Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Details)

v3.20.2
Stockholders' Equity (Details) - USD ($)
3 Months Ended
Sep. 02, 2020
Aug. 31, 2020
Jun. 18, 2020
Jun. 08, 2020
Jun. 05, 2020
Feb. 04, 2020
Mar. 06, 2019
Oct. 31, 2020
Jul. 31, 2020
Jul. 31, 2019
Apr. 30, 2020
Dec. 30, 2019
Dec. 13, 2018
Nov. 05, 2018
Mar. 13, 2012
Stockholders Equity [Line Items]                              
Preferred stock, shares authorized (in shares)                 1,000,000   1,000,000        
Preferred stock issued (in shares)                 0   0        
Preferred stock outstanding (in shares)                 0   0        
Common stock, shares authorized (in shares)                 40,000,000   40,000,000        
Common stock issued for stock options exercised for cash                 $ 1,269,982 $ 45,190          
Common stock issued for warrants exercised for cash                 1,081,792            
Modification charge for warrants exercised                 $ 25,966            
Subsequent Event                              
Stockholders Equity [Line Items]                              
Share price (in dollars per share) $ 9.49                            
Loan Agreements                              
Stockholders Equity [Line Items]                              
Warrants granted, exercise price (in dollars per share)             $ 6.00                
Revolving Credit Facility | Credit Facility Agreement                              
Stockholders Equity [Line Items]                              
Exercise price of warrants (in dollars per share)                           $ 5.85  
Number of securities called by warrants or rights (in shares)                           92,049  
Cooperman Warrants                              
Stockholders Equity [Line Items]                              
Decrease in exercise price of common stock purchase warrants         5.00%                    
Proceeds from warrant exercises       $ 1,081,792                      
Number of securities called by warrants or rights (in shares)       192,049                      
Cooperman Warrants | Loan Agreements                              
Stockholders Equity [Line Items]                              
Warrants granted, exercise price (in dollars per share)         $ 5.70   $ 6.00                
Cooperman Warrants | Revolving Credit Facility | Credit Facility Agreement                              
Stockholders Equity [Line Items]                              
Exercise price of warrants (in dollars per share)         $ 5.56                 $ 5.85  
Equity Incentive Plan                              
Stockholders Equity [Line Items]                              
Number of shares authorized (in shares)                             3,500,000
Common stock, shares remaining for future issuance (in shares)                 74,032 10,852          
2018 Equity Incentive Plan                              
Stockholders Equity [Line Items]                              
Number of shares authorized (in shares)                       1,100,000 500,000    
Common Stock                              
Stockholders Equity [Line Items]                              
Common stock issued for stock options exercised for cash (in shares)                 415,175 21,876          
Common stock issued for stock options exercised for cash                 $ 415 $ 22          
Common stock issued for warrants exercised for cash (in shares)                 192,049            
Common stock issued for warrants exercised for cash                 $ 192            
Share price (in dollars per share)           $ 9.49                  
Restricted Stock                              
Stockholders Equity [Line Items]                              
Unvested shares of restricted common stock outstanding (in shares)                 16,448 49,672          
Total unrecognized compensation expense                 $ 59,651 $ 225,129          
Compensation expense                 10,524            
Unrecognized compensation costs                 $ 60,000            
Weighted average recognition period                 1 year 6 months            
Stock Incentive Plan and Stock Option Grants to Employees and Directors                              
Stockholders Equity [Line Items]                              
Options granted (in shares)                 0            
Stock options                              
Stockholders Equity [Line Items]                              
Compensation expense                 $ 168,734            
Unrecognized compensation costs                 $ 550,000            
Weighted average recognition period                 2 years            
Restricted Stock Units (RSUs)                              
Stockholders Equity [Line Items]                              
Unvested shares of restricted common stock outstanding (in shares)                 801,468   643,175        
Total unrecognized compensation expense                 $ 4,400,000            
Restricted shares granted (in shares)           375,000     158,793            
Vesting period of award (in years)                 3 years            
Award vesting rights (as a percent)     50.00%                        
Amortization expense                 $ 111,211            
Compensation expense                 307,852            
Unrecognized compensation costs                 $ 4,400,000            
Weighted average recognition period     4 years     4 years     4 years            
Restricted Stock Units (RSUs) | Subsequent Event                              
Stockholders Equity [Line Items]                              
Award vesting rights (as a percent) 35.00%                            
Amortization expense               $ 1,600,000              
Restricted Stock Units (RSUs) | Share-based Payment Arrangement, Tranche One                              
Stockholders Equity [Line Items]                              
Award vesting rights (as a percent)           10.00%                  
Minimum closing price of common stock (in dollars per share)           $ 9                  
Consecutive trading days           20 days                  
Restricted Stock Units (RSUs) | Share-based Payment Arrangement, Tranche One | Subsequent Event                              
Stockholders Equity [Line Items]                              
Restricted shares granted (in shares)   37,500                          
Award vesting rights (as a percent)   10.00%                          
Minimum closing price of common stock (in dollars per share)   $ 9                          
Consecutive trading days   20 days                          
Restricted Stock Units (RSUs) | Share-based Payment Arrangement, Tranche Two                              
Stockholders Equity [Line Items]                              
Award vesting rights (as a percent)           25.00%                  
Minimum closing price of common stock (in dollars per share)           $ 10                  
Consecutive trading days           20 days                  
Restricted Stock Units (RSUs) | Share-based Payment Arrangement, Tranche Two | Subsequent Event                              
Stockholders Equity [Line Items]                              
Restricted shares granted (in shares) 93,750                            
Award vesting rights (as a percent) 25.00%                            
Minimum closing price of common stock (in dollars per share) $ 10                            
Consecutive trading days 20 days                            
Restricted Stock Units (RSUs) | Share-based Payment Arrangement, Tranche Three                              
Stockholders Equity [Line Items]                              
Minimum closing price of common stock (in dollars per share)           $ 12                  
Consecutive trading days           20 days                  
Restricted Stock Units (RSUs) | Minimum                              
Stockholders Equity [Line Items]                              
Grant price of award (in dollars per share)                 $ 6.95            
Restricted Stock Units (RSUs) | Maximum                              
Stockholders Equity [Line Items]                              
Grant price of award (in dollars per share)                 $ 10.62