Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Additional Information (Details)

v3.20.2
Stock-Based Compensation - Additional Information (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2020
Dec. 31, 2019
Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Stock options shares outstanding 4,459,922 4,459,922 3,107,066  
Common stock, shares issued 46,267,525 46,267,525 19,208,077  
Aggregate intrinsic value of exercised stock options   $ 74,000    
Employee options        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Unrecognized stock-based compensation cost $ 10,500,000 $ 10,500,000    
Estimated weighted average amortization period   2 years 7 months 6 days    
2018 Equity Incentive Plan        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares available for future issuance 1,353,793 1,353,793    
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   $ 2.71    
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 2,643,868 2,643,868    
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 1,816,054 1,816,054    
Aggregate intrinsic value of exercised stock options $ 52,000 $ 74,000    
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 500,141 500,141   200,000
Common stock, shares issued 83,083 83,083    
Authorized an offering beginning period   Nov. 16, 2018    
Authorized an offering ending period   May 15, 2019    
Authorized an additional offering beginning period   May 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%