Tableau Software 10-K 25 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Statement - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Feb. 23, 2016	Jun. 30, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Entity Registrant Name	TABLEAU SOFTWARE INC
Entity Central Index Key	1,303,652
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 5.9
Common Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		54,825,718
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		19,323,479

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 795,900	$ 680,613
Accounts receivable, net	131,784	99,910
Prepaid expenses and other current assets	16,977	10,777
Income taxes receivable	78	229
Deferred income taxes	0	18,732
Total current assets	944,739	810,261
Property and equipment, net	72,350	45,627
Deferred income taxes	1,544	5,879
Deposits and other assets	12,078	3,895
Total assets	1,030,711	865,662
Current liabilities
Accounts payable	1,152	1,978
Accrued compensation and employee related benefits	53,003	40,164
Other accrued liabilities	31,838	15,769
Income taxes payable	1,000	378
Deferred revenue	185,608	121,985
Total current liabilities	272,601	180,274
Deferred revenue	12,903	7,825
Other long-term liabilities	11,262	5,557
Total liabilities	$ 296,766	$ 193,656
Commitments and contingencies (Note 7)
Stockholders’ equity (deficit)
Preferred stock	$ 0	$ 0
Additional paid-in capital	805,804	660,668
Accumulated other comprehensive income	643	140
Retained earnings (accumulated deficit)	(72,509)	11,191
Total stockholders' equity	733,945	672,006
Total liabilities and stockholders' equity	1,030,711	865,662
Common Class B
Stockholders’ equity (deficit)
Common Stock	2	2
Common Class A
Stockholders’ equity (deficit)
Common Stock	$ 5	$ 5

Consolidated Balance Sheets - P

Consolidated Balance Sheets - Parenthetical - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Convertible Preferred Stock
Preferred stock par value (USD per share)	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Class B
Common stock par value (USD per share)	$ 0.0001	$ 0.0001
Shares authorized for issuance	75,000,000	75,000,000
Common Stock, Shares, Issued	19,331,666	22,620,509
Common Stock, Shares, Outstanding	19,331,666	22,620,509
Common Class A
Common stock par value (USD per share)	$ 0.0001	$ 0.0001
Shares authorized for issuance	750,000,000	750,000,000
Common Stock, Shares, Issued	53,872,798	47,247,710
Common Stock, Shares, Outstanding	53,872,798	47,247,710

Consolidated Statement of Opera

Consolidated Statement of Operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
License		$ 423,766	$ 279,944	$ 159,930
Maintenance and services		229,821	132,672	72,510
Total revenues		653,587	412,616	232,440
Cost of revenues
License		3,852	1,211	740
Maintenance and services		69,833	35,774	17,784
Total cost of revenues	[1]	73,685	36,985	18,524
Gross profit		579,902	375,631	213,916
Operating expenses
Sales and marketing	[1]	356,723	216,672	123,573
Research and development	[1]	204,131	110,923	60,769
General and administrative	[1]	71,078	41,712	25,905
Total operating expenses		631,932	369,307	210,247
Operating income (loss)		(52,030)	6,324	3,669
Other income (expense), net		1,223	858	(804)
Income (loss) before income tax expense (benefit)		(50,807)	7,182	2,865
Income tax expense (benefit)		32,893	1,309	(4,211)
Net income (loss)		$ (83,700)	$ 5,873	$ 7,076
Net income (loss) per share:
Basic (in USD per share)		$ (1.17)	$ 0.09	$ 0.14
Diluted (in USD per share)		$ (1.17)	$ 0.08	$ 0.12
Weighted average shares used to compute net income per share attributable to common stockholder
Basic (in shares)		71,701	67,591	50,564
Diluted (in shares)		71,701	74,319	59,092
Cost of Revenues
Share-based Compensation [Abstract]
Allocated share-based compensation expense		$ 7,031	$ 2,227	$ 473
Sales and Marketing
Share-based Compensation [Abstract]
Allocated share-based compensation expense		45,205	18,203	5,429
Research and Development
Share-based Compensation [Abstract]
Allocated share-based compensation expense		55,269	20,794	5,832
General and Administrative
Share-based Compensation [Abstract]
Allocated share-based compensation expense		$ 11,963	$ 5,794	$ 2,723
[1]	Includes stock-based compensation expense as follows: Year Ended December 31, 2015 2014 2013 (in thousands)Cost of revenues$7,031 $2,227 $473Sales and marketing45,205 18,203 5,429Research and development55,269 20,794 5,832General and administrative11,963 5,794 2,723

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (83,700)	$ 5,873	$ 7,076
Other comprehensive income (loss):
Foreign currency translation, net	503	211	(70)
Comprehensive income (loss)	$ (83,197)	$ 6,084	$ 7,006

Consolidated Statements of Shar

Consolidated Statements of Shareholders Equity Statement - USD ($) $ in Thousands	Total	Public Offering [Member]	Common Stock (Class A and B)	Common Stock (Class A and B)Public Offering [Member]	Additional Paid-in Capital	Additional Paid-in CapitalPublic Offering [Member]	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Preferred Stock [Member]Convertible Preferred Stock
Balances (in shares), period start at Dec. 31, 2012			34,317,137						17,416,317
Balances, period start at Dec. 31, 2012	$ 9,943		$ 4		$ 11,698		$ (1)	$ (1,758)	$ 20,031
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from issuance of common stock (in shares)			4,235,232	6,230,000
Proceeds from issuance of common stock	10,523	$ 176,975	$ 1	$ 1	10,522	$ 176,974
Conversion of preferred stock to common stock (in shares)			17,416,317						17,416,317
Conversion of preferred stock to common stock	20,031		$ 1		20,030				$ (20,031)
Stock-based compensation expense	14,457				14,457
Excess tax benefit from stock-based compensation	5,725				5,725
Other comprehensive income (loss)	(70)						(70)
Net income (loss)	7,076							7,076
Balances (in shares), period end at Dec. 31, 2013			62,198,686						0
Balances, period end at Dec. 31, 2013	244,660		$ 7		239,406		(71)	5,318	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from issuance of common stock (in shares)			3,669,533	4,000,000
Proceeds from issuance of common stock	16,151	$ 344,077			16,151	$ 344,077
Stock-based compensation expense	47,018				47,018
Excess tax benefit from stock-based compensation	14,016				14,016
Other comprehensive income (loss)	211						211
Net income (loss)	5,873							5,873
Balances (in shares), period end at Dec. 31, 2014			69,868,219						0
Balances, period end at Dec. 31, 2014	672,006		$ 7		660,668		140	11,191	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from issuance of common stock (in shares)			3,336,245
Proceeds from issuance of common stock	20,117				20,117
Stock-based compensation expense	119,468				119,468
Excess tax benefit from stock-based compensation	5,551				5,551
Other comprehensive income (loss)	503						503
Net income (loss)	(83,700)							(83,700)
Balances (in shares), period end at Dec. 31, 2015			73,204,464						0
Balances, period end at Dec. 31, 2015	$ 733,945		$ 7		$ 805,804		$ 643	$ (72,509)	$ 0

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net income (loss)	$ (83,700)	$ 5,873	$ 7,076
Adjustment to reconcile net income (loss) to net cash provided by operating activities
Depreciation and amortization expense	23,667	13,512	6,850
Stock-based compensation expense	119,468	47,018	14,457
Excess tax benefit from stock-based compensation	(5,629)	(14,061)	(5,725)
Deferred income taxes	28,558	(899)	(3,052)
Changes in operating assets and liabilities
Accounts receivable, net	(34,225)	(41,015)	(30,001)
Prepaid expenses, deposits and other assets	(13,783)	(6,950)	(4,758)
Income taxes receivable	147	1,816	(961)
Deferred revenue	71,383	62,752	34,740
Accounts payable and accrued liabilities	30,224	21,181	19,037
Income taxes payable	664	224	62
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	136,774	89,451	37,725
Investing activities
Purchases of property and equipment	(45,130)	(36,748)	(17,607)
Sales of property and equipment	0	1,694	0
Payments for (Proceeds from) Other Investing Activities	(1,000)	0	0
Net cash used in investing activities	(46,130)	(35,054)	(17,607)
Financing activities
Proceeds from public offering, net of underwriters' discount and offering costs	0	344,077	176,974
Proceeds from issuance of common stock	20,117	16,151	10,522
Excess tax benefit from stock-based compensation	5,629	14,061	5,725
Net cash provided by financing activities	25,746	374,289	193,221
Effect of exchange rate changes on cash and cash equivalents	(1,103)	(747)	33
Net increase in cash and cash equivalents	115,287	427,939	213,372
Cash and cash equivalents
Beginning of year	680,613	252,674	39,302
End of year	795,900	680,613	252,674
Supplemental Cash Flow Information [Abstract]
Cash paid for income taxes	959	569	367
Cash paid for interest	8	19	1
Conversion of preferred stock to common stock	0	0	20,031
Accrued purchases of property and equipment	10,012	4,776	2,469
Asset retirement obligations recognized, net	271	667	0
Property and equipment acquired under build-to-suit lease	0	11,600	0
Sale Leaseback Transactions, Gross Proceeds	$ 0	$ 11,600	$ 0

