Mandiant (MNDT) 10-Q 3 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	FIREEYE, INC.
Entity Central Index Key	1,370,880
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		195,004,563

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	[1]
Current assets:
Cash and cash equivalents	$ 351,370	$ 180,891
Short-term investments	723,975	715,911
Accounts receivable, net of allowance for doubtful accounts of $2,522 and $2,503 at June 30, 2018 and December 31, 2017, respectively	120,893	146,317
Inventories	6,744	5,746
Prepaid expenses and other current assets	92,632	93,799
Total current assets	1,295,614	1,142,664
Property and equipment, net	81,373	71,357
Goodwill	999,888	984,661
Intangible assets, net	168,229	187,388
Deposits and other long-term assets	69,370	72,767
TOTAL ASSETS	2,614,474	2,458,837
CURRENT LIABILITIES:
Accounts payable	32,308	35,684
Accrued and other current liabilities	20,512	19,569
Accrued compensation	58,379	59,588
Deferred revenue, current portion	525,617	546,615
Total current liabilities	636,816	661,456
Convertible senior notes, net	939,447	779,578
Deferred revenue, non-current portion	353,939	363,485
Other long-term liabilities	23,844	22,102
Total liabilities	1,954,046	1,826,621
Commitments and contingencies (NOTE 10)
Stockholders' equity:
Common stock, par value of $0.0001 per share; 1,000,000 shares authorized, 194,987 shares and 187,105 shares issued and outstanding as of June 30, 2018 and December 31, 2017, respectively	20	19
Additional paid-in capital	3,064,955	2,891,441
Treasury stock, at cost; 3,333 shares as of June 30, 2018 and December 31, 2017	(150,000)	(150,000)
Accumulated other comprehensive loss	(3,495)	(2,881)
Accumulated deficit	(2,251,052)	(2,106,363)
Total stockholders’ equity	660,428	632,216
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 2,614,474	$ 2,458,837
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 2,522	$ 2,503
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (shares)	194,987,000	187,105,000
Common stock, shares outstanding (shares)	194,987,000	187,105,000
Treasury stock (shares)	3,333,000	3,333,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	[1]	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Total revenue	$ 202,696	$ 191,722		$ 401,766	$ 376,481	[1]
Cost of revenue:
Total cost of revenue	67,282	67,794		135,211	133,541	[1]
Total gross profit	135,414	123,928		266,555	242,940	[1]
Operating expenses:
Research and development	63,575	60,747		129,771	119,099
Sales and marketing	94,196	92,413		191,447	191,401
General and administrative	26,179	27,805		54,597	55,420
Total operating expenses	183,950	180,965		375,815	365,920
Operating loss	(48,536)	(57,037)		(109,260)	(122,980)
Interest income	3,383	2,168		6,323	4,200
Interest expense	(13,605)	(12,385)		(26,322)	(24,630)
Other income (expense), net	(12,690)	(120)		(12,966)	112
Loss before income taxes	(71,448)	(67,374)		(142,225)	(143,298)
Provision for income taxes	1,411	965		2,464	2,258
Net loss attributable to common stockholders	$ (72,859)	$ (68,339)		$ (144,689)	$ (145,556)	[1]
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	$ (0.38)	$ (0.39)		$ (0.77)	$ (0.83)
Weighted average shares used in computing net loss per share attributable to common stockholders, basic and diluted (shares)	189,696	176,645		188,085	174,453
Product, subscription and support
Revenue:
Total revenue	$ 167,429	$ 158,097		$ 332,902	$ 311,826	[1]
Cost of revenue:
Total cost of revenue	46,136	47,636		93,565	94,059	[1]
Professional services
Revenue:
Total revenue	35,267	33,625		68,864	64,655	[1]
Cost of revenue:
Total cost of revenue	$ 21,146	$ 20,158		$ 41,646	$ 39,482	[1]
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018		Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (72,859)	$ (68,339)	[1]	$ (144,689)		$ (145,556)	[1]
Change in net unrealized gain (losses) on available-for-sale investments, net of tax	981	26		(614)	[1]	349
Comprehensive loss	$ (71,878)	$ (68,313)	[1]	$ (145,303)		$ (145,207)
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss		$ (144,689)	$ (145,556)	[1]
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization		44,601	52,773	[1]
Stock-based compensation		81,040	83,286	[1]
Non-cash interest expense related to convertible senior notes		20,144	18,566	[1]
Loss on repurchase of convertible senior notes		10,764	0	[1]
Deemed repayment of convertible senior notes attributable to accreted debt discount		(43,575)	0	[1]
Change in fair value of contingent earn-out liability		0	(54)	[1]
Deferred income taxes		(60)	251	[1]
Other		2,372	3,467	[1]
Changes in operating assets and liabilities, net of business acquisitions:
Accounts receivable		24,892	16,198	[1]
Inventories		(2,266)	(573)	[1]
Prepaid expenses and other assets		4,892	(1,505)	[1]
Accounts payable		(4,152)	3,793	[1]
Accrued liabilities		949	(2,610)	[1]
Accrued compensation		(1,209)	(6,881)	[1]
Deferred revenue		(30,545)	(57,929)	[1]
Other long-term liabilities		1,742	8,352	[1]
Net cash used in operating activities		(35,100)	(28,422)	[1]
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment and demonstration units		(26,645)	(17,312)	[1]
Purchases of short-term investments		(218,842)	(222,910)	[1]
Proceeds from maturities of short-term investments		209,045	213,514	[1]
Proceeds from sales of short-term investments		0	3,620	[1]
Business acquisitions, net of cash acquired		(5,945)	0	[1]
Lease deposits		26	(144)	[1]
Net cash used in investing activities		(42,361)	(23,232)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments for contingent earn-outs		0	(38,928)	[1]
Proceeds from issuance of convertible senior notes, net of issuance costs		584,405	0	[1]
Purchase of capped calls		(65,220)	0	[1]
Repurchase of convertible senior notes		(286,817)	0	[1]
Payment related to shares withheld for taxes		0	(590)	[1]
Proceeds from employee stock purchase plan		10,993	10,764	[1]
Proceeds from exercise of equity awards		4,579	11,183	[1]
Net cash provided by (used in) financing activities		247,940	(17,571)	[1]
Net change in cash and cash equivalents		170,479	(69,225)	[1]
Cash and cash equivalents, beginning of period	[1]	180,891	223,667
Cash and cash equivalents, end of period		351,370	154,442	[1]
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for income taxes		2,283	1,444	[1]
Cash paid for interest		5,791	6,038	[1]
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Common stock issued in connection with acquisitions		15,387	0	[1]
Convertible senior note issuance costs included in accounts payable and accrued expense		579	0	[1]
Purchases of property and equipment and demonstration units in accounts payable and accrued liabilities		$ 14,129	$ 7,883	[1]
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
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”) provide comprehensive intelligence-based cybersecurity solutions that allow organizations to prepare for, prevent, respond to and remediate cyber attacks. Our portfolio of cyber security products and services is designed to detect and prevent attacks, as well as enable rapid discovery and response when a breach occurs. We accomplish this with products and services that adapt to changes in the threat environment in a cycle of innovation that incorporates our threat intelligence, machine-based technologies and cyber security expertise. Our core competitive advantages include: • Our high efficacy detection and prevention of known and unknown threats using machine-learning, behavioral analytics, and other intelligence-driven analysis (IDA) technologies, combined with our proprietary Multi-vector Virtual Execution (MVX) engine; • Our intelligence on threats and threat actors, based on the continuous flow of new attack data from our global network of sensors and virtual machines, as well as intelligence gathered by our security researchers, security operations analysts and incident responders; and • Our accumulated security expertise derived from responding to thousands of significant breaches over the past decade. Our threat detection and prevention products encompass appliance-based (virtual and physical) and cloud solutions for network, email, and endpoint security, and are designed to detect and block known and unknown attacks. These products are complemented by our network forensics, cloud-based threat intelligence and analytics, managed detection and response services, cyber security consulting and incident response offerings. In combination, our products and services enable a proactive approach to cybersecurity that extends across the security operations cycle to reduce organizations’ overall cyber-risk at a lower total cost of ownership. In the three months ended June 30, 2018 , we issued $600 million aggregate principal amount of 0.875% Convertible Senior Notes due 2024 (the "2024 Notes"), in a private placement to qualified institutional purchasers pursuant to an exemption from registration provided by Section 4(a)(2) and Rule 144A under the Securities Act of 1933, as amended (the "Securities Act"). We recognized total net proceeds after the initial purchasers' discount and issuance costs of $584.4 million . In connection with the issuance of the 2024 Notes, we also entered into capped call transactions (the "Capped Calls") with certain parties affiliated with the initial purchasers of the 2024 Notes. We paid approximately $65.2 million for the Capped Calls, which have an initial strike price of $23.17 per share, which corresponds to the initial conversion price of the 2024 Notes. The Capped Calls have an initial cap price of $34.32 per share subject to certain adjustments as set forth in the confirmations for the Capped Calls. In May 2018, in a separate transaction, we repurchased $340.2 million aggregate principal of existing 1.000% Convertible Senior Notes due 2035 (the "Series A Notes"). We used $330.4 million of the net proceeds from the 2024 Notes offering to repurchase such portion of the Series A Notes. In January 2018, we completed the acquisition of privately-held X15 Software, Inc. ("X15"), a data management company. As consideration for the acquisition, we paid cash consideration of $5.3 million and issued 1,016,334 shares of our common stock with an estimated fair value of $15.4 million . In October 2017, we acquired Clean Communications Limited (d/b/a The Email Laundry) ("The Email Laundry"), a privately-held email security company. We paid cash consideration of $4.3 million and issued 259,425 shares of our common stock with an estimated fair value of $4.4 million . The majority of our products, subscriptions and services are sold to end-customers through distributors, resellers, and strategic partners, with a lesser percentage of sales directly to our 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 unaudited condensed consolidated financial statements have been prepared on the same basis as our annual consolidated 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 six months ended June 30, 2018 are not necessarily indicative of the results to be expected for the year ending December 31, 2018 or for any other interim period or for any other future year. The balance sheet as of December 31, 2017 has been derived from audited consolidated financial statements at that date but does not include all information required by U.S. GAAP for annual consolidated financial statements. The accompanying unaudited 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, 2017 included in our Annual Report on Form 10-K for the year ended December 31, 2017 . The Company adopted Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASC 606"), effective January 1, 2018 using the full retrospective method. The cumulative effect of the adoption was recognized as an increase to accumulated deficit of $113.0 million on January 1, 2018 and impacted certain other prior period amounts. Certain amounts and disclosures set forth in this Quarterly Report on Form 10-Q have been updated to comply with the new standards. 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, determining the nature and timing of satisfaction of performance obligations, determining the standalone selling price ("SSP") of performance obligations, subscriptions and services, commissions expense including the period of benefit of customer acquisition cost, bonus expense, future taxable income, contract manufacturer liabilities, litigation and settlement costs and other loss contingencies, fair value of our equity awards, achievement of targets for performance stock units, fair value of the liability and equity components of the Convertible Senior Notes and the purchase price allocation of acquired businesses. We base our estimates on historical experience and 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 Except for the accounting policies for revenue recognition and the associated treatments of deferred revenue, deferred cost of revenue and deferred commissions, updated as a result of adopting ASC 606, there have been no significant changes to our significant accounting policies as of and for the three and six months ended June 30, 2018 , as compared to the significant accounting policies described in our Annual Report on Form 10-K for the year ended December 31, 2017 . Revenue from Contracts with Customers Revenue is recognized when all of the following criteria are met: • Identification of the contract, or contracts, with a customer - A contract with a customer exists when (i) we enter into an enforceable contract with a customer that defines each party’s rights regarding the goods or services to be transferred and identifies the payment terms related to these goods or services, (ii) the contract has commercial substance and the parties are committed to perform, and (iii) we determine that collection of substantially all consideration to which it will be entitled in exchange for goods or services that will be transferred is probable based on the customer’s intent and ability to pay the promised consideration. • Identification of the performance obligations in the contract - Performance obligations promised in a contract are identified based on the goods or services that will be transferred to the customer that are both capable of being distinct, whereby the customer can benefit from the goods or service either on its own or together with other resources that are readily available from third parties or from us, and are distinct in the context of the contract, whereby the transfer of the goods or services is separately identifiable from other promises in the contract. To the extent a contract includes multiple promised goods or services, we apply judgment to determine whether promised goods or services are capable of being distinct and distinct in the context of the contract. If these criteria are not met the promised goods or services are accounted for as a combined performance obligation. • Determination of the transaction price - The transaction price is determined based on the consideration to which we will be entitled in exchange for transferring goods or services to the customer adjusted for estimated variable consideration, if any. We typically estimate the transaction price impact of discounts offered to the customers for early payments on receivables or rebates based on sales target achievements. Constraints are applied when estimating variable considerations based on historical experience where applicable. • Allocation of the transaction price to the performance obligations in the contract - If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative SSP basis. Determination of SSP requires judgement. We determine standalone selling price taking into account available information such as historical selling prices of the performance obligation, geographic location, overall strategic pricing objective, market conditions and internally approved pricing guidelines related to the performance obligations. • Recognition of revenue when, or as, we satisfy performance obligation - We satisfy performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at or over the time the related performance obligation is satisfied by transferring a promised good or service to a customer. Nature of Products and Services We generate revenue from the sales of physical and virtual security appliances (products), subscriptions, support and maintenance and professional services, primarily through our indirect relationships with our partners or direct relationships with end customers through our direct sales force. We account for our performance obligations in accordance with ASC 606, and all related interpretations. Our security appliance deliverables include proprietary operating system software, which together with regular security intelligence updates deliver the essential functionality of our appliance-based security products. We combine intelligence dependent appliances and software licenses with the related intelligence subscription and support as a single performance obligation. As a result, we recognize intelligence-dependent appliance and software license revenue ratably over the longer of the estimated useful life of the related appliance and license (when our contracts contain material right of renewal options) or the contractual term, rather than recognizing revenue at the time of shipping. For subscription and support contracts where the term is less than the estimated useful life of the appliance and software license, the intelligence subscription and support revenue is recognized ratably over the contractual term and the allocated value of the material right performance obligations is recognized in the period between the end of the contractual term and the estimated useful life of the appliance. Where our contracts do not contain material right of renewal options, or the contractual term is longer than the useful life, we expect to recognize appliance and software license revenue ratably over the contractual term. Significant judgement is required in estimating the useful life of our security appliances that are dependent on intelligence and assessing the material rights associated with it. Revenue from subscriptions to our cloud-based services, which allow customers to use our hosted security software over a contracted period without taking possession of the software and managed services where FireEye provides managed detection and response services for the customer are recognized over the contractual term. We also have a small portion of our revenue from appliances and software that are not dependent on regular threat intelligence updates. Revenue from these appliances and software is therefore recognized when ownership is transferred to our customers, typically upon shipment. Professional services, which include incident response, compromise assessments, and other security consulting services are offered on a time-and-materials basis or through a fixed fee arrangement, and we recognize the associated revenue as the services are delivered. Contract Balances Accounts Receivable Trade accounts receivable are recorded at the billable amount where we have the unconditional right to bill, net of allowances for doubtful accounts. The allowance for doubtful accounts is based on our assessment of the collectability of accounts. Management regularly reviews the adequacy of the allowance for doubtful accounts by considering the age of each outstanding invoice, each customer's expected ability to pay and collection history, when applicable, to determine whether a specific allowance is appropriate. Accounts receivable deemed uncollectible are charged against the allowance for doubtful accounts when identified. Deferred Revenue (Contract Liabilities) and Contract Assets Deferred revenue consists of amounts that have been invoiced and for which the Company has the right to bill, but that have not been recognized as revenue because the related goods or services have not been transferred. Deferred revenue that will be realized during the succeeding 12-month period is recorded as current, and the remaining deferred revenue is recorded as non-current. Deferred revenue presented in the consolidated balance sheet and notes thereto is net of contract assets. Our contract assets consist of assets typically resulting when revenue recognized exceeds the amount billed or billable to the customer due to allocation of transaction price. Our contract assets were immaterial as of June 30, 2018 and December 31, 2017 . In instances where the timing of revenue recognition differs from the timing of invoicing, we have determined our contracts generally do not include a significant financing component. The primary purpose of our invoicing terms is to provide customers with simplified and predictable ways of purchasing our products and services, not to receive financing from our customers or to provide customers with financing. Examples include invoicing at the beginning of a subscription term with revenue recognized ratably over the contract period. Assets Recognized from Costs to Obtain a Contract with a Customer Deferred Commissions Our customer acquisition costs are primarily related to sales commissions and related payroll taxes earned by our sales force and such costs are considered incremental costs to obtain a contract. Sales commissions for initial contracts are deferred and then amortized taking into consideration the pattern of transfer to which the asset relates and may include expected renewal periods where renewal commissions are not commensurate with the initial commissions period. We typically recognize the initial commissions over the longer of the customer relationship (generally estimated to be four years) or over the same period as the initial revenue arrangement to which these costs relate. Renewal commissions not commensurate with the initial commissions paid are generally amortized over the renewal period. Deferred commissions that will amortize within the succeeding 12 month period are classified as current, and included in prepaid expenses and other current assets on the consolidated balance sheet. The remaining balance is classified as non-current, and included in deposits and other long-term assets. As of June 30, 2018 and December 31, 2017 , the amount of deferred commissions included in prepaid expenses and other current assets was $47.5 million and $43.8 million , respectively. The amount of deferred commissions included in deposits and other long-term assets as of June 30, 2018 and December 31, 2017 was $42.4 million and $43.0 million , respectively. Deferred Costs of Revenue Deferred costs of revenue consists of appliance related direct and incremental costs that are capitalized and will be amortized on a systematic basis that is consistent with the pattern of transfer to which the asset relates. Deferred costs of revenue that will be realized within the succeeding 12 month period are classified as current, and included in prepaid expenses and other current assets on the consolidated balance sheets. The remaining balance is classified as non-current, and included in deposits and other long-term assets. As of June 30, 2018 and December 31, 2017 , the amount of deferred costs of revenue classified as current and included in prepaid expenses and other current assets was $18.0 million and $18.4 million , respectively. The amount of deferred costs of revenue classified as non-current and included in deposits and other long-term assets as of June 30, 2018 and December 31, 2017 was $17.2 million and $19.7 million , respectively. ASC 606 Impact to Previously Reported Results We adjusted our condensed consolidated financial statements from amounts previously reported due to the adoption of ASU 2014-09, Revenue from Contracts with Customers (Topic 606). Select condensed consolidated balance sheet line items, which reflect the adoption of this standard, are as follows (in thousands): As of December 31, 2017 Balance Sheet: As Previously Reported Impact of Adoption As Adjusted Accounts receivable, net $ 140,049 6,268 $ 146,317 Prepaid expenses and other current assets $ 34,541 59,258 $ 93,799 Deposits and other long-term assets $ 11,537 61,230 $ 72,767 Deferred revenue, current portion $ 443,064 103,551 $ 546,615 Deferred revenue, non-current portion $ 227,680 135,805 $ 363,485 Stockholders' equity $ 744,816 (112,600 ) $ 632,216 Select unaudited condensed consolidated statement of operations line items, which reflect the adoption of ASC 606, are as follows (in thousands): Three Months Ended June 30, 2017 Condensed Consolidated Statement of Operations As Previously Reported Impact of Adoption As Adjusted Total revenue $ 185,472 6,250 $ 191,722 Total cost of revenue $ 66,692 1,102 $ 67,794 Total operating expenses $ 178,210 2,755 $ 180,965 Operating loss $ (59,430 ) 2,393 $ (57,037 ) Net loss attributable to common stockholders $ (70,732 ) 2,393 $ (68,339 ) Net loss per share attributable to common stockholders, basic and diluted $ (0.40 ) 0.01 $ (0.39 ) Six Months Ended June 30, 2017 Condensed Consolidated Statement of Operations As Previously Reported Impact of Adoption As Adjusted Total revenue $ 359,210 17,271 $ 376,481 Total cost of revenue $ 131,297 2,244 $ 133,541 Total operating expenses $ 359,057 6,863 $ 365,920 Operating loss $ (131,144 ) 8,164 $ (122,980 ) Net loss attributable to common stockholders $ (153,720 ) 8,164 $ (145,556 ) Net loss per share attributable to common stockholders, basic and diluted $ (0.88 ) 0.05 $ (0.83 ) Select unaudited condensed consolidated statement of cash flows line items, which reflect the adoption of ASC 606, are as follows (in thousands): Six Months Ended June 30, 2017 Condensed Consolidated Statement of Cash flows As Previously Reported Impact of Adoption As Adjusted Cash flows from operating activities: Net loss $ (153,720 ) $ 8,164 $ (145,556 ) Changes in operating assets and liabilities, net of business acquisitions: Accounts receivable $ 10,318 5,880 $ 16,198 Prepaid expenses and other assets $ (10,637 ) 9,132 $ (1,505 ) Deferred revenue $ (34,780 ) (23,149 ) $ (57,929 ) Recent Accounting Pronouncements In February 2018, the FASB issued Accounting Standards Update (ASU) 2018-02 that provides companies with an option to reclassify stranded tax effects resulting from enactment of the Tax Cuts and Jobs Act ("TCJA") from accumulated other comprehensive income to retained earnings. The guidance will be effective for the Company beginning in the first quarter of 2019 with early adoption permitted, and would be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the tax rate as a result of TCJA is recognized. The Company has not made a determination as to which alternative methods it will use when it adopts this standard, but does not expect the adoption of this ASU to have a material impact on its results of operations, financial position and cash flows. In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This standard eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge (i.e. Step 2 of the current guidance), instead measuring the impairment charge as the excess of the reporting unit's carrying amount over its fair value (i.e. Step 1 of the current guidance). The guidance is effective for us beginning in the first quarter of 2020, and should be applied prospectively. Early adoption is permitted for impairment testing dates after January 1, 2017. The adoption of this standard is not expected to have a significant impact on our consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This standard changes the impairment model for most financial assets and certain other instruments by introducing a current expected credit loss (CECL) model. The CECL model is a more forward-looking approach based on expected losses rather than incurred losses, requiring entities to estimate and record losses expected over the remaining contractual life of an asset. The guidance is effective for us beginning in the first quarter of 2020. Early adoption beginning in 2019 is permitted. We are currently evaluating the impact the adoption of this guidance will have on our consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). This standard is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The guidance is effective for us beginning in the first quarter of 2019 and may be applied on a modified retrospective basis or prospective basis. Early adoption is permitted. We expect the adoption of this standard to have a material impact on our consolidated financial statements and related disclosures.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
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 and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of June 30, 2018 As of December 31, 2017 Description Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 204 $ — $ — $ 204 $ 208 $ — $ — $ 208 Treasury bills — — — — 3,098 — — 3,098 Commercial Paper — — — — — — — — Total cash equivalents 204 — — 204 3,306 — — 3,306 Short-term investments: Certificates of deposit — — — — — — — — Commercial paper — — — — — 4,987 — 4,987 Corporate notes and bonds — 448,401 — 448,401 — 438,024 — 438,024 U.S. Government agencies — 275,574 — 275,574 — 272,900 — 272,900 Total short-term investments — 723,975 — 723,975 — 715,911 — 715,911 Total assets measured at fair value $ 204 $ 723,975 $ — $ 724,179 $ 3,306 $ 715,911 $ — $ 719,217 We measure certain assets, including goodwill, intangible assets and our equity-method investment in a private company at fair value on a nonrecurring basis when there are identifiable events or changes in circumstances that may have a significant adverse impact on the fair value of these assets. No such events or changes occurred during the six months ended June 30, 2018 . The estimated fair value of the Convertible Senior Notes (as defined in Note 9) as of June 30, 2018 was determined to be $1.1 billion , based on quoted market prices. We consider the fair value of the Convertible Senior Notes to be a Level 2 measurement as they are not actively traded.

