Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

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Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended 12 Months Ended
Nov. 30, 2019
Aug. 31, 2019
Nov. 30, 2018
Aug. 31, 2018
Nov. 30, 2019
Nov. 30, 2018
May 31, 2019
May 22, 2019
Nov. 08, 2018
Apr. 30, 2010
Summary Of Significant Accounting Policies [Line Items]                    
Net loss $ (14,860,468) $ (16,163,999) $ (14,305,380) $ (14,413,569) $ (31,024,467) $ (28,718,950)        
Accumulated (deficit) (260,648,884)       (260,648,884)   $ (229,363,407)      
Balance in excess of federally insured limits 1,300,000       1,300,000   3,300,000      
Impairment charges         0 0        
Pre-launch inventory qualified for capitalization $ 0       $ 0   $ 0      
Estimated future unvested forfeitures         0.00%          
Common stock, shares authorized 700,000,000       700,000,000   700,000,000     100,000,000
Preferred Stock Shares authorized to be issued 5,000,000       5,000,000   5,000,000      
Treasury stock, par value $ 0.001       $ 0.001          
Treasury stock, shares         159,011          
Amortization of discount on convertible notes $ 439,474   52,954   $ 1,469,625 117,534        
Amortization of debt issuance costs         $ 404,340 $ 19,589        
Federal statutory income tax rate, percent         21.00% 28.62%        
Common stock options and warrants to purchase         177,457,255 155,836,676        
Income Tax Expense (Benefit) 0   $ (2,826,919)   $ 0 $ (2,826,919)        
Equity Securities                    
Summary Of Significant Accounting Policies [Line Items]                    
Deferred offering costs $ 2,000,000       2,000,000   $ 4,300,000      
Short-Term Convertible Notes                    
Summary Of Significant Accounting Policies [Line Items]                    
Direct costs associated with the convertible notes             1,000,000      
Amortization of debt issuance costs         404,000 20,000        
Short-Term Convertible Notes | Detachable Common Stock Warrants                    
Summary Of Significant Accounting Policies [Line Items]                    
Debt discount             $ 4,200,000      
Amortization of discount on convertible notes         $ 1,500,000 $ 100,000        
Series B Convertible Preferred Stock                    
Summary Of Significant Accounting Policies [Line Items]                    
Preferred Stock Shares authorized to be issued 400,000       400,000   400,000      
Preferred stock, shares outstanding 92,100       92,100   92,100      
Series C Convertible Preferred Stock                    
Summary Of Significant Accounting Policies [Line Items]                    
Preferred Stock Shares authorized to be issued 20,000       20,000          
Preferred stock, shares outstanding 7,788       7,788          
Common Stock                    
Summary Of Significant Accounting Policies [Line Items]                    
Common shares issued upon conversion of preferred stock         17,550,240 1,330,861 16,497,000      
Common shares issued upon conversion of debt securities         10,048,121 0        
Series C and B Preferred Stock                    
Summary Of Significant Accounting Policies [Line Items]                    
Preferred stock, shares outstanding 99,888       99,888          
Maximum                    
Summary Of Significant Accounting Policies [Line Items]                    
Common stock, shares authorized               700,000,000 600,000,000  
Preferred Stock Shares authorized to be issued             5,000,000      
Minimum                    
Summary Of Significant Accounting Policies [Line Items]                    
Common stock, shares authorized               600,000,000 450,000,000