Selected Quarterly Financial Data Selected Quarterly Financial Data - Additional Information (Details) $ 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, 2015 USD ($)	Apr. 03, 2015 USD ($)	Dec. 31, 2016 USD ($) Employee		Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Income Tax Contingency [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
Gross Margin Percentage		50.70%	46.60%	49.70%	54.30%
Increase (Decrease) in Deferred Revenue and Customer Advances and Deposits				$ 4,800
Provision for excess and obsolete inventories							6,871		1,585	2,569
Amortization of intangibles							14,836		6,502	20,520
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					$ 3,100
Valuation Allowance Deferred Tax Asset Addition							18,291		3,068	39,556
Valuation Allowance Deferred Tax Asset Deductions							8,356		13,722	3,001
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations							1,000		900	9,500
Israel Tax Authority [Member]
Income Tax Contingency [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount									(900)
Vislink plc [Member]
Income Tax Contingency [Line Items]
Cost-method Investments, Other than Temporary Impairment		$ 1,200		1,500					0
VJU Gmbh [Member]
Income Tax Contingency [Line Items]
Cost-method Investments, Other than Temporary Impairment						$ 2,500	2,500
TVN [Member]
Income Tax Contingency [Line Items]
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
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							$ 2,000
TVN Voluntary Departure Plan [Member]
Income Tax Contingency [Line Items]
Number of employees applied for VDP | Employee							83
Restructuring and Related Cost							$ 13,100
Harmonic Two Thousand And Sixteen Restructuring [Member] | TVN Voluntary Departure Plan [Member]
Income Tax Contingency [Line Items]
Restructuring and Related Cost							13,100
Cost of Sales [Member]
Income Tax Contingency [Line Items]
Amortization of intangibles							4,434		$ 719	$ 13,745
Operating Segments [Member] | Cable Edge [Member]
Income Tax Contingency [Line Items]
Provision for excess and obsolete inventories			$ 4,500				4,000
Valuation Allowance, Operating Loss Carryforwards [Member]
Income Tax Contingency [Line Items]
Valuation Allowance Deferred Tax Asset Addition	$ 18,300
Valuation Allowance, Stock-based Compensation [Member]
Income Tax Contingency [Line Items]
Valuation Allowance Deferred Tax Asset Deductions							$ 8,400

[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.