Investments

Investments	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Our investments consisted of the following (in thousands): As of June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalent Short-Term Investments Commercial paper $ — $ — $ — $ — $ — $ — Corporate notes and bonds 450,939 4 (2,542 ) 448,401 — 448,401 U.S. Government agencies 276,531 — (957 ) 275,574 — 275,574 Total $ 727,470 $ 4 $ (3,499 ) $ 723,975 $ — $ 723,975 As of December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalents Short-Term Investments Commercial paper $ 4,989 $ — $ (2 ) $ 4,987 $ — $ 4,987 Corporate notes and bonds 439,851 2 (1,829 ) 438,024 — 438,024 Treasury bills 3,098 — — 3,098 3,098 — U.S. Government agencies 273,950 — (1,050 ) 272,900 — 272,900 Total $ 721,888 $ 2 $ (2,881 ) $ 719,009 $ 3,098 $ 715,911 The following tables present the gross unrealized losses and related fair values of our investments that have been in a continuous unrealized loss position (in thousands): As of June 30, 2018 Less Than 12 Months Greater Than 12 Months Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Commercial paper $ — $ — $ — $ — $ — $ — Corporate notes and bonds 211,707 (1,360 ) 231,668 (1,182 ) 443,375 (2,542 ) U.S. Government agencies 168,440 (732 ) 105,078 (225 ) 273,518 (957 ) Total $ 380,147 $ (2,092 ) $ 336,746 $ (1,407 ) $ 716,893 $ (3,499 ) As of December 31, 2017 Less Than 12 Months Greater Than 12 Months Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Commercial paper $ 4,987 $ (2 ) $ — $ — $ 4,987 $ (2 ) Corporate notes and bonds 284,499 (1,484 ) 153,525 (345 ) 438,024 (1,829 ) U.S. Government agencies 117,132 (486 ) 155,768 (564 ) 272,900 (1,050 ) Total $ 406,618 $ (1,972 ) $ 309,293 $ (909 ) $ 715,911 $ (2,881 ) 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 June 30, 2018 and December 31, 2017 . The following table summarizes the contractual maturities of our investments at June 30, 2018 (in thousands): Amortized Cost Fair Value Due within one year $ 442,938 $ 441,165 Due within one to two years 284,532 282,810 Total $ 727,470 $ 723,975 All available-for-sale securities have been classified as current, based on management's intent and ability to use the funds in current operations. As of June 30, 2018 , we held an 11.1% ownership interest in a private company, which is accounted for under the equity method based on our ability to exercise significant influence over operating and financial policies of the private company. This investment is classified within deposits and other long-term assets on our condensed consolidated balance sheets. The carrying value of this investment was $1.3 million as of June 30, 2018 and $2.1 million as of December 31, 2017 .

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment, net consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Computer equipment and software $ 161,783 $ 144,438 Leasehold improvements 59,039 67,451 Furniture and fixtures 14,485 16,665 Machinery and equipment 447 447 Total property and equipment 235,754 229,001 Less: accumulated depreciation (154,381 ) (157,644 ) Total property and equipment, net $ 81,373 $ 71,357 Depreciation and amortization expense related to property, equipment and demonstration units during the three months ended June 30, 2018 and 2017 was $9.2 million and $11.0 million , respectively. Depreciation and amortization expense related to property, equipment and demonstration units during the six months ended June 30, 2018 and 2017 was $18.6 million and $22.0 million , respectively. During the three months ended June 30, 2018 and 2017 , we capitalized $6.8 million and $3.2 million , respectively, of software development costs primarily related to our cloud subscription offerings. Amortization expense related to capitalized software development costs during the three months ended June 30, 2018 and 2017 was $2.3 million and $1.3 million , respectively. During the six months ended June 30, 2018 and 2017 , we capitalized $11.7 million and $7.9 million , respectively, of software development costs primarily related to our cloud subscription offerings. Amortization expense related to capitalized software development costs during the six months ended June 30, 2018 and 2017 was $4.2 million and $2.1 million , respectively.

Business Combinations

Business Combinations	6 Months Ended
	Jun. 30, 2018
Business Combinations [Abstract]
Business Combinations	Business Combinations Acquisition of The Email Laundry On October 20, 2017, we acquired all outstanding shares of The Email Laundry, a privately held email security company, whose technology is expected to enhance our current email offerings. In connection with this acquisition, we paid cash consideration of $ 4.3 million and issued 259,425 shares of our common stock with an estimated fair value of $ 4.4 million , resulting in total purchase consideration of $ 8.7 million . The purchase price is subject to customary working capital and related adjustments. The purchase price was allocated to intangible assets of $ 2.7 million , goodwill of $6.4 million and tangible net liabilities of $0.4 million . The intangible assets are composed of technology and customer relationships, each with an estimated weighted average useful life of 3 years. The goodwill is primarily attributable to the know-how of the workforce and is not expected to be deductible for U.S. federal income tax purposes. The results of operations of The Email Laundry have been included in our consolidated statements of operations from the acquisition date. Pro forma financial information has not been presented for this acquisition as the impact to our consolidated financial statements was not material. Acquisition of X15 On January 11, 2018, we acquired all outstanding shares of privately held X15, a data management company. We expect that the X15 technology will be incorporated into our platform and analytics capabilities going forward. In connection with this acquisition, we paid cash consideration of $5.3 million and issued 1,016,334 shares of our common stock with an estimated fair value of $15.4 million , resulting in total purchase consideration of $20.7 million . The purchase price was allocated to intangible assets of $6.1 million , goodwill of $15.2 million and tangible net liabilities of $0.6 million . The intangible asset relates to developed technology with an estimated weighted average useful life of 3 years. The goodwill is primarily attributable to the know-how of the workforce and is not expected to be deductible for U.S. federal income tax purposes. The results of operations of X15 have been included in our consolidated statements of operations from the acquisition date. Pro forma financial information has not been presented for this acquisition as the impact to our consolidated financial statements was not material. Goodwill and Purchased Intangible Assets Goodwill increased approximately $15.2 million for the six months ended June 30, 2018 due to the acquisition of X15. There were no other changes in the carrying amount of goodwill. Purchased intangible assets consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Developed technology $ 110,003 $ 103,903 Content 158,700 158,700 Customer relationships 111,090 111,090 Contract backlog 12,500 12,500 Trade names 15,560 15,560 Non-competition agreements 1,400 1,400 Total intangible assets 409,253 403,153 Less: accumulated amortization (241,024 ) (215,765 ) Total net intangible assets $ 168,229 $ 187,388 Amortization expense of intangible assets during the three months ended June 30, 2018 and 2017 was $12.7 million and $14.8 million , respectively. Amortization expense of intangible assets during the six months ended June 30, 2018 and 2017 was $25.3 million and $29.6 million , respectively. The expected future annual amortization expense of intangible assets as of June 30, 2018 is presented below (in thousands): Years Ending December 31, Amount 2018 (remaining six mont hs) $ 25,067 2019 48,441 2020 33,903 2021 29,337 2022 18,209 and thereafter 13,272 Total $ 168,229

Restructuring Charges

Restructuring Charges	6 Months Ended
	Jun. 30, 2018
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring Charges We initiated a series of restructuring activities in February 2016, including a restructuring plan approved by our Board of Directors in August 2016 designed to reduce operating expenses and align our expense structure with our growth expectations. This restructuring plan resulted in a 10% reduction in our workforce, the consolidation of certain real estate facilities and the impairment of certain assets in 2016. The following table sets forth a summary of restructuring activities during the six months ended June 30, 2018 (in thousands): Facilities costs Balance, December 31, 2017 $ 935 Cash payments (92 ) Other adjustments (13 ) Balance, June 30, 2018 $ 830 Other adjustments represent relief of unused benefits, changes in fair value and foreign currency fluctuations. The remaining restructuring balance of $0.8 million at June 30, 2018 is for non-cancelable lease costs which we expect to pay over the terms of the related obligations through the third quarter of 2024, net of sublease income.

