Mandiant (MNDT) 10-Q 5 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 31, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'FIREEYE, INC.	'
Entity Central Index Key	'0001370880	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding (in shares)	'	150,419,888

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$98,843	$173,918
Short-term investments	299,022	0
Accounts receivable, net of allowance for doubtful accounts of $930 at September 30, 2014 and $20 at December 31, 2013	155,798	95,772
Inventories	5,765	5,663
Deferred tax assets, current portion	26,775	14,584
Prepaid expenses and other current assets	31,508	25,230
Total current assets	617,711	315,167
Property and equipment, net	84,095	64,765
Goodwill	750,275	706,327
Intangible assets, net	273,314	281,377
Deposits and other long-term assets	10,366	8,677
TOTAL ASSETS	1,735,761	1,376,313
CURRENT LIABILITIES:	'	'
Accounts payable	30,198	34,128
Accrued and other current liabilities	20,574	17,677
Accrued compensation	66,308	41,625
Deferred revenue, current portion	160,768	110,535
Total current liabilities	277,848	203,965
Deferred revenue, non-current portion	122,153	76,979
Deferred tax liabilities, non-current portion	36,068	45,147
Other long-term liabilities	6,553	2,120
Total liabilities	442,622	328,211
Commitments and contingencies (NOTE 9)	'	'
Stockholders' equity:	'	'
Common stock, par value of $0.0001 per share; 1,000,000 shares authorized, 150,130 shares and 137,758 shares issued and outstanding as of September 30, 2014 and December 31, 2013, respectively	15	14
Additional paid-in capital	1,855,016	1,271,590
Accumulated other comprehensive loss	-326	0
Accumulated deficit	-561,566	-223,502
Total stockholders’ equity	1,293,139	1,048,102
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$1,735,761	$1,376,313

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Allowance for doubtful accounts	$930	$20
Common stock, par value (usd per share)	$0.00	$0.00
Common stock, shares authorized (shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (shares)	150,130,000	137,758,000
Common stock, shares outstanding (shares)	150,130,000	137,758,000

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenue:	'	'	'	'
Product	$48,375	$23,729	$110,310	$55,957
Subscription and services	65,836	18,923	172,370	48,333
Total revenue	114,211	42,652	282,680	104,290
Cost of revenue:	'	'	'	'
Product	15,440	7,358	39,515	18,124
Subscription and services	29,488	6,079	82,286	12,481
Total cost of revenue	44,928	13,437	121,801	30,605
Total gross profit	69,283	29,215	160,879	73,685
Operating expenses:	'	'	'	'
Research and development	54,707	20,492	150,085	44,570
Sales and marketing	111,625	44,414	283,070	110,577
General and administrative	30,119	11,704	89,150	29,385
Restructuring charges	2,769	0	2,769	0
Total operating expenses	199,220	76,610	525,074	184,532
Operating loss	-129,937	-47,395	-364,195	-110,847
Interest income	228	1	456	53
Interest expense	-6	-243	-17	-519
Other expense, net	-636	-4,206	-1,018	-7,129
Loss before income taxes	-130,351	-51,843	-364,774	-118,442
Benefit from income taxes	-10,320	-917	-26,710	-320
Net loss attributable to common stockholders	($120,031)	($50,926)	($338,064)	($118,122)
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	($0.83)	($1.61)	($2.41)	($5.41)
Weighted average shares used in computing net loss per share attributable to common stockholders, basic and diluted (shares)	144,923	31,590	140,285	21,838

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Loss Statement (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net loss	($120,031)	($50,926)	($338,064)	($118,122)
Other comprehensive loss, net of tax:	'	'	'	'
Change in net unrealized loss on available-for-sale investments	-216	0	-326	0
Comprehensive loss	($120,247)	($50,926)	($338,390)	($118,122)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net loss	($338,064)	($118,122)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	67,631	12,344
Stock-based compensation expense	106,607	16,344
Deferred income taxes	-30,142	0
Other	1,702	5,363
Changes in operating assets and liabilities, net of acquisition of business:	'	'
Accounts receivable	-60,041	-20,727
Inventories	162	-5,174
Prepaid expenses and other assets	-2,138	-5,676
Accounts payable	-8,359	6,115
Accrued and other current liabilities	6,684	3,711
Accrued compensation	25,415	6,481
Deferred revenue	95,107	54,370
Other long-term liabilities	4,434	547
Net cash used in operating activities	-131,002	-44,424
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Purchases of property and equipment and demonstration units	-55,466	-35,956
Purchases of marketable securities	-352,401	0
Maturities of marketable securities	50,780	0
Acquisition of business, net of cash acquired	-55,058	-3,872
Lease deposits	-565	-1,636
Net cash used in investing activities	-412,710	-41,464
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Net proceeds from initial public offering	0	322,863
Net proceeds from issuance of stock	444,338	0
Borrowing from line of credit	0	10,000
Net proceeds from issuance of convertible preferred stock	0	9,988
Repayment of term loan	0	-2,147
Proceeds from exercise of equity awards	24,299	5,400
Repayment of notes receivable from stockholders	0	7,294
Net cash provided by financing activities	468,637	353,398
Net change in cash and cash equivalents	-75,075	267,510
Cash and cash equivalents, beginning of year	173,918	60,200
Cash and cash equivalents, end of year	98,843	327,710
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:	'	'
Cash paid for interest	17	493
Cash paid for income taxes	2,338	303
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:	'	'
Deferred initial public offering costs in accounts payable and accrued liabilities	0	1,583
Common stock issued in connection with acquisition	0	800
Conversion of preferred stock warrants to common stock warrants	0	10,067
Purchases of property and equipment and demonstration units in accounts payable and accrued liabilities	$8,022	$12,520

Description_of_Business_and_Su

Description of Business and Summary of Significant Accounting Policies (Notes)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Description of Business and Summary of Significant Accounting Policies	'
	Description of Business and Summary of Significant Accounting Policies
	Description of Business
	FireEye, Inc., with principal executive offices located in Milpitas, California, was incorporated as NetForts, Inc. on February 18, 2004, under the laws of the State of Delaware, and changed its name to FireEye, Inc. on September 7, 2005.
	FireEye, Inc. and its wholly owned subsidiaries (collectively, the “Company”, “we”, “us” or “our”) is a leader in stopping advanced cyber attacks that use advanced malware, zero-day exploits, and APT (“Advanced Persistent Threat”) tactics. Our solutions supplement traditional and next-generation firewalls, Intrusion Prevention Systems ("IPS”), anti-virus, and gateways, which cannot stop advanced threats, leaving security holes in networks. We offer a solution that detects and blocks attacks across both Web and email threat vectors as well as latent malware resident on file shares. Our solutions address all stages of an attack lifecycle with a signature-less engine utilizing stateful attack analysis to detect zero-day threats.
	In March 2014, we completed our follow-on public offering in which we issued and sold 5,582,215 shares of common stock at a price of $82.00 per share. We received aggregate proceeds of $446.5 million from the sale of shares of common stock, net of underwriters’ discounts and commissions of $11.2 million, but before deducting offering expenses of approximately $2.2 million. Another 8,417,785 shares were sold by certain selling stockholders, which included 796,846 shares sold pursuant to the exercise of vested outstanding options by our employees. We did not receive any of the proceeds from the sales of shares by the selling stockholders.
	We sell the majority of our products, subscriptions and services to end-customers through distributors, resellers, and strategic partners, with a lesser percentage of sales directly to end-customers.
	Basis of Presentation and Consolidation
	The accompanying unaudited condensed consolidated financial statements include the accounts of FireEye, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP"), and following the requirements of the Securities and Exchange Commission ("SEC"), for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, that are necessary for a fair statement of our financial information. The results of operations for the three and nine months ended September 30, 2014 are not necessarily indicative of the results to be expected for the year ending December 31, 2014 or for any other interim period or for any other future year. The balance sheet as of December 31, 2013 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for annual consolidated financial statements.
	The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2013 included in our Annual Report on Form 10-K, which was filed with the SEC on March 3, 2014.
	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Such management estimates include, but are not limited to, the best estimate of selling price for our products and services, commissions expense, future taxable income, contract manufacturer liabilities, litigation and settlement costs and other loss contingencies, fair value of our common and preferred stock, stock options and preferred stock warrant liability, and the purchase price allocation of acquired businesses. We base our estimates on historical experience and also on assumptions that we believe are reasonable. Changes in facts or circumstances may cause us to change our assumptions and estimates in future periods, and it is possible that actual results could differ from current or revised future estimates.
	Summary of Significant Accounting Policies
	There have been no significant changes to our significant accounting policies as of and for the three and nine months ended September 30, 2014, as compared to the significant accounting policies described in our Annual Report on Form 10-K for the year ended December 31, 2013, except for the inclusion of a new policy related to short-term investments, and a revision to our policy on revenue recognition.
	Short-term Investments
	We classify our investments in debt and equity securities as available-for-sale and record these investments at fair value. Investments with an original maturity of three months or less at the date of purchase are considered cash equivalents, while all other investments are classified as short-term or long-term based on the nature of the investments, their maturities, and their availability for use in current operations. Unrealized gains and losses are reported as a component of other comprehensive loss. Realized gains and losses are determined based on the specific identification method, and are reflected in earnings. We regularly review our investment portfolio to identify and evaluate investments that have indicators of possible impairment. Factors considered in determining whether a loss is other-than-temporary include, but are not limited to: the length of time and extent a security’s fair value has been below its cost, the financial condition and near-term prospects of the investee, the credit quality of the security’s issuer, likelihood of recovery and our intent and ability to hold the security for a period of time sufficient to allow for any anticipated recovery in value. For our debt instruments, we also evaluate whether we have the intent to sell the security or it is more likely than not that we will be required to sell the security before recovery of its cost basis.
	Investments are considered to be impaired when a decline in fair value is judged to be other-than-temporary. Fair value is calculated based on publicly available market information or other estimates determined by management. If the cost of an investment exceeds its fair value, we evaluate, among other factors, general market conditions, credit quality of debt instrument issuers, the duration and extent to which the fair value is less than cost, and whether we have plans to sell the security, or it is more likely than not that we will be required to sell the security, before recovery. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to other income (expense) and a new cost basis in the investment is established.
	Revenue Recognition
	We generate revenue from the sales of products, subscriptions and support and maintenance, and professional services through our indirect relationships with our partners as well as end-customers through our direct sales force. Our products include operating system software that is integrated into the appliance hardware and is deemed essential to its functionality. As a result, we account for revenue in accordance with Accounting Standards Codification 605, Revenue Recognition, and all related interpretations as all of our security appliance deliverables include proprietary operating system software, which together deliver the essential functionality of our products. Our professional services consist primarily of time and materials based contracts, and the revenue is recognized as costs are incurred at amounts represented by the agreed-upon billing amounts. Revenue from fixed-price professional services engagements are recognized under the proportional performance method of accounting.
	In June 2014, we started shipping all Email Threat Prevention appliances with software that allows customers to benefit from the product without the associated subscription services.  Consistent with our Web and File Threat Prevention products, revenue therefore is recognized at the time of shipment.
	Recent Accounting Pronouncements
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). This standard provides a single model for revenue arising from contracts with customers and supersedes current revenue recognition guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance is effective for us beginning in the first quarter of 2017. Early adoption is not permitted. The guidance permits companies to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. We are currently evaluating the impact the adoption will have on our consolidated financial statements and related disclosures.
	In August 2014, the FASB issued ASU 2014-15, Disclosures of Uncertainties About an Entity’s Ability to Continue as a Going Concern. This standard provides guidance on how and when reporting entities must disclose going-concern uncertainties in their financial statements. The guidance is effective for us beginning in the first quarter of 2017. Early adoption is permitted.