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Tableau Software, Inc., a Delaware corporation, and its wholly-owned subsidiaries (the "Company", "we", "us" or "our") are headquartered in Seattle, Washington. Our software products put the power of data into the hands of everyday people, allowing a broad population of business users to engage with their data, ask questions, solve problems and create value. Based on innovative core technologies originally developed at Stanford University, our products dramatically reduce the complexity, inflexibility and expense associated with traditional business intelligence applications. We currently offer five key products; Tableau Desktop, a self-service, powerful analytics product for anyone with data; Tableau Server, a business intelligence platform for organizations; Tableau Online, a hosted software-as-a-service ("SaaS") version of Tableau Server; Tableau Public, a free cloud-based platform for analyzing and sharing public data; and Vizable, a free iOS application used to easily analyze data on a tablet.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Accounting Principles The consolidated financial statements and accompanying notes were prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Reclassifications In the consolidated statements of convertible preferred stock and stockholders' equity, certain prior year amounts have been reclassified to conform to the current year presentation. Specifically, the line items for issuance of common stock upon exercise of stock options and issuance of restricted stock units have been combined to one line item, issuance of common stock. There was no change to total stockholders' equity as a result of the reclassification. In the consolidated statements of cash flows, certain prior year amounts have been reclassified to conform to the current year presentation. Specifically, the line items for provision for doubtful accounts and accounts receivable has been combined to one line item, accounts receivable, net. There was no change to the net cash flows from operating, investing, or financing activities as a result of the reclassification. Public Offerings In May 2013, we completed our initial public offering ("IPO") whereby 9,430,000 shares of Class A common stock were sold to the public at a price of $31.00 per share. We sold 6,230,000 shares of Class A common stock and the selling stockholders sold 3,200,000 shares of Class A common stock. We received aggregate proceeds of $177.0 million from the IPO, net of underwriters' discounts and commissions, and offering expenses. Upon the closing of the IPO, all shares of our outstanding convertible preferred stock automatically converted into shares of Class B common stock. In March 2014, we closed a follow-on public offering, in which we sold 4,000,000 shares of our Class A common stock at a price to the public of $89.25 per share. The aggregate offering price for shares sold in the offering was approximately $344.1 million , net of underwriters' discounts and commissions, and offering expenses. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates include depreciable lives for property and equipment, stock-based compensation, income taxes, accrued liabilities and collectability of accounts receivable. Actual results could differ from those estimates. Foreign Currency The financial statements of our foreign subsidiaries with a functional currency other than U.S. dollars have been translated into U.S. dollars. Assets and liabilities of these subsidiaries are translated at the exchange rate in effect at each period-end. Income statement amounts are translated at the average rate of exchange prevailing during the period. Translation adjustments arising from the use of differing exchange rates from period to period are included in other comprehensive income (loss). Gains and losses on foreign currency transactions are included in income. Foreign currency transaction gain (loss) was $0.6 million , $0.6 million and $(0.9) million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Risks and Uncertainties Inherent in our business are various risks and uncertainties, including our limited history of operating our business at its current scale and development of advanced technologies in a rapidly changing industry. These risks include our ability to manage our rapid growth and our ability to attract new customers and expand sales to existing customers, as well as other risks and uncertainties. In the event that we do not successfully implement our business plan, certain assets may not be recoverable, certain liabilities may not be paid and investments in our capital stock may not be recoverable. Our success depends upon the acceptance of our technology, development of sales and distribution channels, and our ability to generate significant revenues from the sale of our technology. Segments We follow the authoritative literature that established annual and interim reporting standards for an enterprise's operating segments and related disclosures about its products and services, geographic regions and major customers. We operate our business as one operating segment. Our chief operating decision makers ("CODM") are our Chief Executive Officer and Chief Financial Officer, who review financial information presented on a consolidated basis for purposes of making operating decisions, assessing financial performance and allocating resources. Revenue Recognition We generate revenues primarily in the form of software license fees and related maintenance and services fees. License fees include perpetual, term and subscription license fees. Maintenance and services fees primarily consist of fees for maintenance services (including support and unspecified upgrades and enhancements when and if they are available), training, and professional services that are not essential to functionality of the software. We recognize revenues when all of the following conditions are met: • there is persuasive evidence of an arrangement; • the software or services have been delivered to the customer; • the amount of fees to be paid by the customer is fixed or determinable; and • the collection of the related fees is probable. We use click-through license agreements, signed agreements and purchase orders as evidence of an arrangement. We deliver all of our software electronically. Electronic delivery occurs when we provide the customer with access to the software and license key via a secure portal. We assess whether the fee is fixed or determinable at the outset of the arrangement. Our typical terms of payment are due 30 days from delivery. We assess collectability based on a number of factors such as collection history and creditworthiness of the customer. If we determine that collectability is not probable, revenue is deferred until collectability becomes probable, generally upon receipt of cash. Substantially all of our software licenses are sold in multiple-element arrangements that include maintenance and may include professional services and training. Vendor specific objective evidence ("VSOE") of the fair value is not available for software licenses as they are never sold without maintenance. VSOE of the fair value generally exists for all undelivered elements and any services that are not essential to the functionality of the delivered software. We account for delivered software licenses under the residual method. Maintenance agreements consist of fees for providing software updates on a when and if available basis and technical support for software products ("post-contract support" or "PCS") for an initial term, generally one year. We have established VSOE of the fair value for maintenance on perpetual licenses based on stated substantive renewal rates or the price when sold on a standalone basis. Stated renewal rates are considered to be substantive if they are at least 15% of the actual price charged for the software license. VSOE of the fair value for standalone sales is considered to have been established when a substantial majority of individual sales transactions within the previous 12 months falls within a reasonably narrow range, which we have defined to be plus or minus 15% of the median sales price of actual standalone sales transactions. License arrangements may include professional services and training. In determining whether professional services and training revenues should be accounted for separately from license revenues, we evaluate: • whether such services are considered essential to the functionality of the software using factors such as the nature of the software products; • whether they are ready for use by the customer upon receipt; • the nature of the services, which typically do not involve significant customization to or development of the underlying software code; • the availability of services from other vendors; • whether the timing of payments for license revenues coincides with performance of services; and • whether milestones or acceptance criteria exist that affect the realizability of the software license fee. Revenues related to training are billed on a fixed fee basis and accordingly recognized as training services are delivered. Payments received in advance of services performed are deferred and recognized when the related services are performed. To date, professional services have not been considered essential to the functionality of the software. The VSOE of the fair value of our professional services and training is based on the price for these same services when they are sold separately. Revenues related to professional services are billed on a time and materials basis and, accordingly, are recognized as the services are performed. When software is licensed for a specified term or on a subscription basis, fees for support and maintenance are generally bundled with the license fee over the entire term of the contract. In these cases, we do not have VSOE of the fair value for support and maintenance. Revenues related to term license fees are recognized ratably over the contract term beginning on the date the customer has access to the software license key and continuing through the end of the contract term. We do not offer refunds and therefore have not recorded any sales return allowance for any of the periods presented. Upon a periodic review of outstanding accounts receivable, amounts that are deemed to be uncollectable are written off against the allowance for doubtful accounts. We account for taxes collected from customers and remitted to governmental authorities on a net basis and exclude them from revenues. Cash and Cash Equivalents We consider all highly liquid investments purchased with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents are recorded at cost, which approximates fair value. We maintain cash and cash equivalent balances which exceed the insured limits by the Federal Deposit Insurance Corporation. Accounts Receivable Accounts receivable consist of amounts billed and currently due from customers. Our accounts receivable are subject to collection risk. Our gross accounts receivable is reduced for this risk by a provision for doubtful accounts. This provision is for estimated losses resulting from the inability of our customers to make required payments. It is an estimate and is regularly evaluated for adequacy by taking into consideration a combination of factors. We look at factors such as past collection experience, credit quality of the customer, age of the receivable balance, and current economic conditions. These factors are reviewed to determine whether a provision for doubtful accounts should be recorded to reduce the receivable balance to the amount believed to be collectible. Activity related to our provision for doubtful accounts was as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Balance at the beginning of the period $ 1,111 $ 805 $ 307 Bad debt expense 250 747 789 Accounts written off (473 ) (441 ) (291 ) Balance at the end of the period $ 888 $ 1,111 $ 805 Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives range from approximately one to twelve years. Leasehold improvements are amortized over the shorter of the estimated useful life or the remaining lease term. When assets are retired or disposed of, the cost and accumulated depreciation are removed from the accounts, and any resulting gains or losses are included in results of operations. Maintenance and repairs that do not improve or extend the lives of the respective assets are charged to expense in the period incurred. Leases and Asset Retirement Obligations Leases are categorized at their inception as either operating or capital leases. Within some lease agreements, rent holidays and other incentives are included. Rent expense is recognized on a straight-line method, over the term of the agreement generally beginning once control of the space is achieved, without regard to deferred payment terms, such as rent holidays that defer the commencement date of required rent payments. Additionally, incentives received are treated as a reduction of expense over the term of the agreement. Leased buildings under build-to-suit lease arrangements are capitalized and included in property and equipment when we are involved in the construction of the structural improvements or take construction risk prior to the commencement of the lease. Upon completion of the construction under the build-to-suit leases, we assess whether those arrangements qualify for sales recognition under the sale-leaseback accounting guidance. Liabilities are established for the present value of estimated future costs to retire leasehold improvements at the termination or expiration of a lease. A corresponding asset is recorded in the period in which the obligation is incurred. Such assets are amortized over the estimated useful life of the asset, and the recorded liabilities are accreted to the future value of the estimated retirement costs. Impairment of Long-Lived Assets We evaluate the recoverability of long-lived assets in accordance with authoritative guidance on accounting for the impairment or disposal of long-lived assets. We evaluate long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Such impairment is recognized in the event the carrying value of such assets exceeds their fair value. If the carrying value of the net assets assigned exceeds the fair value of the assets, then the second step of the impairment test is performed in order to determine the implied fair value. No impairment of long-lived assets occurred in the periods presented. Software Development Costs Software development costs associated with the development of new products, enhancements of existing products and quality assurance activities consists of employee, consulting and other external personnel costs. The costs incurred internally from the research and development ("R&D") of computer software products are charged to expense until technological feasibility has been established for the product. Once technological feasibility is established, all software costs are capitalized until the product is available for release to customers. Judgment is required in determining when technological feasibility of a product is established. To date, we have determined that technological feasibility of software products is reached shortly before the products are released. Costs incurred after establishment of technological feasibility have not been material, and therefore, we have expensed all R&D costs as they were incurred. R&D expenses primarily consist of personnel related costs attributable to our R&D personnel and allocated overhead, which includes facilities related costs. We capitalize certain costs relating to software developed or modified solely to meet our internal requirements and for which there are no substantive plans to market the software. To date, we have not capitalized any such costs as these costs have not been material. Intangible Asset Costs Costs related to filing and pursuing patent and trademark applications are expensed as incurred, as recoverability of such expenditures is uncertain. These intangible asset-related legal costs are generally reported as a component of general and administrative expenses. Advertising Expenses We expense all advertising costs as incurred and classify such costs as sales and marketing expenses. Advertising expenses for the years ended December 31, 2015 , 2014 and 2013 were $11.3 million , $7.6 million and $4.9 million , respectively. Income Taxes Income taxes are accounted for under the asset and liability method in accordance with authoritative guidance for income taxes. Deferred income tax assets are recognized for deductible temporary differences, net operating loss carryforwards, and tax credit carryforwards if it is more likely than not that the tax benefits will be realized. We considered future taxable income, historical operating results, and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance. In 2015, we recorded a valuation allowance to reduce our U.S. federal and state deferred income tax assets to the net amount that we believe is more likely than not to be realized. In the event we determine that we are able to realize our deferred income tax assets in excess of our net recorded amount, we would reduce the valuation allowance associated with the deferred income tax assets in the period the determination is made, which may result in a tax benefit in the statement of operations. Deferred income tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred income tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Concentrations of Credit Risk Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. We extend credit to customers based upon an evaluation of the customer's financial condition and generally collateral is not required. As of December 31, 2015 and 2014 , no individual customer accounted for 10% or more of total accounts receivable. For the years ended December 31, 2015 , 2014 and 2013 , no individual customer represented 10% or more of our total revenues. Stock-Based Compensation We record compensation expense for stock-based transactions including employee and non-employee stock option and restricted stock unit ("RSU") awards granted under our 2004 Equity Incentive Plan ("2004 Plan") and 2013 Equity Incentive Plan ("2013 Plan" and together with the 2004 Plan, the "Plans") and shares of Class A common stock issued under our 2013 Employee Stock Purchase Plan ("2013 ESPP"). Stock-based compensation expense is measured and recognized in the financial statements based on fair value. The fair value of each RSU award is determined based on the closing price of our Class A common stock as reported on the New York Stock Exchange on the date of grant. The fair value of each stock option award is determined at the date of grant by applying the Black-Scholes option pricing model. We also use the Black-Scholes option pricing model to determine the fair value of each common share issued under the 2013 ESPP. The fair value for 2013 ESPP grants is determined on the first day of each offering period. The Black-Scholes option pricing model utilizes the value of our underlying common stock at the measurement date, the expected or contractual term of the option or offering period, the expected volatility of our common stock, risk-free interest rates and expected dividend yield of our common stock. Prior to our IPO in May 2013, because our stock was not publicly traded we estimated the fair value of our common stock. Our board of directors considered numerous objective and subjective factors to determine the fair value of our common stock at each meeting at which awards were approved. The factors included, but were not limited to: (i) contemporaneous third-party valuations of our common stock; (ii) the prices, rights, preferences and privileges of our preferred stock that was then outstanding relative to those of our common stock; (iii) the lack of marketability of our common stock; (iv) our actual operating and financial results; (v) current business conditions and projections; and (vi) the likelihood of achieving a liquidity event, such as an IPO or merger or acquisition, given prevailing market conditions. After the completion of our IPO, our common stock has been valued by reference to the closing price of our Class A common stock as reported on the New York Stock Exchange. Measurement of stock-based compensation is subject to periodic adjustment as the underlying equity instruments vest. We recognize compensation expense for only the portion of awards expected to vest. Therefore, we apply an estimated forfeiture rate that was derived from historical employee termination behavior. If the actual number of forfeitures differs from the estimates, adjustments to stock-based compensation expense may be required in future periods. We compute the timing of excess tax benefits from the exercise of stock options and the vesting and settlement of RSUs under the "with-and-without" approach. Under this approach, we will not record an excess tax benefit until such time as a cash tax benefit is recognized. We include the impact of the excess tax benefits in the calculation of certain tax attributes such as the R&D tax credit and do not prepare separate computations considering the cascading impacts of the excess tax deduction. We compute the pool of excess tax benefits available to offset any future shortfalls in the tax benefits actually realized as a single pool for employees and non-employees. Fair Value Measurements We categorize assets and liabilities recorded at fair value on our consolidated balance sheets based upon the level of judgment associated with inputs used to measure their fair value. The levels of the fair value hierarchy are as follows: • Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs are quoted prices for similar assets and liabilities in active markets or quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. • Level 3—Inputs are unobservable inputs based on our own assumptions and valuation techniques used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. We establish fair value of our assets and liabilities using the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date and using a fair value hierarchy based on the inputs used to measure fair value. The carrying amounts reported in the consolidated financial statements approximate the fair value for cash equivalents, accounts receivable, accounts payable, and accrued and other current liabilities, due to their short-term nature. Recent Accounting Pronouncements In May 2014, as part of its ongoing efforts to assist in the convergence of GAAP and International Financial Reporting Standards ("IFRS"), the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-09 related to revenue recognition. The new guidance sets forth a new five-step revenue recognition model that replaces the prior revenue recognition guidance in its entirety and is intended to eliminate numerous industry-specific pieces of revenue recognition guidance that have historically existed in GAAP. The underlying principle of the new standard is that a business or other organization will recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 provides retrospective or modified prospective methods of initial adoption and is effective for annual periods beginning after December 15, 2017 and interim periods within those annual periods. Early adoption is permitted for annual periods beginning after December 15, 2016 and interim periods within those annual periods. We are currently evaluating the method of adoption and the impact that this standard will have on our consolidated financial statements. In August 2014, the FASB issued ASU 2014-15 related to status as a going concern. The new guidance explicitly requires that management assess an entity's ability to continue as a going concern and may require additional detailed disclosures. ASU 2014-15 is effective for annual periods beginning after December 15, 2016 and interim periods within those annual periods. Though permitted, we do not plan to early adopt. We do not believe that this standard will have an impact on our consolidated financial statements. In April 2015, the FASB issued ASU 2015-05 related to a customer's accounting for fees paid in a cloud computing arrangement. The new guidance requires that management evaluate each cloud computing arrangement in order to determine whether it includes a software license that must be accounted for separately from hosted services. ASU 2015-05 applies the same guidance cloud service providers use to make this determination and also eliminates the existing requirement for customers to account for software licenses they acquire by analogizing to the guidance on leases. ASU 2015-05 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2015 and provides the option of applying the guidance prospectively to all arrangements entered into or materially modified after the effective date or on a retrospective basis. Early adoption is permitted. This standard will not have a significant impact on our consolidated financial statements. In November 2015, the FASB issued ASU 2015-17 requiring all deferred income tax assets and liabilities, and any related valuation allowances, to be classified as noncurrent on the balance sheet. The guidance is intended to reduce the complexity inherent in recording deferred income tax assets for financial reporting purposes, as it eliminates the need to separately identify the net current and net noncurrent deferred income tax asset or liability in each jurisdiction and allocate valuation allowances. We have elected to prospectively adopt the accounting standard for the current fiscal year. Prior periods were not retrospectively adjusted. This adoption did not have a significant impact on our consolidated financial statements.

