Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Additional Information (Details)

v3.21.2
Stock-Based Compensation - Additional Information (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Stock options shares outstanding 7,311,862   7,311,862   4,489,122  
Common stock, shares issued 48,146,308   48,146,308   46,359,743  
Aggregate intrinsic value of exercised stock options     $ 66,000      
Expected dividend yield     0.00% 0.00%    
Maximum            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Expected term 6 years 1 month 6 days 6 years 6 years 1 month 6 days 6 years    
Minimum            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Expected term 5 years 6 months 5 years 6 months 5 years 6 months 5 years    
Employee options            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Unrecognized stock-based compensation cost $ 17,000,000.0   $ 17,000,000.0      
Estimated weighted average amortization period     2 years 10 months 24 days      
ESPP            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Expected term     6 months      
2018 Equity Incentive Plan            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Shares available for future issuance 757,664   757,664      
Number of shares will increase automatically through every year on specified date     --01-01      
Number of shares increase automatically continuing through maximum period     beginning on January 1, 2019 and continuing through and including January 1, 2028      
Weighted average grant date fair value of options granted     $ 3.97      
2018 Equity Incentive Plan | Common Stock            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Maximum number of shares authorized available for issuance 1,600,692   1,600,692      
Increase in number of shares reserved for issuance as percentage of total number of shares of capital stock outstanding on last date of preceding calendar year     5.00%      
2018 Equity Incentive Plan | Maximum | Common Stock            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Maximum number of shares authorized available for issuance 4,000,000   4,000,000      
2018 Equity Incentive Plan | Employee options            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Stock options shares outstanding 5,518,256   5,518,256      
2018 Equity Incentive Plan | Incentive Stock Options | Maximum | Common Stock            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Maximum number of shares issued upon exercise of incentive stock options 12,500,000   12,500,000      
2015 Equity Incentive Plan            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Vesting period     4 years      
Options to purchase of common stock outstanding 1,793,606   1,793,606      
2015 Equity Incentive Plan | Maximum            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Options granted expiry period     10 years      
2018 Employee Stock Purchase Plan | Common Stock            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Shares available for future issuance 764,334   764,334     200,000
Common stock, shares issued 193,890   193,890      
Authorized an offering beginning period     Nov. 16, 2018      
Authorized an offering ending period     May 15, 2019      
Authorized an additional offering beginning period     May 16, 2021      
2018 Employee Stock Purchase Plan | Maximum | Common Stock            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Percentage of annual increase in number of common stock shares     1.00%      
Annual increase in number of common stock shares     375,000      
Option price per share of common stock at fair market value     85.00%      
2015 and 2018 Equity Incentive Plan            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Aggregate intrinsic value of exercised stock options $ 25,000   $ 66,000