Fair_Value_Measurements_Notes

Fair Value Measurements (Notes)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	Fair Value Measurements
	The accounting guidance for fair value measurements provides a framework for measuring fair value on either a recurring or nonrecurring basis, whereby the inputs used in our valuation techniques are assigned a hierarchical level. The following are the three levels of inputs to measure fair value:
	•Level 1: Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.
	•	Level 2: Inputs that reflect quoted prices for identical assets or liabilities in less active markets; quoted prices for similar assets or liabilities in active markets; benchmark yields, reported trades, broker/dealer quotes, inputs other than quoted prices that are observable for the assets or liabilities; or inputs that are derived principally from or corroborated by observable market data by correlation or other means.
	•	Level 3: Unobservable inputs that reflect our own assumptions incorporated in valuation techniques used to measure fair value. These assumptions are required to be consistent with market participant assumptions that are reasonably available.
	We consider an active market to be one in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis, and consider an inactive market to be one in which there are infrequent or few transactions for the asset or liability, the prices are not current, or price quotations vary substantially either over time or among market makers. Where appropriate, our own or the counterparty’s non-performance risk is considered in measuring the fair values of assets.
	The following table presents our assets measured at fair value on a recurring basis using the above input categories (in thousands):
		As of September 30, 2014								As of December 31, 2013
	Description	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
	Assets
	Cash equivalents:
	Money market funds	$	20,311	$	—	$	—	$	20,311	$	132,518	$	—	$	—	$	132,518
	Total cash equivalents	$	20,311	$	—	$	—	$	20,311	$	132,518	$	—	$	—	$	132,518
	Short-term investments:
	Certificates of deposit	—		4,751		—		4,751		—		—		—		—
	Commercial paper	—		2,750		—		2,750		—		—		—		—
	Corporate notes and bonds	—		148,424		—		148,424		—		—		—		—
	U.S. Government agencies	—		143,097		—		143,097		—		—		—		—
	Total short-term investments	$	—	$	299,022	$	—	$	299,022	$	—	$	—	$	—	$	—
	Total assets measured at fair value	$	20,311	$	299,022	$	—	$	319,333	$	132,518	$	—	$	—	$	132,518

ShortTerm_Investments_Notes

Short-Term Investments (Notes)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Short-Term Investments	'
	Short-Term Investments
	Our investments consisted of the following as of September 30, 2014 (in thousands):
		Available-for-Sale Securities
		Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses			Estimated Fair Value		Short-term investment
	Certificates of deposit	$	4,760	—			$	(9	)	$	4,751	$	4,751
	Commercial paper	2,750		—			—			2,750		2,750
	Corporate notes and bonds	148,571		12			(159		)	148,424		148,424
	U.S. Government agencies	143,267		1			(171		)	143,097		143,097
	Total	$	299,348	$	13		$	(339	)	$	299,022	$	299,022
	The following table presents our investments that had gross unrealized losses, the duration of which was less than twelve months, as of September 30, 2014 (in thousands):
		Total
		Estimated Fair Value		Unrealized Loss
	Certificates of deposit	$	4,511	$	(9	)
	Corporate notes and bonds	117,993		(159		)
	U.S. Government agencies	119,075		(171		)
	Total	$	241,579	$	(339	)
	There were no investments with unrealized losses for twelve months or greater as of September 30, 2014.
	Unrealized losses related to these investments are due to interest rate fluctuations as opposed to credit quality. In addition, we do not intend to sell, and it is not more likely than not that we would be required to sell, these investments before recovery of their cost basis. As a result, there is no other-than-temporary impairment for these investments as of September 30, 2014.
	The following table summarizes the contractual maturities of our investments at September 30, 2014 (in thousands):
		Amortized Cost		Fair Value
	Due within one year	$	160,789	$	160,767
	Due within one to two years	138,559		138,255
	Total	$	299,348	$	299,022
	All available-for-sale securities have been classified as current, based on management's intent and ability to use the funds in current operations.

Property_and_Equipment_Notes

Property and Equipment (Notes)	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property and Equipment	'
	Property and Equipment
	Property and equipment, net consisted of the following as of the dates below (in thousands):
		As of September 30,			As of December 31,
		2014			2013
	Computer equipment and software	$	77,309		$	57,403
	Leasehold improvements	33,150			15,660
	Furniture and fixtures	11,995			6,035
	Machinery and equipment	447			756
	Total property and equipment	122,901			79,854
	Less: accumulated depreciation	(38,806		)	(15,089		)
	Total property and equipment, net	$	84,095		$	64,765
	Depreciation and amortization expense related to property and equipment and demonstration units during the three months ended September 30, 2014 and 2013 was $12.7 million and $4.9 million, respectively. Depreciation and amortization expense related to property and equipment and demonstration units during the nine months ended September 30, 2014 and 2013 was $32.6 million and $11.5 million, respectively.

Business_Combinations_Notes

Business Combinations (Notes)	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Business Combinations	'
	Business Combinations
	On May 9, 2014, we acquired all outstanding shares of privately held nPulse Technologies, Inc. (“nPulse”), a performance leader in network forensics based in Charlottesville, Virginia. The acquisition of nPulse strengthens our position as a leader in advanced threat detection and incident response management solutions.
	The total purchase consideration of $56.6 million consisted of $55.2 million in cash, $0.1 million of equity awards assumed, and 54,319 shares of our common stock, with a fair value of $1.3 million which will vest upon the achievement of milestones. The number of shares was fixed at the completion of the acquisition, and is the maximum number of shares that can vest over a period of approximately three and half years from the acquisition date.
	The acquisition of nPulse was accounted for in accordance with the acquisition method of accounting for business combinations with FireEye as the accounting acquirer. We expensed the related acquisition costs of $0.5 million in general and administrative expenses. Under the purchase method of accounting, the total purchase consideration is allocated to the preliminary tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values. The total purchase price was allocated using information currently available to us. As a result, we may continue to adjust the preliminary purchase price allocation after obtaining more information regarding asset valuations, liabilities assumed, and revisions of preliminary estimates. Total allocation of the preliminary purchase price allocation is as follows (in thousands):
		Amount
	Net tangible liabilities assumed	$	(1,833	)
	Intangible assets	24,700
	Deferred tax asset	442
	Deferred tax liability	(8,368		)
	Goodwill	41,671
	Total preliminary purchase price allocation	$	56,612
	None of the goodwill is expected to be deductible for U.S. federal income tax purposes.
	Intangible assets consist primarily of developed technology, customer relationships and in-process research and development. Developed technology intangible includes a combination of patented and unpatented technology, trade secrets, computer software and research processes that represent the foundation for the existing and planned new products and services. Customer relationships intangible relates to nPulse’s ability to sell existing, in-process and future products and services to its existing and potential customers. The in-process research and development intangible represents the estimated fair value of acquired research projects which have not reached technological feasibility at acquisition date but are expected to be developed into products and services within one year of the acquisition date. The preliminary estimated useful life and fair values of the identifiable intangible assets are as follows (in thousands):
		Preliminary Estimated Useful Life (in years)		Amount
	Developed technology	6		$	10,100
	Customer relationships	8		8,000
	In-process research and development	N/A		6,600
	Total			$	24,700
	The results of operations of nPulse have been included in our condensed consolidated statements of operations from the acquisition date. Revenue and net income from nPulse through September 30, 2014 were not material. Pro forma results of operations have not been presented because the acquisition was not material to our results of operations.
	On December 30, 2013, we acquired privately held Mandiant Corporation (“Mandiant”), a leading provider of advanced end point security products and security incident response management solutions.
	The purchase price allocation for the acquisition of Mandiant will be finalized in calendar year 2014. The following is the total preliminary purchase price allocation of the estimated purchase consideration based on the available information as of September 30, 2014 (in thousands):
		Amount
	Net tangible assets	$	10,797
	Intangible assets	276,200
	Deferred tax liability	(91,098		)
	Goodwill	704,891
	Total preliminary purchase price allocation	$	900,790
	The preliminary estimated useful life and fair values of the identifiable intangible assets as of September 30, 2014 are as follows (in thousands):
		Preliminary Estimated Useful Life (in years)		Amount
	Developed technology	6-Apr		$	54,600
	In-process research and development	N/A		1,400
	Content	10		128,600
	Customer relationships	8		65,400
	Contract backlog	3-Jan		13,800
	Trade names	4		12,400
	Total			$	276,200
	Goodwill and Purchased Intangible Assets
	The changes in the carrying amount of goodwill for the nine months ended September 30, 2014 are as follows (in thousands):
		Amount
	Balance as of December 31, 2013	$	706,327
	Acquisitions and adjustments	43,948
	Balance as of September 30, 2014	$	750,275
	Purchased intangible assets consisted of the following as of the dates below (in thousands):
		As of September 30, 2014				As of December 31, 2013
	Developed technology	$	70,393			$	60,093
	Content	128,600				128,500
	Customer relationships	75,300				67,900
	Contract backlog	13,800				12,600
	Trade names	12,400				12,400
	Total intangible assets subject to amortization	300,493				281,493
	Less: accumulated amortization	(34,979		)		(1,516		)
	Net intangible assets subject to amortization	265,514				279,977
	In-process research and development	7,800				1,400
	Total net intangible assets	$	273,314			$	281,377
	Amortization expense of intangible assets for the three months ended September 30, 2014 and 2013 was $11.5 million and $0.4 million, respectively. Amortization expense of intangible assets for the nine months ended September 30, 2014 and 2013 was $33.5 million and $0.9 million, respectively.
	The expected annual amortization expense of intangible assets as of September 30, 2014 is presented below (in thousands):
	Years Ending December 31,	Intangible Assets
	2014 (remaining three months)	$	11,478
	2015	45,114
	2016	44,498
	2017	38,553
	2018	27,608
	2019 and thereafter	98,263
Total intangible assets subject to amortization	265,514
Total intangible assets with indefinite lives	7,800
Total	$	273,314
Out of Period Adjustments
During the three months ended March 31, 2014, we made adjustments to correct errors related to the purchase of Mandiant, which resulted in an increase in additional paid-in capital of $3.1 million, an increase in intangible assets of approximately $0.7 million, a decrease in current liabilities of $0.2 million and an increase in goodwill of approximately $2.2 million.
During the three months ended September 30, 2014, we made adjustments to correct an error related to the over accrual of $1.0 million for an accrued bonus assumed in the acquisition of Mandiant. This resulted in a decrease in current liabilities of $1.0 million and an increase in goodwill of $1.0 million.
Because these errors, both individually and in the aggregate, were not material to any of the prior years’ financial statements and the impact of correcting these errors in the current period is not material to the March 31, 2014 and September 30, 2014 condensed consolidated financial statements, we recorded the correction of these errors in the March 31, 2014 and September 30, 2014 condensed consolidated financial statements.

