Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Additional Information (Details)

v3.21.1
Stock-Based Compensation - Additional Information (Details) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Stock options shares outstanding 7,149,840   4,489,122  
Common stock, shares issued 48,079,868   46,359,743  
Aggregate intrinsic value of exercised stock options $ 41,000      
Expected term 6 years      
Expected dividend yield 0.00% 0.00%    
Maximum        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expected term   5 years 10 months 24 days    
Minimum        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expected term   5 years    
Employee options        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Unrecognized stock-based compensation cost $ 18,400,000      
Estimated weighted average amortization period 3 years 1 month 6 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 929,904      
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 $ 3.95      
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      
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      
2018 Equity Incentive Plan | Employee options        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Stock options shares outstanding 5,350,986      
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      
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 1,798,854      
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 820,556     200,000
Common stock, shares issued 137,668      
Authorized an offering beginning period Nov. 16, 2018      
Authorized an offering ending period May 15, 2019      
Authorized an additional offering beginning period Nov. 16, 2020      
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 $ 41,000