Restructuring and Related Charges - Additional Information (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 02, 2015 USD ($)	Sep. 26, 2014 USD ($)	Oct. 02, 2015 USD ($) Employees	Sep. 26, 2014 USD ($) Employees	Dec. 31, 2014 USD ($) Employees	Dec. 31, 2013 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	$ 510,000	$ 403,000	$ 739,000	$ 915,000
Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			759,000		$ 2,200,000
Harmonic 2013 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		$ 403,000		$ 915,000	900,000	$ 2,200,000
Fixed Asset Impairment [Member] | Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges					1,100,000
Contract Termination [Member] | Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges					300,000
Other Restructuring [Member] | Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			0		100,000
Employee Severance And Benefit Arrangements [Member] | Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 759,000		$ 600,000
Number of positions eliminated | Employees			22		19
Restructuring and Related Cost, Incurred Cost	$ 510,000		$ 739,000
Employee Severance And Benefit Arrangements [Member] | Harmonic 2013 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | Employees				25