Block (XYZ) 10-K 27 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2016	Feb. 17, 2017	Jun. 30, 2016
Class of Stock [Line Items]
Entity Registrant Name	Square, Inc.
Entity Central Index Key	1,512,673
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Public Float			$ 1.4
Class A
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		208,288,497
Class B
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		158,902,579

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 452,030	$ 461,329
Short-term investments	59,901	0
Restricted cash	22,131	13,537
Settlements receivable	321,102	142,727
Customer funds held	43,574	9,446
Loans held for sale	42,144	604
Merchant cash advance receivable, net	4,212	36,473
Other current assets	56,331	41,447
Total current assets	1,001,425	705,563
Property and equipment, net	88,328	87,222
Goodwill	57,173	56,699
Acquired intangible assets, net	19,292	26,776
Long-term investments	27,366	0
Restricted cash	14,584	14,686
Other assets	3,194	3,826
Total assets	1,211,362	894,772
Current liabilities:
Accounts payable	12,602	18,869
Customers payable	388,058	215,365
Customer funds obligation	43,574	9,446
Accrued transaction losses	20,064	17,176
Accrued expenses	39,543	44,401
Other current liabilities	73,623	28,945
Total current liabilities	577,464	334,202
Debt (Note 11)	0	0
Other liabilities	57,745	52,522
Total liabilities	635,209	386,724
Commitments and contingencies (Note 16)
Stockholders’ equity:
Preferred stock, $0.0000001 par value: 100,000,000 shares authorized at December 31, 2016 and December 31, 2015. None issued and outstanding at December 31, 2016 and December 31, 2015.	0	0
Additional paid-in capital	1,357,381	1,116,882
Accumulated other comprehensive loss	(1,989)	(1,185)
Accumulated deficit	(779,239)	(607,649)
Total stockholders’ equity	576,153	508,048
Total liabilities and stockholders’ equity	1,211,362	894,772
Class A Common Stock
Stockholders’ equity:
Common stock	0	0
Class B Common Stock
Stockholders’ equity:
Common stock	$ 0	$ 0

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Preferred stock, par value (in USD per share)	$ 0.00	$ 0.00
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A
Common stock, par value (in USD per share)	$ 0.00	$ 0.00
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	198,746,620	31,717,133
Common stock, shares outstanding (in shares)	198,746,620	31,717,133
Class B
Common stock, par value (in USD per share)	$ 0.00	$ 0.00
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	165,800,756	303,232,312
Common stock, shares outstanding (in shares)	165,800,756	303,232,312

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Hardware revenue	$ 44,307	$ 16,377	$ 7,323
Total net revenue	1,708,721	1,267,118	850,192
Cost of Revenue [Abstract]
Hardware costs	68,562	30,874	18,330
Amortization of acquired technology	8,028	5,639	1,002
Total cost of revenue	1,132,683	897,088	624,118
Gross profit	576,038	370,030	226,074
Operating expenses:
Product development	268,537	199,638	144,637
Sales and marketing	173,876	145,618	112,577
General and administrative	251,993	143,466	94,220
Transaction, loan and advance losses	51,235	54,009	24,081
Amortization of acquired customer assets	850	1,757	1,050
Total operating expenses	746,491	544,488	376,565
Operating loss	(170,453)	(174,458)	(150,491)
Interest and other (income) expense, net	(780)	1,613	2,162
Loss before income tax	(169,673)	(176,071)	(152,653)
Provision for income taxes	1,917	3,746	1,440
Net loss	(171,590)	(179,817)	(154,093)
Deemed dividend on Series E preferred stock	0	(32,200)	0
Net loss attributable to common stockholders	$ (171,590)	$ (212,017)	$ (154,093)
Net loss per share attributable to common stockholders:
Basic (in USD per share)	$ (0.50)	$ (1.24)	$ (1.08)
Diluted (in USD per share)	$ (0.50)	$ (1.24)	$ (1.08)
Weighted-average shares used to compute net loss per share attributable to common stockholders:
Basic (in shares)	341,555	170,498	142,042
Diluted (in shares)	341,555	170,498	142,042
Subscription and services-based
Revenue:
Revenue	$ 129,351	$ 58,013	$ 12,046
Cost of Revenue [Abstract]
Transaction, software, and data product costs	43,132	22,470	2,973
Customers Other than Starbucks | Transaction-based
Revenue:
Revenue	1,456,160	1,050,445	707,799
Cost of Revenue [Abstract]
Transaction, software, and data product costs	943,200	672,667	450,858
Starbucks | Transaction-based
Revenue:
Revenue	78,903	142,283	123,024
Cost of Revenue [Abstract]
Transaction, software, and data product costs	$ 69,761	$ 165,438	$ 150,955

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (171,590)	$ (179,817)	$ (154,093)
Net foreign currency translation adjustments	(716)	(356)	(114)
Net unrealized loss on revaluation of intercompany loans	(11)	(22)	0
Net unrealized loss on marketable securities	(77)	0	0
Total comprehensive loss	$ (172,394)	$ (180,195)	$ (154,207)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	IPO	Series E	Convertible preferred stock	Convertible preferred stockSeries E	Class A and B common stock	Class A and B common stockIPO	Additional paid-in capital	Additional paid-in capitalIPO	Accumulated other comprehensive loss	Accumulated deficit
Beginning balance at Dec. 31, 2013	$ 162,294			$ 366,197		$ 0		$ 38,329		$ (693)	$ (241,539)