Restructuring_Charges_Notes

Restructuring Charges (Notes)	9 Months Ended
	Sep. 30, 2014
Restructuring and Related Activities [Abstract]	'
Restructuring Charges	'
	Restructuring Charges
	We initiated a business restructuring plan in August 2014 to reduce our cost structure and improve efficiency, resulting in workforce reductions and the consolidation of certain real estate facilities. We expect such activities to be substantially completed by December 31, 2014.
	Restructuring costs totaled $2.8 million for the three and nine months ended September 30, 2014, respectively.
	The following table sets forth a summary of restructuring activities during the nine months ended September 30, 2014 (in thousands):
		Severance and related costs			Facilities costs			Total costs
	Balance, December 31, 2013	$	—		$	—		$	—
	Provision for restructuring charges	1,509			376			1,885
	Cash payments	(1,206		)	(78		)	(1,284		)
	Balance, September 30, 2014	$	303		$	298		$	601
	The provision for restructuring charges shown above excludes $0.9 million of non-cash fixed asset write-offs.
	The remaining restructuring balance of $0.6 million at September 30, 2014 consists of $0.3 million for employee severance expenses, which the Company expects to pay out by December 31, 2014, and $0.3 million related to non-cancelable lease costs, which the Company expects to pay over the terms of the related obligations through the third quarter of 2017, less estimated sublease income.

Deferred_Revenue_Notes

Deferred Revenue (Notes)	9 Months Ended
	Sep. 30, 2014
Revenue Recognition [Abstract]	'
Deferred Revenue	'
	Deferred Revenue
	Deferred revenue consisted of the following as of the dates below (in thousands):
		As of September 30, 2014		As of December 31, 2013
	Product, current	$	9,914	$	13,823
	Subscription and services, current	150,854		96,712
	Total deferred revenue, current	160,768		110,535
	Product, non-current	6,077		6,711
	Subscription and services, non-current	116,076		70,268
	Total deferred revenue, non-current	122,153		76,979
	Total deferred revenue	$	282,921	$	187,514

Credit_Facility_Notes

Credit Facility (Notes)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Credit Facility	'
	Credit Facility
	We are able to borrow up to $25.0 million under a revolving line of credit facility. There were no amounts borrowed during the nine months ended September 30, 2014. The maturity date for the revolving line of credit facility is December 31, 2014. Borrowings under the line of credit are collateralized by all of our assets, excluding intellectual property. As of September 30, 2014 and December 31, 2013, there were no amounts outstanding under the revolving line of credit.

Commitments_and_Contingencies_

Commitments and Contingencies (Notes)	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Leases
	We lease our facilities under various non-cancelable operating leases, which expire through the year ending May 2025. Rent expense is recognized using the straight-line method over the term of the lease. Rent expense was $2.7 million and $1.0 million for the three months ended September 30, 2014 and 2013, respectively. Rent expense was $8.0 million and $2.5 million for the nine months ended September 30, 2014 and 2013, respectively.
	The aggregate future non-cancelable minimum rental payments on our operating leases as of September 30, 2014 is presented below (in thousands):
	Years Ending December 31,	Amount
	2014 (remaining three months)	$	2,745
	2015	9,461
	2016	7,425
	2017	6,379
	2018	3,537
	2019 and thereafter	12,608
	Total	$	42,155
	We are party to letters of credit totaling $1.5 million and $0.9 million as of September 30, 2014 and December 31, 2013 issued primarily in support of operating leases at several of our facilities. These letters of credit are collateralized by a line with our bank. No amounts have been drawn against these letters of credit.
	Contract Manufacturer Commitments
	Our independent contract manufacturers procure components and assemble our products based on our forecasts. These forecasts are based on estimates of future demand for our products, which are in turn based on historical trends and an analysis from our sales and product marketing organizations, adjusted for overall market conditions. In order to reduce manufacturing lead times and plan for adequate supply, we may issue forecasts and orders for components and products that are non-cancelable. As of September 30, 2014 and December 31, 2013, we had non-cancellable open orders of $27.0 million and $16.7 million, respectively. We are required to record a liability for firm, noncancelable, and unconditional purchase commitments with contract manufacturers and suppliers for quantities in excess of our future demand forecasts. To date we have not been required to accrue any costs for such noncancelable commitments.
	Purchase Obligations
	As of September 30, 2014, we had approximately $9.1 million of non-cancellable firm purchase commitments primarily for purchases of software and services.
	Litigation
	We accrue for contingencies when we believe that a loss is probable and that we can reasonably estimate the amount of any such loss. We have made an assessment of the probability of incurring any such losses and whether or not those losses are estimable.
	On June 20, 2014, a purported stockholder class action lawsuit was filed in the Superior Court of California, County of Santa Clara, against the Company, the members of our Board of Directors, our Chief Financial Officer, and the underwriters of our March 2014 follow-on public offering.  On July 17, 2014, a substantially similar lawsuit was filed in the same court against the same defendants. The complaints allege violations of the federal securities laws on behalf of a purported class consisting of purchasers of the Company's common stock pursuant or traceable to the registration statement and prospectus for the follow-on public offering, and seek unspecified compensatory damages and other relief.  The Company intends to defend the litigation vigorously.  Based on information currently available, the Company has determined that the amount of any possible loss or range of possible loss is not reasonably estimable.
	We are also subject to legal proceedings, claims and litigation, including intellectual property litigation, arising in the ordinary course of business. Such matters are subject to many uncertainties and outcomes and are not predictable with assurance.
	To the extent there is a reasonable possibility that a loss exceeding amounts already recognized may be incurred and the amount of such additional loss would be material, we will either disclose the estimated additional loss or state that such an estimate cannot be made. We do not currently believe that it is reasonably possible that additional losses in connection with litigation arising in the ordinary course of business would be material.
	Indemnification
	Under the indemnification provisions of our standard sales related contracts, we agree to defend our customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments entered on such claims. Our exposure under these indemnification provisions is generally limited to the total amount paid by our customer under the agreement. However, certain agreements include indemnification provisions that could potentially expose us to losses in excess of the amount received under the agreement. In addition, we indemnify our officers, directors, and certain key employees for actions taken while they are or were serving in good faith in such capacities. Through September 30, 2014, there have been no claims under any indemnification provisions.

Common_Shares_Reserved_for_Iss

Common Shares Reserved for Issuance (Notes)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Common Shares Reserved for Issuance	'
	Common Shares Reserved for Issuance
	Under our amended and restated certificate of incorporation, we are authorized to issue 1,000,000,000 shares of common stock with a par value of $0.0001 per share as of September 30, 2014 and December 31, 2013. Each share of common stock outstanding is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the Board of Directors, subject to the prior rights of holders of all classes of convertible preferred stock outstanding. There were no shares of convertible preferred stock outstanding as of September 30, 2014 or December 31, 2013.
	As of September 30, 2014 and December 31, 2013, we had reserved shares of common stock for issuance as follows (in thousands):
		As of September 30,	As of December 31,
		2014	2013
	Reserved under stock award plans	41,171	40,226
	Warrants to purchase common stock	—	312
	ESPP	3,273	2,500
	Total	44,444	43,038

