Summary of Significant Accounting Policies - Additional Information (Detail)		3 Months Ended	12 Months Ended
		Dec. 31, 2014 Customer segment	Dec. 31, 2016 USD ($) Customer segment	Dec. 31, 2015 USD ($) Customer	Dec. 31, 2014 USD ($) Customer
Cash and cash equivalents maximum maturity			3 months	3 months	3 months
Restricted Cash and Investments			$ 1,800,000
Restricted cash (3)	[1]		$ 731,000	$ 1,093,000
Revenue recognition period, associated with service and maintenance agreement			1 year
Percentage of revenue recognized upon completion contract method			100.00%
Number of reporting units			2
Goodwill, Acquired During Period			$ 41,670,000
Goodwill, Impairment Loss			0	0	$ 0
Capitalized Computer Software, Impairments					1,100,000
Foreign Currency Transaction Gain (Loss), before Tax			$ 200,000	500,000	400,000
Discount rate			1.50%
Research and Development Expense			$ 98,401,000	87,545,000	93,061,000
Reimbursements of Engineering Spending			6,000,000
R&D Tax Credits			129,000	178,000	841,000
Advertising expense			1,400,000	1,400,000	$ 200,000
Defined Benefit Plan, Benefit Obligation			$ 4,264,000
Net Accumulated Gain or Loss as a Percentage of Projected Plan Benefit Obligation			10.00%
More Likely Than Not Threshold Recognition of Uncertain Tax Position			50.00%
Number of reportable segments | segment		2	2
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent				$ 15,900,000
Furniture and Fixtures [Member]
Property, plant and equipment estimated useful life			5 years
Internal Use Software [Member]
Property, plant and equipment estimated useful life			3 years
Machinery and Equipment [Member]
Property, plant and equipment estimated useful life			4 years
Leasehold Improvements [Member]
Property, plant and equipment estimated useful life			10 years
Property, plant and equipment leasehold improvements useful lives			shorter of the remaining useful lives of the assets, up to 10 years, or the lease term of the respective assets
Forward Contracts [Member]
Derivative, Term of Contract			12 months
Forward Contracts [Member] | Designated as Hedging Instrument [Member]
Derivative, Term of Contract			12 months
Software [Member]
Property, plant and equipment estimated useful life			3 years
Accounts Receivable [Member]
Number of significant customers for accounts receivable | Customer			0	0
Entity-wide revenue, major customer, revenue or accounts receivable percentage			10.00%	10.00%
Net Revenue [Member]
Entity-wide revenue, major customer, revenue or accounts receivable percentage			10.00%	10.00%
Number Of Customers Accounting For More Than Ten Percent Of Revenue Other Than Comcast | Customer		0	0	0	0
Net Revenue [Member] | Comcast [Member]
Entity-wide revenue, major customer, revenue or accounts receivable percentage				12.00%	16.00%
Customer Concentration Risk [Member] | Net Revenue [Member] | Comcast [Member]
Entity-wide revenue, major customer, revenue or accounts receivable percentage				12.00%	16.00%
TVN [Member]
Goodwill, Acquired During Period			$ 41,700,000
R&D Tax Credits			$ 6,100,000
Other Pension Plan [Member]
Discount rate			4.25%
LIBOR, Advances, Maturity Period, Variable Rate			4 years
Other Pension Plan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Basis Spread on Variable Rate			2.50%
Other Pension Plan, Postretirement or Supplemental Plans [Member]
Discount rate			1.50%
Defined Benefit Pension Plan Annual Service and Interest Costs at Fair Value, Assumptions Used to Estimate Fair Value, Weighted Average Life			10 years

[1] The restricted cash balances are held as cash collateral security for certain bank guarantees. These restricted funds are invested in bank deposits and cannot be withdrawn from the Company’s accounts without the prior written consent of the applicable secured party. Additionally, as of December 31, 2016, the Company had approximately $1.1 million of restricted cash for the bank guarantee associated with the TVN French Subsidiary’s office building lease. This amount is reported under “Other Long-term Assets” on the Company’s Consolidated Balance Sheets.