Segment Information - Summary Financial Infomation by reportable segments (Details) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 26, 2020 USD ($)	Jun. 28, 2019 USD ($)	Jun. 26, 2020 USD ($) segment	Jun. 28, 2019 USD ($)
Segment Reporting Information [Line Items]
Total net revenue	[1]	$ 73,994	$ 84,865	$ 152,411	$ 164,971
Gross Profit		37,773	43,928	74,511	85,777
Operating income (loss)		(9,554)	(7,764)	$ (27,603)	(16,172)
Number of Reportable Segments | segment				2
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total net revenue		73,994	84,865	$ 152,411	164,971
Gross Profit		38,152	45,507	76,473	89,177
Operating income (loss)		(5,115)	(2,807)	(14,647)	(6,661)
Operating Segments [Member] | Video [Member]
Segment Reporting Information [Line Items]
Total net revenue		47,453	71,625	101,825	138,801
Gross Profit		26,024	41,444	53,931	80,046
Operating income (loss)		(4,237)	4,459	(10,504)	6,427
Operating Segments [Member] | Cable Access [Member]
Segment Reporting Information [Line Items]
Total net revenue		26,541	13,240	50,586	26,170
Gross Profit		12,128	4,063	22,542	9,131
Operating income (loss)		$ (878)	$ (7,266)	$ (4,143)	$ (13,088)

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