Segment Information, Geographic Information And Customer Concentration Segment Information - Summary Financial Information by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019		Sep. 27, 2019		Jun. 28, 2019		Mar. 29, 2019		Dec. 31, 2018		Sep. 28, 2018		Jun. 29, 2018		Mar. 30, 2018		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenue	$ 122,178		$ 115,725		$ 84,865		$ 80,106		$ 113,655		$ 100,616		$ 99,160		$ 90,127		$ 402,874	[1]	$ 403,558	[1]	$ 358,246	[1]
Gross profit	$ 61,695	[2]	$ 75,540	[2]	$ 43,928	[2]	$ 41,849	[2]	$ 60,321	[2]	$ 50,102	[2]	$ 51,603	[2]	$ 47,183	[2]	223,012		209,209		169,820
Operating Income (Loss)																	13,083		(5,011)		(70,877)	[3]
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue																	402,874		403,558	[4]	358,246
Gross profit																	230,704		217,199	[4]	182,306
Operating Income (Loss)																	38,008		24,414	[4]	(25,178)	[3]
Operating Segments [Member] | Video [Member]
Segment Reporting Information [Line Items]
Revenue																	278,028		313,828	[4]	319,473
Gross profit																	162,156		178,170	[4]	173,414
Operating Income (Loss)																	15,837		26,170	[4]	(2,024)
Operating Segments [Member] | Cable Access [Member]
Segment Reporting Information [Line Items]
Revenue																	124,846		89,730	[4]	38,773
Gross profit																	68,548		39,029	[4]	8,892
Operating Income (Loss)																	$ 22,171		$ (1,756)	[4]	$ (23,154)

[1] Revenue is attributed to countries based on the location of the customer.

[2] Gross margin in the first, second and fourth quarter of fiscal 2019 was 52.2%, 51.8% and 50.5%. The movement in gross margin in these quarters was primarily due to product mix. Gross margin increased to 65.3% in the third quarter of 2019 primarily due to the recognition of $37.5 million in software license revenue from the Comcast CableOS software license agreement during the third quarter of fiscal 2019. Gross margin decreased to 49.8% during the third quarter of 2018 compared to 52.0% during the second quarter of 2018 and increased to 53.1% during the fourth quarter primarily as a result of product mix.

[3] For the year ended December 31, 2017, the unallocated corporate expenses included acquisition- and integration-related costs, French VDP costs (see Note 11, “Restructuring and Related charges,” for more information on French VDP) and Cable Access product line inventory obsolescence costs, totaling $7.9 million. In addition, in fiscal 2017, the unallocated corporate expenses included $8.0 million of Avid litigation settlement cost and associated legal fees (see Note 20, “Legal Proceedings,” for more information). The remaining unallocated corporate expenses for all years presented above include primarily other restructuring charges and excess facilities charges.

[4] The Company has historically employed an aggregate allocation methodology based on total revenues to attribute professional services revenue and sales expenses between its Video and Cable Access segments. Beginning in the fourth quarter of 2017, the Company prospectively changed to a more precise attribution methodology as the activities of selling and supporting the CableOS solution have become increasingly distinct from those of Video solutions. The impact of making this change for the fiscal year ended December 31, 2017 compared to the Company’s historical approach was an increase in operating loss of $5.9 million from the Video segment and a corresponding decrease in operating loss of the Cable Access segment. The Company believes that the updated allocation methodology provides greater clarity regarding the operating metrics of the Video and Cable Access business segments.