Goodwill and Identified Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill, beginning	$ 382,963	$ 10,136
Goodwill, ending	385,574	382,963
Ziptronix, Inc
Goodwill [Roll Forward]
Goodwill acquired through the acquisition of DTS/Purchase price adjustment related to the acquisition		$ 372,827
DTS
Goodwill [Roll Forward]
Goodwill acquired through the acquisition of DTS/Purchase price adjustment related to the acquisition	2,611
Goodwill, ending	375,438
Semiconductor and IP licensing segment
Goodwill [Roll Forward]
Goodwill, ending	377,900
Product licensing segment
Goodwill [Roll Forward]
Goodwill, ending	$ 7,700