Restructuring and Related Charges - Activities in Restructuring Accrual (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 03, 2015	Jun. 27, 2014	Jul. 03, 2015	Jun. 27, 2014	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Product cost of revenue	$ 0	$ 0	$ 0	$ 79,000
Restructuring and related charges	185,000	284,000	229,000	433,000
Total Restructuring and Related Charges	185,000	$ 284,000	229,000	$ 512,000
Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance			322,000
Restructuring charges			246,000		$ 2,200,000
Adjustments to restructuring provisions			(17,000)
Cash payments			(458,000)
Ending Balance	93,000		93,000		322,000
Harmonic Two Thousand And Fifteen Restructuring [Member] | Employee Severance And Benefit Arrangements [Member]
Restructuring Cost and Reserve [Line Items]
Total Restructuring and Related Charges	185,000		229,000
Restructuring Reserve [Roll Forward]
Beginning Balance			305,000
Restructuring charges			246,000		600,000
Adjustments to restructuring provisions			(11,000)
Cash payments			(447,000)
Ending Balance	93,000		93,000		305,000
Harmonic Two Thousand And Fifteen Restructuring [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance			17,000
Restructuring charges			0		100,000
Adjustments to restructuring provisions			(6,000)
Cash payments			(11,000)
Ending Balance	$ 0		$ 0		$ 17,000