Equity_Award_Plans_Notes

Equity Award Plans (Notes)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Equity Award Plans	'
	Equity Award Plans
	We have operated under our 2013 Equity Incentive Plan ("2013 Plan") since our initial public offering ("IPO") in September 2013. Our 2013 Plan provides for the issuance of restricted stock and the granting of options, stock appreciation rights, performance shares, performance units and restricted stock units to our employees, officers, directors, and consultants. Awards granted under the 2013 Plan vest over the periods determined by the Board of Directors or compensation committee of the Board of Directors, generally four years, and stock options granted under the 2013 Plan expire no more than ten years after the date of grant. In the case of an incentive stock option granted to an employee who at the time of grant owns stock representing more than 10% of the total combined voting power of all classes of stock, the exercise price shall be no less than 110% of the fair value per share on the date of grant, and the award shall expire five years from the date of grant. For options granted to any other employee, the per share exercise price shall be no less than 100% of the fair value per share on the date of grant. In the case of non-statutory stock options and options granted to consultants, the per share exercise price shall be no less than 100% of the fair value per share on the date of grant. Approximately 13.8 million shares of our common stock was reserved for future grants as of September 30, 2014 under the 2013 Plan.
	Our 2013 Employee Stock Purchase Plan ("ESPP") allows eligible employees to acquire shares of our common stock at 85% of the lower of the fair market value of our common stock on the first trading day of each offering period or on the exercise date. Our ESPP provides for annual increases in the number of shares available for issuance on the first day of each fiscal year. As of September 30, 2014, an aggregate of 3,272,660 shares of common stock were available for future issuance under our ESPP, including 1,377,575 shares of common stock that became available under the ESPP on January 1, 2014 pursuant to the provisions of the ESPP that automatically increase the share reserve under such plan each year.
	From time to time, we also grant restricted common stock or restricted stock awards outside of our equity incentive plans to certain employees in connection with acquisitions.
	Stock Option Activity
	A summary of the activity for our stock option changes during the reporting periods and a summary of information related to options exercisable, vested, and expected to vest are presented below (in thousands, except per share amounts):
		Options Outstanding
		Number of			Weighted-				Weighted-Average Grant Date Fair Value Per Share				Weighted-		Aggregate
		Shares			Average								Average		Intrinsic Value
					Exercise Price								Contractual
													Life (years)
	Balance— December 31, 2013	27,422			$	5.82							8.3		$	1,036,224
	Granted	676			72.6				$	72.6
	Exercised	(5,468	)		2.9										210,389
	Cancelled	(1,369	)		8.88
	Assumed in acquisition	63			20.6
	Balance— September 30, 2014	21,324			$	8.53							7.55		$	499,899
	Options vested and expected to vest—September 30, 2014	20,761			$	8.4							7.52		$	488,605
	Options exercisable—September 30, 2014	9,261			$	4.07							6.55		$	245,347
	Restricted Stock Award ("RSA") and Restricted Stock Unit ("RSU") Activity
	A summary of restricted stock awards and restricted stock units are presented below (in thousands, except per share amounts):
		Number of Shares			Weighted-Average Grant Date Fair Value Per Share				Weighted-		Aggregate
									Average		Intrinsic Value
									Contractual
									Life (years)
	Unvested balance— December 31, 2013	3,602							1.7		$	157,108
	Granted	5,741			$	43.84
	Vested	(779	)
	Cancelled/forfeited	(523	)
	Unvested balance —September 30, 2014	8,041							1.77		245,722
	Expected to vest—September 30, 2014	7,476							1.77		$	228,465
	We issued into escrow 241,362 restricted stock awards, with an estimated fair value of $6.4 million, for certain employees from the nPulse acquisition. These awards will be released from escrow to such employees if specified performance milestones are met within approximately three and a half years from May 2014, the acquisition date. These awards are also contingent upon the related employees’ continuous employment with us, and we have determined that it is probable that such performance milestones will be met. As such, compensation expense is being recorded over the requisite service period of three and half years. These restricted stock awards are reflected within amounts granted in the table above.
	Stock-Based Compensation
	We record stock-based compensation based on the fair value of stock options on grant date using the Black-Scholes option-pricing model. We determine the fair value of shares of common stock to be issued under the ESPP using the Black-Scholes option-pricing model. The fair value of restricted stock units and restricted stock awards equals the market value of the underlying stock on the date of grant. We granted performance-based restricted stock units and restricted stock awards to certain employees which vest upon the achievement of certain performance conditions, subject to the employees’ continued service relationship with us. We assess the probability of vesting at each reporting period and adjust our compensation cost based on the probability assessment. We recognize such compensation expense on a straight-line basis over the service provider’s requisite service period.
	The following table summarizes the assumptions used in the Black-Scholes option-pricing model to determine fair value of our stock options:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2014		2013		2014		2013
	Fair value of common stock	$29.79		$12.90 - $20		$27.89-$75.87		$6.05-$20.00
	Risk-free interest rate	1.77%		1.6% - 2.1%		1.77%-1.96%		0.6% - 2.1%
	Expected term (in years)	6		6-May		6		6-Apr
	Volatility	51%		49% - 54%		51%-53%		49% - 54%
	Dividend yield	—%		—%		—%		—%
	The following table summarizes the assumptions used in the Black-Scholes option-pricing model to determine fair value of our common shares to be issued under the ESPP:
		Nine Months Ended September 30,
		2014		2013
	Fair value of common stock	$23.02		$20.00
	Risk-free interest rate	0.05% - 0.09%		0.10%
	Expected term (in years)	0.5 - 1.0		0.7 - 1.2
	Volatility	45%		42% - 45%
	Dividend yield	—%		—%
	Stock-based compensation expense is included in costs and expenses as follows (in thousands):
		Three Months Ended September 30,								Nine Months Ended
										September 30,
		2014				2013				2014				2013
	Cost of product revenue	$	243			$	143			$	624			$	279
	Cost of subscription and services revenue	3,430				762				10,455				1,330
	Research and development	7,648				2,350				20,054				4,425
	Sales and marketing	22,543				3,784				47,154				5,878
	General and administrative	9,296				1,775				28,320				4,432
	Total	$	43,160			$	8,814			$	106,607			$	16,344
	As of September 30, 2014, total compensation cost related to stock-based awards not yet recognized was $325.0 million, net of estimated forfeitures, which is expected to be amortized on a straight-line basis over the weighted-average remaining vesting period of approximately three years.

Income_Taxes_Notes

Income Taxes (Notes)	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	We account for income taxes under the asset and liability method. Under this method, deferred income tax assets and liabilities are determined based upon the difference between the financial statement carrying amounts and the tax basis of assets and liabilities and are measured using the enacted tax rate expected to apply to taxable income in the years in which the differences are expected to be reversed.
	Our benefit for income taxes for the three months ended September 30, 2014 and 2013 reflects an effective tax rate of 7.92% and 1.77%, respectively. Our benefit for income taxes for the nine months ended September 30, 2014 and 2013 reflects an effective tax rate of 7.32% and 0.27%, respectively. The tax benefit for the three and nine month periods ended September 30, 2014 is primarily due to an increase in U.S. deferred tax assets primarily related to current year operating losses and stock-based compensation for which no U.S. valuation allowance is required. The valuation allowance is not required to the extent that deferred tax liabilities on acquisition-related intangibles are available as a source of income for the U.S. deferred tax assets. The tax benefit was also partially due to the reduction in U.S. deferred tax liabilities previously established in purchase accounting, partially offset by foreign and state income tax expense. The tax benefit for the three and nine months ended September 30, 2013 is primarily due to a reduction of the U.S. valuation allowance resulting from recording a deferred tax liability on the acquisition-related intangibles for which no tax benefit will be derived, partially offset by foreign and state income tax expense.

Net_Loss_Per_Share_Notes

Net Loss Per Share (Notes)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Net Loss per Share	'
	Net Loss per Share
	Basic loss per share is calculated by dividing net loss by the weighted average number of common shares outstanding during the period, less shares subject to repurchase, and excludes any dilutive effects of employee share based awards and warrants. Diluted net income per common share is computed giving effect to all potential dilutive common shares, including common stock issuable upon exercise of stock options, and unvested restricted common stock and stock units. As we had net losses for the three and nine months ended September 30, 2014 and 2013, all potential common shares were determined to be anti-dilutive.
	The following table sets forth the computation of net loss per common share (in thousands, except per share amounts):
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014				2013			2014			2013
	Numerator:
	Net loss	$	(120,031	)		$	(50,926	)	$	(338,064	)	$	(118,122	)
	Denominator:
	Weighted average number of shares outstanding—basic and diluted	144,923				31,590			140,285			21,838
	Net loss per share—basic and diluted	$	(0.83	)		$	(1.61	)	$	(2.41	)	$	(5.41	)
	The following outstanding options, unvested shares, warrants, and convertible preferred stock were excluded (as common stock equivalents) from the computation of diluted net loss per common share for the periods presented as their effect would have been antidilutive (in thousands):
		As of September 30,
		2014			2013
	Options to purchase common stock	21,324			22,707
	Unvested early exercised common shares	2,676			5,240
	Unvested restricted stock awards and units	8,041			2,140
	Warrants to purchase common stock	—			616
	ESPP shares	406			—

Employee_Benefit_Plan_Notes

Employee Benefit Plan (Notes)	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefit Plan	'
	Employee Benefit Plan
	401(k) Plan
	We have established a 401(k) tax-deferred savings plan (the “401(k) Plan”) which permits participants to make contributions by salary deduction pursuant to Section 401(k) of the Internal Revenue Code of 1986, as amended. We maintain the 401(k) Plan that provides our eligible employees other than Mandiant employees with an opportunity to save for retirement on a tax-advantaged basis. In addition, we maintain a tax qualified plan for employees of the Mandiant subsidiary that was assumed in the Mandiant acquisition. All participants’ interests in their deferrals are 100% vested when contributed under both 401(k) plans. We have made no matching contributions into our 401(k) plan since inception. The Mandiant 401(k) plan provides for a match of 100% of the first 4% of an eligible employee’s compensation contributed. Matching contributions under the Mandiant 401(k) plan are 100% vested when made. Under both 401(k) plans, pre-tax contributions are allocated to each participant’s individual account and are then invested in selected investment alternatives according to the participants’ directions. Each 401(k) plan is intended to qualify under Sections 401(a) and 501(a) of the Code. As a tax-qualified retirement plan, contributions to each 401(k) plan and earnings on those contributions are not taxable to the employees until distributed from the 401(k) plan, and all contributions are deductible by us when made. Our contributions to the Mandiant 401(k) plan were $0.7 million and $2.1 million for the three and nine months ended September 30, 2014, respectively.

Segment_Information_Notes

Segment Information (Notes)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	Segment Information
	We conduct business globally and are primarily managed on a geographic basis. Our chief executive officer, who is our chief operating decision maker, reviews financial information presented on a consolidated basis accompanied by information about revenue by geographic region for purposes of allocating resources and evaluating financial performance. We have one business activity, and there are no segment managers who are held accountable for operations, operating results, and plans for levels, components, or types of products or services below the consolidated unit level. Accordingly, we are considered to be in a single reportable segment and operating unit structure.
	Revenue by geographic region based on the billing address is as follows (in thousands):
		Three Months Ended September 30,				Nine Months Ended
						September 30,
		2014		2013		2014		2013
	Revenue:
	United States	$	86,628	$	30,435	$	211,992	$	75,793
	EMEA	15,017		6,292		38,940		14,706
	APAC	9,502		4,491		22,450		10,315
	Other	3,064		1,434		9,298		3,476
	Total revenue	$	114,211	$	42,652	$	282,680	$	104,290
	For the three and nine months ended September 30, 2014, we had one customer, Carahsoft Technology Corporation, which accounted for 13% and 12% of our revenue, respectively. For the three months ended September 30, 2013, we had two customers, Carahsoft Technology Corporation and Accuvant, which accounted for 16% and 10% of our revenue, respectively, while no customers accounted for more than 10% of our revenue for the nine months ended September 30, 2013. Carahsoft Technology Corporation also accounted for 13% of our accounts receivable as of September 30, 2014.
	Substantially all of our assets were attributable to operations in the United States as of September 30, 2014 and December 31, 2013.

