Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.3.1.900
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
 3 Months Ended 9 Months Ended 12 Months Ended
Feb. 29, 2016
Feb. 28, 2015
Feb. 29, 2016
Feb. 28, 2015
May. 31, 2015
May. 31, 2010
Summary Of Significant Accounting Policies [Line Items]            
Common stock, par value $ 0.001   $ 0.001   $ 0.001  
Net loss $ (5,046,835) $ (2,721,653) $ (19,206,442) $ (11,085,087)    
Accumulated (deficit) (90,728,744)   (90,728,744)   $ (71,522,302)  
Balance in excess of federally insured limits 10,094,000   10,094,000   1,164,000  
Impairment charges 0 $ 0 0 $ 0    
Pre-launch inventory qualified for capitalization 0   $ 0   0  
Estimated future unvested option forfeitures     0.00%      
Direct costs associated with the convertible notes         $ 605,000  
Amortization of debt issuance costs     $ 604,625      
Common stock options and warrants to purchase     62,736,584 23,055,950    
Unrecognized benefits $ 0   $ 0      
Reclassification Adjustment            
Summary Of Significant Accounting Policies [Line Items]            
Common stock, par value $ 0.001   $ 0.001   $ 0.001  
Preferred stock, par value $ 0.001   $ 0.001   0.001  
Equity Securities            
Summary Of Significant Accounting Policies [Line Items]            
Deferred offering costs $ 3,850,000   $ 3,850,000      
Short-Term Convertible Notes            
Summary Of Significant Accounting Policies [Line Items]            
Amortization of debt issuance costs $ 0   $ 605,000      
Series B Convertible Preferred Stock            
Summary Of Significant Accounting Policies [Line Items]            
Common stock, par value           $ 0.001
Preferred stock, par value $ 0.001   $ 0.001   $ 0.001 $ 0.001
Preferred Stock Shares authorized to be issued 400,000   400,000   400,000  
Common stock options and warrants to purchase 95,100   95,100   95,100  
Common shares issued upon conversion of preferred stock     951,000      
Minimum            
Summary Of Significant Accounting Policies [Line Items]            
Income tax examination, year under examination     2012      
Maximum            
Summary Of Significant Accounting Policies [Line Items]            
Preferred Stock Shares authorized to be issued 5,000,000   5,000,000