Deferred Commissions

Deferred Commissions	6 Months Ended
	Jun. 30, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Commissions	Deferred Commissions We capitalize most of our commission expenses and related payroll taxes and amortize them on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. Changes in the balance of total deferred commissions for the periods presented are as follows (in thousands): Three Months Ended June 30, 2018 As of March 31, 2018 $ 87,012 Commissions capitalized 17,013 Commissions recognized (14,054 ) As of June 30, 2018 $ 89,971 Six Months Ended June 30, 2018 As of December 31, 2017 $ 86,779 Commissions capitalized 30,499 Commissions recognized (27,307 ) As of June 30, 2018 $ 89,971 There was no impairment loss in relation to the commissions capitalized for the periods presented.

Deferred Revenue

Deferred Revenue	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Deferred Revenue	Deferred Revenue Deferred revenue consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017* Product, subscription and support, current $ 476,818 $ 496,218 Professional services, current 48,799 50,397 Total deferred revenue, current 525,617 546,615 Product, subscription and support, non-current 353,927 363,313 Professional services, non-current 12 172 Total deferred revenue, non-current 353,939 363,485 Total deferred revenue $ 879,556 $ 910,100 Changes in the balance of unearned revenue for the periods presented are as follows (in thousands): Three Months Ended June 30, 2018 As of March 31, 2018 $ 886,136 Billings for the period 196,116 Revenue recognized (202,696 ) As of June 30, 2018 $ 879,556 Six Months Ended June 30, 2018 As of December 31, 2017* $ 910,100 Billings for the period 371,222 Revenue recognized (401,766 ) As of June 30, 2018 $ 879,556 *Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard. Remaining Performance Obligations Transaction price allocated to remaining performance obligations represents contracted revenue that has not yet been recognized, which includes deferred revenue and non-cancelable contracts that will be invoiced and recognized as revenue in future periods ("backlog"). While deferred revenue is recorded on our balance sheet as a liability, backlog is not recorded in revenue, unearned revenue or elsewhere in our consolidated financial statements until we establish a contractual right to invoice, at which point it is recorded as revenue or deferred revenue as appropriate. As of June 30, 2018 , the aggregate amount of the transaction price allocated to remaining performance obligations was $879.6 million in deferred revenue and $17.4 million in backlog. We have used the practical expedient to not disclose backlog related to the comparative period under ASC 606. We expect that the amount of backlog relative to the total value of our contracts will change from year to year due to several factors, including the amount invoiced early in the contract term, the timing and duration of customer agreements, varying invoicing cycles of agreements and changes in customer financial circumstances. Accordingly, we believe that fluctuations in backlog are not always a reliable indicator of future revenues and we do not utilize backlog as a key management metric internally. We expect to recognize these remaining performance obligations as follows (in percentages): Total Less than 1 year 1-2 years 2-3 years More than 3 years Deferred revenue 100% 60% 25% 12% 3% Backlog 100% 57% 34% 8% 1%

Convertible Senior Notes

Convertible Senior Notes	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Convertible Senior Notes	Convertible Senior Notes Convertible Senior Notes due 2024 On May 24, 2018, we issued $525.0 million aggregate principal amount of the 2024 Notes in a private placement to qualified institutional purchasers pursuant to an exemption from registration provided by Section 4(a)(2) and Rule 144A under the Securities Act. In addition, on June 5, 2018, we issued an additional $75.0 million aggregate principal amount of the 2024 Notes pursuant to the full exercise of the initial purchasers' option to purchase additional 2024 Notes, in a private placement exempt from the registration requirements of the Securities Act. The net proceeds from the offerings, after deducting the initial purchasers' discount of approximately $15.0 million and the issuance costs of approximately $0.6 million , were $584.4 million . We used (i) approximately $330.4 million of the net proceeds to repurchase approximately $340.2 million in principal amount outstanding of the Series A Notes in negotiated transactions with institutional investors and (ii) approximately $65.2 million of the net proceeds from the offering of the 2024 Notes to enter into the Capped Calls. The 2024 Notes are unsecured obligations and rank senior in right of payment to any of our indebtedness that is expressly subordinated in right of payment to the 2024 Notes. They rank equally in right of payment with all of our existing and future liabilities that are not expressly subordinated to the 2024 Notes including the Series A Notes and the Series B Notes (as defined below); and effectively rank junior in right of payment to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness. The 2024 Notes are structurally junior to all indebtedness and other liabilities (including trade payables) of our subsidiaries. The 2024 Notes do not contain any financial covenants and do not restrict us from paying dividends or issuing or repurchasing other securities. The 2024 Notes bear interest at 0.875% per year, payable semiannually in arrears on June 1 and December 1 of each year, beginning December 1, 2018. The 2024 Notes mature on June 1, 2024, unless earlier repurchased, redeemed or converted. The initial conversion rate of the 2024 Notes is 43.1667 shares of our common stock per $1,000 of principal amount of the 2024 Notes, which is equivalent to an initial conversion price of approximately $23.17 per share of common stock. The conversion rate of the 2024 Notes may be adjusted pursuant to the terms of the indenture governing the 2024 Notes upon the occurrence of certain specified events, but not for accrued and unpaid interest. Holders may convert the 2024 Notes at their option in multiples of $1,000 principal amount prior to the business day preceding March 1, 2024, only under the following circumstances: • during any calendar quarter commencing after the calendar quarter ended on September 30, 2018 (and only during such calendar quarter), if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price of the 2024 Notes on each applicable trading day; • during the five business day period after any five consecutive trading day period (the "measurement period") in which the trading price per $1,000 principal amount of the 2024 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate for the notes on each such trading day; • if we call any or all of the 2024 Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the relevant redemption date; or • upon the occurrence of specified corporate events, as specified in each indenture governing the 2024 Notes. Regardless of the foregoing conditions, holders may convert their 2024 Notes at their option in multiples of $1,000 principal amount during the period from, and including, March 1, 2024 to the close of business on the second scheduled trading day immediately preceding the maturity date. Upon conversion, the 2024 Notes can be settled in cash, shares of our common stock or any combination of cash and shares of common stock at our option. Holders may also require us to repurchase the 2024 Notes if we undergo a "fundamental change," as defined in each indenture governing the 2024 Notes, at a repurchase price equal to 100% of the principal amount, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. Additionally, we may redeem for cash all or any portion of the 2024 Notes on or after June 5, 2021, if the last reported sale price of our common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the notes to be redeemed, plus any accrued and unpaid interest to, but excluding, the redemption date. As of June 30, 2018, none of the conditions permitting holders to convert their 2024 Notes had been satisfied and no shares of our common stock had been issued in connection with any conversions of the 2024 Notes. Based on the closing price of our common stock of $15.39 per share on June 29, 2018, the conversion value of the 2024 Notes was less than the principal amount of the 2024 Notes outstanding on a per 2024 Note basis. In accordance with accounting for debt with conversions and other options, we bifurcated the principal amount of the 2024 Notes into liability and equity components. The initial liability component of the 2024 Notes was valued at $458.3 million based on the contractual cash flows discounted at an appropriate comparable market non-convertible debt borrowing rate at the date of issuance of 5.5% with the equity component representing the residual amount of the proceeds of $141.7 million , which was recorded as a debt discount. Issuance costs were allocated pro rata based on the relative initial carrying amounts of the liability and equity components. As a result, transaction costs of $0.5 million and $0.1 million and initial purchasers' discount of $11.5 million and $3.5 million were attributable to the liability component ("debt discounts") and equity component of the 2024 Notes, respectively. The debt discount and the issuance costs allocated to the liability component are amortized as additional interest expense over the term of the 2024 Notes using the effective interest method of 3.8% for all periods presented. The liability and equity components of the 2024 Notes consisted of the following (in thousands): As of June 30, 2018 2024 Notes Liability component: Principal $ 600,000 Less: 2024 Notes debt discounts, net of amortization (151,400 ) Net carrying amount $ 448,600 The unamortized issuance costs as of June 30, 2018 will be amortized over a weighted-average remaining period of approximately 6 years. Interest expense for the three and six months ended June 30, 2018 related to the 2024 Notes consisted of the following (in thousands): Three and Six Months Ended June 30, 2018 2024 Notes Coupon interest $ 520 Amortization of 2024 Notes debt discounts 2,259 Total interest expense recognized $ 2,779 In connection with the 2024 Notes offering, the Company entered into Capped Calls with certain counterparties affiliated with the initial purchasers of the 2024 Notes. The Capped Calls are expected to reduce potential dilution of earnings per share upon conversion of the 2024 Notes, and have an initial strike price of $23.17 per share, which corresponds to the initial conversion price of the 2024 Notes and which have a cap price of $34.32 per share. The Capped Calls do not meet the criteria for separate accounting as a derivative as they are indexed to our own stock and are accounted for as freestanding financial instruments. The premiums paid for the purchase of the Capped Calls in the amount of $65.2 million have been recorded as a reduction of the Company's additional paid-in capital in stockholder's equity in the accompanying Condensed Consolidated Financial Statements and fair values of the Capped Calls are not re-measured at each reporting period. Convertible Senior Notes due 2035 In June 2015, we issued $460.0 million principal amount of Series A Notes and $460.0 million principal amount of 1.625% Convertible Senior Notes due 2035 (the “Series B Notes” and together with the Series A Notes, the "2035 Notes" and the 2035 Notes, together with the 2024 Notes, the "Convertible Senior Notes"), including the full exercise of the initial purchasers' over-allotment option, in a private placement to qualified institutional purchasers pursuant to an exemption from registration provided by Section 4(a)(2) and Rule 144A under the Securities Act. The net proceeds after the initial purchasers' discount of $23.0 million and issuance costs of $0.5 million from the 2035 Notes were $896.5 million . The Series A Notes and Series B Notes bear interest at 1.000% per year and 1.625% per year, respectively, payable semiannually in arrears on June 1 and December 1 of each year, beginning December 1, 2015. The 2035 Notes mature on June 1, 2035, unless earlier repurchased, redeemed or converted. The 2035 Notes are unsecured obligations and rank senior in right of payment to any of our indebtedness that is expressly subordinated in right of payment to the 2035 Notes. They rank equally in right of payment with all of our existing and future liabilities that are not expressly subordinated to the 2035 Notes and effectively rank junior in right of payment to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness. They are structurally junior to all indebtedness and other liabilities (including trade payables) of our subsidiaries. The 2035 Notes do not contain any financial covenants and do not restrict us from paying dividends or issuing or repurchasing our other securities. The initial conversion rate on each series of 2035 Notes is 16.4572 shares of our common stock per $1,000 principal amount of 2035 Notes, which is equivalent to an initial conversion price of approximately $60.76 per share of common stock. The conversion rate of each series of 2035 Notes may be adjusted upon the occurrence of certain specified events, but not for accrued and unpaid interest. Holders may convert the 2035 Notes at their option in multiples of $1,000 principal amount prior to March 1, 2035, excluding the period from March 1, 2020 to June 1, 2020 in the case of the Series A Notes and March 1, 2022 to June 1, 2022 in the case of the Series B Notes, only under the following circumstances: • during any calendar quarter commencing after the calendar quarter ended on September 30, 2015 (and only during such calendar quarter), if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price for the 2035 Notes of the relevant series on each applicable trading day; • during the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of Series A Notes or Series B Notes, as applicable, for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate for the notes of the relevant series on each such trading day; • if we call any or all of the 2035 Notes of a series for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the relevant redemption date; or • upon the occurrence of specified corporate events, as specified in each indenture governing the 2035 Notes. Regardless of the foregoing conditions, holders may convert their 2035 Notes at their option in multiples of $1,000 principal amount at any time during the period from March 1, 2020 to June 1, 2020 in the case of the Series A Notes and during the period from March 1, 2022 to June 1, 2022 in the case of the Series B Notes, or after March 1, 2035 until maturity for either series of 2035 Notes. Upon conversion, the 2035 Notes can be settled in cash, shares of our common stock or any combination thereof at our option. We may be required by holders of the 2035 Notes to repurchase all or any portion of their 2035 Notes at 100% of the principal amount plus accrued and unpaid interest, on each of June 1, 2020, June 1, 2025 and June 1, 2030, in the case of the Series A Notes, and each of June 1, 2022, June 1, 2025 and June 1, 2030 in the case of the Series B Notes. Holders may also require us to repurchase the 2035 Notes if we undergo a "fundamental change," as defined in each indenture governing the 2035 Notes, at a purchase price equal to 100% of the principal amount, plus accrued and unpaid interest. Additionally, we may redeem for cash all or any portion of the Series B Notes on or after June 1, 2020 until June 1, 2022 if the last reported sale price of our common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending not more than three trading days immediately preceding the date we provide notice of redemption. We also may redeem for cash all or any portion of the Series A Notes on or after June 1, 2020 until maturity and all or any portion of the Series B Notes on or after June 1, 2022 until maturity, regardless of the foregoing sale price condition. In accordance with accounting for debt with conversions and other options, we allocated the principal amount of the 2035 Notes into liability and equity components. We also allocated the total amount of initial purchasers' discount and transaction costs incurred to the liability and equity components using the same proportions as the proceeds from the 2035 Notes. Transaction costs of $0.4 million and $0.1 million and initial purchasers' discount of $17.6 million and $5.4 million were attributable to the liability component and equity component of the 2035 Notes, respectively. Repurchase of portion of Series A Notes In May 2018, we used approximately $330.4 million of the net proceeds from the offering of the 2024 Notes to repurchase $340.2 million in principal amount of the Series A Notes. The repurchase was accounted for as a partial extinguishment of the Series A Notes. The consideration of approximately $330.4 million used to repurchase the Series A Notes was allocated between the liability and equity components of the amount extinguished by determining the fair value of the liability component immediately prior to the debt extinguishment and allocating that portion of the repurchase price to the liability component in the amount of $317.4 million . The residual of the repurchase price of $13.0 million was allocated to the equity component of the Series A Notes as a reduction of additional paid-in capital. The fair value of the debt extinguished was calculated using a discount rate of 4.5% , representing an estimate of the Company's borrowing rate at the date of repurchase with a remaining expected life of two years. As part of the repurchase, we wrote-off a portion of the unamortized debt issuance cost apportioned to the principal amount of Series A Notes repurchased. We also recorded a loss on extinguishment of the Series A Notes of $10.8 million in Other Expense, net, representing the difference between the consideration attributed to the liability component and the sum of the net carrying amount of the liability component and unamortized costs. As of June 30, 2018 , $119.8 million aggregate principal amount of the Series A Notes remains outstanding. The liability and equity components of the remaining portion of Series A Notes and Series B Notes consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Series A Notes Series B Notes Series A Notes Series B Notes Liability component: Principal $ 119,828 $ 460,000 $ 460,000 $ 460,000 Less: 2035 Notes debt discount, net of amortization (11,248 ) (77,733 ) (53,762 ) (86,660 ) Net carrying amount $ 108,580 $ 382,267 $ 406,238 $ 373,340 Equity component, net of issuance costs $ 79,555 $ 117,834 $ 92,567 $ 117,834 The unamortized discounts and issuance costs as of June 30, 2018 will be amortized over a weighted-average remaining period of approximately 4 years. Interest expense for the three and six months ended June 30, 2018 related to the 2035 Notes consisted of the following (in thousands): Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 Series A Notes Series B Notes Series A Notes Series B Notes Coupon interest $ 788 $ 1,848 $ 1,938 $ 3,717 Amortization of 2035 Notes debt discount 3,700 4,490 8,957 8,927 Total interest expense recognized $ 4,488 $ 6,338 $ 10,895 $ 12,644 Effective interest rate on the liability component 6.3 % 6.7 % 6.3 % 6.8 % Interest expense for the three and six months ended June 30, 2017 related to the 2035 Notes consisted of the following (in thousands): Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 Series A Notes Series B Notes Series A Notes Series B Notes Coupon interest $ 1,150 $ 1,869 $ 2,300 $ 3,738 Amortization of 2035 Notes debt discount 5,058 4,283 10,051 8,515 Total interest expense recognized $ 6,208 $ 6,152 $ 12,351 $ 12,253 Effective interest rate on the liability component 6.4 % 6.8 % 6.4 % 6.9 % Prepaid Forward Stock Purchase In connection with the issuance of the 2035 Notes, we also entered into privately negotiated prepaid forward stock purchase transactions (each a “Prepaid Forward”) with one of the initial purchasers of the 2035 Notes (the “Forward Counterparty”), pursuant to which we paid approximately $150.0 million . The amount of the prepaid is equivalent to approximately 3.3 million shares which are to be settled on or around June 1, 2020 and June 1, 2022, respectively, subject to any early settlement, in whole or in part, of each Prepaid Forward. The Prepaid Forwards are intended to facilitate privately negotiated derivative transactions by which investors in the 2035 Notes will be able to hedge their investment in the 2035 Notes. In the event we pay any cash dividends on our common stock, the Forward Counterparty will pay an equivalent amount back to us. The related shares were accounted for as a repurchase of common stock, and are presented as Treasury Stock in the unaudited condensed consolidated balance sheets. The 3.3 million shares of common stock purchased under the Prepaid Forwards are excluded from weighted-average shares outstanding for basic and diluted EPS purposes although they remain legally outstanding.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases We lease our facilities under various non-cancelable operating leases, which expire on various dates through the year ending December 31, 2027. Rent expense is recognized using the straight-line method over the term of the lease. Rent expense, net of sublease income, was $5.2 million and $4.4 million for the three months ended June 30, 2018 and 2017 , respectively. Rent expense, net of sublease income, was $9.8 million and $8.5 million for the six months ended June 30, 2018 and 2017 , respectively. The aggregate future non-cancelable minimum rental payments on our operating leases, as of June 30, 2018 , are as follows (in thousands): Years Ending December 31, Amount 2018 (remaining six months) $ 7,330 2019 15,980 2020 15,671 2021 14,202 2022 11,937 2023 and thereafter 53,618 Total $ 118,738 Total future non-cancelable minimum rental payments have not been reduced by future minimum sublease rentals totaling $5.9 million . We are party to letters of credit totaling $3.7 million and $3.3 million as of June 30, 2018 and December 31, 2017 , respectively, issued primarily in support of operating leases for 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. We may issue forecasts and orders for components and products that are non-cancelable to reduce manufacturing lead times and plan for adequate supply. As of June 30, 2018 and December 31, 2017 , we had non-cancelable open orders of $12.5 million and $11.6 million , respectively. We are required to record a liability for firm, non-cancelable and unconditional purchase commitments with contract manufacturers and suppliers for quantities in excess of our future demand forecasts. As of June 30, 2018 , we have not accrued any significant costs for such non-cancelable commitments. Purchase Obligations As of June 30, 2018 , we had approximately $13.7 million of non-cancelable firm purchase commitments primarily for purchases of software and services. In situations in which we have received delivery of the goods or services as of June 30, 2018 under purchase orders outstanding as of the same date, such amounts are reflected in the condensed consolidated balance sheet as accounts payable or accrued liabilities and are excluded from the $13.7 million . Litigation From time to time, we are involved in claims and legal proceedings that arise in the ordinary course of business. Any claims or proceedings against us, whether meritorious or not, could be time consuming, result in costly litigation, require significant amounts of management time, result in the diversion of significant operational resources, or require us to enter into agreements which may not be available on terms favorable to us or at all. 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 June 30, 2018 , there have been no claims under any indemnification provisions.