Description_of_Business_and_Su1

Description of Business and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Presentation and Consolidation	'
	Basis of Presentation and Consolidation
	The accompanying unaudited condensed consolidated financial statements include the accounts of FireEye, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP"), and following the requirements of the Securities and Exchange Commission ("SEC"), for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, that are necessary for a fair statement of our financial information. The results of operations for the three and nine months ended September 30, 2014 are not necessarily indicative of the results to be expected for the year ending December 31, 2014 or for any other interim period or for any other future year. The balance sheet as of December 31, 2013 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for annual consolidated financial statements.
	The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2013 included in our Annual Report on Form 10-K, which was filed with the SEC on March 3, 2014.
Use of Estimates	'
	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Such management estimates include, but are not limited to, the best estimate of selling price for our products and services, commissions expense, future taxable income, contract manufacturer liabilities, litigation and settlement costs and other loss contingencies, fair value of our common and preferred stock, stock options and preferred stock warrant liability, and the purchase price allocation of acquired businesses. We base our estimates on historical experience and also on assumptions that we believe are reasonable. Changes in facts or circumstances may cause us to change our assumptions and estimates in future periods, and it is possible that actual results could differ from current or revised future estimates.
Short-term Investments	'
	Short-term Investments
	We classify our investments in debt and equity securities as available-for-sale and record these investments at fair value. Investments with an original maturity of three months or less at the date of purchase are considered cash equivalents, while all other investments are classified as short-term or long-term based on the nature of the investments, their maturities, and their availability for use in current operations. Unrealized gains and losses are reported as a component of other comprehensive loss. Realized gains and losses are determined based on the specific identification method, and are reflected in earnings. We regularly review our investment portfolio to identify and evaluate investments that have indicators of possible impairment. Factors considered in determining whether a loss is other-than-temporary include, but are not limited to: the length of time and extent a security’s fair value has been below its cost, the financial condition and near-term prospects of the investee, the credit quality of the security’s issuer, likelihood of recovery and our intent and ability to hold the security for a period of time sufficient to allow for any anticipated recovery in value. For our debt instruments, we also evaluate whether we have the intent to sell the security or it is more likely than not that we will be required to sell the security before recovery of its cost basis.
	Investments are considered to be impaired when a decline in fair value is judged to be other-than-temporary. Fair value is calculated based on publicly available market information or other estimates determined by management. If the cost of an investment exceeds its fair value, we evaluate, among other factors, general market conditions, credit quality of debt instrument issuers, the duration and extent to which the fair value is less than cost, and whether we have plans to sell the security, or it is more likely than not that we will be required to sell the security, before recovery. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to other income (expense) and a new cost basis in the investment is established.
Revenue Recognition	'
	Revenue Recognition
	We generate revenue from the sales of products, subscriptions and support and maintenance, and professional services through our indirect relationships with our partners as well as end-customers through our direct sales force. Our products include operating system software that is integrated into the appliance hardware and is deemed essential to its functionality. As a result, we account for revenue in accordance with Accounting Standards Codification 605, Revenue Recognition, and all related interpretations as all of our security appliance deliverables include proprietary operating system software, which together deliver the essential functionality of our products. Our professional services consist primarily of time and materials based contracts, and the revenue is recognized as costs are incurred at amounts represented by the agreed-upon billing amounts. Revenue from fixed-price professional services engagements are recognized under the proportional performance method of accounting.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). This standard provides a single model for revenue arising from contracts with customers and supersedes current revenue recognition guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance is effective for us beginning in the first quarter of 2017. Early adoption is not permitted. The guidance permits companies to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. We are currently evaluating the impact the adoption will have on our consolidated financial statements and related disclosures.
	In August 2014, the FASB issued ASU 2014-15, Disclosures of Uncertainties About an Entity’s Ability to Continue as a Going Concern. This standard provides guidance on how and when reporting entities must disclose going-concern uncertainties in their financial statements. The guidance is effective for us beginning in the first quarter of 2017. Early adoption is permitted.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Fair Value of Assets and Liabilities	'
	The following table presents our assets measured at fair value on a recurring basis using the above input categories (in thousands):
		As of September 30, 2014								As of December 31, 2013
	Description	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
	Assets
	Cash equivalents:
	Money market funds	$	20,311	$	—	$	—	$	20,311	$	132,518	$	—	$	—	$	132,518
	Total cash equivalents	$	20,311	$	—	$	—	$	20,311	$	132,518	$	—	$	—	$	132,518
	Short-term investments:
	Certificates of deposit	—		4,751		—		4,751		—		—		—		—
	Commercial paper	—		2,750		—		2,750		—		—		—		—
	Corporate notes and bonds	—		148,424		—		148,424		—		—		—		—
	U.S. Government agencies	—		143,097		—		143,097		—		—		—		—
	Total short-term investments	$	—	$	299,022	$	—	$	299,022	$	—	$	—	$	—	$	—
	Total assets measured at fair value	$	20,311	$	299,022	$	—	$	319,333	$	132,518	$	—	$	—	$	132,518

ShortTerm_Investments_Tables

Short-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Summary of Available-for-sale Securities	'
	Our investments consisted of the following as of September 30, 2014 (in thousands):
		Available-for-Sale Securities
		Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses			Estimated Fair Value		Short-term investment
	Certificates of deposit	$	4,760	—			$	(9	)	$	4,751	$	4,751
	Commercial paper	2,750		—			—			2,750		2,750
	Corporate notes and bonds	148,571		12			(159		)	148,424		148,424
	U.S. Government agencies	143,267		1			(171		)	143,097		143,097
	Total	$	299,348	$	13		$	(339	)	$	299,022	$	299,022
Summary of Unrealized Losses on Investments	'
	The following table presents our investments that had gross unrealized losses, the duration of which was less than twelve months, as of September 30, 2014 (in thousands):
		Total
		Estimated Fair Value		Unrealized Loss
	Certificates of deposit	$	4,511	$	(9	)
	Corporate notes and bonds	117,993		(159		)
	U.S. Government agencies	119,075		(171		)
	Total	$	241,579	$	(339	)
Summary of Contractual Maturities	'
	The following table summarizes the contractual maturities of our investments at September 30, 2014 (in thousands):
		Amortized Cost		Fair Value
	Due within one year	$	160,789	$	160,767
	Due within one to two years	138,559		138,255
	Total	$	299,348	$	299,022

Property_and_Equipment_Tables

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Schedule of Property and Equipment	'
	Property and equipment, net consisted of the following as of the dates below (in thousands):
		As of September 30,			As of December 31,
		2014			2013
	Computer equipment and software	$	77,309		$	57,403
	Leasehold improvements	33,150			15,660
	Furniture and fixtures	11,995			6,035
	Machinery and equipment	447			756
	Total property and equipment	122,901			79,854
	Less: accumulated depreciation	(38,806		)	(15,089		)
	Total property and equipment, net	$	84,095		$	64,765

Business_Combinations_Tables

Business Combinations (Tables)	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Schedule of Purchase Price	'
	The following is the total preliminary purchase price allocation of the estimated purchase consideration based on the available information as of September 30, 2014 (in thousands):
		Amount
	Net tangible assets	$	10,797
	Intangible assets	276,200
	Deferred tax liability	(91,098		)
	Goodwill	704,891
	Total preliminary purchase price allocation	$	900,790
	Total allocation of the preliminary purchase price allocation is as follows (in thousands):
		Amount
	Net tangible liabilities assumed	$	(1,833	)
	Intangible assets	24,700
	Deferred tax asset	442
	Deferred tax liability	(8,368		)
	Goodwill	41,671
	Total preliminary purchase price allocation	$	56,612
Schedule of Preliminary Acquired Intangible Assets	'
	The preliminary estimated useful life and fair values of the identifiable intangible assets as of September 30, 2014 are as follows (in thousands):
		Preliminary Estimated Useful Life (in years)		Amount
	Developed technology	6-Apr		$	54,600
	In-process research and development	N/A		1,400
	Content	10		128,600
	Customer relationships	8		65,400
	Contract backlog	3-Jan		13,800
	Trade names	4		12,400
	Total			$	276,200
	The preliminary estimated useful life and fair values of the identifiable intangible assets are as follows (in thousands):
		Preliminary Estimated Useful Life (in years)		Amount
	Developed technology	6		$	10,100
	Customer relationships	8		8,000
	In-process research and development	N/A		6,600
	Total			$	24,700
Schedule of Goodwill	'
	The changes in the carrying amount of goodwill for the nine months ended September 30, 2014 are as follows (in thousands):
		Amount
	Balance as of December 31, 2013	$	706,327
	Acquisitions and adjustments	43,948
	Balance as of September 30, 2014	$	750,275
Schedule of Purchased Intangible Assets	'
	Purchased intangible assets consisted of the following as of the dates below (in thousands):
		As of September 30, 2014				As of December 31, 2013
	Developed technology	$	70,393			$	60,093
	Content	128,600				128,500
	Customer relationships	75,300				67,900
	Contract backlog	13,800				12,600
	Trade names	12,400				12,400
	Total intangible assets subject to amortization	300,493				281,493
	Less: accumulated amortization	(34,979		)		(1,516		)
	Net intangible assets subject to amortization	265,514				279,977
	In-process research and development	7,800				1,400
	Total net intangible assets	$	273,314			$	281,377
Schedule of Expected Future Amortization Expense	'
	The expected annual amortization expense of intangible assets as of September 30, 2014 is presented below (in thousands):
	Years Ending December 31,	Intangible Assets
	2014 (remaining three months)	$	11,478
	2015	45,114
	2016	44,498
	2017	38,553
	2018	27,608
	2019 and thereafter	98,263
	Total intangible assets subject to amortization	265,514
	Total intangible assets with indefinite lives	7,800
	Total	$	273,314

Restructuring_Charges_Tables

Restructuring Charges (Tables)	9 Months Ended
	Sep. 30, 2014
Restructuring and Related Activities [Abstract]	'
Summary of Restructuring Activities	'
	The following table sets forth a summary of restructuring activities during the nine months ended September 30, 2014 (in thousands):
		Severance and related costs			Facilities costs			Total costs
	Balance, December 31, 2013	$	—		$	—		$	—
	Provision for restructuring charges	1,509			376			1,885
	Cash payments	(1,206		)	(78		)	(1,284		)
	Balance, September 30, 2014	$	303		$	298		$	601

Deferred_Revenue_Tables

Deferred Revenue (Tables)	9 Months Ended
	Sep. 30, 2014
Revenue Recognition [Abstract]	'
Schedule of Deferred Revenue	'
	Deferred revenue consisted of the following as of the dates below (in thousands):
		As of September 30, 2014		As of December 31, 2013
	Product, current	$	9,914	$	13,823
	Subscription and services, current	150,854		96,712
	Total deferred revenue, current	160,768		110,535
	Product, non-current	6,077		6,711
	Subscription and services, non-current	116,076		70,268
	Total deferred revenue, non-current	122,153		76,979
	Total deferred revenue	$	282,921	$	187,514

