Segment Information (Schedule Of Net Revenue from Service Provider Customers by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Segment Reporting Information [Line Items]
Net revenue	$ 288,928	$ 269,411	$ 255,276	$ 245,201	$ 274,149	$ 251,950	$ 251,685	$ 261,385	$ 1,058,816	$ 1,039,169	[1]	$ 1,143,445	[1]
Connected Home
Segment Reporting Information [Line Items]
Net revenue									771,060	768,261	[1]	846,929	[1]
SMB
Segment Reporting Information [Line Items]
Net revenue									287,756	270,908	[1]	296,516	[1]
Service Provider
Segment Reporting Information [Line Items]
Net revenue									160,295	193,454		254,155
Service Provider | Connected Home
Segment Reporting Information [Line Items]
Net revenue									156,671	190,186		249,980
Service Provider | SMB
Segment Reporting Information [Line Items]
Net revenue									$ 3,624	$ 3,268		$ 4,175

[1] Prior period amounts have not been adjusted to conform with ASC 606 as the Company adopted ASC 606 under the modified retrospective method.