Rocket Fuel 10-Q 15 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 30, 2014
Document and Entity Information	'	'
Entity Registrant Name	'Rocket Fuel Inc.	'
Entity Central Index Key	'0001477200	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	35,142,204
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets:	'	'
Cash and cash equivalents	$218,174	$113,873
Accounts receivable, net	83,293	90,502
Deferred tax assets	207	207
Prepaid expenses	2,688	2,164
Other current assets	6,868	3,962
Total current assets	311,230	210,708
Property, equipment and software, net	37,283	25,794
Restricted cash	2,294	0
Other assets	1,026	1,006
Total assets	351,833	237,508
Current Liabilities:	'	'
Accounts payable	34,305	39,910
Accrued and other current liabilities	24,940	21,584
Deferred revenue	878	918
Current portion of capital leases	777	203
Debt, Current	8,493	7,243
Total current liabilities	69,393	69,858
Long-term debt—Less current portion	18,368	19,568
Capital leases—Less current portion	1,568	412
Deferred rent—Less current portion	7,445	3,909
Deferred tax liabilities	207	207
Other liabilities	387	387
Total liabilities	97,368	94,341
Commitments and contingencies (Note 12)	'	'
Stockholders’ Equity	'	'
Common stock, $0.001 par value— 1,000,000,000 authorized as of March 31, 2014 and December 31, 2013, respectively; 35,108,736 and 32,825,992 issued and outstanding as of March 31, 2014 and December 31, 2013, respectively	35	33
Additional paid-in capital	310,113	187,624
Accumulated other comprehensive loss	17	-15
Accumulated deficit	-55,700	-44,475
Total stockholders’ equity	254,465	143,167
Total liabilities and stockholders’ equity	$351,833	$237,508

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	35,108,736	32,825,992
Common stock, shares outstanding	35,108,736	32,825,992

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]	'	'
Revenue	$74,397	$38,212
Cost of revenue	37,535	20,671
Gross profit	36,862	17,541
Operating expenses:	'	'
Research and development	7,241	2,412
Sales and marketing	29,759	16,230
General and administrative	10,340	5,177
Total operating expenses	47,340	23,819
Loss from operations	-10,478	-6,278
Other expense, net:	'	'
Interest expense	-414	-124
Other income (expense)—net	-19	-519
Change in fair value of convertible preferred stock warrant liability	0	-1,097
Other expense, net	-433	-1,740
Loss before income taxes	-10,911	-8,018
Provision for income taxes	-314	-54
Net loss	($11,225)	($8,072)
Basic and diluted net loss per share attributable to common stockholders	($0.33)	($0.97)
Basic and diluted weighted-average shares used to compute net loss per share attributable to common stockholders	34,033	8,298

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Statement of Comprehensive Income [Abstract]	'		'
Net loss	($11,225)		($8,072)
Other comprehensive loss:	'		'
Foreign currency translation adjustments	32	[1]	-31	[1]
Comprehensive loss	($11,193)		($8,103)
[1]	Reclassifications out of Other comprehensive income (loss) into Net loss were not significant.

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2013	$143,167	$33	$187,624	($15)	($44,475)
Balance (in shares) at Dec. 31, 2013	'	32,825,992	'	'	'
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'
Issuance of common stock upon exercises of employee stock options, net of repurchases	1,379	0	1,379	'	'
Issuance of common stock upon exercises of employee stock options, net of repurchases (in shares)	287,578	278,744	'	'	'
Issuance of common stock upon exercise vesting of restricted stock units	0	0	'	'	'
Issuance of common stock upon exercise vesting of restricted stock units (in shares)	'	4,000	'	'	'
Issuance of stock, net of issuance costs	115,437	2	115,435	'	'
Issuance of stock, net of issuance costs (in shares)	'	2,000,000	'	'	'
Stock-based compensation	5,528	'	5,528	'	'
Foreign currency translation adjustment	32	'	'	32	'
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	147	'	147	'	'
Net loss	-11,225	'	'	'	-11,225
Balance at Mar. 31, 2014	$254,465	$35	$310,113	$17	($55,700)
Balance (in shares) at Mar. 31, 2014	'	35,108,736	'	'	'

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
OPERATING ACTIVITIES:	'	'
Net loss	($11,225)	($8,072)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	2,920	1,389
Provision for doubtful accounts	34	0
Stock-based compensation	5,125	1,565
Amortization of debt discount	50	0
Excess tax benefit from share-based activity	-147	0
Change in fair value of preferred stock warrant liability	0	1,097
Changes in operating assets and liabilities:	'	'
Accounts receivable	7,175	-548
Prepaid expenses	-523	-318
Other current assets	-2,908	86
Other assets	-128	-2
Accounts payable	-5,004	-1,806
Accrued and other liabilities	-100	924
Deferred rent	3,570	27
Deferred revenue	-40	38
Net cash used in operating activities	-1,201	-5,620
INVESTING ACTIVITIES:	'	'
Purchases of property, equipment and software	-7,177	-1,756
Capitalized internal-use software development costs	-1,757	-1,708
Restricted cash	-2,281	0
Net cash used in investing activities	-11,215	-3,464
FINANCING ACTIVITIES:	'	'
Proceeds from the issuance of common stock in follow-on public offering, net of underwriting discounts and commission	116,510	0
Issuance costs related to initial and follow-on public offering	-985	-170
Proceeds from exercise of vested common stock options	1,058	18
Proceeds from early exercise of unvested common stock options	2	227
Repurchases of common stock options early exercised	-1	0
Excess tax benefit from stock-based activity	147	0
Repayment of capital lease obligations	-38	0
Proceeds from issuance of long-term debt	0	10,000
Repayment of long-term debt	0	-113
Net cash provided by financing activities	116,693	9,962
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	24	-38
CHANGE IN CASH AND CASH EQUIVALENTS	104,301	840
CASH AND CASH EQUIVALENTS—Beginning of period	113,873	14,896
CASH AND CASH EQUIVALENTS—End of period	218,174	15,736
SUPPLEMENTAL DISCLOSURES OF OTHER CASH FLOW INFORMATION:	'	'
Cash paid for income taxes	200	90
Cash paid for interest	347	80
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES:	'	'
Purchases of property and equipment recorded in accounts payable and accruals	5,585	230
Offering costs recorded in accrued liabilities	216	393
Property, plant and equipment acquired under capital lease obligations	1,769	0
Vesting of early exercised options	303	61
Stock-based compensation capitalized in internal-use software costs	$403	$0