Common Shares Reserved for Issu

Common Shares Reserved for Issuance	6 Months Ended
	Jun. 30, 2018
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 100,000,000 shares of convertible preferred stock with a par value of $0.0001 per share, none of which were issued and outstanding as of June 30, 2018 or December 31, 2017 . 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 June 30, 2018 and December 31, 2017 . 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 our Board of Directors, subject to the prior rights of holders of all classes of convertible preferred stock outstanding. We had reserved shares of common stock for issuance as follows (in thousands): As of June 30, 2018 As of December 31, 2017 Reserved under stock award plans 39,449 35,838 Convertible Senior Notes 35,442 15,141 Employee Stock Purchase Plan (ESPP) 3,817 2,985 Total 78,708 53,964

Equity Award Plans

Equity Award Plans	6 Months Ended
	Jun. 30, 2018
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. Our 2013 Plan provides for annual increases in the number of shares available for issuance on the first day of each fiscal year. Awards granted under the 2013 Plan vest over the periods determined by our Board of Directors or compensation committee of our 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. Stock that is purchased prior to vesting is subject to our right of repurchase at any time following termination of the participant's service for so long as such stock remains unvested. Approximatel y 12.8 million shares and 11.7 million shares of our common stock were reserved for future grants as of June 30, 2018 and December 31, 2017 , respectively, 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. An aggregate of approximately 3.8 million shares and 3.0 million shares of common stock were available for future issuance as of June 30, 2018 and December 31, 2017 , respectively, under our ESPP. 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 period and a summary of information related to options outstanding and options exercisable are presented below (in thousands, except per share amounts and contractual life years): Options Outstanding Number of Shares Weighted- Average Exercise Price (per share) Weighted- Aggregate Intrinsic Value Balance — December 31, 2017 4,433 $ 12.31 4.8 $ 28,090 Exercised (648 ) 7.07 6,562 Cancelled (91 ) 41.37 Balance — June 30, 2018 3,694 $ 12.51 4.5 $ 27,273 Options exercisable — June 30, 2018 3,694 $ 12.51 4.5 $ 27,273 Restricted Stock Award ("RSA") and Restricted Stock Unit ("RSU") Activity A summary of the activity for our restricted common stock, RSAs and RSUs, including those subject to performance conditions, during the reporting period and a summary of information related to unvested restricted common stock, RSAs and RSUs, including those with vesting subject to the achievement of a performance condition, are presented below (in thousands, except per share amounts and contractual life years): Number of Weighted- Weighted- Aggregate Unvested balance — December 31, 2017 20,017 $ 17.09 1.3 $ 284,255 Granted 10,186 15.13 Vested (5,173 ) 18.08 Cancelled (2,067 ) 16.78 Unvested balance — June 30, 2018 22,963 $ 15.78 1.4 $ 353,401 Unvested awards for which the requisite service period has not been rendered and vesting is subject to the achievement of a performance condition — June 30, 2018 4,152 $ 15.40 0.9 $ 63,897 Stock-Based Compensation We record stock-based compensation based on the fair value as determined on the date granted. We determine the fair value of stock options and 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 grant 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 this probability assessment. We recognize such compensation expense on a straight-line basis over the employee's requisite service period. 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 for the offering periods beginning in May 2018: Three and Six Months Ended June 30, 2018 Three and Six Months Ended June 30, 2017 Fair value of common stock $16.69 $15.65 Risk-free interest rate 2.08% - 2.23% 1.05% - 1.12% Expected term (in years) 0.5 - 1.0 0.5 - 1.0 Volatility 32% - 35% 50% - 52% Dividend yield —% —% Stock-based compensation expense related to stock options, ESPP and restricted stock unit awards is included in the condensed consolidated statements of operations as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Cost of product, subscription and support revenue $ 3,558 $ 4,017 $ 7,180 $ 8,377 Cost of professional services revenue 3,448 3,375 7,350 7,047 Research and development 12,418 14,057 26,771 28,582 Sales and marketing 12,223 10,219 25,200 24,234 General and administrative 7,245 7,729 14,539 15,046 Total $ 38,892 $ 39,397 $ 81,040 $ 83,286 As of June 30, 2018 , total compensation cost related to stock-based awards not yet recognized was $286.2 million , which is expected to be amortized on a straight-line basis over the weighted-average remaining vesting period of approximately 2.7 years.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
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. We recognized a provision for income taxes of $1.4 million and $1.0 million for the three months ended June 30, 2018 and 2017 , respectively. For both the three months ended June 30, 2018 and 2017 , the provision for income taxes was primarily comprised of income taxes in foreign jurisdictions and withholding taxes.

Net Loss per Share

Net Loss per Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share Basic net 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 potentially dilutive common shares, including common stock issuable upon exercise of stock options, conversion of the Convertible Senior Notes, and unvested restricted common stock and stock units. As we had net losses for the three and six months ended June 30, 2018 and 2017 , all potentially dilutive 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 June 30, Six Months Ended June 30, 2018 2017* 2018 2017* Numerator: Net loss $ (72,859 ) $ (68,339 ) $ (144,689 ) $ (145,556 ) Denominator: Weighted average number of shares outstanding—basic and diluted 189,696 176,645 188,085 174,453 Net loss per share—basic and diluted $ (0.38 ) $ (0.39 ) $ (0.77 ) $ (0.83 ) * Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard. The following outstanding options and unvested shares 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 anti-dilutive (in thousands): As of June 30, 2018 2017 Options to purchase common stock 3,694 5,474 Unvested early exercised common shares — — Unvested restricted stock awards and units 22,963 21,994 Convertible senior notes 35,442 15,141 ESPP shares 156 210

Employee Benefit Plan

Employee Benefit Plan	6 Months Ended
	Jun. 30, 2018
Retirement Benefits [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. All participants’ interests in their deferrals are 100% vested when contributed. We are responsible for administrative costs of the 401(k) Plan and have made no matching contributions into our 401(k) Plan since inception. Under the 401(k) Plan, pre-tax contributions are allocated to each participant’s individual account and are then invested in selected investment alternatives according to the participants’ directions. The 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 the 401(k) Plan and earnings on those contributions are not taxable to the employees until distributed, and all contributions are deductible by us when and if made.

Segment and Major Customers Inf

Segment and Major Customers Information	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Segment and Major Customers Information	Segment and Major Customers Information Disaggregation of revenue by geography 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 define our regions into United States ("U.S."), Europe, the Middle East, and Africa ("EMEA"), Asia Pacific and Japan ("APAC"), and all remaining geographies (primarily Latin America and Canada) included in Others. 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 June 30, 2018 2017* 2018 2017* 2018 2017* 2018 2017* US EMEA APAC Other Product and related subscription and support $ 75,104 $ 75,917 $ 21,393 $ 19,715 $ 20,787 $ 18,631 $ 5,107 $ 4,843 Cloud subscription and managed services 30,394 28,501 6,462 4,106 5,410 4,623 2,771 1,759 Professional services 22,887 24,663 4,275 3,290 4,078 3,911 4,028 1,763 Total revenue $ 128,385 $ 129,081 $ 32,130 $ 27,111 $ 30,275 $ 27,165 $ 11,906 $ 8,365 Six Months Ended June 30, 2018 2017* 2018 2017* 2018 2017* 2018 2017* US EMEA APAC Other Product and related subscription and support $ 148,732 $ 147,114 $ 43,318 $ 38,187 $ 40,535 $ 36,389 $ 10,899 $ 9,600 Cloud subscription and managed services 60,249 59,442 13,107 8,164 10,819 9,641 5,242 3,286 Professional services 45,352 47,810 9,723 6,161 6,576 6,880 7,214 3,807 Total revenue $ 254,333 $ 254,366 $ 66,148 $ 52,512 $ 57,930 $ 52,910 $ 23,355 $ 16,693 We generate revenue from sales of our products and related subscriptions and support, cloud subscription and managed services, and professional services. Our product and related subscription and support revenue consists primarily of revenue from the sale of our intelligence-dependent security appliances and software, subscriptions to our dynamic threat intelligence (DTI) updates, and support and maintenance. Our intelligent-dependent security appliances include NX (network security), EX (email security), HX (endpoint security), and FX (file security). Product and related subscription and support also includes our enterprise forensic solutions (PX) network forensics appliance and our central management system (CMS) management appliance. Because these PX and CMS appliances are not dependent on regular threat intelligence updates, revenue is recognized upon shipment. Cloud subscription and managed services consists of revenue from the sale of our cloud-based email security, our Threat Analytics Platform (TAP), our Helix orchestration and automation platform, and our standalone threat intelligence subscriptions. Professional services revenue consists of revenue from the sale of security consulting services, including incident response, compromise and security program assessments, red teaming and training. The following table depicts the disaggregation of revenue according to revenue type and is consistent with how we evaluate our financial performance (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2018 2017* 2018 2017* Revenue by Category Product and related subscription and support $ 122,392 $ 119,107 $ 243,484 $ 231,291 Cloud subscription and managed services 45,037 38,990 89,418 80,535 Professional services 35,267 33,625 68,864 64,655 Total revenue $ 202,696 $ 191,722 $ 401,766 $ 376,481 Long lived assets by geography Long lived assets by geographic region based on physical location is as follows (in thousands): As of June 30, 2018 As of December 31, 2017 Property and Equipment, net: United States $ 71,702 $ 60,202 International 9,671 11,155 Total property and equipment, net $ 81,373 $ 71,357 For each of the three months ended June 30, 2018 and 2017 , one distributor represented 20% for each period and one reseller represented 15% and 12% , respectively, of our total revenue. For the six months ended June 30, 2018 and 2017 , one distributor represented 20% and 19% , respectively, and one reseller represented 15% and 12% , respectively, of our total revenue. As of June 30, 2018 , one customer represented 15% of our net accounts receivable balance, and as of December 31, 2017 , no customer represented 10% or more of our net accounts receivable balance. * Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Description of Business and S23

