Convertible Notes and Credit Facilities - Additional Information (Detail)			12 Months Ended
		Dec. 14, 2015 shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 22, 2014 USD ($)
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.00%
Debt Instrument, Face Amount			$ 128,250,000	$ 128,250,000
Debt Issuance Cost				4,100,000
Payments of Debt Issuance Costs			582,000	3,527,000	$ 0
Proceeds from convertible debt			$ 0	128,250,000	$ 0
Stock Repurchased and Retired During Period, Shares | shares			0
Debt Instrument, Convertible, Conversion Ratio			173.9978
Debt Conversion, Converted Instrument, Amount			$ 1,000
Debt Instrument, Convertible, Conversion Price | $ / shares			$ 5.75
Percentage Of Principal Amount Of Convertible Notes Is Equal To Repurchase Price			100.00%
Debt Instrument Convertible Allocated Amount of Equity Component			$ 26,925,000	26,925,000
Debt Instrument Convertible Equity Component Issuance Cost			863,000	863,000
Other Loans Payable	[1]		1,400,000
Loans Payable to Bank	[2]		$ 17,930,000
Stock price greater or equal 130 percent of Note Conversion Price [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Threshold Trading Days			20
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger			130.00%
Debt Instrument, Convertible, Threshold Consecutive Trading Days			30 days
Note price less than 98 percent of stock price times conversion rate [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount			$ 1,000
Debt Instrument, Convertible, Threshold Trading Days			5
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger			98.00%
Debt Instrument, Convertible, Threshold Consecutive Trading Days			5 days
Foreign Line of Credit [Member] | BPI France [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Fair Value of Amount Outstanding			$ 0
Line of Credit Facility, Maximum Borrowing Capacity			2,100,000			€ 2,000,000
Restricted Cash and Cash Equivalents			200,000			€ 200,000
Standby letters of credit [Member] | JPMorgan Chase [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity							$ 10,000,000
Revolving Credit Facility [Member] | JPMorgan Chase [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity							$ 20,000,000
Privately Negotiated Transactions [Member]
Debt Instrument [Line Items]
Proceeds from convertible debt				49,900,000
Stock Repurchased and Retired During Period, Shares | shares		11,100,000
Long-term Debt [Member]
Debt Instrument [Line Items]
Debt Issuance Cost				$ 3,200,000
TVN [Member]
Debt Instrument [Line Items]
Income Taxes Receivable			25,700,000
TVN [Member] | Other Current Assets [Member]
Debt Instrument [Line Items]
Other Loans Payable			$ 400,000
Loans Backed By French Research And Development Tax Credit Receivables [Member] | TVN [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			0.60%			0.60%
Loans Payable to Bank			$ 14,700,000
Adjusted EURIBOR Rate, Term			1 month
Debt Instrument, Basis Spread on Variable Rate			1.30%
Loans Backed By French Government Agencies for R&D Innovation Projects [Member] | TVN [Member]
Debt Instrument [Line Items]
Loans Payable to Bank			$ 3,300,000

[1] One of the term loans with a certain financial institution contains annual covenants that require the TVN French Subsidiary to maintain a minimum working capital balance and various other financial covenants and restrictions that limit the French Subsidiary’s ability to incur additional indebtedness. The annual covenant is based on French statutory year-end results and the TVN French Subsidiary failed the 2016 covenant test primarily due to the Company’s plan to integrate TVN’s operations into other subsidiaries for tax planning and logistic purpose. The Company has informed the financial institution of the 2016 covenant test results and has made plans to pay off the entire loan balance of approximately $0.4 million in early 2017 and as a result, the entire loan balance is recorded under “Other debts and capital lease obligations, current,” in the Consolidated Balance Sheets.

[2] As of December 31, 2016, the Company’s TVN French Subsidiary had an aggregate of $17.9 million of loans due to various financing programs of French government agencies, $14.7 million of which is related to loans backed by R&D tax credit receivables. As of December 31, 2016, the TVN French Subsidiary had an aggregate of $25.7 million of R&D tax credit receivables from the French government from 2017 through 2020. (See Note 10, “Certain Balance Sheet Components-Prepaid expenses and other current assets,” for more information). These tax loans have a fixed rate of 0.6%, plus EURIBOR 1 month plus 1.3% and matures between 2017 through 2019. The remaining loans of $3.3 million at December 31, 2016 primarily relates to financial support from French government agencies for R&D innovation projects at minimal interest rates and these loans mature between 2020 through 2023.