Balance Sheet Components - Accounts Receivable, Net, Prepaid Expenses and Other Current Assets, Inventories, Property and Equipment, Net (Detail) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Accounts receivable, net:
Accounts receivable		$ 103,511	$ 73,855
Less: allowances for doubtful accounts, returns and discounts		(4,433)	(4,340)
Total		99,078	69,515
Prepaid expenses and other current assets:
Prepaid inventories to contract manufacturer(1)	[1]	4,736	8,500
Prepaid maintenance, royalty, rent and property taxes		7,003	5,974
Other Prepayments		4,730	2,762
Deferred cost of revenue		10,470	4,601
French R&D tax credits receivable(2)	[2]	6,279
Restricted cash(3)	[3]	1,341	1,093
Other		3,960	2,073
Prepaid Expense and Other Assets, Current		38,519	25,003
Inventories:
Raw materials		9,417	5,421
Work-in-process		1,328	1,950
Finished goods		13,397	19,827
Inventory, Supplies, Net of Reserves		11,686	11,621
Total inventories, net		35,828	38,819
Property and equipment, net:
Furniture and fixtures		9,110	7,808
Machinery and equipment		99,172	93,010
Capitalized software		34,703	29,391
Leasehold improvements		14,005	10,000
Property and equipment, gross		156,990	140,209
Less: accumulated depreciation and amortization		(121,845)	(113,197)
Property and equipment, net		35,145	27,012
Accrued Liabilities, Current [Abstract]
Accrued employee compensation and related expenses		18,420	12,083
Accrued sales and use tax and property taxes		1,861	1,743
Accrued TVN contingent consideration (1)		0
Accrued warranty		5,079	3,913
Accrued royalty payments		2,597	873
Contingent inventory reserves		2,485	1,315
Customer deposits		5,020	953
Others		14,907	10,474
Accrued Liabilities, Current		$ 50,369	$ 31,354

[1] From time to time, the Company makes advance payment to a supplier for future inventory in order to secure more favorable pricing. As of September 30, 2016, the Company had $8.5 million of prepaid inventory and accounts payable of approximately $3.8 million with one of its suppliers. Based on the agreement with this supplier, the Company has the right to set off the amount owed with the amount owed by the supplier, and in October 2016, according to the terms of the supplier agreement, the Company notified the supplier of its intent to net the balances in the fourth quarter of 2016. Based on the guidance in ASC 210-20, as of September 30, 2016, the Company took a net position on the balance sheet and elected to net $3.8 million of prepaid inventories with accounts payable

[2] 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 French 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 French R&D tax credits recoverable are subject to audit by the French government and during the second quarter of 2016, the French government approved the 2012 claim and refunded $5.8 million to the TVN French Subsidiary. The remaining R&D tax credit receivables at September 30, 2016 were approximately $25.1 million and are expected to be recoverable from 2017 through 2020 with $6.3 million reported under “Prepaid and other Current Assets” and $18.8 million reported under “Other Long-term Assets” on the Company’s Condensed Consolidated Balance Sheets. Pursuant to the TVN Purchase Agreement, the Company is indemnified by the selling shareholders with respect to the validity and recoverability of the outstanding TVN French Subsidiary R&D tax credit receivables.

[3] The restricted cash balances are primarily 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 September 30, 2016, 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.