Description of Business and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
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 unaudited condensed consolidated financial statements have been prepared on the same basis as our annual consolidated 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 six months ended June 30, 2018 are not necessarily indicative of the results to be expected for the year ending December 31, 2018 or for any other interim period or for any other future year. The balance sheet as of December 31, 2017 has been derived from audited consolidated financial statements at that date but does not include all information required by U.S. GAAP for annual consolidated financial statements. The accompanying unaudited 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, 2017 included in our Annual Report on Form 10-K for the year ended December 31, 2017 . The Company adopted Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASC 606"), effective January 1, 2018 using the full retrospective method. The cumulative effect of the adoption was recognized as an increase to accumulated deficit of $113.0 million on January 1, 2018 and impacted certain other prior period amounts. Certain amounts and disclosures set forth in this Quarterly Report on Form 10-Q have been updated to comply with the new standards.
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, determining the nature and timing of satisfaction of performance obligations, determining the standalone selling price ("SSP") of performance obligations, subscriptions and services, commissions expense including the period of benefit of customer acquisition cost, bonus expense, future taxable income, contract manufacturer liabilities, litigation and settlement costs and other loss contingencies, fair value of our equity awards, achievement of targets for performance stock units, fair value of the liability and equity components of the Convertible Senior Notes and the purchase price allocation of acquired businesses. We base our estimates on historical experience and 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.
Revenue from Contracts with Customers	Revenue from Contracts with Customers Revenue is recognized when all of the following criteria are met: • Identification of the contract, or contracts, with a customer - A contract with a customer exists when (i) we enter into an enforceable contract with a customer that defines each party’s rights regarding the goods or services to be transferred and identifies the payment terms related to these goods or services, (ii) the contract has commercial substance and the parties are committed to perform, and (iii) we determine that collection of substantially all consideration to which it will be entitled in exchange for goods or services that will be transferred is probable based on the customer’s intent and ability to pay the promised consideration. • Identification of the performance obligations in the contract - Performance obligations promised in a contract are identified based on the goods or services that will be transferred to the customer that are both capable of being distinct, whereby the customer can benefit from the goods or service either on its own or together with other resources that are readily available from third parties or from us, and are distinct in the context of the contract, whereby the transfer of the goods or services is separately identifiable from other promises in the contract. To the extent a contract includes multiple promised goods or services, we apply judgment to determine whether promised goods or services are capable of being distinct and distinct in the context of the contract. If these criteria are not met the promised goods or services are accounted for as a combined performance obligation. • Determination of the transaction price - The transaction price is determined based on the consideration to which we will be entitled in exchange for transferring goods or services to the customer adjusted for estimated variable consideration, if any. We typically estimate the transaction price impact of discounts offered to the customers for early payments on receivables or rebates based on sales target achievements. Constraints are applied when estimating variable considerations based on historical experience where applicable. • Allocation of the transaction price to the performance obligations in the contract - If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative SSP basis. Determination of SSP requires judgement. We determine standalone selling price taking into account available information such as historical selling prices of the performance obligation, geographic location, overall strategic pricing objective, market conditions and internally approved pricing guidelines related to the performance obligations. • Recognition of revenue when, or as, we satisfy performance obligation - We satisfy performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at or over the time the related performance obligation is satisfied by transferring a promised good or service to a customer. Nature of Products and Services We generate revenue from the sales of physical and virtual security appliances (products), subscriptions, support and maintenance and professional services, primarily through our indirect relationships with our partners or direct relationships with end customers through our direct sales force. We account for our performance obligations in accordance with ASC 606, and all related interpretations. Our security appliance deliverables include proprietary operating system software, which together with regular security intelligence updates deliver the essential functionality of our appliance-based security products. We combine intelligence dependent appliances and software licenses with the related intelligence subscription and support as a single performance obligation. As a result, we recognize intelligence-dependent appliance and software license revenue ratably over the longer of the estimated useful life of the related appliance and license (when our contracts contain material right of renewal options) or the contractual term, rather than recognizing revenue at the time of shipping. For subscription and support contracts where the term is less than the estimated useful life of the appliance and software license, the intelligence subscription and support revenue is recognized ratably over the contractual term and the allocated value of the material right performance obligations is recognized in the period between the end of the contractual term and the estimated useful life of the appliance. Where our contracts do not contain material right of renewal options, or the contractual term is longer than the useful life, we expect to recognize appliance and software license revenue ratably over the contractual term. Significant judgement is required in estimating the useful life of our security appliances that are dependent on intelligence and assessing the material rights associated with it. Revenue from subscriptions to our cloud-based services, which allow customers to use our hosted security software over a contracted period without taking possession of the software and managed services where FireEye provides managed detection and response services for the customer are recognized over the contractual term. We also have a small portion of our revenue from appliances and software that are not dependent on regular threat intelligence updates. Revenue from these appliances and software is therefore recognized when ownership is transferred to our customers, typically upon shipment. Professional services, which include incident response, compromise assessments, and other security consulting services are offered on a time-and-materials basis or through a fixed fee arrangement, and we recognize the associated revenue as the services are delivered. In instances where the timing of revenue recognition differs from the timing of invoicing, we have determined our contracts generally do not include a significant financing component. The primary purpose of our invoicing terms is to provide customers with simplified and predictable ways of purchasing our products and services, not to receive financing from our customers or to provide customers with financing. Examples include invoicing at the beginning of a subscription term with revenue recognized ratably over the contract period. Deferred Costs of Revenue Deferred costs of revenue consists of appliance related direct and incremental costs that are capitalized and will be amortized on a systematic basis that is consistent with the pattern of transfer to which the asset relates. Deferred costs of revenue that will be realized within the succeeding 12 month period are classified as current, and included in prepaid expenses and other current assets on the consolidated balance sheets. The remaining balance is classified as non-current, and included in deposits and other long-term assets. Deferred Revenue (Contract Liabilities) and Contract Assets Deferred revenue consists of amounts that have been invoiced and for which the Company has the right to bill, but that have not been recognized as revenue because the related goods or services have not been transferred. Deferred revenue that will be realized during the succeeding 12-month period is recorded as current, and the remaining deferred revenue is recorded as non-current. Deferred revenue presented in the consolidated balance sheet and notes thereto is net of contract assets. Our contract assets consist of assets typically resulting when revenue recognized exceeds the amount billed or billable to the customer due to allocation of transaction price. Deferred Commissions Our customer acquisition costs are primarily related to sales commissions and related payroll taxes earned by our sales force and such costs are considered incremental costs to obtain a contract. Sales commissions for initial contracts are deferred and then amortized taking into consideration the pattern of transfer to which the asset relates and may include expected renewal periods where renewal commissions are not commensurate with the initial commissions period. We typically recognize the initial commissions over the longer of the customer relationship (generally estimated to be four years) or over the same period as the initial revenue arrangement to which these costs relate. Renewal commissions not commensurate with the initial commissions paid are generally amortized over the renewal period. Deferred commissions that will amortize within the succeeding 12 month period are classified as current, and included in prepaid expenses and other current assets on the consolidated balance sheet. The remaining balance is classified as non-current, and included in deposits and other long-term assets.
Accounts Receivable	Accounts Receivable Trade accounts receivable are recorded at the billable amount where we have the unconditional right to bill, net of allowances for doubtful accounts. The allowance for doubtful accounts is based on our assessment of the collectability of accounts. Management regularly reviews the adequacy of the allowance for doubtful accounts by considering the age of each outstanding invoice, each customer's expected ability to pay and collection history, when applicable, to determine whether a specific allowance is appropriate. Accounts receivable deemed uncollectible are charged against the allowance for doubtful accounts when identified.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2018, the FASB issued Accounting Standards Update (ASU) 2018-02 that provides companies with an option to reclassify stranded tax effects resulting from enactment of the Tax Cuts and Jobs Act ("TCJA") from accumulated other comprehensive income to retained earnings. The guidance will be effective for the Company beginning in the first quarter of 2019 with early adoption permitted, and would be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the tax rate as a result of TCJA is recognized. The Company has not made a determination as to which alternative methods it will use when it adopts this standard, but does not expect the adoption of this ASU to have a material impact on its results of operations, financial position and cash flows. In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This standard eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge (i.e. Step 2 of the current guidance), instead measuring the impairment charge as the excess of the reporting unit's carrying amount over its fair value (i.e. Step 1 of the current guidance). The guidance is effective for us beginning in the first quarter of 2020, and should be applied prospectively. Early adoption is permitted for impairment testing dates after January 1, 2017. The adoption of this standard is not expected to have a significant impact on our consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This standard changes the impairment model for most financial assets and certain other instruments by introducing a current expected credit loss (CECL) model. The CECL model is a more forward-looking approach based on expected losses rather than incurred losses, requiring entities to estimate and record losses expected over the remaining contractual life of an asset. The guidance is effective for us beginning in the first quarter of 2020. Early adoption beginning in 2019 is permitted. We are currently evaluating the impact the adoption of this guidance will have on our consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). This standard is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The guidance is effective for us beginning in the first quarter of 2019 and may be applied on a modified retrospective basis or prospective basis. Early adoption is permitted. We expect the adoption of this standard to have a material impact on our consolidated financial statements and related disclosures.
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.

Description of Business and S24

Description of Business and Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Adoption of ASC 606	We adjusted our condensed consolidated financial statements from amounts previously reported due to the adoption of ASU 2014-09, Revenue from Contracts with Customers (Topic 606). Select condensed consolidated balance sheet line items, which reflect the adoption of this standard, are as follows (in thousands): As of December 31, 2017 Balance Sheet: As Previously Reported Impact of Adoption As Adjusted Accounts receivable, net $ 140,049 6,268 $ 146,317 Prepaid expenses and other current assets $ 34,541 59,258 $ 93,799 Deposits and other long-term assets $ 11,537 61,230 $ 72,767 Deferred revenue, current portion $ 443,064 103,551 $ 546,615 Deferred revenue, non-current portion $ 227,680 135,805 $ 363,485 Stockholders' equity $ 744,816 (112,600 ) $ 632,216 Select unaudited condensed consolidated statement of operations line items, which reflect the adoption of ASC 606, are as follows (in thousands): Three Months Ended June 30, 2017 Condensed Consolidated Statement of Operations As Previously Reported Impact of Adoption As Adjusted Total revenue $ 185,472 6,250 $ 191,722 Total cost of revenue $ 66,692 1,102 $ 67,794 Total operating expenses $ 178,210 2,755 $ 180,965 Operating loss $ (59,430 ) 2,393 $ (57,037 ) Net loss attributable to common stockholders $ (70,732 ) 2,393 $ (68,339 ) Net loss per share attributable to common stockholders, basic and diluted $ (0.40 ) 0.01 $ (0.39 ) Six Months Ended June 30, 2017 Condensed Consolidated Statement of Operations As Previously Reported Impact of Adoption As Adjusted Total revenue $ 359,210 17,271 $ 376,481 Total cost of revenue $ 131,297 2,244 $ 133,541 Total operating expenses $ 359,057 6,863 $ 365,920 Operating loss $ (131,144 ) 8,164 $ (122,980 ) Net loss attributable to common stockholders $ (153,720 ) 8,164 $ (145,556 ) Net loss per share attributable to common stockholders, basic and diluted $ (0.88 ) 0.05 $ (0.83 ) Select unaudited condensed consolidated statement of cash flows line items, which reflect the adoption of ASC 606, are as follows (in thousands): Six Months Ended June 30, 2017 Condensed Consolidated Statement of Cash flows As Previously Reported Impact of Adoption As Adjusted Cash flows from operating activities: Net loss $ (153,720 ) $ 8,164 $ (145,556 ) Changes in operating assets and liabilities, net of business acquisitions: Accounts receivable $ 10,318 5,880 $ 16,198 Prepaid expenses and other assets $ (10,637 ) 9,132 $ (1,505 ) Deferred revenue $ (34,780 ) (23,149 ) $ (57,929 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on a Recurring Basis	The following table presents our assets and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of June 30, 2018 As of December 31, 2017 Description Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 204 $ — $ — $ 204 $ 208 $ — $ — $ 208 Treasury bills — — — — 3,098 — — 3,098 Commercial Paper — — — — — — — — Total cash equivalents 204 — — 204 3,306 — — 3,306 Short-term investments: Certificates of deposit — — — — — — — — Commercial paper — — — — — 4,987 — 4,987 Corporate notes and bonds — 448,401 — 448,401 — 438,024 — 438,024 U.S. Government agencies — 275,574 — 275,574 — 272,900 — 272,900 Total short-term investments — 723,975 — 723,975 — 715,911 — 715,911 Total assets measured at fair value $ 204 $ 723,975 $ — $ 724,179 $ 3,306 $ 715,911 $ — $ 719,217

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Summary of Investments	Our investments consisted of the following (in thousands): As of June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalent Short-Term Investments Commercial paper $ — $ — $ — $ — $ — $ — Corporate notes and bonds 450,939 4 (2,542 ) 448,401 — 448,401 U.S. Government agencies 276,531 — (957 ) 275,574 — 275,574 Total $ 727,470 $ 4 $ (3,499 ) $ 723,975 $ — $ 723,975 As of December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalents Short-Term Investments Commercial paper $ 4,989 $ — $ (2 ) $ 4,987 $ — $ 4,987 Corporate notes and bonds 439,851 2 (1,829 ) 438,024 — 438,024 Treasury bills 3,098 — — 3,098 3,098 — U.S. Government agencies 273,950 — (1,050 ) 272,900 — 272,900 Total $ 721,888 $ 2 $ (2,881 ) $ 719,009 $ 3,098 $ 715,911
Summary of Gross Unrealized Losses and Fair Value of Investments in a Continuous Unrealized Loss Position	The following tables present the gross unrealized losses and related fair values of our investments that have been in a continuous unrealized loss position (in thousands): As of June 30, 2018 Less Than 12 Months Greater Than 12 Months Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Commercial paper $ — $ — $ — $ — $ — $ — Corporate notes and bonds 211,707 (1,360 ) 231,668 (1,182 ) 443,375 (2,542 ) U.S. Government agencies 168,440 (732 ) 105,078 (225 ) 273,518 (957 ) Total $ 380,147 $ (2,092 ) $ 336,746 $ (1,407 ) $ 716,893 $ (3,499 ) As of December 31, 2017 Less Than 12 Months Greater Than 12 Months Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Commercial paper $ 4,987 $ (2 ) $ — $ — $ 4,987 $ (2 ) Corporate notes and bonds 284,499 (1,484 ) 153,525 (345 ) 438,024 (1,829 ) U.S. Government agencies 117,132 (486 ) 155,768 (564 ) 272,900 (1,050 ) Total $ 406,618 $ (1,972 ) $ 309,293 $ (909 ) $ 715,911 $ (2,881 )
Summary of Contractual Maturities of Investments	The following table summarizes the contractual maturities of our investments at June 30, 2018 (in thousands): Amortized Cost Fair Value Due within one year $ 442,938 $ 441,165 Due within one to two years 284,532 282,810 Total $ 727,470 $ 723,975

