Stock-Based Compensation - Options (Details) - USD ($)		12 Months Ended
	Jan. 18, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
2013 Plan and 2018 Plan
Unrecognized compensation expense
Unrecognized compensation expense		$ 6,200,000
2013 Plan and 2018 Plan | Selling, general and administrative expense
Unrecognized compensation expense
Total compensation expense		$ 7,800,000	$ 7,600,000	$ 6,700,000
Stock options | 2018 Plan
Stock-based compensation
Minimum fair market value per share of underlying stock used to determine option grant price, as a percent	100.00%
Expiration of stock options	10 years
Outstanding
Outstanding Balance at beginning of the year (in shares)		3,570,300
Granted (in shares)		2,050,600
Forfeited (in shares)		(683,200)
Outstanding Balance at the end of the year (in shares)		4,937,700	3,570,300
Exercisable (in shares)		0
Weighted Average Exercise Price
Outstanding Balance at the beginning of the year		$ 6.06
Outstanding Balance at the end of the year (in shares)		4.14	$ 6.06
Weighted average Grant Date fair Value
Outstanding balance at the beginning of the period		2.69
Granted		0.94
Forfeited		2.64
Outstanding balance at the end of the period		$ 1.97	$ 2.69
Additional information
Average Remaining Vesting Period		2 years 3 months 7 days	2 years 11 months 1 day
Aggregate Intrinsic Value		$ 9,719,000	$ 9,590,000
Stock options | 2018 Plan | Minimum
Stock-based compensation
Vesting period		2 years
Stock options | 2018 Plan | Maximum
Stock-based compensation
Vesting period		4 years