Convertible Preferred Stock - Summary of Fair Value of Convertible Preferred Stock Tranche Liability Determined Using Option Pricing Model (Details)	Feb. 09, 2017 yr
Probability of Milestone Closing
Class of Stock [Line Items]
Convertible preferred stock tranche liability, measurement input	0.999
Expected Years Closing
Class of Stock [Line Items]
Convertible preferred stock tranche liability, measurement input	0.0
Discount Rate
Class of Stock [Line Items]
Convertible preferred stock tranche liability, measurement input	0.010
Risk-free Interest Rate
Class of Stock [Line Items]
Convertible preferred stock tranche liability, measurement input	0.0084
Expected Dividend Yield
Class of Stock [Line Items]
Convertible preferred stock tranche liability, measurement input	0.000