Related Party Transactions - Narrative (Details)		5 Months Ended	12 Months Ended
	Jul. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Nov. 29, 2016 USD ($)
Dow
Related Party Transaction [Line Items]
Payment amount for services		$ 8,731,000	$ 5,138,000	$ 8,361,000
Outstanding payable			1,200,000	$ 100,000
Director | Mutual services agreement
Related Party Transaction [Line Items]
Outstanding payable			0
Consulting fee, daily					$ 5,000
Consulting hours provided for each hour of technical support given, ratio					0.5
Expenses paid per service agreement			$ 0
Dow | Transition service agreement, set-up fee
Related Party Transaction [Line Items]
Payment amount for services	$ 5,000,000
Dow | Import inventory costs
Related Party Transaction [Line Items]
Payment amount for services	$ 600,000