Balance Sheet Detail

Balance Sheet Detail	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Detail	Balance Sheet Detail Property and equipment, net consisted of the following: Useful Life December 31, (in months) 2015 2014 (in thousands) Computer equipment and software 36 $ 73,052 $ 43,340 Furniture and fixtures 36 14,602 8,493 Leasehold improvements 10-150 26,656 15,444 Construction in progress 7,140 5,397 121,450 72,674 Less: Accumulated depreciation and amortization (49,100 ) (27,047 ) $ 72,350 $ 45,627 Depreciation and amortization expense was $23.7 million , $13.5 million and $6.9 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Accrued compensation and employee related benefits consisted of the following: December 31, 2015 2014 (in thousands) Accrued commissions $ 17,518 $ 17,913 Accrued bonuses 16,882 10,931 Accrued vacation 10,425 7,368 Other 8,178 3,952 Total $ 53,003 $ 40,164

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of our income (loss) before income tax expense (benefit) consisted of the following: Year Ended December 31, 2015 2014 2013 (in thousands) United States $ (27,779 ) $ 6,217 $ 2,182 International (23,028 ) 965 683 Total $ (50,807 ) $ 7,182 $ 2,865 Income tax expense (benefit) consisted of the following: Year Ended December 31, 2015 2014 2013 (in thousands) United States $ 28,630 $ (937 ) $ (4,704 ) International 4,263 2,246 493 Total $ 32,893 $ 1,309 $ (4,211 ) The provision (benefit) for income taxes consisted of the following: Year Ended December 31, 2015 2014 2013 (in thousands) Current Federal $ 4,009 $ 11,057 $ 3,732 State 771 2,359 741 Foreign 5,240 2,802 531 Total current income tax expense 10,020 16,218 5,004 Deferred Federal 22,011 (12,970 ) (8,772 ) State 1,839 (1,383 ) (404 ) Foreign (977 ) (556 ) (39 ) Total deferred income tax expense (benefit) 22,873 (14,909 ) (9,215 ) Total income tax expense (benefit) $ 32,893 $ 1,309 $ (4,211 ) Our effective tax rate differs from the U.S. federal statutory rate primarily due to the provision of a valuation allowance on our U.S. federal and state deferred income tax assets in 2015. Our effective tax rate for the years ended December 31, 2015 and 2014 was (64.7)% and 18.2% , respectively. The year-over-year change in the effective tax rate is primarily due to the $46.7 million deferred income tax asset valuation allowance recorded in the fourth quarter of 2015 which reduced our U.S. federal and state deferred income tax assets to the net amount we believe is more likely than not to be realized. A reconciliation of the U.S. federal statutory income tax provision (benefit) to the effective income tax provision (benefit) for each year is as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Income tax provision (benefit) at statutory rate $ (17,783 ) $ 2,514 $ 1,003 State taxes, net of federal tax benefit (896 ) 207 67 Impact of foreign income taxes 10,582 1,340 235 Research and development and other tax credits (10,187 ) (6,499 ) (7,840 ) Non-deductible stock-based compensation 3,174 2,929 1,845 Non-deductible meals and entertainment 1,395 832 582 Change in valuation allowance 46,737 — — Other, net (129 ) (14 ) (103 ) Total income tax expense (benefit) $ 32,893 $ 1,309 $ (4,211 ) The tax effects of temporary differences and carryforwards that gave rise to deferred income tax assets and liabilities consisted of the following: December 31, 2015 2014 (in thousands) Deferred income tax assets Tax credit carryforwards $ 9,704 $ 2,082 Stock-based compensation 21,924 10,499 Accrued compensation 11,819 10,529 Deferred revenue 2,425 1,015 Deferred rent 3,589 1,717 Depreciation and amortization 2,018 334 Other 553 569 Total deferred income tax assets 52,032 26,745 Deferred income tax liabilities Prepaid assets 3,757 2,142 Total deferred income tax liabilities 3,757 2,142 Net deferred income tax assets before valuation allowance 48,275 24,603 Less: Valuation allowance (46,737 ) — Net deferred income tax assets $ 1,538 $ 24,603 Reported As: Deferred income taxes - current — 18,732 Deferred income taxes - long-term 1,544 5,879 Other accrued liabilities — (7 ) Other long-term liabilities (6 ) (1 ) Net deferred income tax assets $ 1,538 $ 24,603 As of December 31, 2014, we presented all current deferred income tax assets and liabilities within the same tax jurisdiction as a single amount. Long-term deferred income tax assets and liabilities are presented using the same methodology. However, as a result of the FASB issuing ASU 2015-17, as of December 31, 2015, all deferred income tax assets and liabilities, and any related valuation allowances, are classified as noncurrent on the balance sheet. We did not retrospectively adjust prior periods. We determine our deferred income tax assets and liabilities based on differences between the financial reporting and tax basis of assets and liabilities using the enacted tax rates and laws that will be in effect when we expect the differences to reverse . A valuation allowance is recorded when it is more likely than not that all or some portion of the deferred income tax assets will not be realized. We regularly assess the need for a valuation allowance against our deferred income tax assets by considering both positive and negative evidence related to whether it is more likely than not that our deferred income tax assets will be realized. In evaluating our ability to recover our deferred income tax assets within the jurisdiction from which they arise, we consider all available positive and negative evidence, including scheduled reversals of deferred income tax liabilities, projected future taxable income, tax-planning strategies, and results of recent operations. In the fourth quarter of 2015 , a valuation allowance of $46.7 million was established for our U.S. federal and state deferred income tax assets, in part due to our current three-year cumulative GAAP net loss adjusted for permanent tax differences, which is a significant piece of negative evidence for recording the valuation allowance in the current period. We will continue to reassess the future realizability of our U.S. deferred income tax assets and adjust the valuation allowance accordingly. Our assumptions, judgments and estimates relative to the value of net deferred income taxes take into account predictions of the amount and category of future taxable income, such as income from operations or capital gains income. Actual operating results and the underlying amount and category of income in future years could render our current assumptions, judgments and estimates of recoverable net deferred income taxes inaccurate. Any of the assumptions, judgments and estimates mentioned above could cause our actual income tax obligations to differ from our estimates, thus materially impacting our financial position and results of operations. Net operating loss ("NOL") carryforwards created by excess tax benefits from the exercise of stock options or the vesting of RSUs are not recorded as deferred income tax assets. To the extent such NOL carryforwards are utilized, the benefit realized will increase stockholders' equity. At December 31, 2015 , for income tax return purposes we have gross NOL carryforwards totaling $679.2 million and tax credit carryforwards of $37.0 million , the majority of which relates to the U.S. These carryforwards may be subject to limitations under the Internal Revenue Code and other applicable tax laws. If not utilized, a portion of the carryforwards will begin to expire in 2022. We are subject to income taxes in the United States and in numerous foreign jurisdictions. The statute of limitations for adjustments to our historic tax obligations will vary from jurisdiction to jurisdiction. Furthermore, net operating loss and tax credit carryforwards may be subject to adjustment after the expiration of the statute of limitations of the year such net operating losses and tax credits originated. In general, the tax years for U.S. federal and state income tax purposes that remain open for examination are for 2005 and forward due to our net operating loss carryforwards. Income tax expense includes both U.S. and international income taxes. Except as required under U.S. tax law, we do not provide for U.S. income taxes on our undistributed earnings of foreign subsidiaries that have not been previously taxed, because we intend to invest such undistributed earnings indefinitely outside of the U.S. If our intent changes or if these funds are needed for our U.S. operations, we would be required to accrue or pay U.S. taxes on some or all of these undistributed earnings. As of December 31, 2015 , cash held by foreign subsidiaries was $24.5 million . Currently, we have no undistributed earnings of foreign subsidiaries indefinitely invested outside of the U.S. We have reserves for taxes to address potential exposures involving tax positions that we believe could be challenged by taxing authorities even though we believe the positions we have taken are appropriate. We believe our tax reserves are adequate to cover potential liabilities. We review the tax reserves as circumstances warrant and adjust the reserves as events occur that affect our potential liability for additional taxes. It is often difficult to predict the final outcome or timing of resolution of any particular tax matter. Various events, some of which cannot be predicted, such as clarification of tax law by administrative or judicial means, may occur and would require us to increase or decrease our reserves and effective income tax rate. The total gross amount of unrecognized tax benefits was $10.8 million , $7.1 million and $3.4 million as of December 31, 2015 , 2014 and 2013 , respectively. This increase relates primarily to the R&D tax credits generated in the current year. These amounts represent the gross amount of exposure in individual jurisdictions and do not reflect any additional benefits expected to be realized if such positions were not sustained. To the extent that any uncertain tax positions are resolved in our favor, it may have a positive impact on our effective income tax rate. We do not expect any material decrease on our unrecognized tax position within the next twelve months. The following table shows the gross changes in our unrecognized tax position. Year Ended December 31, 2015 2014 2013 (in thousands) Balance, beginning of period $ 7,116 $ 3,441 $ 448 Gross increases to tax positions related to prior periods 545 — 5 Gross decreases to tax positions related to prior periods — — (153 ) Gross increases related to current tax positions 3,120 3,675 3,141 Balance, end of period $ 10,781 $ 7,116 $ 3,441 We recognize interest and, if applicable, penalties for any uncertain tax positions as a component of income tax expense. No penalties or interest were recognized or accrued for at December 31, 2015 , 2014 and 2013 . On July 27, 2015, the U.S. Tax Court issued an opinion related to litigation in Altera Corp v. Commissioner. This litigation relates to the treatment of stock-based compensation expense in an inter-company cost-sharing arrangement with one of Altera's foreign subsidiaries. In its opinion, the U.S. Tax Court invalidated the portion of the Treasury regulations requiring the inclusion of stock-based compensation expense in such inter-company cost-sharing arrangements. The final resolution of this litigation remains uncertain as the Internal Revenue Service ("IRS") could appeal the U.S. Tax Court's decision. Therefore, for the year ended December 31, 2015 , we have not recorded any potentially favorable benefit related to the current or prior periods. We will continue to monitor developments related to this case and the potential impact of those developments on our current and future financial statements.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Common Stock Our certificate of incorporation, as amended and restated, authorizes us to issue 75,000,000 shares of Class B common stock, $0.0001 par value per share, and 750,000,000 shares of Class A common stock, $0.0001 par value per share. The rights of the holders of Class A and Class B common stock are identical, except with respect to voting and conversion. Each holder of Class B common stock is entitled to ten votes per share and each holder of Class A common stock is entitled to one vote per share. Shares of Class B common stock may be converted into Class A common stock at any time at the option of the stockholder, and are automatically converted upon sale or transfer to Class A common stock, subject to certain limited exceptions. At its discretion, the board of directors may declare dividends on shares of common stock, subject to the rights of our preferred stockholders, if any. Upon liquidation or dissolution, holders of common stock will receive distributions only after preferred stock preferences have been satisfied. Preferred Stock Our certificate of incorporation, as amended and restated, authorizes us to issue 10,000,000 shares of preferred stock at $0.0001 par value per share. Our board of directors has the authority to provide for the issuance of all the shares in one or more series. At its discretion, our board of directors may designate the voting rights and preferences of the preferred stock. As of December 31, 2015 and 2014 , no shares of preferred stock were outstanding.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Our 2004 Plan authorizes the granting of options to purchase shares of our Class B common stock, RSUs and other stock-based awards to our employees, consultants, officers and directors. In December 2012, we modified the 2004 Plan to increase the number of shares of Class B common stock authorized thereunder to 26,473,282 . Our 2013 Plan, which was the successor to our 2004 Plan, authorizes the granting of options to purchase shares of our Class A common stock, RSUs and other stock-based awards to our employees, consultants, officers and directors. Options granted under the Plans may be incentive or nonstatutory stock options. Incentive stock options may only be granted to employees. The term of each option is stated in the award agreement, but shall be no more than ten years from the date of grant. The board of directors determines the period over which options and RSUs become vested. Currently, the vesting period for our options and RSUs is typically four years. Our 2013 ESPP allows eligible employees to purchase shares of our Class A common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to plan limitations. The 2013 ESPP currently includes purchase periods approximately six months in duration starting on the first trading date on or after June 1 st and December 1 st of each year. Participants are able to purchase shares of our common stock at 85% of the lower of its fair market value on (i) the first day of the purchase period or on (ii) the purchase date, which is the last day of the purchase period. As of December 31, 2015, 3,320,668 shares were authorized under the 2013 ESPP. There were no shares purchased under the 2013 ESPP in 2015 as we commenced the first offering period on December 1, 2015. A summary of the option activity under the Plans during the year ended December 31, 2015 is presented below: Options Outstanding Shares Weighted Average Exercise Price Per Share Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value (in years) (in thousands) Balances at December 31, 2014 8,515,879 $ 8.76 Options exercised (2,458,549 ) 8.18 Options canceled (26 ) 12.78 Options forfeited (103,533 ) 13.69 Balances at December 31, 2015 5,953,771 $ 8.92 5.99 $ 507,885 Vested and expected to vest at December 31, 2015 5,932,740 $ 8.89 5.98 $ 506,247 Exercisable at December 31, 2015 4,646,524 $ 7.69 5.71 $ 402,075 The stock options are exercisable at a price equal to the market value of the underlying shares of common stock on the date of the grant. For periods prior to the IPO this value was determined by our board of directors. After the IPO, this value was determined by reference to the closing price of our Class A common stock on the New York Stock Exchange on the date of the grant. The total intrinsic value of options exercised during 2015 , 2014 and 2013 was $224.6 million , $258.0 million and $199.3 million , respectively. The total fair value of options vested during 2015 , 2014 and 2013 was $11.7 million , $15.0 million and $11.6 million , respectively. We grant RSU awards to our employees, consultants, officers and directors under the provisions of the 2013 Plan. The fair value of an RSU is determined by using the closing price of our Class A common stock as reported on the New York Stock Exchange on the date of grant. An RSU award entitles the holder to receive shares of the Company's Class A common stock as the award vests, which is generally based on length of service. The Company's non-vested RSUs do not have nonforfeitable rights to dividends or dividend equivalents. The following provides a summary of the RSU activity during the year ended December 31, 2015 : Number of Shares Underlying Outstanding RSUs Weighted-Average Grant-Date Fair Value per RSU Non-Vested outstanding at December 31, 2014 2,818,661 $ 77.77 RSUs granted 3,671,156 101.52 RSUs vested (877,696 ) 77.44 RSUs forfeited (206,044 ) 86.74 Non-Vested outstanding at December 31, 2015 5,406,077 $ 93.61 The weighted-average grant date fair value of RSUs granted in 2015 , 2014 and 2013 was $101.52 , $80.05 and $64.04 , respectively. The total fair value of RSUs vested during 2015 and 2014 was $89.1 million and $12.0 million , respectively. There were no RSUs vested in 2013. Stock-based compensation expense is amortized using the straight-line method over the requisite service period. As of December 31, 2015 , total unrecognized compensation expense, adjusted for estimated forfeitures, related to stock options and non-vested RSUs was approximately $424.4 million which is expected to be recognized over a period of 3.1 years . The summary of shares available for issuance for equity based awards (including stock options and RSUs) is as follows: Shares Available for Grant 2013 Plan 2013 ESPP Balances at December 31, 2014 6,229,892 2,621,986 Authorized 3,493,410 698,682 Granted (3,671,156 ) — Canceled 26 — Forfeited 309,577 — Balances at December 31, 2015 6,361,749 3,320,668 Pursuant to the provisions of our 2013 Plan, the number of shares authorized for issuance increases annually on January 1 st by the lesser of 5% of the total number of shares of our capital stock outstanding on December 31 st of the preceding calendar year or an amount determined by our board of directors. Pursuant to the provisions of our 2013 ESPP, the number of shares authorized for issuance increases annually on January 1 st by the lesser of 1% of the total number of shares of our capital stock outstanding on December 31 st of the preceding calendar year, 4,000,000 shares of Class A common stock, or an amount determined by our board of directors. There are no shares available for grant under our 2004 plan. Valuation Assumptions Stock-based payments to employees are measured based on the grant date fair value of the awards and recognized in the consolidated statements of operations over the period during which the employee is required to perform services in exchange for the award. This is generally four years for stock options and RSU awards and six -months for shares issued under the 2013 ESPP. For the years ended December 31, 2015 and 2014 , there were no options granted. The weighted average grant date fair value of stock options granted for the year ended December 31, 2013 was $10.78 . For the year ended December 31, 2013 , the fair value of options was estimated using the Black-Scholes option pricing model with the following assumptions: Year Ended December 31, 2013 Risk-free interest rates 1.11% Expected term 5 years Expected dividends None Expected volatility 46.8% For the years ended December 31, 2015 , 2014 and 2013 , there were no common shares issued under the 2013 ESPP. For the year ended December 31, 2015 , the fair value of common shares to be issued under the 2013 ESPP was estimated using the Black-Scholes option pricing model with the following assumptions: Year Ended December 31, 2015 Risk-free interest rates 0.42% Expected term 0.5 years Expected dividends None Expected volatility 47.97% The weighted-average, risk-free interest rates are based on the rates for a U.S. Treasury zero coupon issue with a term that approximates the expected life of the award at the date closest to the grant date for stock options and to the first date of the purchase period for shares expected to be issued under our 2013 ESPP. The expected term represents the period that our stock-based awards are expected to be outstanding. For awards of stock options, the expected term assumptions were determined based on actual experience adjusted for expected employee exercise behavior. The expected term for shares expected to be issued under our 2013 ESPP is based on the duration of each purchase period, which is approximately six months. We have not paid and do not expect to pay dividends. We estimate expected future volatility based on the annualized daily historical volatility of our stock price. For periods prior to our IPO, there was no active external or internal market for our common shares. We lacked sufficient historical volatility of our share price, and accordingly, we based our volatility on an estimate of similar entities whose share prices were publicly available. The estimation of stock awards that will ultimately vest requires judgment, and to the extent actual results or updated estimates differ from our current estimates, such amounts will be recorded as a cumulative adjustment in the period the estimates are revised. We consider many factors when estimating expected forfeitures, including the types of awards, employee class and historical experience. Forfeitures were estimated at the time of grant and revised if necessary in subsequent periods if actual forfeitures differed from those estimates. Actual results, and future changes in estimates, may differ substantially from our current estimates.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Lease Commitments We conduct our operations in leased facilities under leases expiring at various dates through 2029 . We recognize rent expense on a straight-line basis over the defined lease periods. Total rent expense under operating leases was approximately $18.3 million , $7.2 million and $4.7 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Future minimum lease payments under non-cancellable operating leases as of December 31, 2015 are as follows (in thousands): Year Ending December 31, 2016 $ 22,957 2017 33,065 2018 41,301 2019 44,293 2020 42,712 Thereafter 259,175 Total minimum lease payments $ 443,503 Contractual Commitments Our contractual commitments are associated with agreements that are enforceable and legally binding and that specify all significant terms, including fixed or minimum services to be used, fixed, minimum or variable price provisions, and the approximate timing of the transaction. Obligations under contracts that we can cancel without a significant penalty are not included. As of December 31, 2015 , our contractual commitments were $11.6 million . Legal Proceedings We are subject to certain routine legal proceedings, as well as demands and claims that arise in the normal course of our business. We make a provision for a liability relating to legal matters when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. These provisions are reviewed and adjusted to reflect the impacts of negotiations, estimated settlements, legal rulings, advice of legal counsel and other information and events pertaining to a particular matter. We are not aware of any pending legal proceedings that we believe, individually or in the aggregate, would be expected to have a material adverse effect on our business, operating results, or financial condition. We may, in the future, be party to litigation arising in the ordinary course of business, including claims that we allegedly infringe upon third party intellectual property rights. Such claims, even if not meritorious, could result in the expenditure of significant financial and management resources.

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Retirement Plan	Retirement Plan We offer a salary deferral 401(k) plan for our U.S. employees. The plan allows employees to contribute a percentage of their pretax earnings annually, subject to limitations imposed by the IRS. The plan also allows us to make matching contributions, subject to certain limitations. We contributed approximately $2.8 million and $1.3 million for the years ended December 31, 2015 and 2014 , respectively, to the 401(k) plan. For the year ended December 31, 2013, we made no contributions to the 401(k) plan.

Segments and Information about

Segments and Information about Revenues by Geographic Region	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segments and Information about Revenues by Geographic Area	Segments and Information about Revenues by Geographic Area The following table presents our revenues by geographic region of end users who purchased products or services for the periods presented below: Year Ended December 31, 2015 2014 2013 (in thousands) United States and Canada $ 489,329 $ 318,835 $ 186,725 International 164,258 93,781 45,715 Total revenues $ 653,587 $ 412,616 $ 232,440 Substantially all of our long-lived assets are located in the United States as of December 31, 2015 and 2014 .