Beginning balance (in shares) at Dec. 31, 2013				134,528,520		138,017,900
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(154,093)										(154,093)
Shares issued in connection with:
Issuance of stock			$ 148,748		$ 148,748
Issuance of stock (in shares)					9,700,289
Exercise of stock options	8,685							8,685
Exercise of stock options (in shares)						9,403,147
Issuance of common stock in connection with business combinations	59,576							59,576
Issuance of common stock in connection with business combinations (in shares)						8,384,156
Issuance of common stock	0							0
Issuance of common stock (in shares)						24,220
Vesting of early exercised stock options	11,128							11,128
Contribution of stock	0
Contribution of stock (in shares)				(8,976,000)
Repurchase of common stock	0
Repurchase of common stock (in shares)						(1,225,740)
Change in other comprehensive loss	(114)									(114)
Share-based compensation	36,100							36,100
Tax benefit from share-based award activity	1,348							1,348
Ending balance at Dec. 31, 2014	273,672			$ 514,945		$ 0		155,166		(807)	(395,632)
Ending balance (in shares) at Dec. 31, 2014				135,252,809		154,603,683
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(179,817)										(179,817)
Shares issued in connection with:
Issuance of stock		$ 245,726	$ 29,952		$ 29,952				$ 245,726
Issuance of stock (in shares)					1,940,058		29,700,000
Conversion of Series A, B, C, D & E preferred stock upon initial public offering to common stock	0			$ (544,897)				544,897
Conversion of Series A, B, C, D & E preferred stock upon initial public offering to common stock (in shares)				(137,192,867)		137,192,867
Deemed dividend on Series E preferred stock	$ 0							32,200			(32,200)
Deemed dividend on Series E preferred stock (in shares)	10,299,696					10,299,696
Exercise of stock options	$ 14,766							14,766
Exercise of stock options (in shares)						5,544,785
Issuance of common stock in connection with business combinations	35,776							35,776
Issuance of common stock in connection with business combinations (in shares)						3,591,014
Issuance of common stock	0							0
Issuance of common stock (in shares)						3,777
Vesting of early exercised stock options	4,958							4,958
Contribution of stock	0
Contribution of stock (in shares)						(5,068,238)
Repurchase of common stock	0
Repurchase of common stock (in shares)						(918,139)
Change in other comprehensive loss	(378)									(378)
Share-based compensation	82,292							82,292
Tax benefit from share-based award activity	1,101							1,101
Ending balance at Dec. 31, 2015	508,048			$ 0		$ 0		1,116,882		(1,185)	(607,649)
Ending balance (in shares) at Dec. 31, 2015				0		334,949,445
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (171,590)										(171,590)
Shares issued in connection with:
Exercise of stock options (in shares)	24,328,414
Exercise of stock options and warrants	$ 82,438							82,438
Purchases under employee stock purchase plan	14,201							14,201
Purchases under employee stock purchase plan (in shares)						1,852,900
Exercise of stock options and warrants (in shares)						24,413,821
Vesting of RSUs	0
Vesting of RSUs (in shares)						3,392,726
Vesting of early exercised stock options	2,313							2,313
Cancellation of shares related to business combinations	0
Cancellation of shares related to business combinations (in shares)						(228)
Repurchase of common stock	0
Repurchase of common stock (in shares)						(61,288)
Change in other comprehensive loss	(804)									(804)
Share-based compensation	141,547							141,547
Ending balance at Dec. 31, 2016	$ 576,153			$ 0		$ 0		$ 1,357,381		$ (1,989)	$ (779,239)
Ending balance (in shares) at Dec. 31, 2016				0		364,547,376

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (171,590)	$ (179,817)	$ (154,093)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	37,745	27,626	18,586
Share-based compensation	138,786	82,292	36,100
Excess tax benefit from share-based payment activity	0	(1,101)	(1,348)
Provision for transaction losses	50,819	43,379	18,478
Provision for uncollectible receivables related to merchant cash advances	1,159	6,240	2,431
Deferred provision for income taxes	58	26	(2,664)
(Gain) loss on disposal of property and equipment	(49)	270	133
Changes in operating assets and liabilities:
Settlements receivable	(178,405)	(27,420)	(50,361)
Customer funds held	(34,128)	(6,462)	(2,985)
Purchase of loans held for sale	(668,976)	(816)	0
Proceeds from sales and principal payments of loans held for sale	627,627	21	0
Merchant cash advance receivable	31,102	(13,411)	(31,733)
Other current assets	(14,986)	(12,430)	(14,323)
Other assets	631	1,220	(636)
Accounts payable	(2,147)	7,831	179
Customers payable	172,446	69,547	49,971
Customer funds obligation	34,128	6,462	2,985
Charge-offs and recoveries to accrued transaction losses	(47,931)	(34,655)	(17,514)
Accrued expenses	(409)	21,450	8,113
Other current liabilities	44,102	19,760	3,007
Other liabilities	3,149	11,111	23,295
Net cash (used in) provided by operating activities	23,131	21,123	(112,379)
Cash flows from investing activities:
Purchase of marketable securities	(164,766)	0	0
