Restructuring and Related Charges - Additional Information (Detail) $ in Thousands		3 Months Ended			12 Months Ended	15 Months Ended
		Mar. 31, 2017 USD ($) Employees	Dec. 31, 2016 USD ($) Employees	Apr. 01, 2016 USD ($)	Dec. 31, 2016 USD ($) Employees	Mar. 31, 2017 USD ($)	Jan. 04, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		$ 1,787		$ 2,583
Restructuring and related charges		1,279		2,612
Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost					$ 20,000
Charges for 2016 Harmonic Restructuring Plan		1,732
Restructuring and related charges		55
Facility Closing [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost					2,200
Charges for 2016 Harmonic Restructuring Plan		25
Restructuring and related charges		0
Employee Severance And Benefit Arrangements [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost					$ 17,800
Number of positions eliminated | Employees					118
Employee Severance [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Charges for 2016 Harmonic Restructuring Plan	[1]	630
Restructuring and related charges	[1]	55
TVN Voluntary Departure Plan [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Charges for 2016 Harmonic Restructuring Plan	[2]	1,077
Restructuring and related charges	[2]	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		$ 2,200		3,100	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
Number of employees required to work beyond minimum statutory notice period under VDP | Employees			11
Accrued Voluntary Departure Plan, Current			$ 14,800		$ 14,800
TVN [Member] | Employee Severance And Benefit Arrangements [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | Employees		7			83
TVN [Member] | Employee Severance [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Postemployment Benefits, Period Expense		$ 1,100
Charges for 2016 Harmonic Restructuring Plan		700
TVN [Member] | TVN Voluntary Departure Plan [Member]
Restructuring Cost and Reserve [Line Items]
Charges for 2016 Harmonic Restructuring Plan		1,100	13,100
Defined Benefit Plan, Benefits Paid						$ 7,100
Postemployment Benefits Liability		$ 7,200				$ 7,200
San Jose CA Excess Facility [Member] | Facility Closing [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Charges for 2016 Harmonic Restructuring Plan				$ 1,400
Fair Value of Excess Facility Restructuring							$ 2,500
Deferred Rent Credit							$ 1,100
Restructuring and related charges			$ 600

[1] The Company anticipates that the remaining severance and benefits accrual at March 31, 2017 will be fully paid in 2017.

[2] See discussion of the TVN VDP above for future estimated payments through 2020.