NATURE_OF_BUSINESS_AND_SUMMARY

NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	'
	NOTE 1. NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Rocket Fuel Inc. (the “Company”) was incorporated as a Delaware corporation on March 25, 2008. The Company is a provider of an artificial-intelligence digital advertising solution. The Company is headquartered in Redwood City, California, and has offices in various cities across the United States. The Company established a wholly-owned subsidiary in the United Kingdom in 2011 and in Canada in 2013. The United Kingdom subsidiary has offices throughout Europe and established a wholly-owned subsidiary in Germany in 2013.
	In September 2013, the Company completed the initial public offering of its common stock (the “IPO”) whereby 4,000,000 shares of common stock were sold by the Company and 600,000 shares of common stock were sold by selling stockholders. The public offering price of the shares sold in the offering was $29.00 per share. The Company did not receive any proceeds from the sale of shares by the selling stockholders. The total gross proceeds from the offering to the Company were $116.0 million. After deducting underwriters’ discounts and commissions and offering expenses, the aggregate net proceeds received by the Company totaled approximately $103.3 million.
	In February 2014, the Company completed an underwritten follow-on public offering (the “Follow-on Offering”) of its common stock in which 2,000,000 shares of common stock were sold by the Company and 3,000,000 shares of common stock were sold by selling stockholders. The public offering price of the shares sold in the offering was $61.00 per share. The Company did not receive any proceeds from the sale of shares by the selling stockholders. The total gross proceeds from the offering to the Company were $122.0 million. After deducting underwriters’ discounts and commissions and offering expenses, the aggregate net proceeds received by the Company totaled approximately $115.4 million.
	Basis of Presentation—The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2013, included in its Annual Report on Form 10-K.
	The condensed consolidated balance sheet as of December 31, 2013 included herein was derived from the audited financial statements as of that date, but does not include all notes and other disclosures required by GAAP.
	In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the financial position, results of operations, and cash flows for the interim periods, but are not necessarily indicative of the results of operations to be anticipated for the full year 2014 or any future period.
	Principles of Consolidation—The consolidated financial statements include the Company and its wholly-owned subsidiaries in the United Kingdom and Canada, which are currently engaged in marketing and selling advertising campaigns. All intercompany transactions and balances have been eliminated in consolidation.
	Use of Estimates—The preparation of unaudited condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and disclosures of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Such estimates include, but are not limited to, provisions for doubtful accounts, the amount of software development costs which should be capitalized, future taxable income, the useful lives of long-lived assets and the assumptions used for purposes of determining stock-based compensation. Actual results could differ from those estimates.
	Foreign Currency Translation—The Company’s foreign subsidiaries record their assets, liabilities and results of operations in their local currencies, which are their functional currencies. The Company translates its subsidiaries' consolidated financial statements into U.S. dollars each reporting period for purposes of consolidation.
	Assets and liabilities of the Company’s foreign subsidiaries are translated at the period-end currency exchange rates, certain equity accounts are translated at historical exchange rates and revenue, expenses, gains and losses are translated at the average currency exchange rates in effect for the period. The effects of these translation adjustments are reported in a separate component of stockholders’ equity titled accumulated other comprehensive income (loss).
	Fair Value of Financial Instruments—The Company’s financial instruments consist principally of cash equivalents, accounts receivable, accounts payable, accrued liabilities, capital lease, term debt and revolving credit facilities. The fair value of the Company’s cash equivalents is determined based on quoted prices in active markets for identical assets for its money market funds. The recorded values of the Company’s accounts receivable, accounts payable and accrued liabilities approximate their current fair values due to the relatively short-term nature of these accounts. The Company believes that the fair value of the capital lease, term debt and revolving credit facilities approximates its recorded amount as of March 31, 2014 as the interest rate on the capital lease, term debt and revolving credit facilities is variable and is based on market interest rates after consideration of default and credit risk.
	Cash and Cash Equivalents—Cash consists of cash maintained in checking and savings accounts. All highly liquid investments purchased with an original maturity date of 90 days or less at the date of purchase are considered to be cash equivalents. Cash equivalents consist of money market funds.
	Restricted Cash—Restricted cash as of March 31, 2014 consists of cash required to be deposited with financial institutions for security deposits for the Company's London, United Kingdom and Paris, France office lease agreements.
	Concentration of Credit Risk—Financial instruments, which potentially subject the Company to significant concentrations of credit risk, consist primarily of cash and accounts receivable. A significant portion of the Company’s cash is held at three major financial institutions, which management assesses to be of high credit quality. The Company has not experienced any losses in such accounts.
	The Company mitigates its credit risk with respect to accounts receivable by performing credit evaluations and monitoring agencies' and advertisers' accounts receivable balances. As of March 31, 2014 and December 31, 2013, no single agency or advertiser accounted for 10% or more of accounts receivable.
	During the three months ended March 31, 2014 and 2013, no single customer represented 10% or more of revenue.
	Provision for Doubtful Accounts—The Company records a provision for doubtful accounts based on historical experience and a detailed assessment of the collectability of its accounts receivable. In estimating the allowance for doubtful accounts, management considers, among other factors, the aging of the accounts receivable, historical write-offs and the credit-worthiness of each customer. If circumstances change, such as higher-than-expected defaults or an unexpected material adverse change in a major customer’s ability to meet its financial obligations, the Company’s estimate of the recoverability of the amounts due could be reduced by a material amount.
	The following table presents the changes in the allowance for doubtful accounts (in thousands):
		Three Months Ended
		March 31,
		2014			2013
	Allowance for doubtful accounts:
	Balance, beginning of period	$	1,057		$	468
	Add: bad debt expense	34			—
	Less: write-offs, net of recoveries	(1		)	—
	Balance, end of period	$	1,090		$	468
	Property and Equipment—Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the related assets. Maintenance and repairs are charged to expense as incurred, and improvements and betterments are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation or amortization, as applicable, are removed from the balance sheet and any resulting gain or loss is reflected in operations in the period realized.
	Construction in progress primarily includes costs related to the leasehold improvements and also includes network equipment infrastructure to support the Company's data centers around the world. Interest capitalized during the periods presented was not material.
	Leasehold improvements are amortized on a straight-line basis over the term of the lease, or the useful life of the assets, whichever is shorter. Depreciation and amortization periods for the Company’s property and equipment are as follows:
	Asset Classification	Estimated Useful Life
	Computer hardware and purchased software	2–3 years
	Capitalized internal-use software costs	2–3 years
	Office equipment, furniture and fixtures	5 years
	Internal-Use Software Development Costs—The Company incurs costs to develop software for internal use. The Company expenses all costs that relate to the planning and post implementation phases of development as research and development expense. The Company capitalizes costs when preliminary efforts are successfully completed, management has authorized and committed project funding, and it is probable that the project will be completed and will be used as intended. Costs incurred for enhancements that are expected to result in additional material functionality are capitalized. The Company capitalized $2.1 million and $1.7 million in internal-use software costs during the three months ended March 31, 2014 and 2013, respectively, which are included in property, equipment and software—net on the condensed consolidated balance sheets.
	Amortization commences when the website or software for internal use is ready for its intended use and the amortization period is the estimated useful life of the related asset, which is generally three years. Amortization expense totaled $1.1 million and $0.8 million for the three months ended March 31, 2014 and 2013, respectively.
	Impairment of Long-lived Assets—The Company periodically reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset is impaired or the estimated useful life is no longer appropriate. If indicators of impairment exist and the undiscounted projected cash flows associated with an asset are less than the carrying amount of the asset, an impairment loss is recorded to write the asset down to its estimated fair value. Fair value is estimated based on discounted future cash flows. No impairment charges were recorded during the three months ended March 31, 2014 and 2013.
	Revenue Recognition—The Company generates revenue by delivering digital advertisements to Internet users through various channels, including display, mobile, social and video.
	The Company recognizes revenue when all four of the following criteria are met:
	•    Persuasive evidence of an arrangement exists
	•    Delivery has occurred or a service has been provided
	•    Customer fees are fixed or determinable
	•    Collection is reasonably assured
	Revenue arrangements are evidenced by a fully-executed insertion order (“IO”). Generally, IOs state the number and type of advertising impressions (cost-per-thousand) to be delivered, the agreed upon rate for each delivered impression, and a fixed period of time for delivery.
	The Company determines collectability by performing ongoing credit evaluations and monitoring its customers’ accounts receivable balances. For new customers and their agents, which may be advertising agencies or other third parties, the Company performs a credit check with an independent credit agency and may check credit references to determine creditworthiness. The Company only recognizes revenue when collection is reasonably assured.
	In the normal course of business, the Company frequently contracts with advertising agencies on behalf of their advertiser clients. The determination of whether revenue should be reported on a gross or net basis is based on an assessment of whether the Company is acting as the principal or an agent in the transaction. In determining whether the Company acts as the principal or an agent, the Company follows the accounting guidance for principal-agent considerations. While none of the factors identified in this guidance is individually considered presumptive or determinative, because the Company is the primary obligor and is responsible for (i) fulfilling the advertisement delivery, (ii) establishing the selling prices for delivery of the advertisements, (iii) selecting the media to fulfill the insertion order, and (iv) performing all billing and collection activities including retaining credit risk, the Company has concluded that it acts as the principal in the majority of these arrangements and therefore reports revenue earned and costs incurred on a gross basis.
	On occasion, the Company has offered customer incentive programs that provide rebates after achieving a specified level of advertising spending. The Company records reductions to revenue for estimated commitments related to these customer incentive programs. For transactions involving incentives, the Company recognizes revenue net of the estimated amount to be paid by rebate, provided that the rebate amount can be reasonably and reliably estimated and the other conditions for revenue recognition have been met. The Company’s policy requires that, if rebates cannot be reliably estimated, revenue is not recognized until reliable estimates can be made or the rebate program lapses.
	In addition, the Company has licensed a self-service version of its technology platform to a Japanese advertising agency, for use by the agency's customers.  Under this licensing agreement, the agency is responsible for the media costs. In this type of arrangement, the Company recognizes its licensing fee revenue on a net basis.
	Multiple-Element Arrangements—The Company enters into arrangements to sell advertising that includes different media placements or ad services that are delivered at the same time, or within close proximity of one another. Beginning on January 1, 2011, the Company adopted new authoritative guidance on multiple element arrangements, using the prospective method for all arrangements entered into or materially modified from the date of adoption. Under this new guidance, the Company allocates arrangement consideration in multiple-deliverable revenue arrangements at the inception of an arrangement to all deliverables or those packages in which all components of the package are delivered at the same time, based on the relative selling price method in accordance with the selling price hierarchy, which includes: (1) vendor-specific objective evidence (“VSOE”), if available; (2) third-party evidence (“TPE”), if VSOE is not available; and (3) best estimate of selling price (“BESP”), if neither VSOE nor TPE is available.
	VSOE—The Company determines VSOE based on its historical pricing and discounting practices for the specific product or service when sold separately. In determining VSOE, the Company requires that a substantial majority of the stand-alone selling prices for these services fall within a reasonably narrow pricing range. The Company has not been able to establish VSOE for any of its advertising offerings.
	TPE—When VSOE cannot be established for deliverables in multiple element arrangements, the Company applies judgment with respect to whether it can establish a selling price based on TPE. TPE is determined based on competitor prices for similar deliverables when sold separately. Generally, the Company’s go-to-market strategy differs from that of its peers and its offerings contain a significant level of differentiation such that the comparable pricing of services cannot be obtained. Furthermore, the Company is unable to reliably determine the selling prices of similar competitor services on a stand-alone basis. As a result, the Company has not been able to establish selling price based on TPE.
	BESP—When it is unable to establish selling price using VSOE or TPE, the Company uses BESP in its allocation of arrangement consideration. The objective of BESP is to determine the price at which the Company would transact a sale if the service were sold on a stand-alone basis. BESP is generally used to allocate the selling price to deliverables in the Company’s multiple element arrangements. The Company determines BESP for deliverables by considering multiple factors, including, but not limited to, prices it charges for similar offerings, market conditions, competitive landscape and pricing practices. In particular, the Company reviews multiple data points to determine BESP, including price lists used by the Company’s sales team in pricing negotiations, historical average and median pricing achieved in prior contractual customer arrangements and input from the Company’s sales operation department regarding what it believes the deliverables could be sold for on a stand-alone basis. BESP is determined at an advertising unit level that is consistent with the Company’s underlying market strategy and stratified based on specific consideration of channel, geography, industry and size, as deemed necessary.
	The Company limits the amount of allocable arrangement consideration to amounts that are fixed or determinable and that are not contingent on future performance or future deliverables. The Company regularly reviews BESP. Changes in assumptions or judgments or changes to the elements in the arrangement could cause a material increase or decrease in the amount of revenue that the Company reports in a particular period.
	The Company recognizes the relative fair value of advertising services as they are delivered, assuming all other revenue recognition criteria are met. Deferred revenue is comprised of contractual billings in excess of recognized revenue and payments received in advance of revenue recognition.
	Cost of Revenue—Cost of revenue consists primarily of media cost for advertising impressions purchased from real-time advertising exchanges and other third parties. Cost of revenue also includes third-party data center costs and the salaries and related costs of the Company’s operations group. This group sets up, initiates and monitors the Company’s advertising campaigns. In addition, depreciation of the data center equipment, rental payments to third-party vendors for data centers and amortization of capitalized internal-use software are included in cost of revenue.
	Research and Development—Research and development expenses include costs associated with the maintenance and ongoing development of the Company’s technology, including compensation and employee benefits and allocated costs associated with the Company’s engineering and research and development departments, as well as costs for contracted services and supplies. Allocated costs include charges for facilities, office expenses, telephones, and other miscellaneous expenses. The Company reviews costs incurred in the application development stage and assesses such costs for potential capitalization.
	Sales and Marketing—Sales and marketing expenses consist primarily of compensation (including commissions) and employee benefits of sales and marketing personnel and related support teams, allocated costs, certain advertising costs, travel, trade shows and marketing materials. Allocated costs include charges for facilities, office expenses, telephones, and other miscellaneous expenses. The Company incurred advertising costs of $1.2 million and $0.1 million for the three months ended March 31, 2014 and 2013, respectively.
	General and Administrative—General and administrative expenses include facilities costs, executive and administrative compensation and employee benefits, depreciation, professional services fees, insurance costs, bad debt and other allocated costs, such as facility-related expenses, supplies and other fixed costs. Allocated costs include charges for facilities, office expenses, telephones, and other miscellaneous expenses.
	Stock-based Compensation—The Company measures compensation expense for all stock-based payment awards, including stock options granted to employees, based on the estimated fair values on the date of the grant. The fair value of each stock option granted is estimated using the Black-Scholes option pricing model. Stock-based compensation is recognized on a straight-line basis over the requisite vesting period, net of estimated forfeitures. The forfeiture rate is based on an analysis of the Company’s actual historical forfeitures.
	The Company accounts for stock options issued to non-employees based on the fair value of the awards determined using the Black-Scholes option pricing model. The fair value of stock options granted to non-employees is re-measured as the stock options vest, and the resulting change in fair value, if any, is recognized in the Company’s condensed consolidated statement of operations during the period the related services are rendered, generally between one and four years.
	Preferred Stock Warrant Liability—Freestanding warrants related to shares that are redeemable or contingently redeemable were classified as a liability on the Company’s condensed consolidated balance sheet. The fully-vested convertible preferred stock warrants were subject to re-measurement at each balance sheet date, and any change in fair value is recognized as a component of other expense, net. As completion of the Company’s initial public offering constituted a liquidation event, the convertible preferred stock warrants were converted into common stock or warrants to purchase common stock, and the liability was reclassified to additional paid-in capital in the third quarter of 2013.
	Income Taxes—The Company accounts for income taxes using an asset and liability approach. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Operating loss and tax credit carry-forwards are measured by applying currently enacted tax laws. Valuation allowances are provided when necessary to reduce net deferred tax assets to an amount that is more likely than not to be realized. Due to uncertainty as to the realization of benefits from deferred tax assets, including net operating loss carry-forwards, research and development and other tax credits, the Company has provided a full valuation allowance reserved against such assets as of March 31, 2014 and December 31, 2013.
	The Company recognizes the tax effects of an uncertain tax position only if it is more likely than not to be sustained based solely on its technical merits as of the reporting date, and then, only in an amount more likely than not to be sustained upon review by the tax authorities. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes.
Deferred Offering Costs—Deferred offering costs consisted primarily of direct incremental costs related to the Company’s public offerings of its common stock. Approximately $0.1 million of deferred offering costs were included in other assets on the Company’s condensed consolidated balance sheet as of December 31, 2013. No deferred offering costs are included as of March 31, 2014. Upon completion of the offerings, these amounts were offset against the proceeds of the offerings.
Recently Issued and Adopted Accounting Pronouncements—Under the Jumpstart Our Business Startups Act (the "JOBS Act"), we qualify as an “emerging growth company.” We have irrevocably elected to opt out of the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, and, therefore, we will be subject to the same new or revised accounting standards as other public companies that are not “emerging growth companies.”
In July 2013, the FASB issued Accounting Standards Update (ASU) No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (ASU 2013-11). The guidance requires an entity to present its unrecognized tax benefits net of its deferred tax assets when settlement in this manner is available under the tax law, which would be based on facts and circumstances as of the balance sheet reporting date and would not consider future events. Gross presentation of unrecognized tax benefit will still be required in the notes to the financial statements. ASU 2013-11 will apply on a prospective basis to all unrecognized tax benefits that exist at the effective date. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of ASU 2013-11 did not have a material impact on our consolidated financial statements.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
FAIR VALUE MEASUREMENTS	'
	NOTE 2.	FAIR VALUE MEASUREMENTS
	Fair value is defined as the price that would be received on the sale of an asset or paid to transfer a liability (exit price) in an orderly transaction between market participants at the measurement date. The FASB has established a fair value hierarchy that distinguishes between (1) market participant assumptions developed based on market data obtained from independent sources (observable inputs) and (2) an entity’s own assumptions about market participant assumptions developed based on the best information available in the circumstances (unobservable inputs). The fair value hierarchy consists of three broad levels, which gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3).
	The three levels of the fair value hierarchy under the guidance for fair value measurement are described below:
	Level 1	Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Pricing inputs are based upon quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. For securities, the valuations are based on quoted prices of the security that are readily and regularly available in an active market, and accordingly, a significant degree of judgment is not required. As of March 31, 2014 and December 31, 2013, the Company used Level 1 assumptions for its money market funds.
	Level 2	Pricing inputs are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities. As of March 31, 2014 and December 31, 2013, the Company did not have any Level 2 financial assets or liabilities.
	Level 3	Pricing inputs are generally unobservable for the assets or liabilities and include situations where there is little, if any, market activity for the investment. The inputs into the determination of fair value require management’s judgment or estimation of assumptions that market participants would use in pricing the assets or liabilities. The fair values are therefore determined using model-based techniques that include option pricing models, discounted cash flow models, and similar techniques. As of March 31, 2014 and December 31, 2013, the Company did not have any Level 3 financial assets or liabilities.
	The carrying amounts of cash equivalents, accounts receivable, prepaid expenses, accounts payable and accrued liabilities approximate fair value due to the short-term nature of these items. Based on the borrowing rates currently available to the Company for debt with similar terms, the carrying value of the capital lease, term debt and line of credit approximate fair value (using Level 2 inputs).
	The following tables set forth the Company’s financial instruments that were measured at fair value on a recurring basis as of March 31, 2014 and December 31, 2013, by level within the fair value hierarchy. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. The Company’s fair value hierarchy for its financial assets and financial liabilities that are carried at fair value are as follows (in thousands):
	31-Mar-14		Fair Value		Level 1		Level 2		Level 3
	Money market funds (included in cash and cash equivalents)		$	127,900	$	127,900	$	—	$	—
	31-Dec-13		Fair Value		Level 1		Level 2		Level 3
	Money market funds (included in cash and cash equivalents)		$	2,900	$	2,900	$	—	$	—