Commitments_and_Contingencies_1

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases	'
	The aggregate future non-cancelable minimum rental payments on our operating leases as of September 30, 2014 is presented below (in thousands):
	Years Ending December 31,	Amount
	2014 (remaining three months)	$	2,745
	2015	9,461
	2016	7,425
	2017	6,379
	2018	3,537
	2019 and thereafter	12,608
	Total	$	42,155

Common_Shares_Reserved_for_Iss1

Common Shares Reserved for Issuance (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Schedule of Stock by Class	'
	As of September 30, 2014 and December 31, 2013, we had reserved shares of common stock for issuance as follows (in thousands):
		As of September 30,	As of December 31,
		2014	2013
	Reserved under stock award plans	41,171	40,226
	Warrants to purchase common stock	—	312
	ESPP	3,273	2,500
	Total	44,444	43,038

Equity_Award_Plans_Tables

Equity Award Plans (Tables)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Activity For Options Outstanding	'
	A summary of the activity for our stock option changes during the reporting periods and a summary of information related to options exercisable, vested, and expected to vest are presented below (in thousands, except per share amounts):
		Options Outstanding
		Number of			Weighted-				Weighted-Average Grant Date Fair Value Per Share				Weighted-		Aggregate
		Shares			Average								Average		Intrinsic Value
					Exercise Price								Contractual
													Life (years)
	Balance— December 31, 2013	27,422			$	5.82							8.3		$	1,036,224
	Granted	676			72.6				$	72.6
	Exercised	(5,468	)		2.9										210,389
	Cancelled	(1,369	)		8.88
	Assumed in acquisition	63			20.6
	Balance— September 30, 2014	21,324			$	8.53							7.55		$	499,899
	Options vested and expected to vest—September 30, 2014	20,761			$	8.4							7.52		$	488,605
	Options exercisable—September 30, 2014	9,261			$	4.07							6.55		$	245,347
Schedule of Activity for Restricted Stock	'
	A summary of restricted stock awards and restricted stock units are presented below (in thousands, except per share amounts):
		Number of Shares			Weighted-Average Grant Date Fair Value Per Share				Weighted-		Aggregate
									Average		Intrinsic Value
									Contractual
									Life (years)
	Unvested balance— December 31, 2013	3,602							1.7		$	157,108
	Granted	5,741			$	43.84
	Vested	(779	)
	Cancelled/forfeited	(523	)
	Unvested balance —September 30, 2014	8,041							1.77		245,722
	Expected to vest—September 30, 2014	7,476							1.77		$	228,465
Schedule of Fair Value Assumptions Used for Stock Options	'
	The following table summarizes the assumptions used in the Black-Scholes option-pricing model to determine fair value of our stock options:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2014		2013		2014		2013
	Fair value of common stock	$29.79		$12.90 - $20		$27.89-$75.87		$6.05-$20.00
	Risk-free interest rate	1.77%		1.6% - 2.1%		1.77%-1.96%		0.6% - 2.1%
	Expected term (in years)	6		6-May		6		6-Apr
	Volatility	51%		49% - 54%		51%-53%		49% - 54%
	Dividend yield	—%		—%		—%		—%
Schedule of Fair Value Assumptions Used for ESPP	'
	The following table summarizes the assumptions used in the Black-Scholes option-pricing model to determine fair value of our common shares to be issued under the ESPP:
		Nine Months Ended September 30,
		2014		2013
	Fair value of common stock	$23.02		$20.00
	Risk-free interest rate	0.05% - 0.09%		0.10%
	Expected term (in years)	0.5 - 1.0		0.7 - 1.2
	Volatility	45%		42% - 45%
	Dividend yield	—%		—%
Schedule of Share-based Compensation Expense	'
	Stock-based compensation expense is included in costs and expenses as follows (in thousands):
		Three Months Ended September 30,								Nine Months Ended
										September 30,
		2014				2013				2014				2013
	Cost of product revenue	$	243			$	143			$	624			$	279
	Cost of subscription and services revenue	3,430				762				10,455				1,330
	Research and development	7,648				2,350				20,054				4,425
	Sales and marketing	22,543				3,784				47,154				5,878
	General and administrative	9,296				1,775				28,320				4,432
	Total	$	43,160			$	8,814			$	106,607			$	16,344

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of Net Loss per Common Share, Basic and Diluted	'
	The following table sets forth the computation of net loss per common share (in thousands, except per share amounts):
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014				2013			2014			2013
	Numerator:
	Net loss	$	(120,031	)		$	(50,926	)	$	(338,064	)	$	(118,122	)
	Denominator:
	Weighted average number of shares outstanding—basic and diluted	144,923				31,590			140,285			21,838
	Net loss per share—basic and diluted	$	(0.83	)		$	(1.61	)	$	(2.41	)	$	(5.41	)
Schedule of Antidilutive Securities Excluded from Net Loss per Share Computation	'
	The following outstanding options, unvested shares, warrants, and convertible preferred stock were excluded (as common stock equivalents) from the computation of diluted net loss per common share for the periods presented as their effect would have been antidilutive (in thousands):
		As of September 30,
		2014			2013
	Options to purchase common stock	21,324			22,707
	Unvested early exercised common shares	2,676			5,240
	Unvested restricted stock awards and units	8,041			2,140
	Warrants to purchase common stock	—			616
	ESPP shares	406			—

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Schedule of Revenue by Geographic Region	'
	Revenue by geographic region based on the billing address is as follows (in thousands):
		Three Months Ended September 30,				Nine Months Ended
						September 30,
		2014		2013		2014		2013
	Revenue:
	United States	$	86,628	$	30,435	$	211,992	$	75,793
	EMEA	15,017		6,292		38,940		14,706
	APAC	9,502		4,491		22,450		10,315
	Other	3,064		1,434		9,298		3,476
	Total revenue	$	114,211	$	42,652	$	282,680	$	104,290

Description_of_Business_and_Su2

Description of Business and Summary of Significant Accounting Policies - Narrative (Details) (USD $)	1 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'	'
Common stock sold (shares)	5,582,215	'
Price per share (usd per share)	$82	'
Proceeds from initial public offering, net of underwriting discounts	$446.50	'
Underwriters discounts and commissions	11.2	'
Offering expenses	$2.20	'
Common stock sold from certain selling stockholders (shares)	8,417,785	'
Options exercised (shares)	796,846	5,468,000

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	$299,022	'
Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	4,751	'
Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	2,750	'
Corporate notes and bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	148,424	'
U.S. Government agencies [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	143,097	'
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	20,311	132,518
Short-term investment	0	0
Total assets measured at fair value	20,311	132,518
Level 1 [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 1 [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 1 [Member] | Corporate notes and bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 1 [Member] | U.S. Government agencies [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 1 [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	20,311	132,518
Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	0	0
Short-term investment	299,022	0
Total assets measured at fair value	299,022	0
Level 2 [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	4,751	0
Level 2 [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	2,750	0
Level 2 [Member] | Corporate notes and bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	148,424	0
Level 2 [Member] | U.S. Government agencies [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	143,097	0
Level 2 [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	0	0
Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	0	0
Short-term investment	0	0
Total assets measured at fair value	0	0
Level 3 [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 3 [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 3 [Member] | Corporate notes and bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 3 [Member] | U.S. Government agencies [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	0	0
Level 3 [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	0	0
Fair Value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	20,311	132,518
Short-term investment	299,022	0
Total assets measured at fair value	319,333	132,518
Fair Value [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	4,751	0
Fair Value [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	2,750	0
Fair Value [Member] | Corporate notes and bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	148,424	0
Fair Value [Member] | U.S. Government agencies [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investment	143,097	0
Fair Value [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and Cash Equivalents	$20,311	$132,518

ShortTerm_Investments_Summary_

Short-Term Investments - Summary of Available-for-sale Securities (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'
Amortized Cost	$299,348
Gross Unrealized Gains	13
Gross Unrealized Losses	-339
Estimated Fair Value	299,022
Short-term investment	299,022
Certificates of deposit [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Amortized Cost	4,760
Gross Unrealized Gains	0
Gross Unrealized Losses	-9
Estimated Fair Value	4,751
Short-term investment	4,751
Commercial paper [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Amortized Cost	2,750
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Value	2,750
Short-term investment	2,750
Corporate notes and bonds [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Amortized Cost	148,571
Gross Unrealized Gains	12
Gross Unrealized Losses	-159
Estimated Fair Value	148,424
Short-term investment	148,424
U.S. Government agencies [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Amortized Cost	143,267
Gross Unrealized Gains	1
Gross Unrealized Losses	-171
Estimated Fair Value	143,097
Short-term investment	$143,097

ShortTerm_Investments_Summary_1

Short-Term Investments - Summary of Unrealized Losses on Investments (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'
Estimated Fair Value	$241,579
Unrealized Loss	-339
Certificates of deposit [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Estimated Fair Value	4,511
Unrealized Loss	-9
Corporate notes and bonds [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Estimated Fair Value	117,993
Unrealized Loss	-159
U.S. Government agencies [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Estimated Fair Value	119,075
Unrealized Loss	($171)

ShortTerm_Investments_Summary_2

Short-Term Investments - Summary of Contractual Maturities (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'
Due within one year, amortized cost	$160,789
Due within one to two years, amortized cost	138,559
Total, amortized cost	299,348
Due within one year, fair value	160,767
Due within one to two years, fair value	138,255
Total, fair value	$299,022

ShortTerm_Investments_Narrativ

Short-Term Investments - Narrative (Details) (USD $)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Unrealized losses greater than twelve months	$0
Other than temporary impairment	$0

Property_and_Equipment_Schedul

Property and Equipment - Schedule of Property and Equipment (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Total property and equipment	$122,901	$79,854
Less: accumulated depreciation	-38,806	-15,089
Total property and equipment, net	84,095	64,765
Computer equipment and Software [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total property and equipment	77,309	57,403
Leasehold improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total property and equipment	33,150	15,660
Furniture and fixtures [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total property and equipment	11,995	6,035
Machinery and equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total property and equipment	$447	$756

Property_and_Equipment_Narrati

Property and Equipment - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'	'	'	'
Depreciation and amortization	$12.70	$4.90	$32.60	$11.50

