Restructuring and Excess Facilities - Restructuring and Asset Impairment Charges COS vs OPEX (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	[1]
Restructuring and Related Activities [Abstract]
Cost of revenue	$ 857	$ 1,279	$ 3,400
Restructuring and Related Cost	2,918	5,307	14,602
Restructuring and related Charges	$ 3,775	$ 6,586	$ 18,002

[1] The restructuring and related charges for the fiscal year ended December 31, 2016 is net of $0.6 million and $1.4 million, in Cost of revenue and Operating expenses - Restructuring and related charges, respectively, of gain from TVN pension curtailment. See “Harmonic 2016 Restructuring Plan” below for additional information.