Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2018

Temporary Equity Disclosure [Abstract]

Summary of Fair Value of Convertible Preferred Stock Tranche Liability Determined Using Option Pricing Model

The fair value of the convertible preferred stock tranche liability was determined using an option pricing model with the following assumptions:

	February 9, 2017
Probability of milestone closing		99.9	%
Expected years closing		0.0
Discount rate		1.0	%
Risk-free interest rate		0.84	%
Expected dividend yield		0.0	%