Concentrations - Narrative (Details)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
One automotive OEM customer | Sales Revenue, Net | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	57.00%	54.00%		54.00%	55.00%
One automotive OEM customer | Accounts Receivable | Credit Concentration
Concentration Risk [Line Items]
Concentration risk, percentage				36.00%		35.00%
Supplier One | Material Purchases | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	25.00%			18.00%
Supplier Two | Material Purchases | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	12.00%			11.00%
Supplier Three | Material Purchases | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%			10.00%
Supplier Four | Material Purchases | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%		34.00%		35.00%