Quarterly report pursuant to Section 13 or 15(d)

2018 Stock Option and Grant Plan - Additional Information (Details)

v3.19.3
2018 Stock Option and Grant Plan - Additional Information (Details) - 2018 Plan - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Unrecognized compensation cost related to unvested stock-based awards   $ 5,650  
Unrecognized compensation cost, weighted average period for recognition   2 years 9 months 18 days  
Founders      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Unrecognized compensation cost related to unvested stock-based awards   $ 1,088  
Unrecognized compensation cost, weighted average period for recognition   1 year 7 months 6 days  
Stock Options      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares reserved for future issuance of equity awards   2,580,453  
Share-based compensation, number of shares available for grant   638,042  
Number of awards granted   988,058 0
Weighted average grant-date fair value of stock options granted   $ 4.77  
Aggregate grant-date fair value of options vested   $ 276  
Risk-free interest rate, minimum   1.39%  
Risk-free interest rate, maximum   2.59%  
Expected volatility, minimum   70.30%  
Expected volatility, maximum   75.50%  
Expected dividend   0.00%  
Stock Options | Minimum      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Percentage of exercise price per share of fair market value 100.00%    
Share-based compensation, vesting period 3 years    
Expected term   3 months 18 days  
Stock Options | Maximum      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Term of stock options after grant date 10 years    
Share-based compensation, vesting period 4 years    
Expected term   6 years 1 month 6 days  
Performance-Based Shares      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Unrecognized compensation cost related to unvested stock-based awards, other than options   $ 527