Restructuring and Excess Facilities - Activities in Restructuring Accrual (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Product cost of revenue	$ 113	$ 315	$ 823
Restructuring and asset impairment charges	1,372	2,761	1,421
Restructuring and Related Cost, Incurred Cost	1,485	3,076	2,244
Harmonic 2015 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	322
Restructuring charges in continued operations	1,617	2,169
Adjustments to restructuring provisions	(132)
Cash payments	(1,341)	(601)
Non-cash write-offs	(202)	(1,246)
Ending Balance	264	322
Harmonic 2015 Restructuring [Member] | Fixed Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0
Restructuring charges in continued operations	0	1,138
Adjustments to restructuring provisions	0
Cash payments	0	0
Non-cash write-offs	0	(1,138)
Ending Balance	0	0
Harmonic 2015 Restructuring [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	305
Restructuring charges in continued operations	1,413	599
Adjustments to restructuring provisions	(126)
Cash payments	(1,328)	(294)
Non-cash write-offs	0	0
Ending Balance	264	305
Harmonic 2015 Restructuring [Member] | Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0
Restructuring charges in continued operations	0	307
Adjustments to restructuring provisions	0
Cash payments	0	(307)
Non-cash write-offs	0	0
Ending Balance	0	0
Harmonic 2015 Restructuring [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	17
Restructuring charges in continued operations	204	125
Adjustments to restructuring provisions	(6)
Cash payments	(13)	0
Non-cash write-offs	(202)	(108)
Ending Balance	0	17
Harmonic 2013 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	179
Restructuring and Related Cost, Incurred Cost		900	2,200
Restructuring charges in continued operations		924	2,168
Adjustments to restructuring provisions		(17)	77
Cash payments		(1,086)	(1,513)
Non-cash write-offs			(553)
Ending Balance		0	179
Harmonic 2013 Restructuring [Member] | Excess Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	0
Restructuring charges in continued operations		32	0
Adjustments to restructuring provisions		0	0
Cash payments		(32)	0
Non-cash write-offs			0
Ending Balance		0	0
Harmonic 2013 Restructuring [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	179
Restructuring charges in continued operations		829	1,663
Adjustments to restructuring provisions		(17)	29
Cash payments		(991)	(1,513)
Non-cash write-offs			0
Ending Balance		0	179
Harmonic 2013 Restructuring [Member] | Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	0
Restructuring charges in continued operations		63	0
Adjustments to restructuring provisions		0	0
Cash payments		(63)	0
Non-cash write-offs			0
Ending Balance		0	0
Harmonic 2013 Restructuring [Member] | Impairment of Leasehold Improvements [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	0
Restructuring charges in continued operations		0	101
Adjustments to restructuring provisions		0	48
Cash payments		0	0
Non-cash write-offs			(149)
Ending Balance		0	0
Harmonic 2013 Restructuring [Member] | Obsolete Inventories [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	0
Restructuring charges in continued operations		0	404
Adjustments to restructuring provisions		0	0
Cash payments		0	0
Non-cash write-offs			(404)
Ending Balance		0	0
HFC Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	13
Charges for HFC Restructuring Plan recorded in discontinued operations			527
Adjustments to restructuring provisions			73
Cash payments		(13)	(587)
Ending Balance		0	13
HFC Restructuring [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	13
Charges for HFC Restructuring Plan recorded in discontinued operations			403
Adjustments to restructuring provisions			102
Cash payments		(13)	(492)
Ending Balance		0	13
HFC Restructuring [Member] | Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 0	0
Charges for HFC Restructuring Plan recorded in discontinued operations			124
Adjustments to restructuring provisions			(29)
Cash payments		0	(95)
Ending Balance		$ 0	$ 0