Undeclared dividend, shares 45,500 35,500