CASH_AND_CASH_EQUIVALENTS

CASH AND CASH EQUIVALENTS	3 Months Ended
	Mar. 31, 2014
Cash and Cash Equivalents [Abstract]	'
CASH AND CASH EQUIVALENTS	'
	NOTE 3.	CASH AND CASH EQUIVALENTS
	Cash and cash equivalents as of March 31, 2014 and December 31, 2013, consisted of the following (in thousands):
		March 31,		December 31,
		2014		2013
	Cash and cash equivalents:
	Cash	$	90,274	$	110,973
	Money market funds	127,900		2,900
	Total cash and cash equivalents	$	218,174	$	113,873

PROPERTY_EQUIPMENT_AND_SOFTWAR

PROPERTY, EQUIPMENT AND SOFTWARE, NET	3 Months Ended
	Mar. 31, 2014
Property, Plant and Equipment [Abstract]	'
PROPERTY, EQUIPMENT AND SOFTWARE, NET	'
	NOTE 4.	PROPERTY, EQUIPMENT AND SOFTWARE, NET
	Property, equipment and software, net as of March 31, 2014 and December 31, 2013, consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Capitalized internal-use software costs	$	16,190		$	14,030
	Computer hardware and software	20,607			17,077
	Furniture and fixtures	4,436			1,735
	Leasehold improvements	10,460			815
	Construction in progress	—			3,622
	Total	51,693			37,279
	Accumulated depreciation and amortization	(14,410		)	(11,485		)
	Total property, equipment and software, net	$	37,283		$	25,794
	Total depreciation and amortization expense, excluding amortization of internal-use software costs, was $1.8 million and $0.6 million for the three months ended March 31, 2014 and 2013, respectively. Amortization expense of internal-use software costs was $1.1 million and $0.8 million for the three months ended March 31, 2014 and 2013, respectively. Refer to Note 6 for details of the Company's capital lease as of March 31, 2014 and December 31, 2013.

ACCRUED_AND_OTHER_CURRENT_LIAB

ACCRUED AND OTHER CURRENT LIABILITIES	3 Months Ended
	Mar. 31, 2014
Payables and Accruals [Abstract]	'
ACCRUED AND OTHER CURRENT LIABILITIES	'
	NOTE 5.	ACCRUED AND OTHER CURRENT LIABILITIES
	Accrued and other current liabilities as of March 31, 2014 and December 31, 2013, consisted of the following (in thousands):
		March 31,		December 31,
		2014		2013
	Payroll and related expenses	$	7,805	$	10,722
	Accrued vacation	3,188		2,220
	Professional services	637		650
	Accrued credit cards	87		774
	Early exercise of unvested stock options	783		1,107
	Employee stock purchase plan	2,811		1,427
	Other accrued expenses	9,629		4,684
	Total accrued and other current liabilities	$	24,940	$	21,584

CAPITAL_LEASES

CAPITAL LEASES	3 Months Ended
	Mar. 31, 2014
Leases [Abstract]	'
CAPITAL LEASES	'
	NOTE 6.	CAPITAL LEASES
	Property and equipment at March 31, 2014 and December 31, 2013 included $2.7 million and $0.6 million, respectively, acquired under capital lease agreements of which the majority consists of computer hardware and software. There was $0.1 million and $0 of accumulated depreciation of property and equipment acquired under these capital leases at March 31, 2014 and December 31, 2013, respectively. The related depreciation is included in depreciation expense.
	Approximate remaining future minimum lease payments under these non-cancelable capital leases as of March 31, 2014 were as follows (in thousands):
	Year ending December 31,		Future Payments
	2014 (remaining 9 months)		$	658
	2015		893
	2016		883
	2017		96
	Thereafter		—
	Total minimum lease payments		$	2,530
	Less: amount representing interest and taxes		(185		)
	Less: current portion of minimum lease payments		(777		)
	Capital lease obligations, net of current portion		$	1,568

OTHER_INCOME_EXPENSENET

OTHER INCOME (EXPENSE)—NET	3 Months Ended
	Mar. 31, 2014
Other Income and Expenses [Abstract]	'
OTHER INCOME (EXPENSE)—NET	'
	NOTE 7.	OTHER INCOME (EXPENSE)—NET
	Other income (expense)—net for the three months ended March 31, 2014 and 2013, consisted of the following (in thousands):
		Three Months Ended
		March 31,
		2014			2013
	Gain (loss) on foreign translation	$	(29	)	$	(556	)
	Other non-operating income (loss), net	10			37
	Total other income (expense)—net	$	(19	)	$	(519	)

DEBT

DEBT	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
DEBT	'
	NOTE 8.	DEBT
	Loan Facility—On December 20, 2013, the Company entered into an Amended and Restated Revolving Credit and Term Loan Agreement (the "Loan Facility") with certain lenders, including Comerica Bank, as administrative agent for the lenders. The Loan Facility provides for an $80.0 million revolving credit facility, with a $5.0 million letter of credit subfacility and a $1.5 million swingline subfacility, and a $20.0 million secured term loan facility. The Loan Facility permits the Company, subject to certain requirements, to request an increase in the maximum revolving commitments under the Loan Facility by up to $25.0 million in additional revolving commitments. Revolving loans may be advanced under the Loan Facility in amounts up to the lesser of the $80.0 million maximum and a borrowing base equal to 85% of the value of eligible accounts receivable. The borrowing base is subject to certain reserves and eligibility criteria. Comerica may also issue letters of credit under the subfacility up to $5.0 million, provided that the aggregate amount of advances outstanding under the revolving facility, the subfacility and the swingline facility do not exceed the lesser of the $80.0 million maximum and the borrowing base amount. If at any time the aggregate amounts outstanding under the revolving facility, the letter of credit subfacility and the swingline facility exceed the lesser of the $80.0 million maximum and the borrowing base then in effect, then the Company must make a prepayment in an amount sufficient to eliminate the excess. Term loans equal to $20.0 million were advanced to the Company under the term loan facility during December 2013. Loan proceeds may be used for general corporate purposes. The Company may prepay revolving loans and term loans under the Loan Facility in whole or in part at any time without premium or penalty, subject to certain conditions.
	Revolving loans bear interest, at our option, at (i) a base rate determined pursuant to the terms of the Loan Facility, plus a spread of 1.75% to 2.50%, or (ii) a LIBOR rate determined pursuant to the terms of the Loan Facility, plus a spread of 2.75% to 3.50%. Term loans bear interest, at our option, at (i) a base rate determined pursuant to the terms of the Loan Facility, plus a spread of 2.75% to 3.50%, or (ii) a LIBOR rate determined pursuant to the terms of the Loan Facility, plus a spread of 3.75% to 4.50%. In each case, the spread is based on the cash reflected on our balance sheet for the preceding fiscal quarter. The base rate is determined by taking the greatest of (i) the prime rate announced by Comerica, (ii) the federal funds rate plus 1.0% and (iii) the daily adjusting LIBOR rate plus 1.0%. Interest is due and payable quarterly in arrears for base rate loans. Interest is due and payable at the end of an interest period (or at each three months interval in the case of loans with interest periods greater than three months) for LIBOR rate loans. Term loans will be repaid in quarterly principal installments of approximately $1.3 million commencing in January 2015, with any remaining principal, together with all accrued and unpaid interest, due and payable on December 20, 2018. Principal, together with all accrued and unpaid interest, on the revolving loans are due and payable on December 20, 2016.
	The Company is required to maintain certain financial covenants under the Loan Facility, including the following:
	EBITDA. The Company is required to maintain specified quarterly EBITDA, which is defined for this purpose, with respect to any fiscal period as an amount equal to the sum of (i) consolidated net income (loss) in accordance with GAAP, after eliminating all extraordinary nonrecurring items of income, plus (ii) depreciation and amortization, income tax expense, total interest expense paid or accrued, non-cash stock-based compensation expense, costs and expenses from permitted acquisitions up to certain limits, costs and expenses in connection with the Loan Facility and any other expenses agreed with Comerica and the lenders less (iii) all extraordinary and non-recurring revenues and gains (including income tax benefits).
	Liquidity ratio. Under the Loan Facility, the ratio of (i) the sum of all cash on deposit with Comerica and certain other domestic financial institutions and the aggregate amount of all eligible accounts receivable to (ii) all indebtedness owing to the lender of the Loan Facility must be at least 1.10 to 1.00.
	The terms of the Loan Facility also require the Company to comply with certain non-financial covenants. As of March 31, 2014, the Company was in compliance with each of the financial and non-financial covenants.
	Future Payments
	Future principal payments of long-term debt as of March 31, 2014 were as follows (in thousands):
	Year ending December 31,		Future Payments
	2014 (remaining 9 months)		$	—
	2015		5,000
	2016		5,000
	2017		5,000
	2018		5,000
	Total		20,000
	Less: current portion of long-term debt		(1,250		)
	Long-term debt, net of current portion		$	18,750
	As of March 31, 2014, the $7.4 million balance outstanding under the revolving credit facility had a maturity date of December 20, 2016, and because the Company has the option to draw upon the facility or repay borrowed funds at any time, the balance is shown as a current liability in the accompanying consolidated balance sheet. Additionally, the debt liabilities on the condensed consolidated balance sheet are net of $0.6 million in debt discounts.

