Segment Information (Schedule of Reportable Segments and Reconciliation of Segment Contribution Income to Income Before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Segment Reporting Information [Line Items]
Total net revenue	$ 230,852	$ 255,276	$ 479,934	$ 500,477
Total segment contribution income	25,624	35,574	67,428	68,308
Corporate and unallocated costs	(15,576)	(25,038)	(34,708)	(47,336)
Amortization of intangibles	(1,682)	(1,966)	(3,692)	(4,045)
Stock-based compensation expense	(6,739)	(7,246)	(13,197)	(14,110)
Separation expense	0	0	(264)	0
Restructuring and other charges	(1,291)	(1,376)	(1,223)	(1,367)
Litigation reserves, net	(10)	(5)	(10)	(5)
Interest income, net	782	1,073	1,483	1,821
Other income (expense), net	487	788	828	(530)
Income before income taxes	1,595	1,804	16,645	2,736
Connected Home
Segment Reporting Information [Line Items]
Total net revenue	167,495	186,424	336,860	360,739
Total segment contribution income	$ 14,204	$ 20,939	$ 33,323	$ 37,151
Segment contribution margin	8.50%	11.20%	9.90%	10.30%
SMB
Segment Reporting Information [Line Items]
Total net revenue	$ 63,357	$ 68,852	$ 143,074	$ 139,738
Total segment contribution income	$ 11,420	$ 14,635	$ 34,105	$ 31,157
Segment contribution margin	18.00%	21.30%	23.80%	22.30%