Net Income (Loss) Per Share

Net Income (Loss) Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Net Income (Loss) Per Share We calculate basic net income (loss) per share by dividing our net income (loss) for the period by the weighted average number of shares of common stock outstanding during the period. Diluted net income (loss) per share is computed giving effect to all potential common shares that were dilutive and outstanding during the period. For the year ended December 31, 2015 , basic net loss per share is the same as diluted net loss per share as the inclusion of all potentially dilutive common shares outstanding is anti-dilutive when we are in a net loss position. The following table presents the computation of basic and diluted net income (loss) per share: Year Ended December 31, 2015 2014 2013 (in thousands, except per share data) Net income (loss) per share - basic Net income (loss) $ (83,700 ) $ 5,873 $ 7,076 Weighted average shares outstanding used to compute basic net income (loss) per share 71,701 67,591 50,564 Net income (loss) per share - basic $ (1.17 ) $ 0.09 $ 0.14 Net income (loss) per share - diluted Net income (loss) $ (83,700 ) $ 5,873 $ 7,076 Weighted average shares outstanding used to compute basic net income (loss) per share 71,701 67,591 50,564 Effect of potentially dilutive shares: Stock awards — 6,728 8,528 Weighted average shares outstanding used to compute diluted net income (loss) per share 71,701 74,319 59,092 Net income (loss) per share - diluted $ (1.17 ) $ 0.08 $ 0.12 The following shares subject to outstanding awards were excluded from the computation of diluted net income (loss) per share for the periods presented as their effect would have been antidilutive: Year Ended December 31, 2015 2014 2013 (in thousands) Shares subject to outstanding common stock awards 11,510 1,967 86

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following table presents the fair value of our financial assets using the fair value hierarchy: December 31, 2015 Description Level 1 Level 2 Level 3 Total (in thousands) Money market funds $ 736,806 $ — $ — $ 736,806 December 31, 2014 Description Level 1 Level 2 Level 3 Total (in thousands) Money market funds $ 667,210 $ — $ — $ 667,210 We have no material financial assets or liabilities measured using Level 2 or Level 3 inputs.

Quarterly Results of Operations

Quarterly Results of Operations	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations	Quarterly Financial Information (Unaudited) The following table contains selected unaudited financial data for each quarter of 2015 and 2014 . The unaudited information should be read in conjunction with our financial statements and these notes to the consolidated financial statements. We believe that the following unaudited information reflects all normal recurring adjustments necessary for a fair presentation of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. Three Months Ended Dec 31, 2015 Sept 30, 2015 June 30, 2015 March 31, 2015 Dec 31, 2014 Sept 30, 2014 June 30, 2014 March 31, 2014 (in thousands, except per share amounts) Total revenues $ 202,750 $ 170,832 $ 149,860 $ 130,145 $ 142,923 $ 104,469 $ 90,673 $ 74,551 Gross profit 181,115 150,956 133,107 114,724 131,312 94,928 82,033 67,358 Net income (loss) (41,321 ) (13,373 ) (18,979 ) (10,027 ) 20,707 (4,631 ) (4,574 ) (5,629 ) Net income (loss) per share: Basic $ (0.57 ) $ (0.19 ) $ (0.27 ) $ (0.14 ) $ 0.30 $ (0.07 ) $ (0.07 ) $ (0.09 ) Diluted $ (0.57 ) $ (0.19 ) $ (0.27 ) $ (0.14 ) $ 0.27 $ (0.07 ) $ (0.07 ) $ (0.09 )

