Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Additional Information (Details)

v3.20.1
Common Stock - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended
Oct. 23, 2019
May 31, 2018
Mar. 31, 2020
Mar. 31, 2019
Jan. 01, 2020
Dec. 31, 2019
Oct. 30, 2019
Jan. 31, 2019
Dec. 31, 2018
Class Of Stock [Line Items]                  
Common stock, authorized shares     150,000,000     150,000,000   29,000,000 21,147,115
Common stock shares modified   2,904,000              
Fair value of common stock shares modified   $ 0.74              
Total compensation cost of common stock shares modified   $ 2,126              
Unrecognized compensation cost, period for recognition   3 years 3 years 1 month 6 days            
Unrecognized compensation cost related to unvested stock-based awards     $ 11,076            
2019 Plan                  
Class Of Stock [Line Items]                  
Shares reserved for issuance 2,342,288       961,361        
Increase in share reserved percentage 4.00%                
Share-based compensation, number of shares available for grant     2,582,689            
2019 ESPP                  
Class Of Stock [Line Items]                  
Shares reserved for issuance 234,229                
Minimum | 2019 ESPP                  
Class Of Stock [Line Items]                  
Shares reserved for issuance               234,229  
Increase in share reserved percentage 1.00%                
Stock Options                  
Class Of Stock [Line Items]                  
Compensation cost recognized     $ 873 $ 496          
Stock Options | 2018 Plan                  
Class Of Stock [Line Items]                  
Number of options granted     1,959,411            
Stock Options | 2019 Plan                  
Class Of Stock [Line Items]                  
Number of options granted     528,072            
Weighted average grant-date fair value of stock options granted     $ 9.44 $ 3.85          
Aggregate grant-date fair value of options vested     $ 388 $ 83          
Stock Options | Minimum | 2018 Plan                  
Class Of Stock [Line Items]                  
Percentage of exercise price per share of fair market value     100.00%            
Share-based compensation, vesting period     3 years            
Stock Options | Maximum | 2018 Plan                  
Class Of Stock [Line Items]                  
Term of stock options after grant date     10 years            
Share-based compensation, vesting period     4 years            
Performance-Based Shares                  
Class Of Stock [Line Items]                  
Unrecognized compensation cost related to unvested stock-based awards, other than options     $ 176            
Founders                  
Class Of Stock [Line Items]                  
Unrecognized compensation cost, period for recognition     1 year 1 month 6 days            
Unrecognized compensation cost related to unvested stock-based awards     $ 744            
Research and Development | Stock Options                  
Class Of Stock [Line Items]                  
Compensation cost recognized     419 360          
Research and Development | Founders                  
Class Of Stock [Line Items]                  
Compensation cost recognized     124 132          
General and Administrative Expense | Stock Options                  
Class Of Stock [Line Items]                  
Compensation cost recognized     454 136          
General and Administrative Expense | Founders                  
Class Of Stock [Line Items]                  
Compensation cost recognized     $ 44 $ 44          
Voting Common Stock                  
Class Of Stock [Line Items]                  
Common stock, authorized shares     143,590,481     143,590,481 143,590,481    
Non-voting Common Stock                  
Class Of Stock [Line Items]                  
Common stock, authorized shares     6,409,519     6,409,519 6,409,519