Redeemable Convertible Preferred Stock - Schedule of Fair Value Assumptions of Redeemable Convertible Preferred Stock Warrants (Details)	Sep. 17, 2019	Dec. 31, 2018
Remaining contractual life (in years)
Class of Stock [Line Items]
Redeemable convertible preferred stock warrant, measurement input, term	1 year 7 months 6 days	2 years 3 months 18 days
Expected volatility
Class of Stock [Line Items]
Redeemable convertible preferred stock warrant, measurement input	0.388	0.392
Risk-free interest rate
Class of Stock [Line Items]
Redeemable convertible preferred stock warrant, measurement input	0.018	0.025
Expected dividend rate
Class of Stock [Line Items]
Redeemable convertible preferred stock warrant, measurement input	0	0