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Accounting Principles	Accounting Principles The consolidated financial statements and accompanying notes were prepared in accordance with accounting principles generally accepted in the United States ("GAAP").
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Reclassifications	Reclassifications In the consolidated statements of convertible preferred stock and stockholders' equity, certain prior year amounts have been reclassified to conform to the current year presentation. Specifically, the line items for issuance of common stock upon exercise of stock options and issuance of restricted stock units have been combined to one line item, issuance of common stock. There was no change to total stockholders' equity as a result of the reclassification. In the consolidated statements of cash flows, certain prior year amounts have been reclassified to conform to the current year presentation. Specifically, the line items for provision for doubtful accounts and accounts receivable has been combined to one line item, accounts receivable, net. There was no change to the net cash flows from operating, investing, or financing activities as a result of the reclassification.
Public Offerings	Public Offerings In May 2013, we completed our initial public offering ("IPO") whereby 9,430,000 shares of Class A common stock were sold to the public at a price of $31.00 per share. We sold 6,230,000 shares of Class A common stock and the selling stockholders sold 3,200,000 shares of Class A common stock. We received aggregate proceeds of $177.0 million from the IPO, net of underwriters' discounts and commissions, and offering expenses. Upon the closing of the IPO, all shares of our outstanding convertible preferred stock automatically converted into shares of Class B common stock. In March 2014, we closed a follow-on public offering, in which we sold 4,000,000 shares of our Class A common stock at a price to the public of $89.25 per share. The aggregate offering price for shares sold in the offering was approximately $344.1 million , net of underwriters' discounts and commissions, and offering expenses.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates include depreciable lives for property and equipment, stock-based compensation, income taxes, accrued liabilities and collectability of accounts receivable. Actual results could differ from those estimates.
Foreign Currency	Foreign Currency The financial statements of our foreign subsidiaries with a functional currency other than U.S. dollars have been translated into U.S. dollars. Assets and liabilities of these subsidiaries are translated at the exchange rate in effect at each period-end. Income statement amounts are translated at the average rate of exchange prevailing during the period. Translation adjustments arising from the use of differing exchange rates from period to period are included in other comprehensive income (loss). Gains and losses on foreign currency transactions are included in income. Foreign currency transaction gain (loss) was $0.6 million , $0.6 million and $(0.9) million for the years ended December 31, 2015 , 2014 and 2013 , respectively.
Risks and Uncertainties	Risks and Uncertainties Inherent in our business are various risks and uncertainties, including our limited history of operating our business at its current scale and development of advanced technologies in a rapidly changing industry. These risks include our ability to manage our rapid growth and our ability to attract new customers and expand sales to existing customers, as well as other risks and uncertainties. In the event that we do not successfully implement our business plan, certain assets may not be recoverable, certain liabilities may not be paid and investments in our capital stock may not be recoverable. Our success depends upon the acceptance of our technology, development of sales and distribution channels, and our ability to generate significant revenues from the sale of our technology.
Segments	Segments We follow the authoritative literature that established annual and interim reporting standards for an enterprise's operating segments and related disclosures about its products and services, geographic regions and major customers. We operate our business as one operating segment. Our chief operating decision makers ("CODM") are our Chief Executive Officer and Chief Financial Officer, who review financial information presented on a consolidated basis for purposes of making operating decisions, assessing financial performance and allocating resources.
Revenue Recognition	Revenue Recognition We generate revenues primarily in the form of software license fees and related maintenance and services fees. License fees include perpetual, term and subscription license fees. Maintenance and services fees primarily consist of fees for maintenance services (including support and unspecified upgrades and enhancements when and if they are available), training, and professional services that are not essential to functionality of the software. We recognize revenues when all of the following conditions are met: • there is persuasive evidence of an arrangement; • the software or services have been delivered to the customer; • the amount of fees to be paid by the customer is fixed or determinable; and • the collection of the related fees is probable. We use click-through license agreements, signed agreements and purchase orders as evidence of an arrangement. We deliver all of our software electronically. Electronic delivery occurs when we provide the customer with access to the software and license key via a secure portal. We assess whether the fee is fixed or determinable at the outset of the arrangement. Our typical terms of payment are due 30 days from delivery. We assess collectability based on a number of factors such as collection history and creditworthiness of the customer. If we determine that collectability is not probable, revenue is deferred until collectability becomes probable, generally upon receipt of cash. Substantially all of our software licenses are sold in multiple-element arrangements that include maintenance and may include professional services and training. Vendor specific objective evidence ("VSOE") of the fair value is not available for software licenses as they are never sold without maintenance. VSOE of the fair value generally exists for all undelivered elements and any services that are not essential to the functionality of the delivered software. We account for delivered software licenses under the residual method. Maintenance agreements consist of fees for providing software updates on a when and if available basis and technical support for software products ("post-contract support" or "PCS") for an initial term, generally one year. We have established VSOE of the fair value for maintenance on perpetual licenses based on stated substantive renewal rates or the price when sold on a standalone basis. Stated renewal rates are considered to be substantive if they are at least 15% of the actual price charged for the software license. VSOE of the fair value for standalone sales is considered to have been established when a substantial majority of individual sales transactions within the previous 12 months falls within a reasonably narrow range, which we have defined to be plus or minus 15% of the median sales price of actual standalone sales transactions. License arrangements may include professional services and training. In determining whether professional services and training revenues should be accounted for separately from license revenues, we evaluate: • whether such services are considered essential to the functionality of the software using factors such as the nature of the software products; • whether they are ready for use by the customer upon receipt; • the nature of the services, which typically do not involve significant customization to or development of the underlying software code; • the availability of services from other vendors; • whether the timing of payments for license revenues coincides with performance of services; and • whether milestones or acceptance criteria exist that affect the realizability of the software license fee. Revenues related to training are billed on a fixed fee basis and accordingly recognized as training services are delivered. Payments received in advance of services performed are deferred and recognized when the related services are performed. To date, professional services have not been considered essential to the functionality of the software. The VSOE of the fair value of our professional services and training is based on the price for these same services when they are sold separately. Revenues related to professional services are billed on a time and materials basis and, accordingly, are recognized as the services are performed. When software is licensed for a specified term or on a subscription basis, fees for support and maintenance are generally bundled with the license fee over the entire term of the contract. In these cases, we do not have VSOE of the fair value for support and maintenance. Revenues related to term license fees are recognized ratably over the contract term beginning on the date the customer has access to the software license key and continuing through the end of the contract term. We do not offer refunds and therefore have not recorded any sales return allowance for any of the periods presented. Upon a periodic review of outstanding accounts receivable, amounts that are deemed to be uncollectable are written off against the allowance for doubtful accounts. We account for taxes collected from customers and remitted to governmental authorities on a net basis and exclude them from revenues.
Cash and Cash Equivalents	Cash and Cash Equivalents We consider all highly liquid investments purchased with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents are recorded at cost, which approximates fair value. We maintain cash and cash equivalent balances which exceed the insured limits by the Federal Deposit Insurance Corporation.
Accounts Receivable	Accounts Receivable Accounts receivable consist of amounts billed and currently due from customers. Our accounts receivable are subject to collection risk. Our gross accounts receivable is reduced for this risk by a provision for doubtful accounts. This provision is for estimated losses resulting from the inability of our customers to make required payments. It is an estimate and is regularly evaluated for adequacy by taking into consideration a combination of factors. We look at factors such as past collection experience, credit quality of the customer, age of the receivable balance, and current economic conditions. These factors are reviewed to determine whether a provision for doubtful accounts should be recorded to reduce the receivable balance to the amount believed to be collectible. Activity related to our provision for doubtful accounts was as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Balance at the beginning of the period $ 1,111 $ 805 $ 307 Bad debt expense 250 747 789 Accounts written off (473 ) (441 ) (291 ) Balance at the end of the period $ 888 $ 1,111 $ 805
Property and Equipment	Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives range from approximately one to twelve years. Leasehold improvements are amortized over the shorter of the estimated useful life or the remaining lease term. When assets are retired or disposed of, the cost and accumulated depreciation are removed from the accounts, and any resulting gains or losses are included in results of operations. Maintenance and repairs that do not improve or extend the lives of the respective assets are charged to expense in the period incurred.
Leases and Asset Retirement Obligations	Leases and Asset Retirement Obligations Leases are categorized at their inception as either operating or capital leases. Within some lease agreements, rent holidays and other incentives are included. Rent expense is recognized on a straight-line method, over the term of the agreement generally beginning once control of the space is achieved, without regard to deferred payment terms, such as rent holidays that defer the commencement date of required rent payments. Additionally, incentives received are treated as a reduction of expense over the term of the agreement. Leased buildings under build-to-suit lease arrangements are capitalized and included in property and equipment when we are involved in the construction of the structural improvements or take construction risk prior to the commencement of the lease. Upon completion of the construction under the build-to-suit leases, we assess whether those arrangements qualify for sales recognition under the sale-leaseback accounting guidance. Liabilities are established for the present value of estimated future costs to retire leasehold improvements at the termination or expiration of a lease. A corresponding asset is recorded in the period in which the obligation is incurred. Such assets are amortized over the estimated useful life of the asset, and the recorded liabilities are accreted to the future value of the estimated retirement costs.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets We evaluate the recoverability of long-lived assets in accordance with authoritative guidance on accounting for the impairment or disposal of long-lived assets. We evaluate long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Such impairment is recognized in the event the carrying value of such assets exceeds their fair value. If the carrying value of the net assets assigned exceeds the fair value of the assets, then the second step of the impairment test is performed in order to determine the implied fair value. No impairment of long-lived assets occurred in the periods presented.
Software Development Costs	Software Development Costs Software development costs associated with the development of new products, enhancements of existing products and quality assurance activities consists of employee, consulting and other external personnel costs. The costs incurred internally from the research and development ("R&D") of computer software products are charged to expense until technological feasibility has been established for the product. Once technological feasibility is established, all software costs are capitalized until the product is available for release to customers. Judgment is required in determining when technological feasibility of a product is established. To date, we have determined that technological feasibility of software products is reached shortly before the products are released. Costs incurred after establishment of technological feasibility have not been material, and therefore, we have expensed all R&D costs as they were incurred. R&D expenses primarily consist of personnel related costs attributable to our R&D personnel and allocated overhead, which includes facilities related costs. We capitalize certain costs relating to software developed or modified solely to meet our internal requirements and for which there are no substantive plans to market the software. To date, we have not capitalized any such costs as these costs have not been material.
