Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.10.0.1
Summary of Significant Accounting Policies - Additional Information (Detail)
 3 Months Ended 5 Months Ended 12 Months Ended
Nov. 01, 2017
shares
Nov. 30, 2018
USD ($)
Aug. 31, 2018
USD ($)
May 31, 2018
USD ($)
$ / shares
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Feb. 28, 2018
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Nov. 30, 2017
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Aug. 31, 2017
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May 31, 2017
USD ($)
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Feb. 28, 2017
USD ($)
Nov. 30, 2016
USD ($)
Aug. 31, 2016
USD ($)
May 31, 2016
USD ($)
Feb. 28, 2016
USD ($)
May 31, 2018
USD ($)
$ / shares
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May 31, 2018
USD ($)
$ / shares
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Dec. 31, 2017
May 31, 2017
USD ($)
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May 31, 2016
USD ($)
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Jun. 07, 2018
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Jun. 06, 2018
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Aug. 24, 2017
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Aug. 24, 2016
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Mar. 18, 2016
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Mar. 17, 2016
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Apr. 30, 2010
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Summary Of Significant Accounting Policies [Line Items]                                                  
Net loss   $ (10,947,685) $ (11,628,273) $ (9,623,623) $ (17,950,100) $ (5,467,333) $ (5,354,385) $ (6,829,651) $ (8,112,432) $ (5,264,593) $ (8,895,015) $ (6,497,169) $ (5,046,835)   $ (50,149,681)   $ (25,763,801) $ (25,703,612)              
Accumulated (deficit)       (173,139,396)       (122,989,715)           $ (173,139,396) (173,139,396)   (122,989,715)                
Balance in excess of federally insured limits       1,100,000       1,500,000           1,100,000 1,100,000   1,500,000                
Impairment charges                             0   0 0              
Pre-launch inventory qualified for capitalization       $ 0       $ 0           $ 0 $ 0   $ 0                
Estimated future unvested forfeitures                             0.00%                    
Common stock, shares authorized | shares 200,000,000     375,000,000       350,000,000           375,000,000 375,000,000   350,000,000       375,000,000 350,000,000 250,000,000 200,000,000 100,000,000
Treasury stock, par value | $ / shares       $ 0.001                   $ 0.001 $ 0.001                    
Treasury stock, shares | shares                             159,011                    
Amortization of discount on convertible notes                             $ 1,666,017     1,791,967              
Direct costs associated with the convertible notes                             400,000                    
Amortization of debt issuance costs                             $ 435,609     $ 604,625              
Common stock options and warrants to purchase | shares                             132,385,269   77,859,626 63,307,150              
Unrecognized benefits       $ 0                   $ 0 $ 0                    
Federal statutory income tax rate, percent                           21.00% 28.60% 35.00% 34.00% 34.00%              
Effective income tax rate reconciliation, at blended income tax rate, percent                           28.62% 28.60%                    
Tax cuts and jobs act of 2017, incomplete accounting, change in tax rate, deferred tax liability, provisional income tax benefit                             $ 17,497,051                    
Provision for taxes on income                             0   $ 0 $ 0              
Equity Securities                                                  
Summary Of Significant Accounting Policies [Line Items]                                                  
Deferred offering costs       3,500,000       $ 1,800,000       3,900,000   $ 3,500,000 3,500,000   1,800,000 3,900,000              
Short-Term Convertible Notes                                                  
Summary Of Significant Accounting Policies [Line Items]                                                  
Amortization of debt issuance costs                             400,000   0 600,000              
Short-Term Convertible Notes | Detachable Common Stock Warrants                                                  
Summary Of Significant Accounting Policies [Line Items]                                                  
Debt discount       $ 1,500,000       $ 92,000.0       $ 0.0   $ 1,500,000 1,500,000   92,000.0 0.0              
Amortization of discount on convertible notes                             $ 1,600,000   $ 0 $ 1,900,000              
Subsequent Event                                                  
Summary Of Significant Accounting Policies [Line Items]                                                  
Common stock, shares authorized | shares                                     450,000,000 375,000,000          
Series B Convertible Preferred Stock                                                  
Summary Of Significant Accounting Policies [Line Items]                                                  
Preferred Stock Shares authorized to be issued | shares       400,000       400,000           400,000 400,000   400,000                
Common stock options and warrants to purchase | shares       92,100       92,100           92,100 92,100   92,100                
Common shares issued upon conversion of preferred stock | shares                             921,000                    
Maximum                                                  
Summary Of Significant Accounting Policies [Line Items]                                                  
Stockholders equity note stock split conversion ratio 0.067                                                
Preferred Stock Shares authorized to be issued | shares       5,000,000                   5,000,000 5,000,000                    
Minimum                                                  
Summary Of Significant Accounting Policies [Line Items]                                                  
Stockholders equity note stock split conversion ratio 0.500