Goodwill and Identified Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Balance at beginning of period	$ 240,618	$ 242,827
Foreign currency translation adjustment	(838)	(2,209)
Balance at end of period	239,780	240,618
Video [Member]
Goodwill [Line Items]
Balance at beginning of period	179,839	182,012
Foreign currency translation adjustment	(857)	(2,173)
Balance at end of period	178,982	179,839
Cable Edge [Member]
Goodwill [Line Items]
Balance at beginning of period	60,779	60,815
Foreign currency translation adjustment	19	(36)
Balance at end of period	$ 60,798	$ 60,779