Restructuring and Related Charges Restructuring and Related Charges - Estimated Future Payments (Details) - TVN [Member] - TVN Voluntary Departure Plan [Member] - Harmonic 2016 Restructuring Plan [Member] $ in Thousands	Mar. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
2017 (remaining nine months)	$ 3,426
2018	3,023
2019	1,494
2020	692
Total	$ 8,635