Business_Combinations_Schedule

Business Combinations - Schedule of Purchase Price (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	9-May-14	Sep. 30, 2014
In Thousands, unless otherwise specified			nPulse Technologies [Member]	Mandiant, Inc. [Member]
Business Acquisition [Line Items]	'	'	'	'
Net tangible assets (liabilities) assumed	'	'	($1,833)	$10,797
Intangible assets	'	'	24,700	276,200
Deferred tax asset	'	'	442	'
Deferred tax liability	'	'	-8,368	-91,098
Goodwill	750,275	706,327	41,671	704,891
Total preliminary purchase price allocation	'	'	$56,612	$900,790

Business_Combinations_Schedule1

Business Combinations - Schedule of Preliminary Acquired Intangible Assets (Details) (USD $)

9-May-14

9-May-14

9-May-14

9-May-14

9-May-14

9-May-14

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

In Thousands, unless otherwise specified

nPulse Technologies [Member]

nPulse Technologies [Member]

nPulse Technologies [Member]

nPulse Technologies [Member]

nPulse Technologies [Member]

nPulse Technologies [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

Mandiant, Inc. [Member]

In Process Research and Development [Member]

Developed Technology [Member]

Developed Technology [Member]

Customer Relationships [Member]

Customer Relationships [Member]

In Process Research and Development [Member]

Developed Technology [Member]

Content [Member]

Customer Relationships [Member]

Contract Backlog [Member]

Trade Names [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Developed Technology [Member]

Contract Backlog [Member]

Developed Technology [Member]

Contract Backlog [Member]

Finite-Lived Intangible Assets [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Finite lived acquired assets, useful life

'

'

'6 years

'

'8 years

'

'

'

'

'10 years

'8 years

'

'4 years

'4 years

'1 year

'6 years

'3 years

Finite lived acquired assets

'

'

'

$10,100

'

$8,000

'

'

$54,600

$128,600

$65,400

$13,800

$12,400

'

'

'

'

Indefinite lived acquired assets

'

6,600

'

'

'

'

'

1,400

'

'

'

'

'

'

'

'

'

Total

$24,700

'

'

'

'

'

$276,200

'

'

'

'

'

'

'

'

'

'

Business_Combinations_Schedule2

Business Combinations - Schedule of Goodwill (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Goodwill [Roll Forward]	'
Balance as of December 31, 2013	$706,327
Acquisitions and adjustments	43,948
Balance as of September 30, 2014	$750,275

Business_Combinations_Schedule3

Business Combinations - Schedule of Purchased Intangible Assets (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'
Total intangible assets subject to amortization	$300,493	$281,493
Less: accumulated amortization	-34,979	-1,516
Net intangible assets subject to amortization	265,514	279,977
In-process research and development	7,800	'
Total net intangible assets	273,314	281,377
Developed Technology [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Total intangible assets subject to amortization	70,393	60,093
Content [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Total intangible assets subject to amortization	128,600	128,500
Customer Relationships [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Total intangible assets subject to amortization	75,300	67,900
Contract Backlog [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Total intangible assets subject to amortization	13,800	12,600
Trade Names [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Total intangible assets subject to amortization	12,400	12,400
In Process Research and Development [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
In-process research and development	$7,800	$1,400

Business_Combinations_Schedule4

Business Combinations - Schedule of Expected Future Amortization Expense (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Business Combinations [Abstract]	'	'
2014 (remaining three months)	$11,478	'
2015	45,114	'
2016	44,498	'
2017	38,553	'
2018	27,608	'
2019 and thereafter	98,263	'
Total intangible assets subject to amortization	265,514	279,977
Total intangible assets with indefinite lives	7,800	'
Total	$273,314	$281,377

Business_Combinations_Narrativ

Business Combinations - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended		0 Months Ended			3 Months Ended			0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	9-May-14	9-May-14	9-May-14	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2014	9-May-14
					nPulse Technologies [Member]	Unvested stock options and restricted stock [Member]	General and administrative [Member]	Purchase of mandiant [Member]	Purchase of mandiant [Member]	Over accrual of bonus [Member]	Maximum [Member]
						nPulse Technologies [Member]	nPulse Technologies [Member]	Mandiant, Inc. [Member]	Mandiant, Inc. [Member]	Mandiant, Inc. [Member]	nPulse Technologies [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Total purchase consideration	'	'	'	'	$56,600,000	'	'	'	'	'	'
Cash paid for acquisition	'	'	'	'	55,200,000	'	'	'	'	'	'
Equity awards assumed	'	'	'	'	'	100,000	'	'	'	'	'
Shares issued for acquisition (shares)	'	'	'	'	'	'	'	'	'	'	54,319
Liabilities incurred	'	'	'	'	1,300,000	'	'	'	'	'	'
Performance milestone determination period	'	'	'	'	'3 years 6 months	'	'	'	'	'	'
Acquisition costs	'	'	'	'	'	'	500,000	'	'	'	'
Amortization of intangible assets	11,500,000	400,000	33,500,000	900,000	'	'	'	'	'	'	'
Adjustment to additional paid in capital	'	'	'	'	'	'	'	'	3,100,000	'	'
Increase in intangible assets	'	'	'	'	'	'	'	'	700,000	'	'
Decrease in current liabilities	'	'	'	'	'	'	'	1,000,000	200,000	'	'
Increase in goodwill	'	'	43,948,000	'	'	'	'	1,000,000	2,200,000	'	'
Accrued bonus	'	'	'	'	'	'	'	'	'	$1,000,000	'

Restructuring_Charges_Summary_

Restructuring Charges - Summary of Restructuring Activities (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Restructuring Reserve [Roll Forward]	'	'	'	'
Provision for restructuring charges	$2,769	$0	$2,769	$0
Employee severance [Member]	'	'	'	'
Restructuring Reserve [Roll Forward]	'	'	'	'
Balance, December 31, 2013	'	'	0	'
Provision for restructuring charges	'	'	1,509	'
Cash payments	'	'	-1,206	'
Balance, September 30, 2014	303	'	303	'
Facility closing [Member]	'	'	'	'
Restructuring Reserve [Roll Forward]	'	'	'	'
Balance, December 31, 2013	'	'	0	'
Provision for restructuring charges	'	'	376	'
Cash payments	'	'	-78	'
Balance, September 30, 2014	298	'	298	'
Excluding non-cash fixed asset write off [Member]	'	'	'	'
Restructuring Reserve [Roll Forward]	'	'	'	'
Balance, December 31, 2013	'	'	0	'
Provision for restructuring charges	'	'	1,885	'
Cash payments	'	'	-1,284	'
Balance, September 30, 2014	$601	'	$601	'

Restructuring_Charges_Narrativ

Restructuring Charges - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Provision for restructuring charges	$2,769	$0	$2,769	$0
Non-cash fixed asset write off [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Provision for restructuring charges	'	'	$900	'

Deferred_Revenue_Schedule_of_D

Deferred Revenue - Schedule of Deferred Revenue (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Revenue Arrangement [Line Items]	'	'
Deferred revenue, current portion	$160,768	$110,535
Deferred revenue, non-current portion	122,153	76,979
Total deferred revenue	282,921	187,514
Product [Member]	'	'
Deferred Revenue Arrangement [Line Items]	'	'
Deferred revenue, current portion	9,914	13,823
Deferred revenue, non-current portion	6,077	6,711
Subscription and services [Member]	'	'
Deferred Revenue Arrangement [Line Items]	'	'
Deferred revenue, current portion	150,854	96,712
Deferred revenue, non-current portion	$116,076	$70,268

Credit_Facility_Narrative_Deta

Credit Facility - Narrative (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Dec. 31, 2013
			Revolving Credit Facility [Member]	Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]	'	'	'	'
Line of credit, maximum borrowing capacity	'	'	$25,000,000	'
Borrowing from line of credit	0	10,000,000	'	'
Line of credit amount outstanding	'	'	$0	$0

Commitments_and_Contingencies_2

Commitments and Contingencies - Schedule of Future Minimum Rental Payments for Operating Leases (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
2014 (remaining three months)	$2,745
2015	9,461
2016	7,425
2017	6,379
2018	3,537
2019 and thereafter	12,608
Total	$42,155

Commitments_and_Contingencies_3

Commitments and Contingencies - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
			claim
Long-term Purchase Commitment [Line Items]	'	'	'	'	'
Rent expense	$2,700,000	$1,000,000	$8,000,000	$2,500,000	'
Letters of credit available	1,500,000	'	1,500,000	'	900,000
Amount drawn against letters of credit	0	'	0	'	'
Non-cancellable open orders	27,000,000	'	27,000,000	'	16,700,000
Number of claims	'	'	0	'	'
Software and Services [Member]	'	'	'	'	'
Long-term Purchase Commitment [Line Items]	'	'	'	'	'
Non-cancellable open orders	$9,100,000	'	$9,100,000	'	'

Common_Shares_Reserved_for_Iss2

Common Shares Reserved for Issuance - Schedule of Stock by Class (Details)	Sep. 30, 2014	Dec. 31, 2013
Class of Stock [Line Items]	'	'
Shares reserved for future issuance (shares)	44,444,000	43,038,000
Reserved under stock award plans [Member]	'	'
Class of Stock [Line Items]	'	'
Shares reserved for future issuance (shares)	41,171,000	40,226,000
Warrants to purchase common stock [Member]	'	'
Class of Stock [Line Items]	'	'
Shares reserved for future issuance (shares)	0	312,000
ESPP [Member]	'	'
Class of Stock [Line Items]	'	'
Shares reserved for future issuance (shares)	3,273,000	2,500,000

Common_Shares_Reserved_for_Iss3

Common Shares Reserved for Issuance - Narrative (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
	vote_per_share
Class of Stock [Line Items]	'	'
Common stock, shares authorized (shares)	1,000,000,000	1,000,000,000
Common stock, par value (usd per share)	$0.00	$0.00
Voting right per common share	1	'
Convertible preferred stock [Member]	'	'
Class of Stock [Line Items]	'	'
Convertible preferred stock outstanding (shares)	0	0

