Geographic and Segment Information - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 Customer	Sep. 30, 2016 Customer	Sep. 30, 2017 Segments Customer	Sep. 30, 2016 Customer
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments | Segments			2
Customer Concentration Risk [Member] | Net Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of customers greater than ten percent threshold	1	2	1	2
Customer Concentration Risk [Member] | Net Sales [Member] | Top Ten Customers [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	58.00%	69.00%	59.00%	65.00%
Number of customers	10	10	10	10
Customer Concentration Risk [Member] | Net Sales [Member] | Top Customer One [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	16.90%	27.80%	15.60%	25.60%
Customer Concentration Risk [Member] | Net Sales [Member] | Top Customer Two [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage		11.20%		11.10%
Geographic Concentration Risk [Member] | Property, Plant and Equipment [Member] | Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage			97.00%