Segment Information (Schedule of Reportable Segments and Reconciliation of Segment Contribution Income to Income Before Income Taxes) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020	Dec. 31, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total net revenue		$ 367,073	$ 378,114	$ 280,052	$ 229,963	$ 252,971	$ 265,858	$ 230,852	$ 249,082	$ 1,255,202	$ 998,763	$ 1,058,816
Total segment contribution income										194,686	135,057	166,482
Corporate and unallocated costs										(77,645)	(70,301)	(89,325)
Amortization of intangibles	[1]									(5,952)	(6,731)	(7,979)
Stock-based compensation expense										(30,505)	(29,137)	(26,461)
Separation expense										0	(264)	(929)
Change in fair value of contingent consideration										2,928	25	0
Restructuring and other charges										(1,702)	(2,077)	(2,198)
Gain/(loss) on investments, net										(6,222)	(224)	(861)
Litigation reserves, net										(44)	(160)	(15)
Interest income										436	2,539	3,980
Other income (expense), net										(5,177)	844	510
Income before income taxes										70,803	29,571	43,204
Connected Home
Segment Reporting Information [Line Items]
Total net revenue										1,007,545	711,391	771,060
Total segment contribution income										$ 152,512	$ 67,775	$ 96,340
Segment contribution margin										15.10%	9.50%	12.50%
SMB
Segment Reporting Information [Line Items]
Total net revenue										$ 247,657	$ 287,372	$ 287,756
Total segment contribution income										$ 42,174	$ 67,282	$ 70,142
Segment contribution margin										17.00%	23.40%	24.40%

[1] Amount excludes amortization expense related to patents within purchased intangibles in cost of revenue.