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, 2018		Sep. 28, 2018		Jun. 29, 2018		Mar. 30, 2018		Dec. 31, 2017		Sep. 29, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenue	$ 113,655		$ 100,616		$ 99,160		$ 90,127		$ 100,974		$ 92,014		$ 82,315		$ 82,943		$ 403,558	[1]	$ 358,246	[1]	$ 405,911	[1]
Gross profit	$ 60,321	[2]	$ 50,102	[2]	$ 51,603	[2]	$ 47,183	[2]	$ 48,572	[2]	$ 47,025	[2]	$ 33,815	[2]	$ 40,408	[2]	209,209		169,820		200,750
Operating Income (Loss)																	(5,011)		(70,877)	[3]	(67,036)	[3]
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue																	403,558		358,246	[4]	405,911
Gross profit																	217,199		182,306	[4]	215,218
Operating Income (Loss)																	24,414		(25,178)	[3],[4]	(168)	[3]
Operating Segments [Member] | Video [Member]
Segment Reporting Information [Line Items]
Revenue																	313,828		319,473	[4]	351,489
Gross profit																	178,170		173,414	[4]	194,044
Operating Income (Loss)																	26,170		(2,024)	[4]	11,963
Operating Segments [Member] | Cable Access [Member]
Segment Reporting Information [Line Items]
Revenue																	89,730		38,773	[4]	54,422
Gross profit																	39,029		8,892	[4]	21,174
Operating Income (Loss)																	$ (1,756)		$ (23,154)	[4]	$ (12,131)

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

[2] 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. Gross margin decreased to 41.1% during the second quarter of 2017 compared to 48.7% during the first quarter of 2017, primarily due to lower service margins and higher inventory obsolescence charges for the Company’s legacy broadcast video inventory due to reduced demand, as well as higher inventory obsolescence charge for our older Cable Edge product lines. The factors negatively impacting the gross margin during the second quarter of 2017 were mostly absent during the third quarter of 2017, and together with a more favorable product mix, the gross margin increased to 51.1% during the third quarter of 2017 compared to 41.1% during the second quarter of 2017.

[3] For the years ended December 31, 2017 and 2016, the unallocated corporate expenses included TVN acquisition- and integration-related costs, TVN VDP costs (see Note 10, “Restructuring and Related charges-TVN VDP,” for more information on TVN VDP ) and Cable Access product line inventory obsolescence costs, totaling $7.9 million and $32.2 million, respectively. In addition, in fiscal 2017, the unallocated corporate expenses included $8.0 million of Avid litigation settlement cost and associated legal fees (see Note 19, “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.