STOCKHOLDERS_EQUITY

STOCKHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
STOCKHOLDERS' EQUITY	'
	NOTE 9.	STOCKHOLDERS’ EQUITY
	Follow-on Offering
	In February 2014, the Company completed an underwritten follow-on public offering of its common stock in which 2,000,000 shares of common stock were sold by the Company and 3,000,000 shares of common stock were sold by selling stockholders. The public offering price of the shares sold in the offering was $61.00 per share. The Company did not receive any proceeds from the sale of shares by the selling stockholders. The total gross proceeds from the offering to the Company were $122.0 million. After deducting underwriters’ discounts and commissions and offering expenses, the aggregate net proceeds received by the Company totaled approximately $115.4 million.
	Reserved Shares of Common Stock—The Company’s shares of capital stock reserved for issuance as of March 31, 2014 were as follows:
		31-Mar-14
	Options outstanding	7,417,535
	Restricted stock units outstanding	473,137
	Available for future stock option and restricted stock unit grants	5,870,342
	Available for future employee stock purchase plan purchases	1,656,319
	Total shares reserved	15,417,333
	2008 Equity Incentive Plan—The 2008 Equity Incentive Plan (the “2008 Plan”) provides for the grant of incentive stock options and nonqualified stock options. The compensation committee of the Company's board of directors has the authority to approve the employees and non-employees to whom options are granted and determine the terms of each option, including (i) the number of shares of common stock subject to the option; (ii) when the option becomes exercisable; (iii) the option exercise price, which, in the case of incentive stock options, must be at least 100% of the fair market value of the common stock as of the date of grant; and (iv) the duration of the option (which, in the case of incentive stock options, may not exceed 10 years). Options granted under the 2008 Plan generally vest over four years and expire no later than 10 years from the date of grant. The Company has terminated the 2008 Plan for future use, and no further equity awards are to be granted under the 2008 Plan. All outstanding awards under the 2008 Plan will continue to be governed by their existing terms.
	Under the terms of the 2008 Plan, certain employees received the right to exercise unvested options. Upon termination of service, an employee’s unvested shares may be repurchased by the Company at the original purchase price. As of March 31, 2014 and December 31, 2013, 241,574 and 315,579 unvested shares, respectively, were subject to repurchase. During the three months ended March 31, 2014 and year ended December 31, 2013, the Company repurchased 8,834 and 5,834 shares of unvested stock, respectively.
	2013 Equity Incentive Plan—The Company’s board of directors adopted and the Company’s stockholders approved a 2013 Equity Incentive Plan (the “2013 Plan”), which became effective September 18, 2013.  The 2013 Plan permits the grant of incentive stock options, within the meaning of Section 422 of the Code, to the Company’s employees and any parent and subsidiary corporations’ employees, and for the grant of nonstatutory stock options, restricted stock, restricted stock units, stock appreciation rights, performance units and performance shares to the Company’s employees, directors and consultants and the Company’s parent and subsidiary corporations’ employees and consultants.
	A total of 5,000,000 shares of common stock were reserved for issuance upon initial adoption of the 2013 Plan.  In addition, the shares to be reserved for issuance under the 2013 Plan will also include shares subject to stock options or similar awards granted under the 2008 Plan that expire or terminate without having been exercised in full and shares issued pursuant to awards granted under the 2008 Plan that are forfeited to or repurchased by the Company (provided that the maximum number of shares that may be added to the 2013 Plan pursuant to this provision is 7,900,000 shares).
	The number of shares available for issuance under the 2013 Plan also includes an annual increase on the first day of each fiscal year beginning in 2014, equal to the least of (i) 4,000,000 shares; (ii) 5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year; or (iii) such other amount as the Company’s board of directors may determine. Effective January 1, 2014, 1,641,299 shares were added to the shares reserved for issuance under the 2013 Plan according to the terms described above.
	The compensation committee of the board of directors has the authority to approve the employees and other service providers to whom equity awards are granted and to determine the terms of each award, subject to the terms of the 2013 Plan.  The compensation committee may determine the number of shares subject to an award, except that awards to non-employee members of the board of directors are determined under the Company's Outside Director Compensation Policy.  Options and stock appreciation rights granted under the 2013 Plan must have a per share exercise price equal to at least 100% of the fair market value of a shares of the Company's common stock as of the date of grant and may not expire later than 10 years from the date of grant.
	The following tables summarize option award activity:
		Number of		Weighted-				Weighted-	Aggregate
		Shares		Average				Average	Intrinsic Value (in thousands)
		Outstanding		Exercise				Remaining
				Price				Contractual
								Life
								(Years)
	Balance at December 31, 2013	7,410,588		$	6.97			8.5	$	404,106
	Options granted (weighted average fair value of $56.97 per share)	369,000		51.16
	Options exercised	-287,578		3.69
	Options forfeited	-74,475		11.82
	Balance at March 31, 2014	7,417,535		$	9.24			8.2	$	253,267
	Options vested and expected to vest—March 31, 2014	6,960,374		$	8.82			8.2	$	240,251
	Options vested and exercisable—March 31, 2014	3,100,165		$	3.89			7.6	$	120,875
	Aggregate intrinsic value represents the difference between the Company’s estimated fair value of its common stock and the exercise price of outstanding in-the-money options. The total intrinsic value of options exercised was approximately $15.3 million and $11.9 million for the three months ended March 31, 2014 and year ended December 31, 2013, respectively.
	Employee Stock-based Compensation—The fair value of options on the date of grant is estimated based on the Black-Scholes option-pricing model using the single-option award approach with the weighted-average assumptions set forth below. Expected term represents the period that the Company’s stock-based awards are expected to be outstanding and is determined based on the simplified method. Due to the lack of historical exercise activity for our company, the simplified method calculates the expected term as the mid-point between the vesting date and the contractual expiration date of the award. Volatility is estimated using comparable public company volatility for similar option terms until a sufficient amount of historical information regarding the volatility of our own common stock share price becomes available. The risk-free interest rate is determined using a U.S. Treasury rate for the period that coincides with the expected term.
	As the Company has never paid cash dividends, and at present, has no intention to pay cash dividends in the future, expected dividends are zero. Expected forfeitures are based on the Company’s historical experience. The Company uses the straight-line method for expense recognition.
	The assumptions used to value stock-based awards granted to employees were as follows:
		Three Months Ended
		March 31,		December 31,
		2014		2013
	Expected term (years)	6.3		5.3–6.6
	Volatility	55.60%		53.8%–64.9%
	Risk-free interest rate	1.85%		1.04%–1.88%
	Dividend yield	—		—
	The following table summarizes the allocation of stock-based compensation and restricted stock expense for employees and non-employees in the accompanying consolidated statements of operations (in thousands):
		Three Months Ended
		March 31,
		2014				2013
	Cost of revenue	$	252			$	27
	Research and development	987				391
	Sales and marketing	2,167				512
	General and administrative	1,551				635
	Total *	$	4,957			$	1,565
	*	The table above includes the impact of the issuance of restricted stock at fair value.
	As of March 31, 2014 and December 31, 2013, unamortized stock-based compensation expense related to unvested common stock options was $32.2 million and $21.7 million, respectively. The weighted-average period over which such stock-based compensation expense will be recognized is approximately 2.6 years.
	Options to Non-employees—The Company did not grant any stock options to non-employees for the three months ended March 31, 2014. The Company granted 5,000 stock options to non-employees for the three months ended March 31, 2013. The definition of an employee includes a non-employee director of the Company. Stock options granted to non-employees are recorded at their fair value on the measurement date. The measurement of stock-based compensation is subject to periodic adjustment as the underlying equity instruments vest. The fair value of options granted to non-employees is expensed when vested.
	The Company recorded $0 and $0.1 million of stock-based compensation expense for options issued to non-employees under the 2008 Plan for three months ended March 31, 2014 and 2013, respectively. Options to non-employees of 3,900 and 8,900 were outstanding as of March 31, 2014 and December 31, 2013, respectively.
	Restricted Stock—The Company issued no shares pursuant to restricted stock purchase agreements during the three months ended March 31, 2014 and 2013, respectively.
	Restricted Stock Units (RSUs)— During the three months ended March 31, 2014, the Company granted 97,585 RSUs, 4,000 shares of common stock were issued upon vesting of RSUs and 2,850 RSUs were canceled. For the three months ended March 31, 2014, the Company recognized stock-based compensation expense associated with the RSUs of $1.8 million. At March 31, 2014, unrecognized compensation expense related to the RSUs was $19.1 million. The unrecognized compensation expense will be amortized on a straight-line basis through 2018.
	Employee Stock Purchase Plan
	In August 2013, the Company’s board of directors adopted and the stockholders approved the Company’s 2013 Employee Stock Purchase Plan (the “ESPP”), which became effective upon adoption by the Company’s board of directors. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The offering periods generally start on the first trading day on or after June 1 and December 1 of each year and end on the first trading day on or before November 30 and May 31 approximately six months later. The administrator may, in its discretion, modify the terms of future offering periods. Due to the timing of the IPO, the first offering period started October 1, 2013 and will end on May 31, 2014.  At the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. As of March 31, 2014, total compensation costs related to rights to purchase shares of common stock under the ESPP but not yet vested were approximately $1.8 million, which will be recognized over the offering period.
	The assumptions used to calculate our stock-based compensation for each stock purchase right granted under the ESPP were as follows:
		Three Months Ended
		March 31, 2014
	Expected term (years)	0.67
	Volatility	66.20%
Risk-free interest rate	0.07%
Dividend yield	—

NET_INCOME_LOSS_PER_SHARE

NET INCOME (LOSS) PER SHARE	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
NET INCOME (LOSS) PER SHARE	'
	NOTE 10.	NET INCOME (LOSS) PER SHARE
	The Company calculates its basic and diluted net income (loss) per share attributable to common stockholders in conformity with the two-class method required for companies with participating securities. Under the two-class method, in periods when the Company has net income, net income attributable to common stockholders is determined by allocating undistributed earnings, calculated as net income less current period convertible preferred stock non-cumulative dividends, between common stock and convertible preferred stock. In computing diluted net income attributable to common stockholders, undistributed earnings are re-allocated to reflect the potential impact of dilutive securities. The Company’s basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period. The diluted net loss per share attributable to common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, convertible preferred stock, options to purchase common stock and preferred stock warrants are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to common stockholders as their effect is antidilutive.
	Basic loss per share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding during the period, less shares subject to repurchase, and excludes any dilutive effects of employee stock-based awards and warrants. Because the Company had net losses for the three months ended March 31, 2014 and 2013, all potential shares of common stock were determined to be anti-dilutive.
	The following table sets forth the computation of net loss per share of common stock (in thousands, except per share amounts):
		Three Months Ended
		March 31,
		2014				2013
	Net loss	$	(11,225	)		$	(8,072	)
	Weighted-average shares used to compute basic and diluted net loss per share	34,033				8,298
	Basic and diluted net loss per share	$	(0.33	)		$	(0.97	)
	The following securities were excluded from the calculation of diluted net loss per share attributable to common stockholders because their effect would have been anti-dilutive for the periods presented (in thousands):
		Three Months Ended
		March 31,
		2014			2013
	Convertible preferred stock	—			19,479
	Employee stock options	7,418			6,904
	Shares subject to repurchase	242			—
	Restricted stock units (RSUs)	473			—
	Employee stock purchase plan	114			—
	Convertible preferred stock warrants	—			267
		8,247			26,650

INCOME_TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
INCOME TAXES	'
	NOTE 11.	INCOME TAXES
	The Company is subject to income tax in the United States as well as other tax jurisdictions in which it conducts business.  Earnings from non-U.S. activities are subject to local country income tax. The Company does not provide for federal income taxes on the undistributed earnings of its foreign subsidiaries as such earnings are to be reinvested indefinitely.
	The Company recorded an income tax provision of $0.3 million and $0.1 million for the three months ended March 31, 2014 and 2013, respectively, related to foreign income taxes and state minimum taxes. The primary difference between the effective tax rate and the federal statutory tax rate in the United States relates to the valuation allowances on the Company’s net operating losses, foreign tax rate differences, and non-deductible stock-based compensation expense.
	Valuation allowances are provided when necessary to reduce net deferred tax assets to an amount that is more likely than not to be realized. Due to uncertainty as to the realization of benefits from deferred tax assets, including net operating loss carry-forwards, research and development and other tax credits, the Company has provided a full valuation allowance reserved against such assets as of March 31, 2014 and December 31, 2013.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	NOTE 12.	COMMITMENTS AND CONTINGENCIES
	Operating Leases—The Company has operating lease agreements for office space for administration, research and development and sales and marketing activities in the United States that expire at various dates, with the latest expiration date in 2024.
	The Company recognizes rent expense on a straight-line basis over the lease term and records the difference between cash rent payments and the recognition of rent expense as a deferred rent liability. Rent expense was $3.2 million and $0.7 million for the three months ended March 31, 2014 and 2013, respectively.
	Approximate remaining future minimum lease payments under these non-cancelable operating leases as of March 31, 2014 were as follows (in thousands):
	Year ending December 31,		Future Payments
	2014 (remaining 9 months)		$	4,611
	2015		13,571
	2016		15,839
	2017		15,815
	2018		14,512
	Thereafter		53,622
			$	117,970
	Please refer to Note 6 for details of the Company's capital lease commitments as of March 31, 2014 and December 31, 2013.
	Letters of Credit and Bank Guarantees—As of March 31, 2014 and December 31, 2013, the Company had irrevocable letters of credit outstanding in the amount of $4.1 million, for the benefit of a landlord related to non-cancelable facilities leases. The letters of credit have various expiration dates, with the latest being June 2025.
	As of March 31, 2014, the Company had $2.3 million in bank guarantees for security deposits for the Company's London, United Kingdom and Paris, France office lease agreements. These amounts are classified as restricted cash on the Company's condensed consolidated balance sheets.
	Indemnification Agreements—In the ordinary course of business, the Company enters into agreements providing for indemnification of varying scope and terms to customers, vendors, lessors, business partners, and other parties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements, services to be provided by the Company or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with directors and certain officers and employees that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors, officers or employees. No demands have been made upon the Company to provide indemnification under such agreements, and thus there are no claims that the Company is aware of that could have a material effect on the Company’s condensed consolidated balance sheets, condensed consolidated statements of operations, condensed consolidated statements of comprehensive loss, or condensed consolidated statements of cash flows.
	Legal Proceedings—We are not currently a party to any legal proceedings, litigation, or claims that could materially affect our business, results of operations, cash flows, or financial position. We may, from time to time, be party to litigation and subject to claims incident to the ordinary course of business. As our growth continues, we may become party to an increasing number of litigation matters and claims. The outcome of litigation and claims cannot be predicted with certainty, and the resolution of any future matters could materially affect our future financial position, results of operations or cash flows.