Intangible Asset Costs	Intangible Asset Costs Costs related to filing and pursuing patent and trademark applications are expensed as incurred, as recoverability of such expenditures is uncertain. These intangible asset-related legal costs are generally reported as a component of general and administrative expenses.
Advertising Expenses	Advertising Expenses We expense all advertising costs as incurred and classify such costs as sales and marketing expenses. Advertising expenses for the years ended December 31, 2015 , 2014 and 2013 were $11.3 million , $7.6 million and $4.9 million , respectively.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method in accordance with authoritative guidance for income taxes. Deferred income tax assets are recognized for deductible temporary differences, net operating loss carryforwards, and tax credit carryforwards if it is more likely than not that the tax benefits will be realized. We considered future taxable income, historical operating results, and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance. In 2015, we recorded a valuation allowance to reduce our U.S. federal and state deferred income tax assets to the net amount that we believe is more likely than not to be realized. In the event we determine that we are able to realize our deferred income tax assets in excess of our net recorded amount, we would reduce the valuation allowance associated with the deferred income tax assets in the period the determination is made, which may result in a tax benefit in the statement of operations. Deferred income tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred income tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. We extend credit to customers based upon an evaluation of the customer's financial condition and generally collateral is not required. As of December 31, 2015 and 2014 , no individual customer accounted for 10% or more of total accounts receivable. For the years ended December 31, 2015 , 2014 and 2013 , no individual customer represented 10% or more of our total revenues.
Stock-Based Compensation	Stock-Based Compensation We record compensation expense for stock-based transactions including employee and non-employee stock option and restricted stock unit ("RSU") awards granted under our 2004 Equity Incentive Plan ("2004 Plan") and 2013 Equity Incentive Plan ("2013 Plan" and together with the 2004 Plan, the "Plans") and shares of Class A common stock issued under our 2013 Employee Stock Purchase Plan ("2013 ESPP"). Stock-based compensation expense is measured and recognized in the financial statements based on fair value. The fair value of each RSU award is determined based on the closing price of our Class A common stock as reported on the New York Stock Exchange on the date of grant. The fair value of each stock option award is determined at the date of grant by applying the Black-Scholes option pricing model. We also use the Black-Scholes option pricing model to determine the fair value of each common share issued under the 2013 ESPP. The fair value for 2013 ESPP grants is determined on the first day of each offering period. The Black-Scholes option pricing model utilizes the value of our underlying common stock at the measurement date, the expected or contractual term of the option or offering period, the expected volatility of our common stock, risk-free interest rates and expected dividend yield of our common stock. Prior to our IPO in May 2013, because our stock was not publicly traded we estimated the fair value of our common stock. Our board of directors considered numerous objective and subjective factors to determine the fair value of our common stock at each meeting at which awards were approved. The factors included, but were not limited to: (i) contemporaneous third-party valuations of our common stock; (ii) the prices, rights, preferences and privileges of our preferred stock that was then outstanding relative to those of our common stock; (iii) the lack of marketability of our common stock; (iv) our actual operating and financial results; (v) current business conditions and projections; and (vi) the likelihood of achieving a liquidity event, such as an IPO or merger or acquisition, given prevailing market conditions. After the completion of our IPO, our common stock has been valued by reference to the closing price of our Class A common stock as reported on the New York Stock Exchange. Measurement of stock-based compensation is subject to periodic adjustment as the underlying equity instruments vest. We recognize compensation expense for only the portion of awards expected to vest. Therefore, we apply an estimated forfeiture rate that was derived from historical employee termination behavior. If the actual number of forfeitures differs from the estimates, adjustments to stock-based compensation expense may be required in future periods. We compute the timing of excess tax benefits from the exercise of stock options and the vesting and settlement of RSUs under the "with-and-without" approach. Under this approach, we will not record an excess tax benefit until such time as a cash tax benefit is recognized. We include the impact of the excess tax benefits in the calculation of certain tax attributes such as the R&D tax credit and do not prepare separate computations considering the cascading impacts of the excess tax deduction. We compute the pool of excess tax benefits available to offset any future shortfalls in the tax benefits actually realized as a single pool for employees and non-employees.
Fair Value Measurements	Fair Value Measurements We categorize assets and liabilities recorded at fair value on our consolidated balance sheets based upon the level of judgment associated with inputs used to measure their fair value. The levels of the fair value hierarchy are as follows: • Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs are quoted prices for similar assets and liabilities in active markets or quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. • Level 3—Inputs are unobservable inputs based on our own assumptions and valuation techniques used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. We establish fair value of our assets and liabilities using the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date and using a fair value hierarchy based on the inputs used to measure fair value. The carrying amounts reported in the consolidated financial statements approximate the fair value for cash equivalents, accounts receivable, accounts payable, and accrued and other current liabilities, due to their short-term nature.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, as part of its ongoing efforts to assist in the convergence of GAAP and International Financial Reporting Standards ("IFRS"), the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-09 related to revenue recognition. The new guidance sets forth a new five-step revenue recognition model that replaces the prior revenue recognition guidance in its entirety and is intended to eliminate numerous industry-specific pieces of revenue recognition guidance that have historically existed in GAAP. The underlying principle of the new standard is that a business or other organization will recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 provides retrospective or modified prospective methods of initial adoption and is effective for annual periods beginning after December 15, 2017 and interim periods within those annual periods. Early adoption is permitted for annual periods beginning after December 15, 2016 and interim periods within those annual periods. We are currently evaluating the method of adoption and the impact that this standard will have on our consolidated financial statements. In August 2014, the FASB issued ASU 2014-15 related to status as a going concern. The new guidance explicitly requires that management assess an entity's ability to continue as a going concern and may require additional detailed disclosures. ASU 2014-15 is effective for annual periods beginning after December 15, 2016 and interim periods within those annual periods. Though permitted, we do not plan to early adopt. We do not believe that this standard will have an impact on our consolidated financial statements. In April 2015, the FASB issued ASU 2015-05 related to a customer's accounting for fees paid in a cloud computing arrangement. The new guidance requires that management evaluate each cloud computing arrangement in order to determine whether it includes a software license that must be accounted for separately from hosted services. ASU 2015-05 applies the same guidance cloud service providers use to make this determination and also eliminates the existing requirement for customers to account for software licenses they acquire by analogizing to the guidance on leases. ASU 2015-05 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2015 and provides the option of applying the guidance prospectively to all arrangements entered into or materially modified after the effective date or on a retrospective basis. Early adoption is permitted. This standard will not have a significant impact on our consolidated financial statements. In November 2015, the FASB issued ASU 2015-17 requiring all deferred income tax assets and liabilities, and any related valuation allowances, to be classified as noncurrent on the balance sheet. The guidance is intended to reduce the complexity inherent in recording deferred income tax assets for financial reporting purposes, as it eliminates the need to separately identify the net current and net noncurrent deferred income tax asset or liability in each jurisdiction and allocate valuation allowances. We have elected to prospectively adopt the accounting standard for the current fiscal year. Prior periods were not retrospectively adjusted. This adoption did not have a significant impact on our consolidated financial statements.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Activity Related to Provision for Doubtful Accounts	Activity related to our provision for doubtful accounts was as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Balance at the beginning of the period $ 1,111 $ 805 $ 307 Bad debt expense 250 747 789 Accounts written off (473 ) (441 ) (291 ) Balance at the end of the period $ 888 $ 1,111 $ 805

Balance Sheet Detail (Tables)

Balance Sheet Detail (Tables)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Property, Plant and Equipment	Property and equipment, net consisted of the following: Useful Life December 31, (in months) 2015 2014 (in thousands) Computer equipment and software 36 $ 73,052 $ 43,340 Furniture and fixtures 36 14,602 8,493 Leasehold improvements 10-150 26,656 15,444 Construction in progress 7,140 5,397 121,450 72,674 Less: Accumulated depreciation and amortization (49,100 ) (27,047 ) $ 72,350 $ 45,627
Accrued Compensation Schedule	Accrued compensation and employee related benefits consisted of the following: December 31, 2015 2014 (in thousands) Accrued commissions $ 17,518 $ 17,913 Accrued bonuses 16,882 10,931 Accrued vacation 10,425 7,368 Other 8,178 3,952 Total $ 53,003 $ 40,164

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The components of our income (loss) before income tax expense (benefit) consisted of the following: Year Ended December 31, 2015 2014 2013 (in thousands) United States $ (27,779 ) $ 6,217 $ 2,182 International (23,028 ) 965 683 Total $ (50,807 ) $ 7,182 $ 2,865
Schedule Of Income Tax Expense Benefit By Geographic Area Table	Income tax expense (benefit) consisted of the following: Year Ended December 31, 2015 2014 2013 (in thousands) United States $ 28,630 $ (937 ) $ (4,704 ) International 4,263 2,246 493 Total $ 32,893 $ 1,309 $ (4,211 )
Schedule of Components of Income Tax Expense (Benefit)	The provision (benefit) for income taxes consisted of the following: Year Ended December 31, 2015 2014 2013 (in thousands) Current Federal $ 4,009 $ 11,057 $ 3,732 State 771 2,359 741 Foreign 5,240 2,802 531 Total current income tax expense 10,020 16,218 5,004 Deferred Federal 22,011 (12,970 ) (8,772 ) State 1,839 (1,383 ) (404 ) Foreign (977 ) (556 ) (39 ) Total deferred income tax expense (benefit) 22,873 (14,909 ) (9,215 ) Total income tax expense (benefit) $ 32,893 $ 1,309 $ (4,211 )
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the U.S. federal statutory income tax provision (benefit) to the effective income tax provision (benefit) for each year is as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Income tax provision (benefit) at statutory rate $ (17,783 ) $ 2,514 $ 1,003 State taxes, net of federal tax benefit (896 ) 207 67 Impact of foreign income taxes 10,582 1,340 235 Research and development and other tax credits (10,187 ) (6,499 ) (7,840 ) Non-deductible stock-based compensation 3,174 2,929 1,845 Non-deductible meals and entertainment 1,395 832 582 Change in valuation allowance 46,737 — — Other, net (129 ) (14 ) (103 ) Total income tax expense (benefit) $ 32,893 $ 1,309 $ (4,211 )
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences and carryforwards that gave rise to deferred income tax assets and liabilities consisted of the following: December 31, 2015 2014 (in thousands) Deferred income tax assets Tax credit carryforwards $ 9,704 $ 2,082 Stock-based compensation 21,924 10,499 Accrued compensation 11,819 10,529 Deferred revenue 2,425 1,015 Deferred rent 3,589 1,717 Depreciation and amortization 2,018 334 Other 553 569 Total deferred income tax assets 52,032 26,745 Deferred income tax liabilities Prepaid assets 3,757 2,142 Total deferred income tax liabilities 3,757 2,142 Net deferred income tax assets before valuation allowance 48,275 24,603 Less: Valuation allowance (46,737 ) — Net deferred income tax assets $ 1,538 $ 24,603 Reported As: Deferred income taxes - current — 18,732 Deferred income taxes - long-term 1,544 5,879 Other accrued liabilities — (7 ) Other long-term liabilities (6 ) (1 ) Net deferred income tax assets $ 1,538 $ 24,603
Schedule of Unrecognized Tax Benefits Roll Forward	The following table shows the gross changes in our unrecognized tax position. Year Ended December 31, 2015 2014 2013 (in thousands) Balance, beginning of period $ 7,116 $ 3,441 $ 448 Gross increases to tax positions related to prior periods 545 — 5 Gross decreases to tax positions related to prior periods — — (153 ) Gross increases related to current tax positions 3,120 3,675 3,141 Balance, end of period $ 10,781 $ 7,116 $ 3,441

