Restructuring and Related Charges - Activities in Restructuring Accrual (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Apr. 01, 2016
Restructuring Reserve [Roll Forward]
Adjustments to restructuring provisions		$ 1,279	$ 2,612
Harmonic 2016 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance		13,544
Restructuring charges		1,732
Adjustments to restructuring provisions		55
Cash payments		(5,724)
Foreign exchange gain (loss)		145
Ending Balance		9,752
Restructuring Reserve, Current	[1]	(5,777)
Restructuring Reserve, Noncurrent	[1]	3,975
Harmonic 2016 Restructuring Plan [Member] | Facility Closing [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance		2,375
Restructuring charges		25
Adjustments to restructuring provisions		0
Cash payments		(433)
Ending Balance		1,967
Restructuring Reserve, Current	[1]	(978)
Restructuring Reserve, Noncurrent	[1]	989
Harmonic 2016 Restructuring Plan [Member] | TVN Voluntary Departure Plan [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	[2]	9,650
Restructuring charges	[2]	1,077
Adjustments to restructuring provisions	[2]	0
Cash payments	[2]	(3,627)
Foreign exchange gain (loss)	[2]	131
Ending Balance	[2]	7,231
Restructuring Reserve, Current	[1],[2]	(4,245)
Restructuring Reserve, Noncurrent	[1],[2]	2,986
Harmonic 2016 Restructuring Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	[3]	1,519
Restructuring charges	[3]	630
Adjustments to restructuring provisions	[3]	55
Cash payments	[3]	(1,664)
Foreign exchange gain (loss)	[3]	14
Ending Balance	[3]	554
Restructuring Reserve, Current	[1],[3]	(554)
Restructuring Reserve, Noncurrent	[1],[3]	$ 0

[1] The current portion and long-term portion of the restructuring liability are reported under “Accrued and other current liabilities” and “Other non-current liabilities”, respectively, on the Company’s Condensed Consolidated Balance Sheets.

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

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