RETIREMENT_PLANS

RETIREMENT PLANS	3 Months Ended
	Mar. 31, 2014
Compensation and Retirement Disclosure [Abstract]	'
RETIREMENT PLANS	'
	NOTE 13.	RETIREMENT PLANS
	The Company has established a 401(k) plan to provide tax deferred salary deductions for all eligible employees. Participants may make voluntary contributions to the 401(k) plan, limited by certain Internal Revenue Service restrictions. The Company is responsible for the administrative costs of the 401(k) plan. The Company does not match employee contributions.

SEGMENTS

SEGMENTS	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
SEGMENTS	'
	NOTE 14.	SEGMENTS
	The Company considers operating segments to be components of the Company's business for which separate financial information is available that is evaluated regularly by the Company’s chief operating decision maker in deciding how to allocate resources and in assessing performance. The chief operating decision maker for the Company is the Chief Executive Officer. The Chief Executive Officer reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. The Company has one business activity, and there are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated unit level. Accordingly, the Company has determined that it has a single operating and reportable segment.
	The following table summarizes total revenue generated through sales personnel located in the respective locations (in thousands):
		Three Months Ended
		March 31,
		2014		2013
	North America	$	62,647	$	32,849
	All Other Countries	11,750		5,363
	Total revenue	$	74,397	$	38,212
	The following table summarizes total long-lived assets in the respective locations (in thousands):
		March 31,		December 31,
		2014		2013
	North America	$	33,637	$	23,956
	All Other Countries	3,646		1,838
	Total long-lived assets	$	37,283	$	25,794
	During the three months ended March 31, 2014 and 2013, no single customer represented 10% or more of revenue. As of March 31, 2014 and December 31, 2013, no single agency or advertiser represented 10% or more of accounts receivable.

SUBSEQUENT_EVENTS

SUBSEQUENT EVENTS	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
SUBSEQUENT EVENTS	'
	NOTE 15.	SUBSEQUENT EVENTS
	No subsequent events occurred that would require adjustment to the financial statements or disclosures included in the financial statements.

NATURE_OF_BUSINESS_AND_SUMMARY1

NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Principles of Consolidation	'
	Principles of Consolidation—The consolidated financial statements include the Company and its wholly-owned subsidiaries in the United Kingdom and Canada, which are currently engaged in marketing and selling advertising campaigns. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	'
	Use of Estimates—The preparation of unaudited condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and disclosures of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Such estimates include, but are not limited to, provisions for doubtful accounts, the amount of software development costs which should be capitalized, future taxable income, the useful lives of long-lived assets and the assumptions used for purposes of determining stock-based compensation. Actual results could differ from those estimates.
Foreign Currency Translation	'
	Foreign Currency Translation—The Company’s foreign subsidiaries record their assets, liabilities and results of operations in their local currencies, which are their functional currencies. The Company translates its subsidiaries' consolidated financial statements into U.S. dollars each reporting period for purposes of consolidation.
	Assets and liabilities of the Company’s foreign subsidiaries are translated at the period-end currency exchange rates, certain equity accounts are translated at historical exchange rates and revenue, expenses, gains and losses are translated at the average currency exchange rates in effect for the period. The effects of these translation adjustments are reported in a separate component of stockholders’ equity titled accumulated other comprehensive income (loss).
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments—The Company’s financial instruments consist principally of cash equivalents, accounts receivable, accounts payable, accrued liabilities, capital lease, term debt and revolving credit facilities. The fair value of the Company’s cash equivalents is determined based on quoted prices in active markets for identical assets for its money market funds. The recorded values of the Company’s accounts receivable, accounts payable and accrued liabilities approximate their current fair values due to the relatively short-term nature of these accounts. The Company believes that the fair value of the capital lease, term debt and revolving credit facilities approximates its recorded amount as of March 31, 2014 as the interest rate on the capital lease, term debt and revolving credit facilities is variable and is based on market interest rates after consideration of default and credit risk.
Cash and Cash Equivalents & Restricted Cash	'
	Cash and Cash Equivalents—Cash consists of cash maintained in checking and savings accounts. All highly liquid investments purchased with an original maturity date of 90 days or less at the date of purchase are considered to be cash equivalents. Cash equivalents consist of money market funds.
	Restricted Cash—Restricted cash as of March 31, 2014 consists of cash required to be deposited with financial institutions for security deposits for the Company's London, United Kingdom and Paris, France office lease agreements.
Concentration of Credit Risk	'
	Concentration of Credit Risk—Financial instruments, which potentially subject the Company to significant concentrations of credit risk, consist primarily of cash and accounts receivable. A significant portion of the Company’s cash is held at three major financial institutions, which management assesses to be of high credit quality. The Company has not experienced any losses in such accounts.
	The Company mitigates its credit risk with respect to accounts receivable by performing credit evaluations and monitoring agencies' and advertisers' accounts receivable balances. As of March 31, 2014 and December 31, 2013, no single agency or advertiser accounted for 10% or more of accounts receivable.
	During the three months ended March 31, 2014 and 2013, no single customer represented 10% or more of revenue.
Provision for Doubtful Accounts	'
	Provision for Doubtful Accounts—The Company records a provision for doubtful accounts based on historical experience and a detailed assessment of the collectability of its accounts receivable. In estimating the allowance for doubtful accounts, management considers, among other factors, the aging of the accounts receivable, historical write-offs and the credit-worthiness of each customer. If circumstances change, such as higher-than-expected defaults or an unexpected material adverse change in a major customer’s ability to meet its financial obligations, the Company’s estimate of the recoverability of the amounts due could be reduced by a material amount.
	The following table presents the changes in the allowance for doubtful accounts (in thousands):
		Three Months Ended
		March 31,
		2014			2013
	Allowance for doubtful accounts:
	Balance, beginning of period	$	1,057		$	468
	Add: bad debt expense	34			—
	Less: write-offs, net of recoveries	(1		)	—
	Balance, end of period	$	1,090		$	468
Property and Equipment	'
	Property and Equipment—Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the related assets. Maintenance and repairs are charged to expense as incurred, and improvements and betterments are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation or amortization, as applicable, are removed from the balance sheet and any resulting gain or loss is reflected in operations in the period realized.
	Construction in progress primarily includes costs related to the leasehold improvements and also includes network equipment infrastructure to support the Company's data centers around the world. Interest capitalized during the periods presented was not material.
	Leasehold improvements are amortized on a straight-line basis over the term of the lease, or the useful life of the assets, whichever is shorter. Depreciation and amortization periods for the Company’s property and equipment are as follows:
	Asset Classification	Estimated Useful Life
	Computer hardware and purchased software	2–3 years
	Capitalized internal-use software costs	2–3 years
	Office equipment, furniture and fixtures	5 years
Internal Use Software Development Costs	'
	Internal-Use Software Development Costs—The Company incurs costs to develop software for internal use. The Company expenses all costs that relate to the planning and post implementation phases of development as research and development expense. The Company capitalizes costs when preliminary efforts are successfully completed, management has authorized and committed project funding, and it is probable that the project will be completed and will be used as intended. Costs incurred for enhancements that are expected to result in additional material functionality are capitalized. The Company capitalized $2.1 million and $1.7 million in internal-use software costs during the three months ended March 31, 2014 and 2013, respectively, which are included in property, equipment and software—net on the condensed consolidated balance sheets.
	Amortization commences when the website or software for internal use is ready for its intended use and the amortization period is the estimated useful life of the related asset, which is generally three years. Amortization expense totaled $1.1 million and $0.8 million for the three months ended March 31, 2014 and 2013, respectively.
Impairment of Long-lived Asset	'
	Impairment of Long-lived Assets—The Company periodically reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset is impaired or the estimated useful life is no longer appropriate. If indicators of impairment exist and the undiscounted projected cash flows associated with an asset are less than the carrying amount of the asset, an impairment loss is recorded to write the asset down to its estimated fair value. Fair value is estimated based on discounted future cash flows. No impairment charges were recorded during the three months ended March 31, 2014 and 2013.
Revenue Recognition	'
	Revenue Recognition—The Company generates revenue by delivering digital advertisements to Internet users through various channels, including display, mobile, social and video.
	The Company recognizes revenue when all four of the following criteria are met:
	•    Persuasive evidence of an arrangement exists
	•    Delivery has occurred or a service has been provided
	•    Customer fees are fixed or determinable
	•    Collection is reasonably assured
	Revenue arrangements are evidenced by a fully-executed insertion order (“IO”). Generally, IOs state the number and type of advertising impressions (cost-per-thousand) to be delivered, the agreed upon rate for each delivered impression, and a fixed period of time for delivery.
	The Company determines collectability by performing ongoing credit evaluations and monitoring its customers’ accounts receivable balances. For new customers and their agents, which may be advertising agencies or other third parties, the Company performs a credit check with an independent credit agency and may check credit references to determine creditworthiness. The Company only recognizes revenue when collection is reasonably assured.
	In the normal course of business, the Company frequently contracts with advertising agencies on behalf of their advertiser clients. The determination of whether revenue should be reported on a gross or net basis is based on an assessment of whether the Company is acting as the principal or an agent in the transaction. In determining whether the Company acts as the principal or an agent, the Company follows the accounting guidance for principal-agent considerations. While none of the factors identified in this guidance is individually considered presumptive or determinative, because the Company is the primary obligor and is responsible for (i) fulfilling the advertisement delivery, (ii) establishing the selling prices for delivery of the advertisements, (iii) selecting the media to fulfill the insertion order, and (iv) performing all billing and collection activities including retaining credit risk, the Company has concluded that it acts as the principal in the majority of these arrangements and therefore reports revenue earned and costs incurred on a gross basis.
	On occasion, the Company has offered customer incentive programs that provide rebates after achieving a specified level of advertising spending. The Company records reductions to revenue for estimated commitments related to these customer incentive programs. For transactions involving incentives, the Company recognizes revenue net of the estimated amount to be paid by rebate, provided that the rebate amount can be reasonably and reliably estimated and the other conditions for revenue recognition have been met. The Company’s policy requires that, if rebates cannot be reliably estimated, revenue is not recognized until reliable estimates can be made or the rebate program lapses.
Multiple-Element Arrangements	'
	Multiple-Element Arrangements—The Company enters into arrangements to sell advertising that includes different media placements or ad services that are delivered at the same time, or within close proximity of one another. Beginning on January 1, 2011, the Company adopted new authoritative guidance on multiple element arrangements, using the prospective method for all arrangements entered into or materially modified from the date of adoption. Under this new guidance, the Company allocates arrangement consideration in multiple-deliverable revenue arrangements at the inception of an arrangement to all deliverables or those packages in which all components of the package are delivered at the same time, based on the relative selling price method in accordance with the selling price hierarchy, which includes: (1) vendor-specific objective evidence (“VSOE”), if available; (2) third-party evidence (“TPE”), if VSOE is not available; and (3) best estimate of selling price (“BESP”), if neither VSOE nor TPE is available.
	VSOE—The Company determines VSOE based on its historical pricing and discounting practices for the specific product or service when sold separately. In determining VSOE, the Company requires that a substantial majority of the stand-alone selling prices for these services fall within a reasonably narrow pricing range. The Company has not been able to establish VSOE for any of its advertising offerings.
	TPE—When VSOE cannot be established for deliverables in multiple element arrangements, the Company applies judgment with respect to whether it can establish a selling price based on TPE. TPE is determined based on competitor prices for similar deliverables when sold separately. Generally, the Company’s go-to-market strategy differs from that of its peers and its offerings contain a significant level of differentiation such that the comparable pricing of services cannot be obtained. Furthermore, the Company is unable to reliably determine the selling prices of similar competitor services on a stand-alone basis. As a result, the Company has not been able to establish selling price based on TPE.
	BESP—When it is unable to establish selling price using VSOE or TPE, the Company uses BESP in its allocation of arrangement consideration. The objective of BESP is to determine the price at which the Company would transact a sale if the service were sold on a stand-alone basis. BESP is generally used to allocate the selling price to deliverables in the Company’s multiple element arrangements. The Company determines BESP for deliverables by considering multiple factors, including, but not limited to, prices it charges for similar offerings, market conditions, competitive landscape and pricing practices. In particular, the Company reviews multiple data points to determine BESP, including price lists used by the Company’s sales team in pricing negotiations, historical average and median pricing achieved in prior contractual customer arrangements and input from the Company’s sales operation department regarding what it believes the deliverables could be sold for on a stand-alone basis. BESP is determined at an advertising unit level that is consistent with the Company’s underlying market strategy and stratified based on specific consideration of channel, geography, industry and size, as deemed necessary.
	The Company limits the amount of allocable arrangement consideration to amounts that are fixed or determinable and that are not contingent on future performance or future deliverables. The Company regularly reviews BESP. Changes in assumptions or judgments or changes to the elements in the arrangement could cause a material increase or decrease in the amount of revenue that the Company reports in a particular period.
	The Company recognizes the relative fair value of advertising services as they are delivered, assuming all other revenue recognition criteria are met. Deferred revenue is comprised of contractual billings in excess of recognized revenue and payments received in advance of revenue recognition.
Cost of Revenue	'
	Cost of Revenue—Cost of revenue consists primarily of media cost for advertising impressions purchased from real-time advertising exchanges and other third parties. Cost of revenue also includes third-party data center costs and the salaries and related costs of the Company’s operations group. This group sets up, initiates and monitors the Company’s advertising campaigns. In addition, depreciation of the data center equipment, rental payments to third-party vendors for data centers and amortization of capitalized internal-use software are included in cost of revenue.
Research and Development	'
	Research and Development—Research and development expenses include costs associated with the maintenance and ongoing development of the Company’s technology, including compensation and employee benefits and allocated costs associated with the Company’s engineering and research and development departments, as well as costs for contracted services and supplies. Allocated costs include charges for facilities, office expenses, telephones, and other miscellaneous expenses. The Company reviews costs incurred in the application development stage and assesses such costs for potential capitalization.
Sales and Marketing	'
	Sales and Marketing—Sales and marketing expenses consist primarily of compensation (including commissions) and employee benefits of sales and marketing personnel and related support teams, allocated costs, certain advertising costs, travel, trade shows and marketing materials. Allocated costs include charges for facilities, office expenses, telephones, and other miscellaneous expenses. The Company incurred advertising costs of $1.2 million and $0.1 million for the three months ended March 31, 2014 and 2013, respectively.
General and Administrative	'
	General and Administrative—General and administrative expenses include facilities costs, executive and administrative compensation and employee benefits, depreciation, professional services fees, insurance costs, bad debt and other allocated costs, such as facility-related expenses, supplies and other fixed costs. Allocated costs include charges for facilities, office expenses, telephones, and other miscellaneous expenses.
Stock-Based Compensation	'
	Stock-based Compensation—The Company measures compensation expense for all stock-based payment awards, including stock options granted to employees, based on the estimated fair values on the date of the grant. The fair value of each stock option granted is estimated using the Black-Scholes option pricing model. Stock-based compensation is recognized on a straight-line basis over the requisite vesting period, net of estimated forfeitures. The forfeiture rate is based on an analysis of the Company’s actual historical forfeitures.
	The Company accounts for stock options issued to non-employees based on the fair value of the awards determined using the Black-Scholes option pricing model. The fair value of stock options granted to non-employees is re-measured as the stock options vest, and the resulting change in fair value, if any, is recognized in the Company’s condensed consolidated statement of operations during the period the related services are rendered, generally between one and four years.
Preferred Stock Warrant Liability	'
	Preferred Stock Warrant Liability—Freestanding warrants related to shares that are redeemable or contingently redeemable were classified as a liability on the Company’s condensed consolidated balance sheet. The fully-vested convertible preferred stock warrants were subject to re-measurement at each balance sheet date, and any change in fair value is recognized as a component of other expense, net. As completion of the Company’s initial public offering constituted a liquidation event, the convertible preferred stock warrants were converted into common stock or warrants to purchase common stock, and the liability was reclassified to additional paid-in capital in the third quarter of 2013.
Income Taxes	'
	Income Taxes—The Company accounts for income taxes using an asset and liability approach. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Operating loss and tax credit carry-forwards are measured by applying currently enacted tax laws. Valuation allowances are provided when necessary to reduce net deferred tax assets to an amount that is more likely than not to be realized. Due to uncertainty as to the realization of benefits from deferred tax assets, including net operating loss carry-forwards, research and development and other tax credits, the Company has provided a full valuation allowance reserved against such assets as of March 31, 2014 and December 31, 2013.
	The Company recognizes the tax effects of an uncertain tax position only if it is more likely than not to be sustained based solely on its technical merits as of the reporting date, and then, only in an amount more likely than not to be sustained upon review by the tax authorities. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes.
Deferred Offering Costs	'
	eferred Offering Costs—Deferred offering costs consisted primarily of direct incremental costs related to the Company’s public offerings of its common stock. Approximately $0.1 million of deferred offering costs were included in other assets on the Company’s condensed consolidated balance sheet as of December 31, 2013. No deferred offering costs are included as of March 31, 2014. Upon completion of the offerings, these amounts were offset against the proceeds of the offerings.
Recently Issued and Adopted Accounting Pronouncements	'
	Recently Issued and Adopted Accounting Pronouncements—Under the Jumpstart Our Business Startups Act (the "JOBS Act"), we qualify as an “emerging growth company.” We have irrevocably elected to opt out of the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, and, therefore, we will be subject to the same new or revised accounting standards as other public companies that are not “emerging growth companies.”
	In July 2013, the FASB issued Accounting Standards Update (ASU) No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (ASU 2013-11). The guidance requires an entity to present its unrecognized tax benefits net of its deferred tax assets when settlement in this manner is available under the tax law, which would be based on facts and circumstances as of the balance sheet reporting date and would not consider future events. Gross presentation of unrecognized tax benefit will still be required in the notes to the financial statements. ASU 2013-11 will apply on a prospective basis to all unrecognized tax benefits that exist at the effective date. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of ASU 2013-11 did not have a material impact on our consolidated financial statements.