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment, net consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Computer equipment and software $ 161,783 $ 144,438 Leasehold improvements 59,039 67,451 Furniture and fixtures 14,485 16,665 Machinery and equipment 447 447 Total property and equipment 235,754 229,001 Less: accumulated depreciation (154,381 ) (157,644 ) Total property and equipment, net $ 81,373 $ 71,357

Business Combinations (Tables)

Business Combinations (Tables)	6 Months Ended
	Jun. 30, 2018
Business Combinations [Abstract]
Schedule of Purchased Intangible Assets	Purchased intangible assets consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Developed technology $ 110,003 $ 103,903 Content 158,700 158,700 Customer relationships 111,090 111,090 Contract backlog 12,500 12,500 Trade names 15,560 15,560 Non-competition agreements 1,400 1,400 Total intangible assets 409,253 403,153 Less: accumulated amortization (241,024 ) (215,765 ) Total net intangible assets $ 168,229 $ 187,388
Schedule of Expected Annual Amortization Expense of Intangible Assets	The expected future annual amortization expense of intangible assets as of June 30, 2018 is presented below (in thousands): Years Ending December 31, Amount 2018 (remaining six mont hs) $ 25,067 2019 48,441 2020 33,903 2021 29,337 2022 18,209 and thereafter 13,272 Total $ 168,229

Restructuring Charges (Tables)

Restructuring Charges (Tables)	6 Months Ended
	Jun. 30, 2018
Restructuring and Related Activities [Abstract]
Summary of Restructuring Activities	The following table sets forth a summary of restructuring activities during the six months ended June 30, 2018 (in thousands): Facilities costs Balance, December 31, 2017 $ 935 Cash payments (92 ) Other adjustments (13 ) Balance, June 30, 2018 $ 830

Deferred Commissions (Tables)

Deferred Commissions (Tables)	6 Months Ended
	Jun. 30, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Commissions	Changes in the balance of total deferred commissions for the periods presented are as follows (in thousands): Three Months Ended June 30, 2018 As of March 31, 2018 $ 87,012 Commissions capitalized 17,013 Commissions recognized (14,054 ) As of June 30, 2018 $ 89,971 Six Months Ended June 30, 2018 As of December 31, 2017 $ 86,779 Commissions capitalized 30,499 Commissions recognized (27,307 ) As of June 30, 2018 $ 89,971

Deferred Revenue (Tables)

Deferred Revenue (Tables)	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Schedule of Deferred Revenue	Deferred revenue consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017* Product, subscription and support, current $ 476,818 $ 496,218 Professional services, current 48,799 50,397 Total deferred revenue, current 525,617 546,615 Product, subscription and support, non-current 353,927 363,313 Professional services, non-current 12 172 Total deferred revenue, non-current 353,939 363,485 Total deferred revenue $ 879,556 $ 910,100 Changes in the balance of unearned revenue for the periods presented are as follows (in thousands): Three Months Ended June 30, 2018 As of March 31, 2018 $ 886,136 Billings for the period 196,116 Revenue recognized (202,696 ) As of June 30, 2018 $ 879,556 Six Months Ended June 30, 2018 As of December 31, 2017* $ 910,100 Billings for the period 371,222 Revenue recognized (401,766 ) As of June 30, 2018 $ 879,556 *Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.
Expected Recognition of Remaining Performance Obligations	We expect to recognize these remaining performance obligations as follows (in percentages): Total Less than 1 year 1-2 years 2-3 years More than 3 years Deferred revenue 100% 60% 25% 12% 3% Backlog 100% 57% 34% 8% 1%

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of the Liability and Equity Components of the Convertible Senior Notes	The liability and equity components of the 2024 Notes consisted of the following (in thousands): As of June 30, 2018 2024 Notes Liability component: Principal $ 600,000 Less: 2024 Notes debt discounts, net of amortization (151,400 ) Net carrying amount $ 448,600 The liability and equity components of the remaining portion of Series A Notes and Series B Notes consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Series A Notes Series B Notes Series A Notes Series B Notes Liability component: Principal $ 119,828 $ 460,000 $ 460,000 $ 460,000 Less: 2035 Notes debt discount, net of amortization (11,248 ) (77,733 ) (53,762 ) (86,660 ) Net carrying amount $ 108,580 $ 382,267 $ 406,238 $ 373,340 Equity component, net of issuance costs $ 79,555 $ 117,834 $ 92,567 $ 117,834
Schedule of Interest Expense related to the Convertible Senior Notes	Interest expense for the three and six months ended June 30, 2018 related to the 2035 Notes consisted of the following (in thousands): Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 Series A Notes Series B Notes Series A Notes Series B Notes Coupon interest $ 788 $ 1,848 $ 1,938 $ 3,717 Amortization of 2035 Notes debt discount 3,700 4,490 8,957 8,927 Total interest expense recognized $ 4,488 $ 6,338 $ 10,895 $ 12,644 Effective interest rate on the liability component 6.3 % 6.7 % 6.3 % 6.8 % Interest expense for the three and six months ended June 30, 2017 related to the 2035 Notes consisted of the following (in thousands): Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 Series A Notes Series B Notes Series A Notes Series B Notes Coupon interest $ 1,150 $ 1,869 $ 2,300 $ 3,738 Amortization of 2035 Notes debt discount 5,058 4,283 10,051 8,515 Total interest expense recognized $ 6,208 $ 6,152 $ 12,351 $ 12,253 Effective interest rate on the liability component 6.4 % 6.8 % 6.4 % 6.9 % Interest expense for the three and six months ended June 30, 2018 related to the 2024 Notes consisted of the following (in thousands): Three and Six Months Ended June 30, 2018 2024 Notes Coupon interest $ 520 Amortization of 2024 Notes debt discounts 2,259 Total interest expense recognized $ 2,779

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Non-cancelable Minimum Rental Payments for Operating Leases	The aggregate future non-cancelable minimum rental payments on our operating leases, as of June 30, 2018 , are as follows (in thousands): Years Ending December 31, Amount 2018 (remaining six months) $ 7,330 2019 15,980 2020 15,671 2021 14,202 2022 11,937 2023 and thereafter 53,618 Total $ 118,738

Common Shares Reserved for Is34

Common Shares Reserved for Issuance (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Schedule of Reserved Shares of Common Stock for Issuance	We had reserved shares of common stock for issuance as follows (in thousands): As of June 30, 2018 As of December 31, 2017 Reserved under stock award plans 39,449 35,838 Convertible Senior Notes 35,442 15,141 Employee Stock Purchase Plan (ESPP) 3,817 2,985 Total 78,708 53,964

Equity Award Plans (Tables)

Equity Award Plans (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of the Activity for Stock Option Changes and Summary of Information Related to Options Vested and Expected to Vest and Options Exercisable	A summary of the activity for our stock option changes during the reporting period and a summary of information related to options outstanding and options exercisable are presented below (in thousands, except per share amounts and contractual life years): Options Outstanding Number of Shares Weighted- Average Exercise Price (per share) Weighted- Aggregate Intrinsic Value Balance — December 31, 2017 4,433 $ 12.31 4.8 $ 28,090 Exercised (648 ) 7.07 6,562 Cancelled (91 ) 41.37 Balance — June 30, 2018 3,694 $ 12.51 4.5 $ 27,273 Options exercisable — June 30, 2018 3,694 $ 12.51 4.5 $ 27,273
Summary of Activity for Restricted Common Stock, RSAs and RSUs and Summary of Information Related to Unvested Restricted Common Stock, RSAs and RSUs and those Expected to Vest	A summary of the activity for our restricted common stock, RSAs and RSUs, including those subject to performance conditions, during the reporting period and a summary of information related to unvested restricted common stock, RSAs and RSUs, including those with vesting subject to the achievement of a performance condition, are presented below (in thousands, except per share amounts and contractual life years): Number of Weighted- Weighted- Aggregate Unvested balance — December 31, 2017 20,017 $ 17.09 1.3 $ 284,255 Granted 10,186 15.13 Vested (5,173 ) 18.08 Cancelled (2,067 ) 16.78 Unvested balance — June 30, 2018 22,963 $ 15.78 1.4 $ 353,401 Unvested awards for which the requisite service period has not been rendered and vesting is subject to the achievement of a performance condition — June 30, 2018 4,152 $ 15.40 0.9 $ 63,897
Schedule of Assumptions used in Black-Scholes Option Pricing Model	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 for the offering periods beginning in May 2018: Three and Six Months Ended June 30, 2018 Three and Six Months Ended June 30, 2017 Fair value of common stock $16.69 $15.65 Risk-free interest rate 2.08% - 2.23% 1.05% - 1.12% Expected term (in years) 0.5 - 1.0 0.5 - 1.0 Volatility 32% - 35% 50% - 52% Dividend yield —% —%
Schedule of Stock-Based Compensation Expense Related to Stock Options, ESPP and Restricted Stock Units and Awards	Stock-based compensation expense related to stock options, ESPP and restricted stock unit awards is included in the condensed consolidated statements of operations as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Cost of product, subscription and support revenue $ 3,558 $ 4,017 $ 7,180 $ 8,377 Cost of professional services revenue 3,448 3,375 7,350 7,047 Research and development 12,418 14,057 26,771 28,582 Sales and marketing 12,223 10,219 25,200 24,234 General and administrative 7,245 7,729 14,539 15,046 Total $ 38,892 $ 39,397 $ 81,040 $ 83,286

Net Loss per Share (Tables)

Net Loss per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Schedule of Computation of Net Loss per Common Share	The following table sets forth the computation of net loss per common share (in thousands, except per share amounts): Three Months Ended June 30, Six Months Ended June 30, 2018 2017* 2018 2017* Numerator: Net loss $ (72,859 ) $ (68,339 ) $ (144,689 ) $ (145,556 ) Denominator: Weighted average number of shares outstanding—basic and diluted 189,696 176,645 188,085 174,453 Net loss per share—basic and diluted $ (0.38 ) $ (0.39 ) $ (0.77 ) $ (0.83 ) * Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.
Schedule of Outstanding Options and Unvested Shares Excluded from Computation of Diluted Net Loss per Share	The following outstanding options and unvested shares 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 anti-dilutive (in thousands): As of June 30, 2018 2017 Options to purchase common stock 3,694 5,474 Unvested early exercised common shares — — Unvested restricted stock awards and units 22,963 21,994 Convertible senior notes 35,442 15,141 ESPP shares 156 210

Segment and Major Customers I37

Segment and Major Customers Information (Tables)	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Disaggregation of Revenue	The following table depicts the disaggregation of revenue according to revenue type and is consistent with how we evaluate our financial performance (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2018 2017* 2018 2017* Revenue by Category Product and related subscription and support $ 122,392 $ 119,107 $ 243,484 $ 231,291 Cloud subscription and managed services 45,037 38,990 89,418 80,535 Professional services 35,267 33,625 68,864 64,655 Total revenue $ 202,696 $ 191,722 $ 401,766 $ 376,481 Revenue by geographic region based on the billing address is as follows (in thousands): Three Months Ended June 30, 2018 2017* 2018 2017* 2018 2017* 2018 2017* US EMEA APAC Other Product and related subscription and support $ 75,104 $ 75,917 $ 21,393 $ 19,715 $ 20,787 $ 18,631 $ 5,107 $ 4,843 Cloud subscription and managed services 30,394 28,501 6,462 4,106 5,410 4,623 2,771 1,759 Professional services 22,887 24,663 4,275 3,290 4,078 3,911 4,028 1,763 Total revenue $ 128,385 $ 129,081 $ 32,130 $ 27,111 $ 30,275 $ 27,165 $ 11,906 $ 8,365 Six Months Ended June 30, 2018 2017* 2018 2017* 2018 2017* 2018 2017* US EMEA APAC Other Product and related subscription and support $ 148,732 $ 147,114 $ 43,318 $ 38,187 $ 40,535 $ 36,389 $ 10,899 $ 9,600 Cloud subscription and managed services 60,249 59,442 13,107 8,164 10,819 9,641 5,242 3,286 Professional services 45,352 47,810 9,723 6,161 6,576 6,880 7,214 3,807 Total revenue $ 254,333 $ 254,366 $ 66,148 $ 52,512 $ 57,930 $ 52,910 $ 23,355 $ 16,693
Summary of Long lived Assets by Geographic Region Based on Physical Location	Long lived assets by geographic region based on physical location is as follows (in thousands): As of June 30, 2018 As of December 31, 2017 Property and Equipment, net: United States $ 71,702 $ 60,202 International 9,671 11,155 Total property and equipment, net $ 81,373 $ 71,357

Description of Business and S38

Description of Business and Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	May 24, 2018	Jan. 11, 2018	Oct. 20, 2017	Jun. 30, 2015	Jun. 30, 2018	Jun. 30, 2017	[1]	Jun. 05, 2018	Mar. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Proceeds from issuance of convertible senior notes, net of issuance costs					$ 584,405,000	$ 0
Purchase of capped calls					65,220,000	0
Repurchase of convertible senior notes					286,817,000	0
Consideration transferred, equity interests					$ 15,387,000	$ 0
Deferred commission recognition period					4 years
Capitalized contract costs					$ 89,971,000				$ 87,012,000	$ 86,779,000
X15 Software, Inc.
Business Acquisition [Line Items]
Purchase consideration, cash paid		$ 5,300,000
Equity interest issuable (shares)		1,016,334
Consideration transferred, equity interests		$ 15,400,000
The Email Laundry
Business Acquisition [Line Items]
Purchase consideration, cash paid			$ 4,300,000
Equity interest issuable (shares)			259,425
Consideration transferred, equity interests			$ 4,400,000
Accounting Standards Update 2014-09 | Retained Earnings
Business Acquisition [Line Items]
Cumulative effect of new accounting principle										113,000,000
Deferred Commissions | Prepaid Expenses and Other Current Assets
Business Acquisition [Line Items]
Capitalized contract costs					47,500,000					43,800,000
Deferred Commissions | Deposits and Other Current Assets
Business Acquisition [Line Items]
Capitalized contract costs					42,400,000					43,000,000
Deferred Costs of Revenue | Prepaid Expenses and Other Current Assets
Business Acquisition [Line Items]
Capitalized contract costs					18,000,000					18,400,000
Deferred Costs of Revenue | Deposits and Other Long-term Assets
Business Acquisition [Line Items]
Capitalized contract costs					17,200,000					$ 19,700,000
Convertible Senior Notes
Business Acquisition [Line Items]
Proceeds from issuance of convertible senior notes, net of issuance costs				$ 896,500,000
Conversion price (in USD per share)				$ 60.76
Convertible Senior Notes | Convertible Senior Notes due 2024
Business Acquisition [Line Items]
Principal amount	$ 525,000,000				$ 600,000,000			$ 75,000,000
Interest rate	0.875%				0.875%
Proceeds from issuance of convertible senior notes, net of issuance costs	$ 584,400,000
Conversion price (in USD per share)	$ 23.17
Cap price (in USD per share)	$ 34.32
Convertible Senior Notes | Series A Notes
Business Acquisition [Line Items]
Principal amount				$ 460,000,000
Interest rate	1.00%			1.00%
Repurchased principal amount of debt	$ 340,200,000
Repurchase of convertible senior notes	$ 330,400,000
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Description of Business and S39

