Product Line, Customer and Geographic Information - Schedule of Revenues and Total Trade Accounts Receivable Represents Customer Accounted for 10% or More Percentage (Detail) - Customer Concentration Risk [Member]

3 Months Ended

12 Months Ended

Mar. 31, 2019

Mar. 31, 2018

Dec. 31, 2018

Sales [Member] | Customer A [Member]

Revenues from External Customers and Long-Lived Assets [Line Items]

Concentration risk percentage

0.00%

11.00%

Trade Accounts Receivable [Member] | Customer B [Member]

Revenues from External Customers and Long-Lived Assets [Line Items]

Concentration risk percentage

13.00%