Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Equity Inventive Plans, Employee Stock Purchase Plan and Stock-Based Compensation - Schedule of Fair Value of ESPP Shares Using Option Pricing Model (Details)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Expected term (in years) 4 years  
Expected volatility   58.00%
2018 Employee Stock Purchase Plan    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Expected term (in years) 6 months  
Expected volatility 74.89%  
Risk-free interest rate 2.44%