Maturities of marketable securities	43,200	0	0
Sales of marketable securities	34,222	0	0
Purchase of property and equipment	(25,433)	(37,432)	(28,794)
Proceeds from sale of property and equipment	296	0	0
Payment for acquisition of intangible assets	(400)	(1,286)	(400)
Increases in restricted cash	(8,492)	(1,878)	(7,075)
Business acquisitions (net of cash acquired)	(1,360)	(4,500)	11,715
Net cash used in investing activities:	(122,733)	(45,096)	(24,554)
Cash flows from financing activities:
Proceeds from issuance of preferred stock, net	0	29,952	148,748
Proceeds from issuance of common stock upon initial public offering, net of offering costs	0	251,257	0
Payments of offering costs related to initial public offering	(5,530)	0	0
Proceeds from debt	0	0	30,000
Principal payments on debt	0	(30,000)	0
Payments of debt issuance costs	0	(1,387)	0
Principal payments on capital lease obligation	(168)	0	0
Proceeds from issuances of common stock from the exercise of options and employee stock purchase plan	96,439	13,840	14,056
Excess tax benefit from share-based payment award	0	1,101	1,348
Net cash provided by financing activities	90,741	264,763	194,152
Effect of foreign exchange rate on cash and cash equivalents	(438)	(1,776)	(1,080)
Net increase (decrease) in cash and cash equivalents	(9,299)	239,014	56,139
Cash and cash equivalents, beginning of the year	461,329	222,315	166,176
Cash and cash equivalents, end of the year	$ 452,030	$ 461,329	$ 222,315

DESCRIPTION OF BUSINESS AND SUM

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Business Square, Inc. (together with its subsidiaries, Square or the Company) is a cohesive commerce ecosystem that helps its sellers start, run, and grow their businesses – from managed payments solutions to point of sale, hardware to software, loans to payroll and more. Businesses and individuals can also use Square Cash, an easy way to send and receive money, as well as Caviar, a food ordering service for restaurants. Square was founded in 2009 and is headquartered in San Francisco, with offices in the United States, Canada, Japan, and Australia. Out of Period Adjustments to Reserve for Transaction Losses During the second quarter of the year ended December 31, 2016 , the Company recorded an out of period adjustment of $6.0 million to transaction, loan and advance losses as a result of a correction to the calculation of its reserve for transaction losses. The adjustment was recorded to correct an understatement of transaction losses in prior periods. Of the total amount of this adjustment, $0.5 million is related to the three months ended March 31, 2016, and $2.6 million and $1.6 million is related to the years ended December 31, 2015 and 2014, respectively. The remaining $1.3 million is related to historical periods. The Company evaluated the error from a qualitative and quantitative perspective in accordance with the requirements of the Securities and Exchange Commission (SEC) Staff Accounting Bulletin No. 99, Materiality, (SAB 99) and concluded that such amounts were not material with respect to the operating loss or net loss for the current fiscal year or any previously reported consolidated financial statements. The correction of this error had no impact on the net cash flows from operations in any of the periods. Immaterial Correction to Cash and Cash Equivalents During the fourth quarter of 2016, the Company identified an error that impacted the consolidated balance sheet as of December 31, 2015, the consolidated statement of cash flows for the years ended December 31, 2015 and 2014, and in the unaudited condensed consolidated balance sheets and statements of cash flows as of and for the three months ended March 31, 2016, the six months ended June 30, 2016, and the nine months ended September 30, 2016, all related to the reported amounts of cash and cash equivalents. During these periods, the Company erroneously classified and reported certain customer funds as cash and cash equivalents instead of classifying these customer funds as a component of current assets. These customer funds represent cash balances stored by customers utilizing the Square Cash app that the customers can withdraw at a subsequent time or use to make transfers or payments, or customer cash that was in transit. The Company held these stored balances as short term deposits with a third-party bank. The effect of correcting these errors was to decrease cash and cash equivalents at December 31, 2015 by $ 9.5 million and increase customer funds as a component of current assets of the same amount. These adjustments did not change current assets, total assets, or net loss. The effect of the revisions within the consolidated statement of cash flows was to decrease the cash flows from operations and the change in cash and cash equivalents for the year ended December 31, 2015 by $ 6.5 million . Management evaluated the materiality of the errors described above from a qualitative and quantitative perspective in accordance with the requirements of the SAB 99. Based on such evaluation, the Company has concluded that their correction would not be material to any individual prior period. Changes to the