Description of Business and Summary of Significant Accounting Policies - Adoption of ASC 606 - Balance Sheet Impact (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	$ 120,893	$ 146,317	[1]
Prepaid expenses and other current assets	92,632	93,799	[1]
Deposits and other long-term assets	69,370	72,767	[1]
Deferred revenue, current portion	525,617	546,615	[1]
Deferred revenue, non-current portion	353,939	363,485	[1]
Stockholders' equity	$ 660,428	632,216	[1]
As Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net		140,049
Prepaid expenses and other current assets		34,541
Deposits and other long-term assets		11,537
Deferred revenue, current portion		443,064
Deferred revenue, non-current portion		227,680
Stockholders' equity		744,816
Impact of Adoption | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net		6,268
Prepaid expenses and other current assets		59,258
Deposits and other long-term assets		61,230
Deferred revenue, current portion		103,551
Deferred revenue, non-current portion		135,805
Stockholders' equity		$ (112,600)
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Description of Business and S40

Description of Business and Summary of Significant Accounting Policies - Adoption of ASC 606 - Statement of Operations Impact (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 202,696	$ 191,722	[1]	$ 401,766	$ 376,481	[1]
Total cost of revenue		67,794			133,541
Total operating expenses	183,950	180,965	[1]	375,815	365,920
Operating loss	(48,536)	(57,037)	[1]	(109,260)	(122,980)
Net loss attributable to common stockholders	$ (72,859)	$ (68,339)	[1]	$ (144,689)	$ (145,556)	[1]
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	$ (0.38)	$ (0.39)	[1]	$ (0.77)	$ (0.83)
As Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		$ 185,472			$ 359,210
Total cost of revenue		66,692			131,297
Total operating expenses		178,210			359,057
Operating loss		(59,430)			(131,144)
Net loss attributable to common stockholders		$ (70,732)			$ (153,720)
Net loss per share attributable to common stockholders, basic and diluted (usd per share)		$ (0.40)			$ (0.88)
Impact of Adoption | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		$ 6,250			$ 17,271
Total cost of revenue		1,102			2,244
Total operating expenses		2,755			6,863
Operating loss		2,393			8,164
Net loss attributable to common stockholders		$ 2,393			$ 8,164
Net loss per share attributable to common stockholders, basic and diluted (usd per share)		$ 0.01			$ 0.05
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Description of Business and S41

Description of Business and Summary of Significant Accounting Policies - Adoption of ASC 606 - Statement of Cash Flows Impact (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Net loss	$ (72,859)	$ (68,339)	[1]	$ (144,689)	$ (145,556)	[1]
Changes in operating assets and liabilities, net of business acquisitions:
Accounts receivable				24,892	16,198	[1]
Prepaid expenses and other assets				4,892	(1,505)	[1]
Deferred revenue				$ (30,545)	(57,929)	[1]
As Previously Reported
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Net loss		(70,732)			(153,720)
Changes in operating assets and liabilities, net of business acquisitions:
Accounts receivable					10,318
Prepaid expenses and other assets					(10,637)
Deferred revenue					(34,780)
Accounting Standards Update 2014-09 | Impact of Adoption
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Net loss		$ 2,393			8,164
Changes in operating assets and liabilities, net of business acquisitions:
Accounts receivable					5,880
Prepaid expenses and other assets					9,132
Deferred revenue					$ (23,149)
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 204	$ 3,306
Total short-term investments	723,975	715,911
Total assets measured at fair value	724,179	719,217
Fair value | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Fair value | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	4,987
Fair value | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	448,401	438,024
Fair value | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	275,574	272,900
Fair value | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	204	208
Fair value | Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	3,098
Fair value | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	204	3,306
Total short-term investments	0	0
Total assets measured at fair value	204	3,306
Level 1 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 1 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 1 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 1 | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	204	208
Level 1 | Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	3,098
Level 1 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Total short-term investments	723,975	715,911
Total assets measured at fair value	723,975	715,911
Level 2 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 2 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	4,987
Level 2 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	448,401	438,024
Level 2 | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	275,574	272,900
Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Level 2 | Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Level 2 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Total short-term investments	0	0
Total assets measured at fair value	0	0
Level 3 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 3 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 3 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 3 | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0	0
Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Level 3 | Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Level 3 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) $ in Billions	Jun. 30, 2018USD ($)
Level 2 | Convertible Senior Notes
Debt Instrument [Line Items]
Fair value of debt	$ 1.1

Investments - Summary of Invest

Investments - Summary of Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 727,470	$ 721,888
Gross Unrealized Gains	4	2
Gross Unrealized Losses	(3,499)	(2,881)
Estimated Fair Value	723,975	719,009
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	0	4,989
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(2)
Estimated Fair Value	0	4,987
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	450,939	439,851
Gross Unrealized Gains	4	2
Gross Unrealized Losses	(2,542)	(1,829)
Estimated Fair Value	448,401	438,024
Treasury bills
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		3,098
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Value		3,098
U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	276,531	273,950
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(957)	(1,050)
Estimated Fair Value	275,574	272,900
Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalent	0	3,098
Cash and Cash Equivalents | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalent	0	0
Cash and Cash Equivalents | Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalent	0	0
Cash and Cash Equivalents | Treasury bills
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalent		3,098
Cash and Cash Equivalents | U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalent	0	0
Short-Term Investments
Debt Securities, Available-for-sale [Line Items]
Short-Term Investments	723,975	715,911
Short-Term Investments | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Short-Term Investments	0	4,987
Short-Term Investments | Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Short-Term Investments	448,401	438,024
Short-Term Investments | Treasury bills
Debt Securities, Available-for-sale [Line Items]
Short-Term Investments		0
Short-Term Investments | U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Short-Term Investments	$ 275,574	$ 272,900

Investments - Summary of Gross

Investments - Summary of Gross Unrealized Losses and Fair Value of Investments in a Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	$ 380,147	$ 406,618
Unrealized Loss, Less Than 12 Months	(2,092)	(1,972)
Fair Value, Greater Than 12 Months	336,746	309,293
Unrealized Loss, Greater Than 12 Months	(1,407)	(909)
Fair Value	716,893	715,911
Unrealized Loss	(3,499)	(2,881)
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	0	4,987
Unrealized Loss, Less Than 12 Months	0	(2)
Fair Value, Greater Than 12 Months	0	0
Unrealized Loss, Greater Than 12 Months	0	0
Fair Value	0	4,987
Unrealized Loss	0	(2)
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	211,707	284,499
Unrealized Loss, Less Than 12 Months	(1,360)	(1,484)
Fair Value, Greater Than 12 Months	231,668	153,525
Unrealized Loss, Greater Than 12 Months	(1,182)	(345)
Fair Value	443,375	438,024
Unrealized Loss	(2,542)	(1,829)
U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	168,440	117,132
Unrealized Loss, Less Than 12 Months	(732)	(486)
Fair Value, Greater Than 12 Months	105,078	155,768
Unrealized Loss, Greater Than 12 Months	(225)	(564)
Fair Value	273,518	272,900
Unrealized Loss	$ (957)	$ (1,050)

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Other than temporary impairment	$ 0	$ 0
Private Company
Schedule of Equity Method Investments [Line Items]
Ownership percentage	11.10%
Investment, carrying value	$ 1,300,000	$ 2,100,000

Investments - Summary of Contra

Investments - Summary of Contractual Maturities of Investments (Details) $ in Thousands	Jun. 30, 2018USD ($)
Investments, Debt and Equity Securities [Abstract]
Due within one year, amortized cost	$ 442,938
Due within one to two years, amortized cost	284,532
Amortized Cost	727,470
Due within one year, fair value	441,165
Due within one to two years, fair value	282,810
Fair Value	$ 723,975

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 235,754	$ 229,001
Less: accumulated depreciation	(154,381)	(157,644)
Total property and equipment, net	81,373	71,357	[1]
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	161,783	144,438
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	59,039	67,451
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	14,485	16,665
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 447	$ 447
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Property and Equipment - Narrat

Property and Equipment - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 9.2	$ 11	$ 18.6	$ 22
Capitalized software development costs	6.8	3.2	11.7	7.9
Amortization of capitalized software development costs	$ 2.3	$ 1.3	$ 4.2	$ 2.1

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($) $ in Thousands	Jan. 11, 2018	Oct. 20, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017		Dec. 31, 2017	[1]
Business Acquisition [Line Items]
Consideration transferred, equity interests					$ 15,387	$ 0	[1]
Goodwill			$ 999,888		999,888			$ 984,661
Amortization expense			$ 12,700	$ 14,800	25,300	$ 29,600
The Email Laundry
Business Acquisition [Line Items]
Purchase consideration, cash paid		$ 4,300
Equity interest issuable (shares)		259,425
Consideration transferred, equity interests		$ 4,400
Total purchase consideration		8,700
Intangible assets		2,700
Goodwill		6,400
Tangible net liabilities		$ 400
Weighted average useful life		3 years
X15 Software, Inc.
Business Acquisition [Line Items]
Purchase consideration, cash paid	$ 5,300
Equity interest issuable (shares)	1,016,334
Consideration transferred, equity interests	$ 15,400
Total purchase consideration	20,700
Intangible assets	6,100
Goodwill	15,200
Tangible net liabilities	$ 600
Weighted average useful life	3 years
Goodwill acquired					$ 15,200
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Business Combinations - Goodwil

Business Combinations - Goodwill and Purchased Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Total intangible assets	$ 409,253	$ 403,153
Less: accumulated amortization	(241,024)	(215,765)
Total	168,229	187,388
Developed technology
Business Acquisition [Line Items]
Total intangible assets	110,003	103,903
Content
Business Acquisition [Line Items]
Total intangible assets	158,700	158,700
Customer relationships
Business Acquisition [Line Items]
Total intangible assets	111,090	111,090
Contract backlog
Business Acquisition [Line Items]
Total intangible assets	12,500	12,500
Trade names
Business Acquisition [Line Items]
Total intangible assets	15,560	15,560
Non-competition agreements
Business Acquisition [Line Items]
Total intangible assets	$ 1,400	$ 1,400

Business Combinations - Schedul

Business Combinations - Schedule of Expected Annual Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Business Combinations [Abstract]
2018 (remaining six months)	$ 25,067
2,019	48,441
2,020	33,903
2,021	29,337
2,022	18,209
and thereafter	13,272
Total	$ 168,229	$ 187,388

Restructuring Charges - Summary

Restructuring Charges - Summary of Restructuring Activities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Restructuring Reserve [Roll Forward]
Balance, June 30, 2018	$ 800
Facilities costs
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017	935
Cash payments	(92)
Other adjustments	(13)
Balance, June 30, 2018	$ 830

Restructuring Charges - Narrati

Restructuring Charges - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Jun. 30, 2018
Restructuring and Related Activities [Abstract]
Percentage reduction in workforce	10.00%
Restructuring reserve		$ 0.8

Deferred Commissions (Details)

Deferred Commissions (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Capitalized Contract Cost [Roll Forward]
As of December 31, 2017	$ 87,012,000	$ 86,779,000
Commissions capitalized	17,013,000	30,499,000
Commissions recognized	(14,054,000)	(27,307,000)
As of June 30, 2018	89,971,000	89,971,000
Commissions capitalized, impairment loss	$ 0	$ 0

Deferred Revenue - Schedule of

Deferred Revenue - Schedule of Deferred Revenue (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Revenue from External Customer [Line Items]
Total deferred revenue, current	$ 525,617		$ 546,615	[1]
Total deferred revenue, non-current	353,939		363,485	[1]
Total deferred revenue	879,556	$ 886,136	910,100
Product and related subscription and support
Revenue from External Customer [Line Items]
Total deferred revenue, current	476,818		496,218
Total deferred revenue, non-current	353,927		363,313
Professional services
Revenue from External Customer [Line Items]
Total deferred revenue, current	48,799		50,397
Total deferred revenue, non-current	$ 12		$ 172
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Deferred Revenue - Changes in D

Deferred Revenue - Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Change in Contract with Customer, Liability [Roll Forward]
As of December 31, 2017	$ 886,136	$ 910,100
Billings for the period	196,116	371,222
Revenue recognized	(202,696)	(401,766)
As of June 30, 2018	$ 879,556	$ 879,556

Deferred Revenue - Narrative (D

Deferred Revenue - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 879,556	$ 886,136	$ 910,100
Backlog	$ 17,400

Deferred Revenue - Remaining Pe

Deferred Revenue - Remaining Performance Obligation (Details)	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Deferred revenue	100.00%
Backlog	100.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue from Contract with Customer [Abstract]
Deferred revenue	60.00%
Backlog	57.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue, expected timing of satisfaction	1 year
Backlog, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue from Contract with Customer [Abstract]
Deferred revenue	25.00%
Backlog	34.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue, expected timing of satisfaction	1 year
Backlog, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Revenue from Contract with Customer [Abstract]
Deferred revenue	12.00%
Backlog	8.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue, expected timing of satisfaction	1 year
Backlog, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-01
Revenue from Contract with Customer [Abstract]
Deferred revenue	3.00%
Backlog	1.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue, expected timing of satisfaction
Backlog, expected timing of satisfaction

