Business Segments, Concentration of Credit Risk and Significant Customers - Schedule of Customers Who Accounted for at Least 10% of Total Net Revenue (Detail) - Net Revenues - Customer Concentration	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Customer A
Significant Customers
Percentage of concentration risk	26.00%	17.00%
Customer B
Significant Customers
Percentage of concentration risk	23.00%	34.00%
Customer C
Significant Customers
Percentage of concentration risk	15.00%	24.00%
Customer D
Significant Customers
Percentage of concentration risk	14.00%		[1]
Customer E
Significant Customers
Percentage of concentration risk	13.00%	10.00%

[1] Represents less than 10%