NATURE_OF_BUSINESS_AND_SUMMARY2

NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Schedule of changes in the allowance for doubtful accounts	'
	The following table presents the changes in the allowance for doubtful accounts (in thousands):
		Three Months Ended
		March 31,
		2014			2013
	Allowance for doubtful accounts:
	Balance, beginning of period	$	1,057		$	468
	Add: bad debt expense	34			—
	Less: write-offs, net of recoveries	(1		)	—
	Balance, end of period	$	1,090		$	468
Schedule of depreciation and amortization periods for the Company's property and equipment	'
	Depreciation and amortization periods for the Company’s property and equipment are as follows:
	Asset Classification	Estimated Useful Life
	Computer hardware and purchased software	2–3 years
	Capitalized internal-use software costs	2–3 years
	Office equipment, furniture and fixtures	5 years

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Company's fair value hierarchy for its financial assets and financial liabilities that are carried at fair value	'
	The Company’s fair value hierarchy for its financial assets and financial liabilities that are carried at fair value are as follows (in thousands):
	31-Mar-14	Fair Value		Level 1		Level 2		Level 3
	Money market funds (included in cash and cash equivalents)	$	127,900	$	127,900	$	—	$	—
	31-Dec-13	Fair Value		Level 1		Level 2		Level 3
	Money market funds (included in cash and cash equivalents)	$	2,900	$	2,900	$	—	$	—

CASH_AND_CASH_EQUIVALENTS_Tabl

CASH AND CASH EQUIVALENTS (Tables)	3 Months Ended
	Mar. 31, 2014
Cash and Cash Equivalents [Abstract]	'
Schedule of cash and cash equivalents	'
	Cash and cash equivalents as of March 31, 2014 and December 31, 2013, consisted of the following (in thousands):
		March 31,		December 31,
		2014		2013
	Cash and cash equivalents:
	Cash	$	90,274	$	110,973
	Money market funds	127,900		2,900
	Total cash and cash equivalents	$	218,174	$	113,873

PROPERTY_EQUIPMENT_AND_SOFTWAR1

PROPERTY, EQUIPMENT AND SOFTWARE, NET (Tables)	3 Months Ended
	Mar. 31, 2014
Property, Plant and Equipment [Abstract]	'
Schedule of property, equipment and software	'
	Property, equipment and software, net as of March 31, 2014 and December 31, 2013, consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Capitalized internal-use software costs	$	16,190		$	14,030
	Computer hardware and software	20,607			17,077
	Furniture and fixtures	4,436			1,735
	Leasehold improvements	10,460			815
	Construction in progress	—			3,622
	Total	51,693			37,279
	Accumulated depreciation and amortization	(14,410		)	(11,485		)
	Total property, equipment and software, net	$	37,283		$	25,794

ACCRUED_AND_OTHER_CURRENT_LIAB1

ACCRUED AND OTHER CURRENT LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2014
Payables and Accruals [Abstract]	'
Schedule of accrued and other current liabilities	'
	Accrued and other current liabilities as of March 31, 2014 and December 31, 2013, consisted of the following (in thousands):
		March 31,		December 31,
		2014		2013
	Payroll and related expenses	$	7,805	$	10,722
	Accrued vacation	3,188		2,220
	Professional services	637		650
	Accrued credit cards	87		774
	Early exercise of unvested stock options	783		1,107
	Employee stock purchase plan	2,811		1,427
	Other accrued expenses	9,629		4,684
	Total accrued and other current liabilities	$	24,940	$	21,584

CAPITAL_LEASES_Tables

CAPITAL LEASES (Tables)	3 Months Ended
	Mar. 31, 2014
Leases [Abstract]	'
Schedule of approximate remaining future minimum lease payments under non-cancelable capital leases	'
	Approximate remaining future minimum lease payments under these non-cancelable capital leases as of March 31, 2014 were as follows (in thousands):
	Year ending December 31,	Future Payments
	2014 (remaining 9 months)	$	658
	2015	893
	2016	883
	2017	96
	Thereafter	—
	Total minimum lease payments	$	2,530
	Less: amount representing interest and taxes	(185		)
	Less: current portion of minimum lease payments	(777		)
	Capital lease obligations, net of current portion	$	1,568

OTHER_INCOME_EXPENSENET_Tables

OTHER INCOME (EXPENSE)—NET (Tables)	3 Months Ended
	Mar. 31, 2014
Other Income and Expenses [Abstract]	'
Schedule of other income (expense), net	'
	Other income (expense)—net for the three months ended March 31, 2014 and 2013, consisted of the following (in thousands):
		Three Months Ended
		March 31,
		2014			2013
	Gain (loss) on foreign translation	$	(29	)	$	(556	)
	Other non-operating income (loss), net	10			37
	Total other income (expense)—net	$	(19	)	$	(519	)

