Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.19.3
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
 3 Months Ended 12 Months Ended
Aug. 31, 2019
Aug. 31, 2018
May 31, 2019
May 22, 2019
Nov. 08, 2018
Jun. 07, 2018
May 31, 2018
Apr. 30, 2010
Summary Of Significant Accounting Policies [Line Items]                
Net loss $ (16,163,999) $ (14,413,569)            
Accumulated (deficit) (245,638,232)   $ (229,363,407)          
Balance in excess of federally insured limits 1,700,000   3,300,000          
Impairment charges 0 0            
Pre-launch inventory qualified for capitalization $ 0   $ 0          
Estimated future unvested forfeitures 0.00%              
Common stock, shares authorized 700,000,000   700,000,000         100,000,000
Preferred Stock Shares authorized to be issued 5,000,000   5,000,000          
Treasury stock, par value $ 0.001              
Treasury stock, shares 159,011              
Amortization of discount on convertible notes $ 1,030,151 64,580            
Amortization of debt issuance costs $ 284,060 $ 9,178            
Federal statutory income tax rate, percent 21.00% 28.62%            
Interest Expense $ 4,157,035 $ 178,388            
Common stock options and warrants to purchase 154,635,055 145,856,851            
Income Tax Expense (Benefit) $ 0 $ 0            
Convertible Notes Payable | Debt Discount [Member]                
Summary Of Significant Accounting Policies [Line Items]                
Interest Expense 600,000              
Convertible Notes Payable | Debt Issuance Cost [Member]                
Summary Of Significant Accounting Policies [Line Items]                
Interest Expense 100,000              
Equity Securities                
Summary Of Significant Accounting Policies [Line Items]                
Deferred offering costs 1,500,000   $ 4,300,000          
Short-Term Convertible Notes                
Summary Of Significant Accounting Policies [Line Items]                
Debt discount 439,000           $ 1,470,000  
Direct costs associated with the convertible notes     1,000,000          
Amortization of debt issuance costs 284,000 9,000            
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 $ 1,030,000 $ 60,000            
Series B Convertible Preferred Stock                
Summary Of Significant Accounting Policies [Line Items]                
Preferred Stock Shares authorized to be issued 400,000   400,000          
Preferred stock, shares outstanding 92,100   92,100          
Series C Convertible Preferred Stock                
Summary Of Significant Accounting Policies [Line Items]                
Preferred stock, shares outstanding 5,000              
Common Stock                
Summary Of Significant Accounting Policies [Line Items]                
Common shares issued upon conversion of preferred stock     10,921,000          
Series C and B Preferred Stock                
Summary Of Significant Accounting Policies [Line Items]                
Preferred stock, shares outstanding 97,100              
Maximum                
Summary Of Significant Accounting Policies [Line Items]                
Common stock, shares authorized       700,000,000 600,000,000 450,000,000    
Preferred Stock Shares authorized to be issued     5,000,000          
Minimum                
Summary Of Significant Accounting Policies [Line Items]                
Common stock, shares authorized       600,000,000 450,000,000 375,000,000