XML 120 R87.htm IDEA: XBRL DOCUMENT v3.20.2
Stockholder's Equity (Deficit) - Summary of Weighted Average Assumptions Used in Black-Sholes Option-pricing Model (Detail) - $ / shares
9 Months Ended 12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Dec. 31, 2019
Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]        
Common stock value (per share) $ 16.36 $ 27.30    
Expected volatility 46.14% 47.94% 48.13% 48.69%
Risk- free interest rate 0.41% 2.15%    
Expected life (years) 7 years 7 years 7 years 7 years
Forfeiture rate 0.00% 0.00%    
Dividend rate 0.00% 0.00%    
Minimum        
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]        
Common stock value (per share)     $ 24.00 $ 18.00
Risk- free interest rate     1.43% 2.86%
Forfeiture rate     0.00% 0.00%
Dividend rate     0.00% 0.00%
Maximum        
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]        
Common stock value (per share)     $ 31.60 $ 24.00
Risk- free interest rate     2.63% 2.89%