DEBT_Tables

DEBT (Tables)	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Schedule of future principal payments of long-term debt	'
	Future principal payments of long-term debt as of March 31, 2014 were as follows (in thousands):
	Year ending December 31,	Future Payments
	2014 (remaining 9 months)	$	—
	2015	5,000
	2016	5,000
	2017	5,000
	2018	5,000
	Total	20,000
	Less: current portion of long-term debt	(1,250		)
	Long-term debt, net of current portion	$	18,750

STOCKHOLDERS_EQUITY_Tables

STOCKHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Schedule of shares of common stock reserved for issuance	'
	The Company’s shares of capital stock reserved for issuance as of March 31, 2014 were as follows:
		31-Mar-14
	Options outstanding	7,417,535
	Restricted stock units outstanding	473,137
	Available for future stock option and restricted stock unit grants	5,870,342
	Available for future employee stock purchase plan purchases	1,656,319
	Total shares reserved	15,417,333
Summary of option award activity	'
	The following tables summarize option award activity:
		Number of		Weighted-				Weighted-	Aggregate
		Shares		Average				Average	Intrinsic Value (in thousands)
		Outstanding		Exercise				Remaining
				Price				Contractual
								Life
								(Years)
	Balance at December 31, 2013	7,410,588		$	6.97			8.5	$	404,106
	Options granted (weighted average fair value of $56.97 per share)	369,000		51.16
	Options exercised	-287,578		3.69
	Options forfeited	-74,475		11.82
	Balance at March 31, 2014	7,417,535		$	9.24			8.2	$	253,267
	Options vested and expected to vest—March 31, 2014	6,960,374		$	8.82			8.2	$	240,251
	Options vested and exercisable—March 31, 2014	3,100,165		$	3.89			7.6	$	120,875
Schedule of assumptions used to value stock-based awards granted to employees	'
	The assumptions used to value stock-based awards granted to employees were as follows:
		Three Months Ended
		March 31,		December 31,
		2014		2013
	Expected term (years)	6.3		5.3–6.6
	Volatility	55.60%		53.8%–64.9%
	Risk-free interest rate	1.85%		1.04%–1.88%
	Dividend yield	—		—
Summary of allocation of stock-based compensation and restricted stock for employees and non-employees	'
	The following table summarizes the allocation of stock-based compensation and restricted stock expense for employees and non-employees in the accompanying consolidated statements of operations (in thousands):
		Three Months Ended
		March 31,
		2014				2013
	Cost of revenue	$	252			$	27
	Research and development	987				391
	Sales and marketing	2,167				512
	General and administrative	1,551				635
	Total *	$	4,957			$	1,565
	*	The table above includes the impact of the issuance of restricted stock at fair value.
Schedule of assumptions used to calculate stock-based compensation for each stock purchase right granted under the ESPP	'
	The assumptions used to calculate our stock-based compensation for each stock purchase right granted under the ESPP were as follows:
		Three Months Ended
		March 31, 2014
	Expected term (years)	0.67
	Volatility	66.20%
	Risk-free interest rate	0.07%
	Dividend yield	—

NET_INCOME_LOSS_PER_SHARE_Tabl

NET INCOME (LOSS) PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Schedule of computation of net loss per common share	'
	The following table sets forth the computation of net loss per share of common stock (in thousands, except per share amounts):
		Three Months Ended
		March 31,
		2014				2013
	Net loss	$	(11,225	)		$	(8,072	)
	Weighted-average shares used to compute basic and diluted net loss per share	34,033				8,298
	Basic and diluted net loss per share	$	(0.33	)		$	(0.97	)
Schedule of anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'
	The following securities were excluded from the calculation of diluted net loss per share attributable to common stockholders because their effect would have been anti-dilutive for the periods presented (in thousands):
		Three Months Ended
		March 31,
		2014			2013
	Convertible preferred stock	—			19,479
	Employee stock options	7,418			6,904
	Shares subject to repurchase	242			—
	Restricted stock units (RSUs)	473			—
	Employee stock purchase plan	114			—
	Convertible preferred stock warrants	—			267
		8,247			26,650

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (Tables)	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of future minimum lease payments under non-cancelable operating leases	'
	Approximate remaining future minimum lease payments under these non-cancelable operating leases as of March 31, 2014 were as follows (in thousands):
	Year ending December 31,	Future Payments
	2014 (remaining 9 months)	$	4,611
	2015	13,571
	2016	15,839
	2017	15,815
	2018	14,512
	Thereafter	53,622
		$	117,970

SEGMENTS_Tables

SEGMENTS (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Schedule of total revenue generated through sales personnel located in the respective locations	'
	The following table summarizes total revenue generated through sales personnel located in the respective locations (in thousands):
		Three Months Ended
		March 31,
		2014		2013
	North America	$	62,647	$	32,849
	All Other Countries	11,750		5,363
	Total revenue	$	74,397	$	38,212
Schedule of total long-lived assets in the respective locations	'
	The following table summarizes total long-lived assets in the respective locations (in thousands):
		March 31,		December 31,
		2014		2013
	North America	$	33,637	$	23,956
	All Other Countries	3,646		1,838
	Total long-lived assets	$	37,283	$	25,794

NATURE_OF_BUSINESS_AND_SUMMARY3

NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $)	1 Months Ended	3 Months Ended			1 Months Ended
	Feb. 28, 2014	Mar. 31, 2014	Mar. 31, 2013	Feb. 18, 2014	Sep. 30, 2013
					Initial Public Offering
Initial public offering	'	'	'	'	'
Sale of Stock, Number of Shares Issued in Transaction	'	'	'	'	4,000,000
Number of shares of common stock sold by the entity	2,000,000	'	'	'	'
Number of shares of common stock sold by selling stockholders	3,000,000	'	'	'	600,000
Issuance Price Per Share (in dollars per share)	'	'	'	$61	$29
Total gross proceeds from the offering	$122,000,000	'	'	'	$116,000,000
Aggregate net proceeds received from offering	$115,400,000	$116,510,000	$0	'	$103,300,000

NATURE_OF_BUSINESS_AND_SUMMARY4

NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) (USD $)	3 Months Ended				12 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
			Cash	Accounts receivable	Accounts receivable	Revenue	Revenue
			Credit concentration	Customer concentration	Customer concentration	Customer concentration	Customer concentration
Concentration of credit risk	'	'	'	'	'	'	'
Number of financial institutions where a significant portion of cash is held	'	'	3	'	'	'	'
Number of customers	'	'	'	0	0	0	0
Impairment of long-lived assets	$0	$0	'	'	'	'	'
Changes in the allowance for doubtful accounts	'	'	'	'	'	'	'
Balance, beginning of period	1,057,000	468,000	'	'	'	'	'
Add: bad debt expense	34,000	0	'	'	'	'	'
Less: write-offs, net of recoveries	-1,000	0	'	'	'	'	'
Balance, end of period	$1,090,000	$468,000	'	'	'	'	'

NATURE_OF_BUSINESS_AND_SUMMARY5

NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 3) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Internal Use Software Development Costs	'	'
Internal-use software costs capitalized	$2,100,000	$1,700,000
Amortization expense	1,100,000	800,000
Impairment of Long-lived Assets	'	'
Impairment of long-lived assets	0	0
Revenue Recognition	'	'
Number of criteria's required to be met for revenue recognition	4	'
Sales and Marketing	'	'
Advertising costs	$1,200,000	$100,000
Computer hardware and purchased software | Minimum	'	'
Property and equipment	'	'
Estimated useful life	'2 years	'
Computer hardware and purchased software | Maximum	'	'
Property and equipment	'	'
Estimated useful life	'3 years	'
Capitalized internal-use software costs | Minimum	'	'
Property and equipment	'	'
Estimated useful life	'2 years	'
Capitalized internal-use software costs | Maximum	'	'
Property and equipment	'	'
Estimated useful life	'3 years	'
Office equipment, furniture and fixtures	'	'
Property and equipment	'	'
Estimated useful life	'5 years	'

NATURE_OF_BUSINESS_AND_SUMMARY6

NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 4) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2014
In Millions, unless otherwise specified			Stock options granted to nonemployees	Stock options granted to nonemployees
			Minimum	Maximum
Stock-based compensation	'	'	'	'
Period during which related services are rendered	'	'	'1 year	'4 years
Deferred Offering Costs	'	'	'	'
Deferred offering costs included in other assets	$0	$0.10	'	'

FAIR_VALUE_MEASUREMENTS_Detail

FAIR VALUE MEASUREMENTS (Details) (Recurring, Money market funds (included in cash and cash equivalents), USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial assets	$127,900	$2,900
Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial assets	127,900	2,900
Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial assets	0	0
Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial assets	$0	$0

CASH_AND_CASH_EQUIVALENTS_Deta

CASH AND CASH EQUIVALENTS (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Cash and cash equivalents	'	'	'	'
Total cash and cash equivalents	$218,174	$113,873	$15,736	$14,896
Cash	'	'	'	'
Cash and cash equivalents	'	'	'	'
Total cash and cash equivalents	90,274	110,973	'	'
Money market funds	'	'	'	'
Cash and cash equivalents	'	'	'	'
Total cash and cash equivalents	$127,900	$2,900	'	'

PROPERTY_EQUIPMENT_AND_SOFTWAR2

PROPERTY, EQUIPMENT AND SOFTWARE, NET (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Property, equipment and software	'	'	'
Total	$51,693,000	'	$37,279,000
Accumulated depreciation and amortization	-14,410,000	'	-11,485,000
Total property, equipment and software, net	37,283,000	'	25,794,000
Depreciation and amortization expense, excluding amortization of internal use software costs	1,800,000	600,000	'
Amortization expense	1,100,000	800,000	'
Capital leases	2,700,000	'	600,000
Capitalized internal-use software costs	'	'	'
Property, equipment and software	'	'	'
Total	16,190,000	'	14,030,000
Computer hardware and software	'	'	'
Property, equipment and software	'	'	'
Total	20,607,000	'	17,077,000
Furniture and fixtures	'	'	'
Property, equipment and software	'	'	'
Total	4,436,000	'	1,735,000
Leasehold improvements	'	'	'
Property, equipment and software	'	'	'
Total	10,460,000	'	815,000
Construction in progress	'	'	'
Property, equipment and software	'	'	'
Total	$0	'	$3,622,000

ACCRUED_AND_OTHER_CURRENT_LIAB2

ACCRUED AND OTHER CURRENT LIABILITIES (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]	'	'
Payroll and related expenses	$7,805	$10,722
Accrued vacation	3,188	2,220
Professional services	637	650
Accrued credit cards	87	774
Early exercise of unvested stock options	783	1,107
Employee stock purchase plan	2,811	1,427
Other accrued expenses	9,629	4,684
Total accrued and other current liabilities	$24,940	$21,584

CAPITAL_LEASES_Details

CAPITAL LEASES (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Leases [Abstract]	'	'
Property and equipment acquired under capital lease agreements	$2,700,000	$600,000
Accumulated depreciation of property and equipment acquired under capital leases agreements	100,000	0
Approximate remaining future minimum lease payments under non-cancelable capital leases	'	'
2014	658,000	'
2015	893,000	'
2016	883,000	'
2017	96,000	'
Thereafter	0	'
Total minimum lease payments	2,530,000	'
Less: amount representing interest and taxes	-185,000	'
Less: current portion of minimum lease payments	-777,000	-203,000
Capital lease obligations, net of current portion	$1,568,000	$412,000

OTHER_INCOME_EXPENSENET_Detail

OTHER INCOME (EXPENSE)—NET (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Other Income and Expenses [Abstract]	'	'
Gain (loss) on foreign translation	($29)	($556)
Other non-operating income (loss), net	10	37
Total other income (expense)-net	($19)	($519)

DEBT_Details

DEBT (Details) (USD $)

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Federal funds rate

Daily adjusting LIBOR rate

Revolving line of credit, as amended in June 2013

Loan Facility

Loan Facility

Revolving line of credit

Revolving line of credit

Revolving line of credit

Revolving line of credit

Letter of credit subfacility

Swing line subfacility

Secured term loan facility

Term loans

Term loans

Term loans

Term loans

Term loans

Revolving line of credit amended in March 2012

Minimum

Base rate

Minimum

Minimum

Maximum

Minimum

Minimum

Maximum

Maximum

Base rate

LIBOR

LIBOR

Base rate

LIBOR

Base rate

LIBOR

Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional revolving commitments

$25,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum amount available for borrowing

