Certain Balance Sheet Components - Narratives (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Income Taxes Receivable, Noncurrent		$ 19,249	$ 22,322
Income Taxes Receivable, Current	[1]	7,305	6,609
Restricted Cash, Noncurrent		0	1,203	$ 1,053
TVN [Member]
Condensed Financial Statements, Captions [Line Items]
Proceeds from Income Tax Refunds		6,400	$ 6,400
Research Tax Credit Carryforward [Member] | TVN [Member]
Condensed Financial Statements, Captions [Line Items]
Income Taxes Receivable, Noncurrent		26,500
Other Noncurrent Assets [Member] | Research Tax Credit Carryforward [Member] | TVN [Member]
Condensed Financial Statements, Captions [Line Items]
Income Taxes Receivable, Noncurrent		$ 19,200

[1] The Company’s TVN subsidiary in France (the “TVN French Subsidiary”) participates in the French Crédit d’Impôt Recherche (“CIR”) program (the “R&D tax credits”) which allows companies to monetize eligible research expenses. The R&D tax credits can be used to offset against income tax payable to the French government in each of the four years after being incurred, or if not utilized, are recoverable in cash. The amount of R&D tax credits recoverable are subject to audit by the French government and during the year ended December 31, 2018 and 2017, the French government approved the 2014 and 2013 claims and refunded $6.4 million to the TVN French Subsidiary in each of the periods, respectively. The remaining R&D tax credits receivable at December 31, 2018 were approximately $26.5 million and are expected to be recoverable from 2019 through 2022 with $7.3 million reported as a component of “Prepaid and other Current Assets” and $19.2 million reported as a component of “Other Long-term Assets” on the Company’s Consolidated Balance Sheets.