Annual report pursuant to Section 13 and 15(d)

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

v3.22.2
Stockholders' Equity - Preferred Stock and Common Stock (Details)
3 Months Ended 12 Months Ended
Mar. 08, 2022
shares
Jan. 03, 2022
USD ($)
$ / shares
shares
Sep. 14, 2020
USD ($)
$ / shares
shares
Sep. 14, 2020
USD ($)
d
$ / shares
Sep. 14, 2020
USD ($)
day
$ / shares
Aug. 31, 2020
USD ($)
Oct. 31, 2020
shares
Apr. 30, 2022
USD ($)
plan
shares
Apr. 30, 2021
USD ($)
$ / shares
shares
Jul. 06, 2022
shares
Jul. 05, 2022
shares
Dec. 22, 2021
shares
Dec. 30, 2020
shares
Apr. 30, 2020
USD ($)
Feb. 04, 2020
$ / shares
Jan. 22, 2020
USD ($)
Schedule Of Stockholders Equity [Line Items]                                
Number of stock-based incentive plans | plan               2                
Transfer of unused awards (in shares) 129,009                              
Common stock, shares authorized (in shares)               60,000,000 40,000,000              
Preferred stock, shares authorized (in shares)               1,000,000 1,000,000              
Preferred stock, shares issued (in shares)               0 0              
Preferred stock, shares outstanding (in shares)               0 0              
Common stock issued for stock options exercised for cash (in shares)               200,000 52,778              
Common stock issued for stock options exercised for cash | $               $ 191,034 $ 2,669,247              
Number of shares of common stock surrendered (in shares)               0 155,486              
Common stock issued for warrants exercised for cash | $               $ 0 $ 1,081,792              
Share price (in dollars per share) | $ / shares                             $ 9.49  
Common stock issued for services | $               $ 0 $ 19,900              
2018 Equity Incentive Plan                                
Schedule Of Stockholders Equity [Line Items]                                
Shares reserved for future issuance (in shares)               812,763                
Common stock, shares authorized (in shares)                       2,350,000 1,600,000      
2012 And 2018 Equity Incentive Plan                                
Schedule Of Stockholders Equity [Line Items]                                
Shares reserved for future issuance (in shares)                 549,739              
Subsequent Event                                
Schedule Of Stockholders Equity [Line Items]                                
Common stock, shares authorized (in shares)                   60,000,000 40,000,000          
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                      
Consecutive trading day period       20 20                      
Debt instrument issued | $     $ 10,000,000 $ 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                      
Convertible Notes | Convertible Notes Payable | Common Stock                                
Schedule Of Stockholders Equity [Line Items]                                
Debt conversion, converted instrument, shares issued (in shares)     1,398,602       1,398,602 10,000,000                
Director | Common Stock                                
Schedule Of Stockholders Equity [Line Items]                                
Granted (in shares)   117,316                            
Grant date fair value | $   $ 279,212                            
Share price (in dollars per share) | $ / shares   $ 2.38                            
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)               58,419 1,389,463              
Common stock issued for stock options exercised for cash | $               $ 58 $ 1,389              
Common stock issued for vested restricted stock units (in shares)               85,576 295,557              
Common stock issued for cashless exercise of stock options (in shares)               30,156 34,773              
Common stock issued for warrants exercised for cash (in shares)               0 192,049              
Common stock issued for warrants exercised for cash | $                 $ 192              
Common stock issued for services (in shares)                 2,000              
Common stock issued for services | $               $ 117 $ 2              
Common Stock | Director                                
Schedule Of Stockholders Equity [Line Items]                                
Common stock issued for services (in shares)               117,316                
Common Stock | Former Director                                
Schedule Of Stockholders Equity [Line Items]                                
Common stock issued for services (in shares)                 2,000              
Grant date share price (in dollars per share) | $ / shares                 $ 9.95              
Common stock issued for services | $                 $ 19,900              
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