Equity_Award_Plans_Schedule_of

Equity Award Plans - Schedule of Activity for Options Outstanding (Details) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'	'	'
Beginning balance, options outstanding (shares)	'	'	27,422,000	'
Options granted (shares)	'	'	676,000	'
Options exercised (shares)	-796,846	'	-5,468,000	'
Options cancelled (shares)	'	'	-1,369,000	'
Options assumed in acquisition (shares)	'	'	63,000	'
Ending balance, options outstanding (shares)	'	21,324,000	21,324,000	27,422,000
Option vested and expected to vest (shares)	'	20,761,000	20,761,000	'
Option exercisable (shares)	'	9,261,000	9,261,000	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]	'	'	'	'
Beginning balance, weighted average exercise price (usd per share)	'	'	$5.82	'
Options granted, weighted average exercise price (usd per share)	'	'	$72.60	'
Options exercised, weighted average exercise price (usd per share)	'	'	$2.90	'
Options cancelled, weighted average exercise price (usd per share)	'	'	$8.88	'
Options assumed in acquisition, weighted average exercise price (usd per share)	'	'	$20.60	'
Ending balance, weighted average exercise price (usd per share)	'	$8.53	$8.53	$5.82
Option vested and expected to vest, weighted average exercise price (usd per share)	'	$8.40	$8.40	'
Option exercisable, weighted average exercise price (usd per share)	'	$4.07	$4.07	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]	'	'	'	'
Options weighted-average grant date fair value per share (usd per share)	'	$29.79	$72.60	'
Beginning balance, options outstanding, weighted average contractual life	'	'	'7 years 6 months 18 days	'8 years 3 months 18 days
Ending balance, options outstanding, weighted average contractual life	'	'	'7 years 6 months 18 days	'8 years 3 months 18 days
Option vested and expected to vest, weighted average contractual life	'	'	'7 years 6 months 7 days	'
Option exercisable, weighted average contractual life	'	'	'6 years 6 months 18 days	'
Beginning balance, options outstanding, aggregate intrinsic value	'	'	$1,036,224	'
Aggregate intrinsic value of options exercised	'	'	210,389	'
Ending balance, options outstanding, aggregate intrinsic value	'	499,899	499,899	1,036,224
Option vested and expected to vest, aggregate intrinsic value	'	488,605	488,605	'
Option exercisable, aggregate intrinsic value	'	$245,347	$245,347	'

Equity_Award_Plans_Schedule_of1

Equity Award Plans - Schedule of Activity for Restricted Stock (Details) (Restricted Stock Awards and Restricted Stock Units [Member], USD $)	9 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Restricted Stock Awards and Restricted Stock Units [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]	'	'
Beginning balance, unvested (shares)	3,602	'
Granted (shares)	5,741	'
Vested (shares)	-779	'
Canceled/forfeited (shares)	-523	'
Ending balance, unvested (shares)	8,041	3,602
Expected to vest (shares)	7,476	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]	'	'
Weighted-Average Grant Date Fair Value Per Share	$43.84	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]	'	'
Beginning balance, weighted-average remaining contractual term	'1 year 9 months 7 days	'1 year 8 months 12 days
Ending balance, weighted-average remaining contractual term	'1 year 9 months 7 days	'1 year 8 months 12 days
Expected to vest, weighted-average remaining contractual term	'1 year 9 months 7 days	'
Beginning balance, aggregate intrinsic value	$157,108	'
Ending balance, aggregate intrinsic value	245,722	157,108
Expected to vest, aggregate intrinsic value	$228,465	'

Equity_Award_Plans_Schedule_of2

Equity Award Plans - Schedule of Fair Value Assumptions Used for Stock Options (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Fair value of common stock (usd per share)	$29.79	'	$72.60	'
Risk-free interest rate	1.77%	'	'	'
Expected term	'6 years	'	'6 years	'
Volatility	51.00%	'	'	'
Dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Fair value of common stock (usd per share)	'	12.9	$27.89	6.05
Risk-free interest rate	'	1.60%	1.77%	0.60%
Expected term	'	'5 years	'	'4 years
Volatility	'	49.00%	51.00%	49.00%
Maximum [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Fair value of common stock (usd per share)	'	20	$75.87	20
Risk-free interest rate	'	2.10%	1.96%	2.10%
Expected term	'	'6 years	'	'6 years
Volatility	'	54.00%	53.00%	54.00%

Equity_Award_Plans_Schedule_of3

Equity Award Plans - Schedule of Fair Value Assumptions Used for ESPP (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Fair value of common stock (usd per share)	$29.79	'	$72.60	'
Risk-free interest rate	1.77%	'	'	'
Expected term	'6 years	'	'6 years	'
Volatility	51.00%	'	'	'
Dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Fair value of common stock (usd per share)	'	12.9	$27.89	6.05
Risk-free interest rate	'	1.60%	1.77%	0.60%
Expected term	'	'5 years	'	'4 years
Volatility	'	49.00%	51.00%	49.00%
Maximum [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Fair value of common stock (usd per share)	'	20	$75.87	20
Risk-free interest rate	'	2.10%	1.96%	2.10%
Expected term	'	'6 years	'	'6 years
Volatility	'	54.00%	53.00%	54.00%
ESPP [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Fair value of common stock (usd per share)	'	'	$23.02	20
Risk-free interest rate	'	'	'	0.10%
Volatility	'	'	45.00%	'
Dividend yield	'	'	0.00%	0.00%
ESPP [Member] | Minimum [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Risk-free interest rate	'	'	0.05%	'
Expected term	'	'	'6 months	'8 months 12 days
Volatility	'	'	'	42.00%
ESPP [Member] | Maximum [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Risk-free interest rate	'	'	0.09%	'
Expected term	'	'	'1 year	'1 year 2 months 12 days
Volatility	'	'	'	45.00%

Equity_Award_Plans_Schedule_of4

Equity Award Plans - Schedule of Share-based Compensation Expense (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	$43,160	$8,814	$106,607	$16,344
Cost of product revenue [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	243	143	624	279
Cost of subscription and services revenue [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	3,430	762	10,455	1,330
Research and development [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	7,648	2,350	20,054	4,425
Sales and marketing [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	22,543	3,784	47,154	5,878
General and administrative [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	$9,296	$1,775	$28,320	$4,432

Equity_Award_Plans_Narrative_D

Equity Award Plans - Narrative (Details) (USD $)	9 Months Ended		9 Months Ended			9 Months Ended	0 Months Ended			0 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	9-May-14	9-May-14	9-May-14	9-May-14
			ESPP [Member]	2013 Plan [Member]	Minimum [Member]	Minimum [Member]	nPulse Technologies [Member]	nPulse Technologies [Member]	nPulse Technologies [Member]	nPulse Technologies [Member]
					2013 Plan [Member]	2013 Plan [Member]		Performance shares [Member]	Performance shares [Member]	Maximum [Member]
						Employee stock option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'	'	'	'
General vesting period	'	'	'	'4 years	'	'	'	'	'	'
Award expiration period from grant date	'	'	'	'10 years	'	'	'	'	'	'
Employee stock ownership, combined voting power of all stock	'	'	'	10.00%	'	'	'	'	'	'
Minimum exercise price as a percentage of the fair value per share	'	'	'	'	110.00%	'	'	'	'	'
Award expiration period, for excess voting power grants	'	'	'	'5 years	'	'	'	'	'	'
Grant date fair value, percentage	'	'	'	'	'	100.00%	'	'	'	'
Shares reserved for future issuance (shares)	44,444,000	43,038,000	3,272,660	13,800,000	'	'	'	'	'	'
Acquisition price at lower of fair market value, percentage	'	'	85.00%	'	'	'	'	'	'	'
Additional shares authorized (shares)	'	'	1,377,575	'	'	'	'	'	'	'
Shares issued for acquisition (shares)	'	'	'	'	'	'	'	241,362	'	54,319
Contingent obligation, employee performance award	'	'	'	'	'	'	'	'	$6.40	'
Performance milestone determination period	'	'	'	'	'	'	'3 years 6 months	'	'	'
Compensation cost not yet recognized	$325	'	'	'	'	'	'	'	'	'
Compensation cost not yet recognized, period for recognition	'3 years	'	'	'	'	'	'	'	'	'

Income_Taxes_Narrative_Details

Income Taxes - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'	'	'
Effective income tax rate	7.92%	1.77%	7.32%	0.27%

Net_Loss_Per_Share_Schedule_of

Net Loss Per Share - Schedule of Net Loss per Common Share, Basic and Diluted (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator:	'	'	'	'
Net loss	($120,031)	($50,926)	($338,064)	($118,122)
Denominator:	'	'	'	'
Weighted average number of shares outstanding—basic and diluted (shares)	144,923	31,590	140,285	21,838
Net loss per share—basic and diluted (usd per share)	($0.83)	($1.61)	($2.41)	($5.41)

Net_Loss_Per_Share_Schedule_of1

Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Net Loss per Share Computation (Details)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Option to purchase common stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from net loss per share (shares)	21,324	22,707
Unvested early exercised common shares [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from net loss per share (shares)	2,676	5,240
Unvested restricted stock awards and units [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from net loss per share (shares)	8,041	2,140
Warrants to purchase common stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from net loss per share (shares)	0	616
ESPP [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from net loss per share (shares)	406	0

Employee_Benefit_Plan_Narrativ

Employee Benefit Plan - Narrative (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]	'	'
Employer contributions vested percentage	'	100.00%
Employer contributions to 401(k)	'	$0
Mandiant, Inc. [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Employer contributions vested percentage	'	100.00%
Employer contributions to 401(k)	$700,000	$2,100,000
Employers match	'	100.00%
Employees contribution	'	4.00%

Segment_Information_Schedule_o

Segment Information - Schedule of Revenue by Geographic Region (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total revenue	$114,211	$42,652	$282,680	$104,290
Operating Segments [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total revenue	114,211	42,652	282,680	104,290
Operating Segments [Member] | United States [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total revenue	86,628	30,435	211,992	75,793
Operating Segments [Member] | EMEA [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total revenue	15,017	6,292	38,940	14,706
Operating Segments [Member] | APAC [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total revenue	9,502	4,491	22,450	10,315
Operating Segments [Member] | Other [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total revenue	$3,064	$1,434	$9,298	$3,476

Segment_Information_Narrative_

Segment Information - Narrative (Details) (Customer Concentration Risk [Member])	3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013
	Sales Revenue, Net [Member]	Sales Revenue, Net [Member]	Carahsoft Technology Corporation [Member]	Carahsoft Technology Corporation [Member]	Carahsoft Technology Corporation [Member]	Carahsoft Technology Corporation [Member]	Accuvant [Member]
	customer	customer	Sales Revenue, Net [Member]	Sales Revenue, Net [Member]	Sales Revenue, Net [Member]	Accounts Receivable [Member]	Sales Revenue, Net [Member]
			customer		customer
Concentration Risk [Line Items]	'	'	'	'	'	'	'
Number of customers	2	0	1	'	1	'	'
Concentration risk	'	'	13.00%	16.00%	12.00%	13.00%	10.00%