Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Preferred Stock and Common Stock (Details)

v3.21.2
Stockholders' Equity - Preferred Stock and Common Stock (Details)
 1 Months Ended 3 Months Ended 12 Months Ended
Sep. 14, 2020
USD ($)
$ / shares
shares
Sep. 14, 2020
USD ($)
d
$ / shares
Sep. 14, 2020
USD ($)
day
$ / shares
Aug. 31, 2020
USD ($)
Jan. 22, 2020
USD ($)
d
$ / shares
shares
Nov. 30, 2019
USD ($)
shares
Apr. 29, 2015
USD ($)
Dec. 31, 2019
USD ($)
shares
Jan. 31, 2021
$ / shares
Jul. 31, 2020
shares
Apr. 30, 2021
USD ($)
shares
Apr. 30, 2020
USD ($)
shares
Jun. 28, 2019
shares
Jun. 27, 2019
shares
Schedule Of Stockholders Equity [Line Items]                            
Preferred stock, shares authorized (in shares)                     1,000,000 1,000,000 1,000,000 10,000,000
Preferred stock, shares issued (in shares)                     0 0    
Preferred stock, shares outstanding (in shares)                     0 0    
Common stock, shares authorized (in shares)                     40,000,000 40,000,000 40,000,000 250,000,000
Common stock issued for stock options exercised for cash (in shares)                     52,778 363,334    
Common stock issued for stock options exercised for cash | $                     $ 2,669,247 $ 962,650    
Number of shares of common stock surrendered (in shares)                     155,486      
Common stock issued for warrants exercised for cash | $                     $ 1,081,792      
Common stock issued for cashless warrant exercise (in shares)                       76,929    
Cashless exercise of warrants (in shares)                       164,929    
Common stock issued for services | $                     19,900      
Proceeds from sale of common stock net of underwriter costs | $         $ 17,267,250   $ 101,502       $ 0 $ 16,044,879    
Common stock issued in equity raise (in dollars per share) | $ / shares         $ 7.15                  
Stock issued during period, value, new issues | $         $ 16,044,879                  
Convertible Notes | Convertible Notes Payable                            
Schedule Of Stockholders Equity [Line Items]                            
Average closing price of common stock (in dollars per share) | $ / shares $ 10.725 $ 10.725 $ 10.725   $ 10.725                  
Consecutive trading day period   20 20   20                  
Debt instrument issued | $ $ 10,000,000 $ 10,000,000 $ 10,000,000   $ 5,000,000                  
Debt instrument, convertible, conversion price (in dollars per share) | $ / shares $ 7.15 $ 7.15 $ 7.15   $ 7.15                  
Convertible Notes | Convertible Notes Payable | Common Stock                            
Schedule Of Stockholders Equity [Line Items]                            
Debt conversion, converted instrument, shares issued (in shares) 1,398,602                          
Preferred Stock | Maximum                            
Schedule Of Stockholders Equity [Line Items]                            
Preferred stock, shares authorized (in shares)                     1,000,000      
Common Stock                            
Schedule Of Stockholders Equity [Line Items]                            
Common stock issued for stock options exercised for cash (in shares)                     1,389,463 277,678    
Common stock issued for stock options exercised for cash | $                     $ 1,389 $ 278    
Common stock issued for vested restricted stock units (in shares)                     295,557 0    
Common stock issued for cashless exercise of stock options (in shares)                     34,773 190,559    
Common stock issued for warrants exercised for cash (in shares)                   192,049 192,049      
Common stock issued for warrants exercised for cash | $                     $ 192      
Common stock issued for cashless warrant exercise (in shares)                       76,929    
Common stock issued for services (in shares)           25,000         2,000      
Common stock issued for services | $           $ 177,500         $ 2      
Common stock issued (in shares)         2,415,000                  
Common Stock | Former Director                            
Schedule Of Stockholders Equity [Line Items]                            
Grant date share price (in dollars per share) | $ / shares                 $ 9.95          
Common Stock | Chief Financial Officer                            
Schedule Of Stockholders Equity [Line Items]                            
Common stock issued (in shares)           15,000   15,000            
Stock issued during period, value, new issues | $           $ 103,350   $ 103,350            
Equity Distribution Agreement                            
Schedule Of Stockholders Equity [Line Items]                            
Common stock, capital shares reserved for future issuance, value | $       $ 12,309,750                    
Number of shares sold (in shares)                     449,632      
Sale of stock, gross proceeds (as a percent)       3.00%                    
Reimbursement expenses | $       $ 50,000                    
Total expenses for offering | $       $ 50,000                    
Over-Allotment Option                            
Schedule Of Stockholders Equity [Line Items]                            
Sale of stock, number of shares issued in transaction         315,000