Annual report pursuant to Section 13 and 15(d)

Equity Incentive Plans, Employee Stock Purchase Plan and Stock-Based Compensation - Schedule of Fair Value of ESPP Shares Using Option Pricing Model (Details)

v3.20.1
Equity Incentive Plans, Employee Stock Purchase Plan and Stock-Based Compensation - Schedule of Fair Value of ESPP Shares Using Option Pricing Model (Details)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected volatility, Minimum 72.72% 54.57% 56.52%
Expected volatility, Maximum 74.89% 62.38% 58.55%
Risk-free interest rate, Minimum 1.42% 2.67% 1.89%
Risk-free interest rate, Maximum 1.42% 3.11% 2.18%
2018 Employee Stock Purchase Plan      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term (in years) 6 months 6 months  
Expected volatility   55.28%  
Expected volatility, Minimum 63.04%    
Expected volatility, Maximum 83.17%    
Risk-free interest rate   2.37%  
Risk-free interest rate, Minimum 1.92%    
Risk-free interest rate, Maximum 2.51%