Restructuring and Excess Facilities - Additional Information (Detail) $ in Thousands		3 Months Ended				12 Months Ended
		Dec. 31, 2016 USD ($) Employees	Sep. 30, 2016 USD ($)	Jul. 01, 2016 USD ($)	Apr. 01, 2016 USD ($)	Dec. 31, 2016 USD ($) Employees Employee		Dec. 31, 2015 USD ($) Employees	Dec. 31, 2014 USD ($) Employee	Dec. 31, 2013 USD ($) Employee	Jan. 04, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost						$ 18,002	[1]	$ 1,485	$ 3,076
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments						1,955
Adjustments to restructuring provisions						14,602		1,372	2,761
TVN Voluntary Departure Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost						$ 13,100
Number of employees applied for VDP | Employee						83
Harmonic 2015 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost								1,500	2,169
Restructuring charges								1,617	2,169
Adjustments to restructuring provisions						$ (70)		$ (132)
Harmonic 2015 Restructuring [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | Employees								56
Restructuring charges								$ 1,413	599
Adjustments to restructuring provisions						(70)		(126)
Harmonic 2013 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost									900	$ 2,200
Restructuring charges								924	2,168
Adjustments to restructuring provisions								(17)	$ 77
Harmonic 2013 Restructuring [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | Employee									25	85
Restructuring charges								829	$ 1,663
Adjustments to restructuring provisions								$ (17)	$ 29
Harmonic Two Thousand And Sixteen Restructuring [Member] | TVN Voluntary Departure Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost						13,100
Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost						20,000
Restructuring and Related Cost, Expected Cost		$ 5,000				5,000
Anticipated Synergies from Restructuring Exit Plan		20,000				20,000
Restructuring charges						19,779
Adjustments to restructuring provisions						247
Harmonic 2016 Restructuring Plan [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost						2,200
Restructuring charges	[2]					1,655
Adjustments to restructuring provisions	[2]					582
Harmonic 2016 Restructuring Plan [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost						$ 17,800
Restructuring and Related Cost, Number of Positions Eliminated | Employees						118
Harmonic 2016 Restructuring Plan [Member] | TVN Voluntary Departure Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	[3]					$ 13,175
Adjustments to restructuring provisions	[3]					0
TVN [Member]
Restructuring Cost and Reserve [Line Items]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments						2,000
Business Combination, Acquisition and Integration Related Expenses		$ 5,200	$ 5,300	$ 3,400	$ 3,000	16,900
Number of employees applied for VDP | Employees		83
Voluntary Departure Plan Anticipated Cost						$ 15,300
Voluntary Departure Plan Benefit Obligation Term						4 years
Fair value of TVN VDP at inception		$ 14,800				$ 14,800
Number of employees required to work beyond minimum statutory notice period under VDP | Employees		11
TVN [Member] | Cost of revenue [Member]
Restructuring Cost and Reserve [Line Items]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments						600
TVN [Member] | Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments						1,400
TVN [Member] | TVN Voluntary Departure Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 13,100
Payments of Voluntary Plan Benefit Obligation						3,500
Voluntary Departure Plan, Liability		9,600				$ 9,600
TVN [Member] | Harmonic 2016 Restructuring Plan [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | Employees						83
San Jose CA Excess Facility [Member] | Harmonic 2016 Restructuring Plan [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges						$ 1,400
Other Liabilities, Fair Value Disclosure											$ 2,500
Deferred Rent Credit											$ 1,100
Adjustments to restructuring provisions		$ 600
Paris France Excess Facility [Member] | Harmonic 2016 Restructuring Plan [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges						$ 200

[1] The restructuring and related charges for the year ended December 31, 2016 is net of $0.6 million and $1.4 million, in product cost of revenue and operating expenses-restructuring and related charges, respectively, of gain from TVN pension curtailment. See Note 13, “Employee Benefit Plans and Stock-based Compensation-TVN Retirement Benefit Plan,” for additional information on gain from TVN pension curtailment.

[2] In December 2016, the Company also exited from an excess facility at its office in Paris, France and recorded $0.2 million of facility exit costs. This liability will be fully paid in the first quarter of 2017.

[3] See discussion on TVN VDP above for future estimated payments under the TVN VDP through 2020.