Annual report pursuant to Section 13 and 15(d)

Private Securities Offerings - Additional Information (Detail)

v3.20.2
Private Securities Offerings - Additional Information (Detail) - USD ($)
1 Months Ended 12 Months Ended
Mar. 04, 2020
Feb. 28, 2020
Dec. 30, 2019
Dec. 20, 2019
May 08, 2019
Mar. 23, 2018
Nov. 30, 2017
Jan. 31, 2020
May 31, 2020
May 31, 2019
May 31, 2018
Jun. 30, 2020
Feb. 04, 2020
Nov. 30, 2019
Apr. 05, 2019
Feb. 13, 2019
Jun. 15, 2018
Nov. 24, 2017
Oct. 11, 2017
Sep. 08, 2017
May 31, 2017
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                           $ 0.45              
Common stock, par value                 $ 0.001 $ 0.001                      
Warrants to purchase common shares, shares                         833,332                
Term of warrants                             5 years            
Common stock issued                 $ 154,552   $ 104,546                    
Proceeds From Exercise Of Warrants                 38,421,468   $ 3,161,131                    
Maximum [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Purchase price, per share                       $ 1.35                  
Minimum [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Purchase price, per share                       $ 0.35                  
Private Warrant Exchange [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Common stock, par value $ 0.001 $ 0.001 $ 0.001 $ 0.001 $ 0.001     $ 0.001                          
Warrants to purchase common shares, shares         7,541,279                                
Proceeds from issuance of common shares         $ 3,000,000                                
Stock issued during period shares warrant exercise 88,000 8,626,745 2,676,000 4,690,000       4,448,000                          
Proceeds From Exercise Of Warrants $ 36,000,000,000 $ 2,200,000 $ 1,100,000 $ 800,000       $ 1,900,000                          
Professional Fees         $ 300,000                                
Share Price     $ 0.50   $ 0.40     $ 0.50                          
Stock Issued During Period, Shares, Warrant Exercised         11,311,917                                
Noncash inducement interest expense         $ 200,000       $ 5,500,000                        
Private Warrant Exchange [Member] | Maximum [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share   $ 0.75 0.50 $ 0.75       0.50                          
Share Price $ 0.75 0.45   0.25                                  
Private Warrant Exchange [Member] | Minimum [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share   0.30 $ 0.50 0.45       $ 0.50                          
Share Price $ 0.45 $ 0.18   $ 0.22                                  
Private Warrant Exchange [Member] | Additional Shares [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Warrants to purchase common shares, shares         3,770,638                                
Stock issued during period shares warrant exercise 8,000 784,245 446,000 1,340,000       408,000                          
Private Warrant Exchange [Member] | Actual Shares [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Stock issued during period shares warrant exercise 80,000 7,842,500 2,230,000 3,350,000       4,040,000                          
Common Stock [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Common stock sold at private equity offering                 379,880   310,526                    
Common stock issued                 $ 380   $ 311                    
Stock issued during period shares warrant exercise                     0                    
Offer To Amend And Exercise [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                                   $ 0.50      
Make Whole Securities [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Common stock sold at private equity offering             503,015                            
Warrants to purchase common shares, shares             251,504                            
Make Whole Securities [Member] | Waiver And Subscription Agreement [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                                     $ 0.75 $ 1.00  
Purchase price, per share                                     $ 0.65 0.75  
Placement Agent                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                             $ 0.50 $ 0.50 $ 0.55        
Warrants to purchase common shares, shares                           655,305 938,790 965,563 133,600        
Term of warrants                     5 years     5 years   5 years 5 years        
Placement Agent | Maximum [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                           $ 0.444              
Placement Agent | Minimum [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                           $ 0.40              
Placement Agent | Make Whole Securities [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share             $ 0.715                            
Warrants to purchase common shares, shares                 26,702                        
Placement Agent | Make Whole Securities [Member] | Waiver And Subscription Agreement [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                                       $ 0.825  
Private Equity Offering                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                   $ 0.75 $ 0.75                   $ 1.00
Warrant covering common stock shares purchased, percentage                   50.00% 100.00%                    
Common stock sold at private equity offering                   46,975,170 35,286,904                    
Common stock, par value                   $ 0.001                      
Proceeds from private equity offering                     $ 17,600,000                    
Warrants to purchase common shares, shares                     35,286,904                    
Proceeds from issuance of common shares                   $ 23,500,000                      
Term of warrants                   5 years 5 years                    
Purchase price, per share                     $ 0.50                    
Private Equity Offering | Placement Agent                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                   $ 0.50 $ 0.55                    
Warrants to purchase common shares, shares                   4,446,917 2,813,491                    
Term of warrants                   5 years                      
Professional Fees                   $ 2,700,000                      
Private Equity Offering | Warrant Holders [Member] | Offer To Amend And Exercise [Member] | Common Stock [Member]                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Common stock issued           $ 2,470,585                              
Private Equity Offering | Warrants                                          
Equity and Equity Units Offering Disclosure [Line Items]                                          
Exercise price of warrants, per share                     $ 0.75                    
Warrants to purchase common shares, shares                   23,487,585