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Option Activity	A summary of the option activity under the Plans during the year ended December 31, 2015 is presented below: Options Outstanding Shares Weighted Average Exercise Price Per Share Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value (in years) (in thousands) Balances at December 31, 2014 8,515,879 $ 8.76 Options exercised (2,458,549 ) 8.18 Options canceled (26 ) 12.78 Options forfeited (103,533 ) 13.69 Balances at December 31, 2015 5,953,771 $ 8.92 5.99 $ 507,885 Vested and expected to vest at December 31, 2015 5,932,740 $ 8.89 5.98 $ 506,247 Exercisable at December 31, 2015 4,646,524 $ 7.69 5.71 $ 402,075
Summary of RSU Activity	The following provides a summary of the RSU activity during the year ended December 31, 2015 : Number of Shares Underlying Outstanding RSUs Weighted-Average Grant-Date Fair Value per RSU Non-Vested outstanding at December 31, 2014 2,818,661 $ 77.77 RSUs granted 3,671,156 101.52 RSUs vested (877,696 ) 77.44 RSUs forfeited (206,044 ) 86.74 Non-Vested outstanding at December 31, 2015 5,406,077 $ 93.61
Schedule Of Equity Based Awards Available	The summary of shares available for issuance for equity based awards (including stock options and RSUs) is as follows: Shares Available for Grant 2013 Plan 2013 ESPP Balances at December 31, 2014 6,229,892 2,621,986 Authorized 3,493,410 698,682 Granted (3,671,156 ) — Canceled 26 — Forfeited 309,577 — Balances at December 31, 2015 6,361,749 3,320,668
Fair Value Assumptions - Options	For the year ended December 31, 2013 , the fair value of options was estimated using the Black-Scholes option pricing model with the following assumptions: Year Ended December 31, 2013 Risk-free interest rates 1.11% Expected term 5 years Expected dividends None Expected volatility 46.8%
Fair Value Assumptions - ESPP	For the year ended December 31, 2015 , the fair value of common shares to be issued under the 2013 ESPP was estimated using the Black-Scholes option pricing model with the following assumptions: Year Ended December 31, 2015 Risk-free interest rates 0.42% Expected term 0.5 years Expected dividends None Expected volatility 47.97%

Commitments and Contigencies (T

Commitments and Contigencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	Future minimum lease payments under non-cancellable operating leases as of December 31, 2015 are as follows (in thousands): Year Ending December 31, 2016 $ 22,957 2017 33,065 2018 41,301 2019 44,293 2020 42,712 Thereafter 259,175 Total minimum lease payments $ 443,503

Segments and Information abou26

Segments and Information about Revenues by Geographic Region (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Reconciliation of Revenue from Segments to Consolidated	The following table presents our revenues by geographic region of end users who purchased products or services for the periods presented below: Year Ended December 31, 2015 2014 2013 (in thousands) United States and Canada $ 489,329 $ 318,835 $ 186,725 International 164,258 93,781 45,715 Total revenues $ 653,587 $ 412,616 $ 232,440

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Schedule of Computation of Earnings Per Share, Basic and Diluted	The following table presents the computation of basic and diluted net income (loss) per share: Year Ended December 31, 2015 2014 2013 (in thousands, except per share data) Net income (loss) per share - basic Net income (loss) $ (83,700 ) $ 5,873 $ 7,076 Weighted average shares outstanding used to compute basic net income (loss) per share 71,701 67,591 50,564 Net income (loss) per share - basic $ (1.17 ) $ 0.09 $ 0.14 Net income (loss) per share - diluted Net income (loss) $ (83,700 ) $ 5,873 $ 7,076 Weighted average shares outstanding used to compute basic net income (loss) per share 71,701 67,591 50,564 Effect of potentially dilutive shares: Stock awards — 6,728 8,528 Weighted average shares outstanding used to compute diluted net income (loss) per share 71,701 74,319 59,092 Net income (loss) per share - diluted $ (1.17 ) $ 0.08 $ 0.12
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following shares subject to outstanding awards were excluded from the computation of diluted net income (loss) per share for the periods presented as their effect would have been antidilutive: Year Ended December 31, 2015 2014 2013 (in thousands) Shares subject to outstanding common stock awards 11,510 1,967 86

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets	The following table presents the fair value of our financial assets using the fair value hierarchy: December 31, 2015 Description Level 1 Level 2 Level 3 Total (in thousands) Money market funds $ 736,806 $ — $ — $ 736,806 December 31, 2014 Description Level 1 Level 2 Level 3 Total (in thousands) Money market funds $ 667,210 $ — $ — $ 667,210

Quarterly Results of Operatio29

Quarterly Results of Operations (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	Three Months Ended Dec 31, 2015 Sept 30, 2015 June 30, 2015 March 31, 2015 Dec 31, 2014 Sept 30, 2014 June 30, 2014 March 31, 2014 (in thousands, except per share amounts) Total revenues $ 202,750 $ 170,832 $ 149,860 $ 130,145 $ 142,923 $ 104,469 $ 90,673 $ 74,551 Gross profit 181,115 150,956 133,107 114,724 131,312 94,928 82,033 67,358 Net income (loss) (41,321 ) (13,373 ) (18,979 ) (10,027 ) 20,707 (4,631 ) (4,574 ) (5,629 ) Net income (loss) per share: Basic $ (0.57 ) $ (0.19 ) $ (0.27 ) $ (0.14 ) $ 0.30 $ (0.07 ) $ (0.07 ) $ (0.09 ) Diluted $ (0.57 ) $ (0.19 ) $ (0.27 ) $ (0.14 ) $ 0.27 $ (0.07 ) $ (0.07 ) $ (0.09 )

Description of Business Narrati

Description of Business Narrative (Details)	Dec. 31, 2015product
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Products	5

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Details)	Mar. 21, 2014USD ($)$ / sharesshares	May. 22, 2013USD ($)$ / sharesshares	Dec. 31, 2015USD ($)segmentcustomer	Dec. 31, 2014USD ($)customer	Dec. 31, 2013USD ($)customer
Class of Stock [Line Items]
Impairment of Long-Lived Assets Held-for-use			$ 0	$ 0	$ 0
Proceeds from IPO			0	344,077,000	176,974,000
Foreign currency transaction gain (loss)			$ 600,000	600,000	(900,000)
Number of operating segments | segment			1
Terms of payment due			30 days
VSOE Sales % variance compared to median sales price of standalone transactions			15.00%
VSOE sales period of evaluation			12 months
Advertising Expense			$ 11,300,000	$ 7,600,000	$ 4,900,000
Accounts receivable | Customer concentration risk
Class of Stock [Line Items]
Number of Customers with more than 10% of Period Receivables | customer			0	0
Revenue | Customer concentration risk
Class of Stock [Line Items]
Number of Customers with More than 10% of Period Revenue | customer			0	0	0
Minimum
Class of Stock [Line Items]
Useful life of property and equipment (in years)			1 year
Maximum
Class of Stock [Line Items]
Useful life of property and equipment (in years)			12 years
Common Class A
Class of Stock [Line Items]
Shares Sold in Public Offering, Including Existing Shares, Number of Shares Sold | shares		9,430,000
Price per share of stock sold in IPO (in $ per share) | $ / shares	$ 89.25	$ 31
Proceeds from public offering, net of underwriters' discount, shares | shares	4,000,000	6,230,000
Number of shares sold by existing shareholders | shares		3,200,000
Proceeds from IPO		$ 177,000,000
Proceeds from Issuance of Common Stock	$ 344,100,000

Summary of Significant Accoun32

Summary of Significant Accounting Policies Activity Related to Allowance for Doubtful Accounts (Details) - Allowance for doubtful accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the beginning of the period	$ 1,111	$ 805	$ 307
Bad debt expense	250	747	789
Accounts written off	(473)	(441)	(291)
Balance at the end of the period	$ 888	$ 1,111	$ 805

Balance Sheet Detail - Property

Balance Sheet Detail - Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 121,450	$ 72,674
Less: Accumulated depreciation and amortization	(49,100)	(27,047)
Property and equipment, net	$ 72,350	45,627
Minimum
Property, Plant and Equipment [Line Items]
Useful life (in months)	1 year
Maximum
Property, Plant and Equipment [Line Items]
Useful life (in months)	12 years
Computer equipment and software
Property, Plant and Equipment [Line Items]
Useful life (in months)	36 months
Property and equipment, Gross	$ 73,052	43,340
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life (in months)	36 months
Property and equipment, Gross	$ 14,602	8,493
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 26,656	15,444
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life (in months)	10 months
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life (in months)	150 months
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 7,140	$ 5,397

Balance Sheet Detail - Addition

Balance Sheet Detail - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Depreciation and amortization expense	$ 23,667	$ 13,512	$ 6,850

Balance Sheet Detail - Accrued

Balance Sheet Detail - Accrued Compensation and Other Employee Related Benefits (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued commissions	$ 17,518	$ 17,913
Accrued bonuses	16,882	10,931
Accrued vacation	10,425	7,368
Other accrued compensation and employee related benefits	8,178	3,952
Total	$ 53,003	$ 40,164

Income Taxes - Income Before Pr

Income Taxes - Income Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States	$ (27,779)	$ 6,217	$ 2,182
International	(23,028)	965	683
Income (loss) before income tax expense (benefit)	$ (50,807)	$ 7,182	$ 2,865

Income Taxes - Income Taxes Exp

Income Taxes - Income Taxes Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Expense Benefit [Line Items]
Provision (benefit) for income taxes	$ 32,893	$ 1,309	$ (4,211)
United States
Income Tax Expense Benefit [Line Items]
Provision (benefit) for income taxes	28,630	(937)	(4,704)
International
Income Tax Expense Benefit [Line Items]
Provision (benefit) for income taxes	$ 4,263	$ 2,246	$ 493

