Stockholders' Equity (Deficit) - Stock Option Repricing - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2016	Dec. 31, 2018	Oct. 31, 2016
Minimum
Class Of Stock [Line Items]
Stock option exercise price per share			$ 5.64
Stock Option Repricing
Class Of Stock [Line Items]
Stock option exercise price per share	$ 5.64
Option conversion basis		one-for-one basis
Granted, Number of shares	5.1
Common stock price per share	$ 5.70
Common stock price per share	$ 7.02
Incremental stock-based compensation	$ 1.0
Expense related to vested shares	0.1
Expense related to unvested shares	$ 0.9