Restructuring and Related Charges - Additional Information (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($)	Oct. 02, 2015 USD ($)	Sep. 30, 2016 USD ($) Employee	Oct. 02, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) Employee	Dec. 31, 2014 USD ($)	Jan. 04, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	$ (28,000)	$ 510,000	$ 4,464,000	$ 739,000
Defined Benefit Pension Plan Liabilities, Current	248,000		248,000
Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Settled without Cash			246,000
Charges for 2016 Harmonic Restructuring Plan			$ 4,862,000
Number of positions eliminated | Employee			22
Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Charges for 2016 Harmonic Restructuring Plan						$ 1,500,000	$ 2,200,000
Number of positions eliminated | Employee						56
Facility Closing [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Fair Value of Excess Facility Restructuring								$ 2,500,000
Deferred Rent Credit								$ 1,100,000
Restructuring Reserve, Settled without Cash			$ 0
Restructuring Charges			1,400,000
Charges for 2016 Harmonic Restructuring Plan	1,400,000		1,445,000
Employee Severance [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Settled without Cash			0
Restructuring Charges			3,100,000
Charges for 2016 Harmonic Restructuring Plan			3,171,000
Other Restructuring [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Settled without Cash			246,000
Charges for 2016 Harmonic Restructuring Plan			246,000
TVN [Member]
Restructuring Cost and Reserve [Line Items]
Business Combination, Acquisition and Integration Related Expenses	5,300,000		11,800,000
Business Combination, Integration Related Costs	4,734,000		7,912,000
Business Combination, Acquisition Related Costs	534,000		3,855,000
TVN [Member] | Operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Business Combination, Integration Related Costs	4,636,000		7,814,000
Business Combination, Acquisition Related Costs	534,000		3,855,000
TVN [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Defined Benefit Pension Plan Liabilities, Current	11,000,000		11,000,000
TVN [Member] | Employee Severance [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Postemployment Benefits, Period Expense	0		0
Scenario, Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Settled without Cash					$ 3,000,000
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Anticipated Synergies from Restructuring Exit Plan	24,000,000		24,000,000
Minimum [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	31,000,000		$ 31,000,000
Expected Project Completion Period			12 months
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Anticipated Synergies from Restructuring Exit Plan	25,000,000		$ 25,000,000
Maximum [Member] | Harmonic 2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	$ 33,000,000		$ 33,000,000