Goodwill and Identified Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 29, 2017 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 237,279
Foreign currency translation adjustment	4,653
Balance at end of period	241,932
Video [Member]
Goodwill [Line Items]
Balance at beginning of period	176,519
Foreign currency translation adjustment	4,603
Balance at end of period	181,122
Cable Edge [Member]
Goodwill [Line Items]
Balance at beginning of period	60,760
Foreign currency translation adjustment	50
Balance at end of period	$ 60,810