Accounts Receivable, Net and Revenue Concentrations - Net Sales to Significant Customers (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Major Customer [Line Items]
Net sales	$ 162,523	$ 177,580	$ 327,221	$ 338,986
Net Sales \| Comcast Corporation
Revenue, Major Customer [Line Items]
Net sales	$ 29,542	$ 42,951	$ 67,517	$ 85,198
Percent of net sales	18.20%	24.20%	20.60%	25.10%
Net Sales \| AT&T
Revenue, Major Customer [Line Items]
Net sales	$ 0	$ 21,740	$ 0	$ 40,940
Percent of net sales	0.00%	12.20%	0.00%	12.10%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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