Stock-Based Compensation - Stock Options (Details) - USD ($)		9 Months Ended	12 Months Ended
	Sep. 19, 2018	Sep. 30, 2018	Dec. 31, 2017
Shares Underlying Options
Exercised (in shares)	(5,000)
Weighted Average Exercise Price
Exercised (in dollars per share)	$ 3.09
Stock options
Shares Underlying Options
Outstanding at the beginning of the period (in shares)		6,906,001
Granted (in shares)		1,337,271
Exercised (in shares)		(5,000)
Forfeited (in shares)		(190,167)
Outstanding at the end of the period (in shares)		8,048,105	6,906,001
Exercisable at June 30, 2018		6,248,160
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)		$ 7.92
Granted (in dollars per share)		4.96
Exercised (in dollars per share)		6.59
Forfeited (in dollars per share)		6.59
Outstanding at the end of the period (in dollars per share)		7.46	$ 7.92
Exercise price (in dollars per share)		$ 7.90
Weighted Average Remaining Contractual Term
Beginning Balance		5 years 2 months 12 days	5 years
Granted, Weighted Average Remaining Contractual Term		9 years 4 months 24 days
Exercisable at June 30, 2018		4 years 1 month 6 days
Aggregate intrinsic Value
Outstanding (in dollars)		$ 365,135
Intrinsic Value (in dollars)		$ 365,135