Balance Sheet Components - Accounts Receivable, Net, Prepaid Expenses and Other Current Assets, Inventories, Property and Equipment, Net (Detail) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Accounts receivable, net:
Accounts receivable		$ 77,179	$ 91,596
Less: allowances for doubtful accounts, returns and discounts		(7,408)	(4,831)
Total		69,771	86,765
Prepaid expenses and other current assets:
Deferred cost of revenue		6,161	6,856
French R&D tax credits receivable(1)	[1]	5,990	5,895
Prepaid maintenance, royalty, rent, property taxes and value added tax		6,657	5,526
Prepaid customer incentive(2)	[2]	746	1,162
Restricted cash(3)	[3]	768	731
Other		7,046	6,149
Prepaid Expense and Other Assets, Current		27,368	26,319
Inventories:
Raw materials		10,501	9,889
Work-in-process		2,856	2,318
Finished goods		14,682	17,776
Service-related spares		11,881	11,210
Total inventories, net		39,920	41,193
Accrued Liabilities, Current [Abstract]
Accrued employee compensation and related expenses		17,965	19,377
Accrued TVN VDP, current (1)		4,245	6,597
Accrued warranty		4,585	4,862
Customer deposits		4,926	4,537
Contingent inventory reserves		2,171	2,210
Accrued royalty payments		1,891	1,912
Others		16,279	15,655
Accrued Liabilities, Current		$ 52,062	$ 55,150

[1] The Company’s acquired 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. The R&D tax credit receivables at March 31, 2017 were approximately $27.5 million and are expected to be recoverable from 2017 through 2020 with $6.0 million reported under “Prepaid and other Current Assets” and $21.5 million reported under “Other Long-term Assets” on the Company’s Condensed Consolidated Balance Sheets.

[2] On September 26, 2016, the Company issued a warrant to purchase shares of its common stock (the “Warrant”) to Comcast pursuant to which Comcast may, subject to certain vesting provisions, purchase up to 7,816,162 shares of the Company’s common stock subject to adjustment in accordance with the terms of the Warrant, for a per share exercise price of $4.76. The portion of the Warrant which vested on September 26, 2016 had a value of approximately $1.6 million and is deemed a customer incentive paid upfront and cumulatively, $0.9 million of this prepaid incentive has been recorded as a reduction to the Company’s net revenues from Comcast. The remaining $0.7 million of this prepaid incentive is reported as an asset under “Prepaid expenses and other current assets” on the Company’s Condensed Consolidated Balance Sheet as of March 31, 2017. The Company considers this asset to be recoverable based on the expectation of Comcast’s future purchase of the pertinent products. The asset will be assessed for impairment if no longer deemed recoverable.

[3] 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 March 31, 2017, the Company recorded 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 Condensed Consolidated Balance Sheets. March 31, 2017December 31, 2016Inventories: Raw materials$10,501 $9,889Work-in-process2,856 2,318Finished goods14,682 17,776Service-related spares11,881 11,210Total$39,920 $41,193