Convertible Senior Notes - Narr

Convertible Senior Notes - Narrative - Convertible Senior Notes (Details)	May 24, 2018USD ($)$ / shares	Jun. 30, 2015USD ($)day$ / shares	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	[1]	Jun. 29, 2018$ / shares	Jun. 05, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes, net of issuance costs			$ 584,405,000	$ 0
Repurchase of convertible senior notes			286,817,000	0
Purchase of capped calls			65,220,000	0
Loss on repurchase of convertible senior notes			$ 10,764,000	$ 0
Convertible Senior Notes
Debt Instrument [Line Items]
Initial purchaser's discount		$ 23,000,000
Debt issuance costs		500,000
Proceeds from issuance of convertible senior notes, net of issuance costs		$ 896,500,000
Shares of common stock (per $1000 principal amount of notes)		0.0164572
Conversion price (in USD per share) | $ / shares		$ 60.76
Threshold note trading days | day		5
Threshold consecutive note trading days		5 days
Threshold percentage of note price trigger		98.00%
Purchase price trigger percentage		100.00%
Redemption price triggered by fundamental change, percentage		100.00%
Redemption price, percentage		100.00%
Remaining discount and issuance cost, weighted average amortization period			4 years
Convertible Senior Notes | Subsequent to September 30, 2015
Debt Instrument [Line Items]
Threshold trading days | day		20
Threshold consecutive trading days | day		30
Threshold percentage of stock price trigger		130.00%
Convertible Senior Notes | Convertible Senior Notes due 2024
Debt Instrument [Line Items]
Principal amount	$ 525,000,000		$ 600,000,000				$ 75,000,000
Interest rate	0.875%		0.875%
Initial purchaser's discount	$ 15,000,000
Debt issuance costs	600,000
Proceeds from issuance of convertible senior notes, net of issuance costs	$ 584,400,000
Shares of common stock (per $1000 principal amount of notes)			0.0431167
Conversion price (in USD per share) | $ / shares	$ 23.17
Equity component of debt	$ 141,700,000
Remaining discount amortization period			6 years
Effective interest rate			3.80%
Cap price (in USD per share) | $ / shares	$ 34.32
Debt amount outstanding			$ 600,000,000
Convertible Senior Notes | Series A Notes
Debt Instrument [Line Items]
Principal amount		$ 460,000,000
Interest rate	1.00%	1.00%
Repurchase of convertible senior notes	$ 330,400,000
Equity component of debt, subsequent adjustments	13,000,000
Repurchased principal amount of debt	$ 340,200,000
Remaining expected life	2 years
Loss on repurchase of convertible senior notes	$ 10,800,000
Debt amount outstanding			119,828,000					$ 460,000,000
Convertible Senior Notes | Series B Notes
Debt Instrument [Line Items]
Principal amount		$ 460,000,000
Interest rate		1.625%
Debt amount outstanding			460,000,000					$ 460,000,000
Convertible Senior Notes | Series B Notes | On or after June 1, 2020 until June 1, 2022
Debt Instrument [Line Items]
Threshold trading days | day		20
Threshold percentage of stock price trigger		130.00%
Required trading days since notice of redemption, not more than		3 days
Convertible Senior Notes | Debt, Liability Component
Debt Instrument [Line Items]
Initial purchaser's discount		$ 17,600,000	11,500,000
Debt issuance costs		400,000	500,000
Carrying amount of convertible debt	$ 458,300,000
Convertible Senior Notes | Debt, Equity Component
Debt Instrument [Line Items]
Initial purchaser's discount		5,400,000	3,500,000
Debt issuance costs		$ 100,000	$ 100,000
Measurement Input, Discount Rate | Convertible Senior Notes | Convertible Senior Notes due 2024
Debt Instrument [Line Items]
Discount rate	0.055
Measurement Input, Discount Rate | Convertible Senior Notes | Series A Notes
Debt Instrument [Line Items]
Discount rate	0.045
Common Stock
Debt Instrument [Line Items]
Closing share price (in USD per share) | $ / shares						$ 15.39
Convertible Senior Notes | Convertible Senior Notes | Series A Notes
Debt Instrument [Line Items]
Repurchase of convertible senior notes	$ 317,400,000
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Convertible Senior Notes - Sche

Convertible Senior Notes - Schedule of the Liability and Equity Components of the Convertible Senior Notes (Details) - Convertible Senior Notes - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Convertible Senior Notes due 2024
Debt Instrument [Line Items]
Principal	$ 600,000
Less: debt discount, net of amortization	(151,400)
Net carrying amount	448,600
Series A Notes
Debt Instrument [Line Items]
Principal	119,828	$ 460,000
Less: debt discount, net of amortization	(11,248)	(53,762)
Net carrying amount	108,580	406,238
Equity component, net of issuance costs	79,555	92,567
Series B Notes
Debt Instrument [Line Items]
Principal	460,000	460,000
Less: debt discount, net of amortization	(77,733)	(86,660)
Net carrying amount	382,267	373,340
Equity component, net of issuance costs	$ 117,834	$ 117,834

Convertible Senior Notes - Sc62

Convertible Senior Notes - Schedule of Interest Expense related to the Convertible Senior Notes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Debt Instrument [Line Items]
Amortization of debt discount			$ (43,575)	$ 0	[1]
Convertible Senior Notes | Convertible Senior Notes due 2024
Debt Instrument [Line Items]
Coupon interest	$ 520		520
Amortization of debt discount	2,259		2,259
Total interest expense recognized	2,779		$ 2,779
Effective interest rate on the liability component			3.80%
Convertible Senior Notes | Series A Notes
Debt Instrument [Line Items]
Coupon interest	788	$ 1,150	$ 1,938	2,300
Amortization of debt discount	3,700	5,058	8,957	10,051
Total interest expense recognized	$ 4,488	$ 6,208	$ 10,895	$ 12,351
Effective interest rate on the liability component	6.30%	6.40%	6.30%	6.40%
Convertible Senior Notes | Series B Notes
Debt Instrument [Line Items]
Coupon interest	$ 1,848	$ 1,869	$ 3,717	$ 3,738
Amortization of debt discount	4,490	4,283	8,927	8,515
Total interest expense recognized	$ 6,338	$ 6,152	$ 12,644	$ 12,253
Effective interest rate on the liability component	6.70%	6.80%	6.80%	6.90%
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Convertible Senior Notes - Na63

Convertible Senior Notes - Narrative - Prepaid Forward Stock Purchase (Details) shares in Millions, $ in Millions	1 Months Ended
	Jun. 30, 2015USD ($)shares
Debt Disclosure [Abstract]
Stock repurchased during period | $	$ 150
Stock repurchase during period (shares) | shares	3.3

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)claim	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Long-term Purchase Commitment [Line Items]
Rent expense	$ 5,200,000	$ 4,400,000	$ 9,800,000	$ 8,500,000
Future minimum sublease rentals	5,900,000		5,900,000
Letters of credit available	3,700,000		3,700,000		$ 3,300,000
Amount drawn against letters of credit	0		0		0
Non-cancellable open orders	12,500,000		$ 12,500,000		$ 11,600,000
Number of claims | claim			0
Software and Services
Long-term Purchase Commitment [Line Items]
Non-cancellable open orders	$ 13,700,000		$ 13,700,000

Commitments and Contingencies65

Commitments and Contingencies - Schedule of Future Non-cancelable Minimum Rental Payments for Operating Leases (Details) $ in Thousands	Jun. 30, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
2018 (remaining six months)	$ 7,330
2,019	15,980
2,020	15,671
2,021	14,202
2,022	11,937
2023 and thereafter	53,618
Total	$ 118,738

Common Shares Reserved for Is66

Common Shares Reserved for Issuance - Narrative (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2018vote_per_share$ / sharesshares	Dec. 31, 2017vote_per_share$ / sharesshares
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) | $ / shares	$ 0.0001	$ 0.0001
Voting right per common share | vote_per_share	1	1
Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (shares)	100,000,000	100,000,000
Preferred stock, par value (usd per share) | $ / shares	$ 0.0001	$ 0.0001
Preferred stock, shares issued (shares)	0	0
Preferred stock outstanding (shares)	0	0

Common Shares Reserved for Is67

Common Shares Reserved for Issuance - Schedule of Reserved Shares of Common Stock for Issuance (Details) - shares shares in Thousands	Jun. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Shares reserved for future issuance (shares)	78,708	53,964
Convertible Senior Notes
Class of Stock [Line Items]
Shares reserved for future issuance (shares)	35,442	15,141
Reserved under stock award plans
Class of Stock [Line Items]
Shares reserved for future issuance (shares)	39,449	35,838
Employee Stock Purchase Plan (ESPP)
Class of Stock [Line Items]
Shares reserved for future issuance (shares)	3,817	2,985

Equity Award Plans - Narrative

Equity Award Plans - Narrative (Details) - USD ($) shares in Thousands, $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (shares)	78,708	53,964
Compensation cost not yet recognized	$ 286.2
Compensation cost not yet recognized, period for recognition	2 years 8 months
Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (shares)	3,817	2,985
Acquisition price at lower of fair market value, percentage	85.00%
2013 Plan
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
Shares reserved for future issuance (shares)	12,800	11,700
2013 Plan | Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value, percentage, no less than	100.00%

Equity Award Plans - Summary of

Equity Award Plans - Summary of the Activity for Stock Option Changes and Summary of Information Related to Options Vested and Expected to Vest and Options Exercisable (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, options outstanding (shares)	4,433
Exercised (shares)	(648)
Cancelled (shares)	(91)
Ending balance, options outstanding (shares)	3,694	4,433
Options exercisable (shares)	3,694
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)	$ 12.31
Exercised, weighted average exercise price (usd per share)	7.07
Cancelled, weighted average exercise price (usd per share)	41.37
Ending balance, weighted average exercise price (usd per share)	12.51	$ 12.31
Options exercisable, weighted average exercise price (usd per share)	$ 12.51
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, weighted average contractual life	4 years 5 months 20 days	4 years 9 months 18 days
Options exercisable, weighted average contractual life	4 years 5 months 20 days
Options outstanding, aggregate intrinsic value	$ 27,273	$ 28,090
Exercised, aggregate intrinsic value	6,562
Options exercisable, aggregate intrinsic value	$ 27,273

Equity Award Plans - Summary 70

Equity Award Plans - Summary of Activity for Restricted Common Stock, RSAs and RSUs and Summary of Information Related to Unvested Restricted Common Stock, RSAs and RSUs and those Expected to Vest (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Beginning balance, unvested (shares)	20,017
Granted (shares)	10,186
Vested (shares)	(5,173)
Cancelled (shares)	(2,067)
Ending balance, unvested (shares)	22,963	20,017
Expected to vest (shares)	4,152
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, unvested, weighted average grant date fair value (per share)	$ 17.09
Weighted average grant date fair value, granted (per share)	15.13
Weighted average grant date fair value, vested (per share)	18.08
Weighted average grant date fair value, cancelled (per share)	16.78
Ending balance, unvested, weighted average grant date fair value (per share)	15.78	$ 17.09
Weighted average grant date fair value, expected to vest (per share)	$ 15.40
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Weighted-average remaining contractual term	1 year 4 months 25 days	1 year 3 months 17 days
Expected to vest, weighted-average remaining contractual term	11 months 4 days
Aggregate intrinsic value	$ 353,401	$ 284,255
Expected to vest, aggregate intrinsic value	$ 63,897

Equity Award Plans - Assumption

Equity Award Plans - Assumptions (Details) - Employee Stock Purchase Plan (ESPP) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in USD per share)	$ 16.69	$ 15.65	$ 16.69	$ 15.65
Risk free interest rate, minimum	2.08%	1.05%	2.08%	1.05%
Risk free interest rate, maximum	2.23%	1.12%	2.23%	1.12%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months	6 months	6 months
Volatility	32.00%	50.00%	32.00%	50.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	1 year	1 year	1 year	1 year
Volatility	35.00%	52.00%	35.00%	52.00%

Equity Award Plans - Schedule o

Equity Award Plans - Schedule of Stock-Based Compensation Expense Related to Stock Options, ESPP and Restricted Stock Units and Awards (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 38,892	$ 39,397	$ 81,040	$ 83,286
Cost of product, subscription and support revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	3,558	4,017	7,180	8,377
Cost of professional services revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	3,448	3,375	7,350	7,047
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	12,418	14,057	26,771	28,582
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	12,223	10,219	25,200	24,234
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 7,245	$ 7,729	$ 14,539	$ 15,046

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 1,411	$ 965	[1]	$ 2,464	$ 2,258
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Computation of Net Loss per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	[1]	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net loss	$ (72,859)	$ (68,339)		$ (144,689)	$ (145,556)	[1]
Denominator:
Weighted average number of shares outstanding—basic and diluted (shares)	189,696	176,645		188,085	174,453
Net loss per share—basic and diluted (usd per share)	$ (0.38)	$ (0.39)		$ (0.77)	$ (0.83)
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Net Loss per Share - Schedule75

Net Loss per Share - Schedule of Outstanding Options and Unvested Shares Excluded from Computation of Diluted Net Loss per Share (Details) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (shares)	3,694	5,474
Unvested early exercised common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (shares)	0	0
Unvested restricted stock awards and units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (shares)	22,963	21,994
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (shares)	35,442	15,141
ESPP shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (shares)	156	210

Employee Benefit Plan - Narrati

Employee Benefit Plan - Narrative (Details)	6 Months Ended
	Jun. 30, 2018USD ($)
Retirement Benefits [Abstract]
Employer contributions vested percentage	100.00%
Employer contributions to 401(k)	$ 0

Segment and Major Customers I77

Segment and Major Customers Information - Schedule of Revenue by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 202,696	$ 191,722	[1]	$ 401,766	$ 376,481	[1]
US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	128,385	129,081		254,333	254,366
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	32,130	27,111		66,148	52,512
APAC
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	30,275	27,165		57,930	52,910
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	11,906	8,365		23,355	16,693
Product and related subscription and support
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	122,392	119,107		243,484	231,291
Product and related subscription and support | US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	75,104	75,917		148,732	147,114
Product and related subscription and support | EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	21,393	19,715		43,318	38,187
Product and related subscription and support | APAC
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	20,787	18,631		40,535	36,389
Product and related subscription and support | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	5,107	4,843		10,899	9,600
Cloud subscription and managed services
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	45,037	38,990		89,418	80,535
Cloud subscription and managed services | US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	30,394			60,249	59,442
Cloud subscription and managed services | EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	6,462	4,106		13,107	8,164
Cloud subscription and managed services | APAC
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	5,410	4,623		10,819	9,641
Cloud subscription and managed services | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,771	1,759		5,242	3,286
Professional services
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	35,267	33,625	[1]	68,864	64,655	[1]
Professional services | US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	22,887			45,352	47,810
Professional services | EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	4,275	3,290		9,723	6,161
Professional services | APAC
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	4,078	3,911		6,576	6,880
Professional services | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 4,028	$ 1,763		$ 7,214	$ 3,807
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Segment and Major Customers I78

Segment and Major Customers Information - Revenue by Product (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 202,696	$ 191,722	[1]	$ 401,766	$ 376,481	[1]
Product and related subscription and support
Segment Reporting Information [Line Items]
Revenue	122,392	119,107		243,484	231,291
Cloud subscription and managed services
Segment Reporting Information [Line Items]
Revenue	45,037	38,990		89,418	80,535
Professional services
Segment Reporting Information [Line Items]
Revenue	$ 35,267	$ 33,625	[1]	$ 68,864	$ 64,655	[1]
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Segment and Major Customers I79

Segment and Major Customers Information - Summary of Long lived Assets by Geographic Region Based on Physical Location (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Entity Location [Line Items]
Total property and equipment, net	$ 81,373	$ 71,357	[1]
United States
Entity Location [Line Items]
Total property and equipment, net	71,702	60,202
International
Entity Location [Line Items]
Total property and equipment, net	$ 9,671	$ 11,155
[1]	Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.

Segment and Major Customers I80

Segment and Major Customers Information - Narrative (Details) - reporting_segment	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Major Customer [Line Items]
Number of reportable segments			1
Customer concentration risk | Sales revenue, net | One Distributor
Revenue, Major Customer [Line Items]
Concentration risk percentage	20.00%	20.00%	20.00%	19.00%
Customer concentration risk | Sales revenue, net | One Reseller
Revenue, Major Customer [Line Items]
Concentration risk percentage	15.00%	12.00%	15.00%	12.00%
Customer concentration risk | Net accounts receivable
Revenue, Major Customer [Line Items]
Concentration risk percentage			15.00%