Income Taxes - Provision for Cu

Income Taxes - Provision for Current and Deferred Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current
Federal	$ 4,009	$ 11,057	$ 3,732
State	771	2,359	741
Foreign	5,240	2,802	531
Total current provision	10,020	16,218	5,004
Deferred
Federal	22,011	(12,970)	(8,772)
State	1,839	(1,383)	(404)
Foreign	(977)	(556)	(39)
Total deferred provision (benefit)	22,873	(14,909)	(9,215)
Total income tax expense (benefit)	$ 32,893	$ 1,309	$ (4,211)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Effective tax rate (percent)		(64.70%)	18.20%
Deferred tax asset valuation allowance	$ (46,700,000)
Net operating loss carryforwards	679,200,000	$ 679,200,000
R&D tax credit carryforwards	37,000,000	37,000,000
Cash held by foreign subsidiaries	24,500,000	24,500,000
Foreign earnings on which US income taxes has not been provided	0	0
Unrecognized tax benefits	$ 10,781,000	10,781,000	$ 7,116,000	$ 3,441,000	$ 448,000
Income tax penalties and interest expense		$ 0	$ 0	$ 0

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes Differs from U.S. Federal Statutory Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax provision (benefit) at statutory rate	$ (17,783)	$ 2,514	$ 1,003
State taxes, net of federal tax benefit	(896)	207	67
Impact of foreign income taxes	10,582	1,340	235
Research and development and other tax credits	(10,187)	(6,499)	(7,840)
Non-deductible stock-based compensation	3,174	2,929	1,845
Non-deductible meals and entertainment	1,395	832	582
Change in valuation allowance	46,737	0	0
Other, net	(129)	(14)	(103)
Total income tax expense (benefit)	$ 32,893	$ 1,309	$ (4,211)

Income Taxes - Deferred Income

Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred income tax assets
Tax credit carryforwards	$ 9,704	$ 2,082
Stock-based compensation	21,924	10,499
Accrued compensation	11,819	10,529
Deferred revenue	2,425	1,015
Deferred rent	3,589	1,717
Depreciation and amortization	2,018	334
Other	553	569
Total deferred income tax assets	52,032	26,745
Deferred income tax liabilities
Prepaid assets	3,757	2,142
Total deferred income tax liabilities	3,757	2,142
Deferred Tax Assets and Liabilities, Net Before Valuation Allowance	48,275	24,603
Less: Valuation allowance	(46,737)	0
Net deferred income tax assets	1,538	24,603
Components of Deferred Tax Assets Reported As
Deferred income taxes - current	0	18,732
Deferred income taxes - long-term	1,544	5,879
Other accrued liabilities	0	(7)
Other long-term liabilities	(6)	(1)
Net deferred income tax assets	$ 1,538	$ 24,603

Income Taxes - Changes in Unrec

Income Taxes - Changes in Unrecognized Tax Position (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance, beginning of period	$ 7,116	$ 3,441	$ 448
Gross increases to tax positions related to prior periods	545	0	5
Gross decreases to tax positions related to prior periods	0	0	(153)
Gross increases related to current tax positions	3,120	3,675	3,141
Balance, end of period	$ 10,781	$ 7,116	$ 3,441

Stockholders' Equity (Details)

Stockholders' Equity (Details)	12 Months Ended
	Dec. 31, 2015votes$ / sharesshares	Dec. 31, 2014$ / sharesshares
Common Class B
Class of Stock [Line Items]
Shares authorized for issuance	75,000,000	75,000,000
Common stock par value (USD per share) | $ / shares	$ 0.0001	$ 0.0001
Votes per share entitled to share holder | votes	10
Common Class A
Class of Stock [Line Items]
Shares authorized for issuance	750,000,000	750,000,000
Common stock par value (USD per share) | $ / shares	$ 0.0001	$ 0.0001
Votes per share entitled to share holder | votes	1
Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (shares)	10,000,000	10,000,000
Preferred stock par value (USD per share) | $ / shares	$ 0.0001	$ 0.0001
Preferred stock outstanding (shares)	0	0

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 424.4
Weighted-average remaining vesting period (in years)	3 years 1 month 6 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period (in years)	10 years
Vesting period (in years)	4 years
Total intrinsic value of options exercised	$ 224.6	$ 258	$ 199.3
Fair value of options vested	$ 11.7	$ 15	$ 11.6
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase in shares authorized for grant, Percent of outstanding shares	5.00%
Shares available for grant	6,361,749	6,229,892
Options granted (in shares)	3,671,156
2013 Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Weighted Average Fair Value, RSUs granted, USD per share	$ 101.52	$ 80.05	$ 64.04
Fair value of RSUs vested in period	$ 89.1	$ 12
RSUs vested in period (in shares)	877,696		0
2013 Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	0	0
Weighted-average grant date fair value of options (USD per share)			$ 10.78
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	6 months
Annual increase in shares authorized for grant, Percent of outstanding shares	1.00%
Annual increase in shares authorized for grant	4,000,000
2004 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	0
2004 Plan | Common Class B
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	26,473,282

Stock-Based Compensation - ESPP

Stock-Based Compensation - ESPP (Details) - ESPP - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued	0	0	0
Vesting period (in years)	6 months
ESPP maximum deduction (percent)	15.00%
ESPP purchase period (in months)	6 months
ESPP purchase price, percent of fair market value	85.00%
Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	3,320,668

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Option Activity Under Stock option Plan (Details) - Stock options $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding, Weighted Average Remaining Contractual Term, Ending Balance	5 years 11 months 26 days
Options Outstanding, Weighted Average Remaining Contractual Term, Vested and Expected to Vest	5 years 11 months 23 days
Options Outstanding, Weighted Average Remaining Contractual Term, Exercisable	5 years 8 months 15 days
Options Outstanding, Aggregate Intrinsic Value | $	$ 507,885
Options Outstanding, Aggregate Intrinsic Value, Vested and Expected to Vest | $	506,247
Options Outstanding, Aggregate Intrinsic Value, Exercisable | $	$ 402,075
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Weighted Average Exercise Price, Beginning of Period, USD per share | $ / shares	$ 8.76
Options Outstanding, Weighted Average Exercise Price, Options exercised, USD per share | $ / shares	8.18
Options Outstanding, Weighted Average Exercise Price, Options canceled, USD per share | $ / shares	12.78
Options Outstanding, Weighted Average Exercise Price, Options forfeited, USD per share | $ / shares	13.69
Options Outstanding, Weighted Average Exercise Price, End of Period, USD per share | $ / shares	8.92
Options Outstanding, Weighted Average Exercise Price Per Share, Vested and Expected to Vest, USD per share | $ / shares	8.89
Options Outstanding, Weighted Average Exercise Price Per Share, Exercisable, USD per share | $ / shares	$ 7.69
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options Outstanding, Shares, Beginning of Period | shares	8,515,879
Options Outstanding, Shares, Exercised | shares	(2,458,549)
Options Outstanding, Shares, Canceled | shares	(26)
Options Outstanding, Shares, Forfeited | shares	(103,533)
Options Outstanding, Shares, End of Period | shares	5,953,771
Options Outstanding, Shares, Vested and Expected to Vest | shares	5,932,740
Options Outstanding, Shares, Exercisable | shares	4,646,524

Stock-Based Compensation - Su47

Stock-Based Compensation - Summary of RSU Activity (Details) - 2013 Plan - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Outstanding Number of Shares
Shares Outstanding, Beginning of Period	2,818,661
RSUs granted	3,671,156
RSUs vested	(877,696)		0
RSUs forfeited	(206,044)
Shares Outstanding, End of Period	5,406,077	2,818,661
Weighted Average Fair Value
Weighted Average Fair Value, Beginning of Period, USD per share	$ 77.77
Weighted Average Fair Value, RSUs granted, USD per share	101.52	$ 80.05	$ 64.04
Weighted Average Fair Value, RSUs vested, USD per share	77.44
Weighted Average Fair Value, RSUs forfeited, USD per share	86.74
Weighted Average Fair Value, End of Period, USD per share	$ 93.61	$ 77.77

Stock-Based Compensation - Equi

Stock-Based Compensation - Equity Based Awards (including Stock Options and RSUs (Details)	12 Months Ended
	Dec. 31, 2015shares
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Equity based awards, beginning of period	6,229,892
Equity based awards, Authorized	3,493,410
Options granted (in shares)	3,671,156
Equity based awards, Canceled	26
Share-Based Compensation Arrangement By Share-Based Payment Award, Forfeited On Period	309,577
Equity based awards, end of period	6,361,749
2013 Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	3,671,156
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	206,044
ESPP | Common Class A
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Equity based awards, beginning of period	2,621,986
Equity based awards, Authorized	698,682
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0
Equity based awards, Canceled	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	0
Equity based awards, end of period	3,320,668

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Options Estimated Using Black-Scholes Option Pricing Model (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates (percent)		1.11%
Expected term (in years)		5 years
Expected dividends		$ 0
Expected volatility (percent)		46.80%
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates (percent)	0.42%
Expected term (in years)	6 months
Expected dividends	$ 0
Expected volatility (percent)	47.97%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 18.3	$ 7.2	$ 4.7
Contractual commitments	$ 11.6

Commitments and Contingencies51

Commitments and Contingencies - Future Minimum Lease Payments under Non-Cancellable Operating Leases (Details) $ in Thousands	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 22,957
2,017	33,065
2,018	41,301
2,019	44,293
2,020	42,712
Thereafter	259,175
Total minimum lease payments	$ 443,503

Retirement Plan Additional Info

Retirement Plan Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Employer matching contributions	$ 2,800,000	$ 1,300,000	$ 0

Segments and Information abou53

Segments and Information about Revenues by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 202,750	$ 170,832	$ 149,860	$ 130,145	$ 142,923	$ 104,469	$ 90,673	$ 74,551	$ 653,587	$ 412,616	$ 232,440
United States and Canada [Member]
Segment Reporting Information [Line Items]
Revenues									489,329	318,835	186,725
International
Segment Reporting Information [Line Items]
Revenues									$ 164,258	$ 93,781	$ 45,715

Net Income (Loss) Per Share - C

Net Income (Loss) Per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income (loss)	$ (41,321)	$ (13,373)	$ (18,979)	$ (10,027)	$ 20,707	$ (4,631)	$ (4,574)	$ (5,629)	$ (83,700)	$ 5,873	$ 7,076
Weighted average shares outstanding used to compute basic net income (loss) per share									71,701	67,591	50,564
Net income (loss) per share - basic (in USD per share)	$ (0.57)	$ (0.19)	$ (0.27)	$ (0.14)	$ 0.30	$ (0.07)	$ (0.07)	$ (0.09)	$ (1.17)	$ 0.09	$ 0.14
Stock awards (in shares)									0	6,728	8,528
Weighted average shares outstanding used to compute diluted net income (loss) per share									71,701	74,319	59,092
Net income (loss) per share - diluted (in USD per share)	$ (0.57)	$ (0.19)	$ (0.27)	$ (0.14)	$ 0.27	$ (0.07)	$ (0.07)	$ (0.09)	$ (1.17)	$ 0.08	$ 0.12

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Shares Excluded From Computation of Diluted Net Income per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Stock (Class A and B)
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Antidilutive securities excluded from computation (in shares)	11,510	1,967	86

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Money market funds - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments fair value	$ 736,806	$ 667,210
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments fair value	736,806	667,210
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments fair value	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments fair value	$ 0	$ 0

Quarterly Results of Operatio57

Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 202,750	$ 170,832	$ 149,860	$ 130,145	$ 142,923	$ 104,469	$ 90,673	$ 74,551	$ 653,587	$ 412,616	$ 232,440
Gross profit	181,115	150,956	133,107	114,724	131,312	94,928	82,033	67,358	579,902	375,631	213,916
Net income (loss)	$ (41,321)	$ (13,373)	$ (18,979)	$ (10,027)	$ 20,707	$ (4,631)	$ (4,574)	$ (5,629)	$ (83,700)	$ 5,873	$ 7,076
Net income (loss) per share - basic (in USD per share)	$ (0.57)	$ (0.19)	$ (0.27)	$ (0.14)	$ 0.30	$ (0.07)	$ (0.07)	$ (0.09)	$ (1.17)	$ 0.09	$ 0.14
Net income (loss) per share - diluted (in USD per share)	$ (0.57)	$ (0.19)	$ (0.27)	$ (0.14)	$ 0.27	$ (0.07)	$ (0.07)	$ (0.09)	$ (1.17)	$ 0.08	$ 0.12