Description of Revenue and Cost of Revenue Line Items The Company has renamed some of the revenue and cost of revenues financial statement line items in its consolidated statements of operations to better describe how the Company monetizes its product offerings. Accordingly, the previously presented transaction revenue and Starbucks transaction revenue have been renamed transaction-based revenue and Starbucks transaction-based revenue, respectively, while software and data product revenue has been renamed subscription and services-based revenue. The products and services revenues included in the previously presented line items remains the same. The cost of revenues line items have similarly been renamed while the components of costs of revenues in the line items have remained the same. Litigation Settlement On June 8, 2016 , a final, definitive settlement agreement (Settlement Agreement) was entered into by Robert E. Morley, REM Holdings 3, LLC, Jack Dorsey, Jim McKelvey, and the Company. The Settlement Agreement required an aggregate total payment of $50.0 million to plaintiffs, including meaningful contributions by Mr. Dorsey and Mr. McKelvey. The Company made a payment of $48.0 million to plaintiffs and met its obligations under the Settlement Agreement. This amount was classified within general and administrative expenses on the consolidated statements of operations for the year ended December 31, 2016 . On June 17, 2016 , the Court entered an Order dismissing the complaints in their entirety, with prejudice. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) and include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, as well as related disclosure of contingent assets and liabilities. Actual results could differ from the Company’s estimates. To the extent that there are material differences between these estimates and actual results, the Company’s financial condition or operating results will be materially affected. The Company bases its estimates on past experience and other assumptions that the Company believes are reasonable under the circumstances, and the Company evaluates these estimates on an ongoing basis. Significant estimates, judgments, and assumptions in these consolidated financial statements include, but are not limited to, those related to revenue recognition, accrued transaction losses, valuation of loans held for sale, business combinations, goodwill and intangible assets, income taxes, and share-based compensation. Revenue Recognition The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery of obligations to its customers has occurred, the related fees are fixed or determinable, and collectibility is reasonably assured. Revenue is generated from the following: Transaction-based revenue and Starbucks transaction-based revenue The Company charges its sellers a transaction fee for managed payments solutions that is generally calculated as a percentage of the total transaction amount processed. The Company selectively offers custom pricing for larger sellers. The Company had a processing agreement with Starbucks, for certain Starbucks-owned stores in the United States. As of December 31, 2016 , Starbucks has completed its previously announced transition to another payments solution provider. The Company recognizes the transaction fees a seller pays to the Company as revenue upon authorization of a transaction by the seller's customer's bank. Revenue is recognized net of refunds, which arise from reversals of transactions initiated by sellers. The Company acts as the merchant of record for its sellers and works directly with payment card networks and banks so that its sellers do not need to manage the complex systems, rules, and requirements of the payments industry. As the merchant of record, Square is liable for settlement of the transactions the Company processes for its sellers. The gross transaction fees collected from sellers are recognized as revenue on a gross basis as the Company is the primary obligor to the seller and is responsible for processing the payment, has latitude in establishing pricing with respect to the sellers and other terms of service, has sole discretion in selecting the third party to perform the settlement, and assumes the credit risk for the transaction processed. Subscription and services-based revenue Subscription and services-based revenue primarily consists of revenue related to services provided through software offerings or deriving from the use of underlying data. Subscription and services-based revenue is primarily generated by Square Capital, Caviar, and other software as a service. Square Capital facilitates a loan that is offered through a partnership with a Utah-chartered, member FDIC industrial bank that is generally repaid through withholding a percentage of the collections of the seller's receivables processed by the Company. During the first quarter of 2016, the Company fully transitioned from offering merchant cash advances (MCAs) to loans. The Company facilitates loans to sellers pre-qualified through an analysis of the aggregated data of the seller’s business which includes, but is not limited to, the seller’s historical processing