'

'

'

'

80,000,000

'

'

'

'

'

'

5,000,000

1,500,000

'

'

'

'

'

'

20,000,000

Maximum amount available for borrowing expressed as a percentage of certain eligible accounts

'

'

'

'

85.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Applicable margin over variable rate basis (as a percent)

'

'

1.00%

1.00%

'

'

'

2.50%

1.75%

2.75%

3.50%

'

'

'

'

2.75%

3.75%

3.50%

4.50%

'

Period of interest only monthly installments

'

'

'

'

'

'3 months

'3 months

'

'

'

'

'

'

'

'

'

'

'

'

'

Quarterly principal installments

'

'

'

'

'

'

'

'

'

'

'

'

'

1,300,000

'

'

'

'

'

'

Liquidity ratio

1.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Future principal payments of long-term debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2014 (remaining 9 months)

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2015

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2016

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2017

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2018

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total

20,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Less: current portion of long-term debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-1,250,000

'

'

'

'

'

Long-term debt, net of current portion

18,368,000

19,568,000

'

'

'

'

'

'

'

'

'

'

'

'

18,750,000

'

'

'

'

'

Amount outstanding

7,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized discounts

$600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

STOCKHOLDERS_EQUITY_Details

STOCKHOLDERS' EQUITY (Details) (USD $)	1 Months Ended	3 Months Ended
	Feb. 28, 2014	Mar. 31, 2014	Mar. 31, 2013	Feb. 18, 2014
STOCKHOLDERS' EQUITY (DEFICIT)	'	'	'	'
Number of shares of common stock sold by the entity	2,000,000	'	'	'
Number of shares of common stock sold by selling stockholders	3,000,000	'	'	'
Issuance Price Per Share (in dollars per share)	'	'	'	$61
Total gross proceeds from the offering	$122,000,000	'	'	'
Aggregate net proceeds received from offering	$115,400,000	$116,510,000	$0	'
Shares of capital stock reserved for issuance	'	'	'	'
Total shares reserved	'	15,417,333	'	'
Employee stock purchase plan	'	'	'	'
Shares of capital stock reserved for issuance	'	'	'	'
Total shares reserved	'	1,656,319	'	'
Options	'	'	'	'
Shares of capital stock reserved for issuance	'	'	'	'
Total shares reserved	'	7,417,535	'	'
Restricted stock units (RSUs)	'	'	'	'
Shares of capital stock reserved for issuance	'	'	'	'
Total shares reserved	'	473,137	'	'
Stock option and restricted stock unit grants	'	'	'	'
Shares of capital stock reserved for issuance	'	'	'	'
Total shares reserved	'	5,870,342	'	'

STOCKHOLDERS_EQUITY_Details_2

STOCKHOLDERS' EQUITY (Details 2) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
Number of Shares Outstanding	'	'	'
Balance at the beginning of the period (in shares)	7,410,588	'	'
Options granted (weighted average fair value of $56.97 per share)	369,000	'	'
Options exercised (in shares)	-287,578	'	'
Options forfeited (in shares)	-74,475	'	'
Balance at the end of the period (in shares)	7,417,535	7,410,588	'
Options vested and expected to vest (in shares)	6,960,374	'	'
Options vested and exercisable (in shares)	3,100,165	'	'
Weighted average fair value (in dollars per share)	$56.97	'	'
Weighted-Average Exercise Price	'	'	'
Balance at the beginning of the period (in dollars per share)	$6.97	'	'
Options granted (weighted average fair value of $56.97 per share)	$51.16	'	'
Options exercised (in dollars per share)	$3.69	'	'
Options forfeited (in dollars per share)	$11.82	'	'
Balance at the end of the period (in dollars per share)	$9.24	$6.97	'
Options vested and expected to vest (in dollars per share)	$8.82	'	'
Options vested and exercisable (in dollars per share)	$3.89	'	'
Weighted-Average Remaining Contractual Life	'	'	'
Balance	'8 years 2 months 12 days	'8 years 6 months	'
Options vested and expected to vest	'8 years 2 months 12 days	'	'
Options vested and exercisable	'7 years 7 months 12 days	'	'
Aggregate Intrinsic Value	'	'	'
Balance	$404,106,000	'	$253,267,000
Options vested and expected to vest	240,251,000	'	'
Options vested and exercisable	120,875,000	'	'
Total intrinsic value of options exercised	$15,300,000	$11,900,000	'
2008 Equity Incentive Plan	'	'	'
Equity Incentive Plans	'	'	'
Exercise price as a percentage of the fair market value of the common stock	100.00%	'	'
Expiration period	'10 years	'	'
Vesting period	'4 years	'	'
Number of shares of unvested stock repurchased	8,834	5,834	'
2013 Equity Incentive Plan	'	'	'
Equity Incentive Plans	'	'	'
Exercise price as a percentage of the fair market value of the common stock	100.00%	'	'
Expiration period	'10 years	'	'
Common stock reserved for issuance	5,000,000	'	'
Number of shares added to current plan for award granted but not exercised in full, pursuant to the terminated equity incentive plan	7,900,000	'	'
Annual increase in number of shares available for issuance on first day of each fiscal year following latest fiscal year	4,000,000	'	'
Annual increase in number of shares available for issuance on first day of each fiscal year following latest fiscal year as a percentage of outstanding common stock, as on last day of the immediately preceding fiscal year	5.00%	'	'
Additional shares authorized	'	1,641,299	'
Options | 2008 Equity Incentive Plan	'	'	'
Equity Incentive Plans	'	'	'
Number of unvested shares	241,574	315,579	241,574

STOCKHOLDERS_EQUITY_Details_3

STOCKHOLDERS' EQUITY (Details 3) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Summary of options outstanding and vested	'	'
Expected dividends	$0	'
Assumptions used to value stock-based awards granted to employees	'	'
Expected term	'6 years 3 months 12 days	'
Volatility (as a percent)	55.60%	'
Volatility, lower end (as a percent)	'	53.80%
Volatility, higher end (as a percent)	'	64.90%
Risk-free interest rate (as a percent)	1.85%	'
Risk-free interest rate, lower end (as a percent)	'	1.04%
Risk-free interest rate, higher end (as a percent)	'	1.88%
Dividend yield (as a percent)	0.00%	0.00%

STOCKHOLDERS_EQUITY_Details_4

STOCKHOLDERS' EQUITY (Details 4) (USD $)

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

In Thousands, unless otherwise specified

Options

Options

Cost of revenue

Cost of revenue

Research and development

Research and development

Sales and marketing

Sales and marketing

General and administrative

General and administrative

Allocation of stock-based compensation and restricted stock for employees and non-employees

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized stock-based compensation expense related to unvested common stock options

$4,957

[1]

$1,565

[1]

$32,200

$21,700

$252

$27

$987

$391

$2,167

$512

$1,551

$635

Weighted-average period over which stock-based compensation expense will be recognized

'

'

'2 years 7 months 12 days

'

'

'

'

'

'

'

'

'

[1]

The table above includes the impact of the issuance of restricted stock at fair value.

STOCKHOLDERS_EQUITY_Details_5

STOCKHOLDERS' EQUITY (Details 5) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended					3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
			2008 Equity Incentive Plan	Employee stock purchase plan	Options to Nonemployees	Options to Nonemployees	Options to Nonemployees	Restricted Stock	Restricted Stock	Restricted Stock Units (RSUs)
					2008 Equity Incentive Plan	2008 Equity Incentive Plan	2008 Equity Incentive Plan
Additional disclosure	'	'	'	'	'	'	'	'	'	'
Options granted (weighted average fair value of $56.97 per share)	369,000	'	'	'	5,000	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	$0	$0.10	'	'	'	$1.80
Options outstanding (in shares)	7,417,535	7,410,588	'	'	3,900	'	8,900	'	'	'
Number of awards issued (in shares)	'	'	'	'	'	'	'	0	0	97,585
Number of awards released (in shares)	'	'	'	'	'	'	'	'	'	4,000
Number of awards cancelled (in shares)	'	'	'	'	'	'	'	'	'	2,850
Unrecognized compensation expense	'	'	'	'	'	'	'	'	'	19.1
Percentage of deduction from eligible compensation authorized by employee to purchase common stock at discount	'	'	'	15.00%	'	'	'	'	'	'
Purchase price expressed as a percentage of fair market value of common stock on the first or the last trading day of the offering period	'	'	100.00%	85.00%	'	'	'	'	'	'
Total compensation costs related to rights to purchase common shares but not yet vested which will be recognized over the offering period	'	'	'	$1.80	'	'	'	'	'	'
Assumptions used to calculate stock-based compensation for each stock purchase right granted under the Employee Stock Purchase Plan (ESPP)	'	'	'	'	'	'	'	'	'	'
Expected term	'6 years 3 months 12 days	'	'	'8 months 1 day	'	'	'	'	'	'
Volatility (as a percent)	55.60%	'	'	66.20%	'	'	'	'	'	'
Risk-free interest rate (as a percent)	1.85%	'	'	0.07%	'	'	'	'	'	'
Dividend yield (as a percent)	0.00%	0.00%	'	0.00%	'	'	'	'	'	'

NET_INCOME_LOSS_PER_SHARE_Deta

NET INCOME (LOSS) PER SHARE (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Computation of net loss per common share	'	'
Net loss	($11,225)	($8,072)
Weighted-average shares used to compute basic and diluted net loss per share	34,033	8,298
Basic and diluted net loss per share (in dollars per share)	($0.33)	($0.97)
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders (in shares)	8,247	26,650
Convertible preferred stock	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders (in shares)	0	19,479
Employee stock options	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders (in shares)	7,418	6,904
Shares subject to repurchase	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders (in shares)	242	0
Restricted stock units (RSUs)	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders (in shares)	473	0
Employee stock purchase plan	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders (in shares)	114	0
Convertible preferred stock warrants	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders	'	'
Anti-dilutive securities that were excluded from the calculation of diluted net loss per share attributable to common stockholders (in shares)	0	267

INCOME_TAXES_Details

INCOME TAXES (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Abstract]	'	'
Provision for income taxes	($314)	($54)

COMMITMENTS_AND_CONTINGENCIES_1

COMMITMENTS AND CONTINGENCIES (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Operating Leases	'	'	'
Rent expense	$3,200,000	$700,000	'
Future minimum lease payments under non-cancelable operating leases	'	'	'
2014 (remaining 9 months)	4,611,000	'	'
2015	13,571,000	'	'
2016	15,839,000	'	'
2017	15,815,000	'	'
2018	14,512,000	'	'
Thereafter	53,622,000	'	'
Total future payments	117,970,000	'	'
Letters of Credit and Bank Guarantees	'	'	'
Irrevocable letters of credit outstanding	4,100,000	'	4,100,000
Bank guarantees for security deposits	$2,294,000	'	$0

SEGMENTS_Details

SEGMENTS (Details) (USD $)	3 Months Ended			3 Months Ended			12 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
	segment			Revenue	Revenue	Accounts receivable	Accounts receivable	North America	North America	All Other Countries	All Other Countries
	manager			Customer concentration	Customer concentration	Customer concentration	Customer concentration
	business_activity
Segment Reporting [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Number of business activities	1	'	'	'	'	'	'	'	'	'	'
Number of segment managers held accountable for operations, operating results or plans for levels or components below the consolidated unit level	0	'	'	'	'	'	'	'	'	'	'
Number of reportable segments	1	'	'	'	'	'	'	'	'	'	'
Number of operating segments	1	'	'	'	'	'	'	'	'	'	'
Segments	'	'	'	'	'	'	'	'	'	'	'
Total revenue	$74,397	$38,212	'	'	'	'	'	$62,647	$32,849	$11,750	$5,363
Total long-lived assets	$37,283	'	$25,794	'	'	'	'	$33,637	$23,956	$3,646	$1,838
Number of customers	'	'	'	0	0	0	0	'	'	'	'