Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Warrants (Details)

v3.21.2
Stockholders' Equity - Warrants (Details)
3 Months Ended 12 Months Ended
Jun. 05, 2020
$ / shares
Apr. 30, 2020
shares
Aug. 20, 2019
investor
shares
Aug. 17, 2019
shares
Mar. 06, 2019
$ / shares
Mar. 05, 2019
shares
Nov. 08, 2018
$ / shares
shares
Nov. 05, 2018
$ / shares
shares
Jul. 31, 2020
USD ($)
Apr. 30, 2021
USD ($)
shares
Apr. 30, 2020
shares
Jun. 08, 2020
shares
Jun. 07, 2019
shares
Jun. 03, 2019
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Common stock issued for warrants exercised for cash | $                   $ 1,081,792        
Modification charge for warrants exercised | $                 $ 25,966 $ 25,966        
Cashless exercise of warrants (in shares)                     164,929      
Number of investors | investor     2                      
Common stock, shares issued (in shares)   21,770,520               25,066,297 21,770,520      
Senior Loans                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Granted (in shares)           200,000                
Investor                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Common stock issued for cashless warrant exercise (in shares)       6,271                    
Investor | Warrant                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Cashless exercise of warrants (in shares)       13,542                    
Investor 1                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Common stock issued for cashless warrant exercise (in shares)     8,970                      
Investor 1 | Warrant                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Cashless exercise of warrants (in shares)     18,818                      
Investor 2                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Common stock issued for cashless warrant exercise (in shares)     42,285                      
Investor 2 | Warrant                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Cashless exercise of warrants (in shares)     88,710                      
Former Director                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Common stock, shares issued (in shares)                           9,806
Former Director | Warrant                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Common stock, shares issued (in shares)                           21,930
Chief Executive Officer                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Common stock, shares issued (in shares)                         9,597  
Advisory Board Member                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Granted (in shares)   50,000                        
Weighted average recognition period   3 years                        
Loan Agreements                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Warrants granted, exercise price (in dollars per share) | $ / shares         $ 6.00                  
Revolving Credit Facility | Credit Facility Agreement                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Exercise price (in dollars per share) | $ / shares             $ 5.85 $ 5.85            
Class of warrant or right, number of securities called by warrants or rights (in shares)             92,049 92,049            
Warrant term             5 years 5 years            
Cooperman Warrants                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Decrease in exercise price of common stock purchase warrants 5.00%                          
Class of warrant or right, number of securities called by warrants or rights (in shares)                       192,049    
Cooperman Warrants | Loan Agreements                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Warrants granted, exercise price (in dollars per share) | $ / shares $ 5.70       $ 6.00                  
Cooperman Warrants | Revolving Credit Facility | Credit Facility Agreement                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Exercise price (in dollars per share) | $ / shares $ 5.56             $ 5.85