volumes, transaction count, chargebacks, growth, and length of time as a Square customer. The loans are originated by a bank partner, from whom the Company purchases the loans obtaining all rights, title, and interest. The loans have no stated coupon rate but the seller is charged a one-time origination fee by the bank partner based upon their risk rating, which is derived primarily from processing activity. It is the Company’s intent to sell all of its rights, title, and interest in certain of these loans to third-party investors for an upfront fee when the loans are sold. The Company records the net amounts paid to the bank as the cost of the loans purchased and subsequently records a gain on sale of the loans to the third-party investors. The Company is retained by the third-party investors to service the loans and earns a servicing fee for facilitating the repayment of these receivables through its payments solutions. The Company recognizes the gain on sale of the loans to the investors as revenue upon transfer of title to investors. The Company records servicing revenue as servicing is delivered. For the loans which are not sold to third-party investors, the Company recognizes a portion of the expected seller repayments over the cost of the loans as revenue in proportion to the loan principal reduction. Caviar is a courier order management app that facilitates food delivery services for restaurants. Caviar revenue consists of seller fees charged to restaurants, delivery fees, and service fees from consumers. All fees are recognized upon delivery of the food, net of refunds. Software as a service provides the use of software on a stand-alone basis for a fee which is recognized ratably as service is provided. Hardware revenue Hardware revenue is generated from sales of contactless and chip readers, chip card readers, Square Stand, and third-party peripherals. Hardware revenue is recorded net of returns and is recognized upon delivery of hardware to the end customer. The Company considers delivery to have occurred once title and risk of loss has been transferred to the end customer. The Company records deferred revenue when it receives payments in advance of the delivery of products. Cost of Revenue Transaction-based costs and Starbucks transaction-based costs Transaction-based costs and Starbucks transaction-based costs consist primarily of interchange fees set by payment card networks that are paid to the card-issuing financial institution, assessment fees paid to payment networks, fees paid to third-party payment card processors, and bank settlement fees. Contracts with third-party payment processors are typically for a term of two to four years. Subscription and services-based costs Subscription and services-based costs consist primarily of Caviar-related costs, which include payments to third-party couriers for deliveries and seller-facing equipment. Cost of revenue for other subscription and services-based costs consists primarily of the amortization related to the development of certain subscription and services-based products. Hardware costs Hardware costs consist of all product costs associated with contactless and chip readers, chip card readers, Square Stand, and third-party peripherals. Product costs include manufacturing-related overhead and personnel costs, certain royalties, packaging, and fulfillment costs. Advertising Costs Advertising costs are expensed as incurred and included in sales and marketing expense on the consolidated statements of operations. Total advertising costs for the years ended December 31, 2016 , 2015 , and 2014 were $58.3 million , $58.3 million , and $45.1 million , respectively. Share-based Compensation Share-based compensation expense relates to stock options, restricted stock units (RSUs), and purchases under the Company’s 2015 Employee Stock Purchase Plan (ESPP) which is measured based on the grant-date fair value. The Company estimates the fair value of stock options and employee stock purchase plan shares granted to employees on the date of grant using the Black-Scholes-Merton option valuation model. The fair value of RSUs is based on the market value of the Company's common stock on grant date. The Company recognizes compensation expense net of estimated forfeitures over the vesting period of the applicable award using the straight-line method. Forfeiture rates are estimated based on historical forfeitures of share-based awards and are adjusted to reflect changes in facts and circumstances, if any. There are unvested restricted shares issued to employees of certain acquired companies. A portion of these awards is generally subject to continued post-acquisition employment, which is accounted for as post-acquisition share-based compensation expense. The shares are measured based on the grant-date fair value and recognized as compensation expense on a straight-line basis over the required service period. Income Taxes The Company reports income taxes under the asset and liability approach. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, as well as net operating loss and tax credit carryforwards. Deferred tax amounts are determined by using the enacted tax rates expected to be in effect when the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance reduces the deferred tax assets to the amount that is more likely than not to be realized. The Company uses financial projections to support its net deferred tax assets, which contain significant assumptions and estimates of future operations. If such assumptions were to differ significantly from actual future results of operations, it may have a material impact on the Company’s ability to realize its deferred tax assets. At the end of each period, the Company assesses the ability to realize the deferred tax assets. If it is more likely than not that the Company would not realize the deferred tax assets, then the Company would establish a valuation allowance for all or a portion of the deferred tax assets. The Company recognizes the effect of uncertain income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that has a greater than 50% likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to uncertain tax positions in the provision for income tax expense on the consolidated statements of operations. Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments, including money market funds, with an original maturity of three months or less when purchased to be cash equivalents. As of December 31, 2016 and 2015 , restricted cash of $22.1 million and $13.5 million , respectively, is related to pledged cash deposited into savings accounts at the financial institutions that process the Company's sellers' payment transactions and as collateral pursuant to an agreement with the originating bank for the Company's loan product. The Company uses the restricted cash to secure letters of credit with the financial institution to provide collateral for cash flow timing differences in the processing of these payments. The Company has recorded this amount as a current asset on the consolidated balance sheets due to the short-term nature of these cash flow timing differences and that there is no minimum time frame during which the cash must remain restricted. As of December 31, 2016 and 2015 , the remaining restricted cash of $14.6 million and $14.7 million , respectively, is primarily related to cash deposited into money market funds that is used as collateral pursuant to multi-year lease agreements entered into in 2012 and 2014 (Note 16 ). The Company has recorded this amount as a non-current asset on the consolidated balance sheets as the terms of the related leases extend beyond one year. Concentration of Credit Risk For the year ended December 31, 2016 , the Company had no customer who accounted for greater than 10% of total net revenue. For the years ended December 31, 2015 and 2014 , the Company had no customer other than Starbucks who accounted for greater than 10% of total net revenue. The Company terminated its relationship with Starbucks during the year ended December 31, 2016. The Company had three third-party processors that represented approximately 52% , 35% , and 10% of settlements receivable as of December 31, 2016 . The Company had three third-party processors that represented approximately 56% , 23% , and 16% of settlements receivable as of December 31, 2015 . Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities, settlements receivables, customer funds held, merchant cash advance receivables, and loans held for sale. The associated risk of concentration for cash and cash equivalents is mitigated by banking with creditworthy institutions. At certain times, amounts on deposit exceed federal deposit insurance limits. The associated risk of concentration for marketable securities is mitigated by holding a diversified portfolio of highly rated investments. Settlements receivable are amounts due from well established payment processing companies and normally take one or two business days to settle which mitigates the associated risk of concentration. The associated risk of concentration for merchant cash advance receivables and loans held for sale is mitigated by ongoing credit evaluations of the Company’s customers. Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value accounting establishes a three-level hierarchy priority for disclosure of assets and liabilities recorded at fair value. The ordering of priority reflects the degree to which objective prices in external active markets are available to measure fair value. The classification of assets and liabilities within the hierarchy is based on whether the inputs to the valuation methodology used for measurement are observable or unobservable. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: • Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date. • Level 2 Inputs: Other than quoted prices included in Level 1 Inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date. Loans Held for Sale The Company facilitates the offering of loans by its bank partner to sellers pre-qualified through an analysis of the aggregated data of the seller’s business which includes, but is not limited to, the seller’s historical processing volumes, transaction count, chargebacks, growth, and length of time as a Square customer. The loans are originated by a bank partner, from whom the Company purchases the loans obtaining all rights, title, and interest. Loans are classified as held for sale upon purchase, as it is the Company’s intent to sell all of its rights, title, and interest in certain of these loans to third-party investors for an agreed-upon purchase price when the loans are sold. A loan that is initially designated as held for sale may be reclassified to held for investment if and when the Company's intent for that loan changes. There have been no reclassifications made to date. Loans are recorded at the lower of cost or fair value. To determine the fair value of loans, the Company utilizes industry standard modeling, such as discounted cash flow models, to arrive at an estimate of fair value. Settlements Receivable Settlements receivable represents amounts due from third-party payment processors for customer transactions. Settlements receivable are typically received within one or two business days of the transaction date. No valuation allowances have been established, as funds are due from large, well-established financial institutions with no historical collections issue. Provision for Uncollectible Receivables Related to MCAs Merchant cash advance receivable, net, represents the aggregate amount of advances to merchants outstanding as of the balance sheet date, net of an allowance for potential uncollectible amounts. The Company estimates the allowance based on an assessment of various factors, including historical experience, merchants’ current processing volume, and other factors that may affect the merchants’ ability to generate future receivables. Additions to the allowance are reflected in current operating results, while charges against the allowance are made when charge-offs are recognized. The additions are classified within transaction and advance losses on the consolidated statements of operations. During the first quarter of 2016, the Company had fully transitioned from offering MCAs to loans. Activity subsequent to this transition relates primarily to updates to the Company's provision estimates for historical balances, write-offs or recoveries. The Company is not exposed to losses for the merchant cash advance receivables that are sold to third-party investors in accordance with the Company’s arrangements with them. Customer Funds Customer funds held represent cash stored by customers within the Square Cash App that the customers would later use to send money or make payments, or customer cash in transit. As of December 31, 2016 and 2015 , the Company held these stored balances as short term deposits within a bank account. Customer funds obligation represents the Company's liability to the customers for the customer funds held. Inventory Inventory is comprised of contactless and chip readers, chip card readers, Square Stand, and third-party peripherals. Inventory is stated at the lower of cost (generally on a first-in, first-out basis) or market. Inventory that is obsolete or in excess of forecasted usage is written down to its estimated net realizable value based on assumptions about future demand and market conditions. Deferred Magstripe Reader Costs The Company capitalizes the cost of its magstripe readers, which are included in other current assets on the consolidated balance sheets. The amount capitalized represents the cost of the readers, including packaging and shipping costs, held on-hand by the Company as of each consolidated balance sheet date. Once the readers are shipped to a third-party distributor or an end-customer, they are recorded as marketing expense on the consolidated statements of operations. Property and Equipment Property and equipment are recorded at historical cost less accumulated depreciation, which is computed on a straight-line basis over the asset’s estimated useful life. The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Three years Furniture and fixtures Seven years Leasehold improvements Lesser of estimated useful life or remaining lease term When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from their respective accounts, and any gain or loss on such sale or disposal is reflected in operating expenses. Capitalized Software The Company capitalizes certain cost incurred in developing internal-use software when capitalization requirements have been met. Costs prior to meeting the capitalization requirements are expensed as incurred. Capitalized costs are included in property and equipment, net, and amortized on a straight-lined basis over the estimated useful life of the software and included in product development costs or allocated to subscription and service-based costs on the consolidated statements of operations. The Company capitalized $7.9 million , $4.5 million and $6.4 million of internally developed software during the years ended December 31, 2016 , 2015 and 2014 , respectively, and recognized $7.1 million , $3.2 million and $2.7 million of amortization expense during the years ended December 31, 2016 , 2015 and 2014 , respectively. Leases The Company leases office space and equipment under non-cancellable capital and operating leases with various expiration dates. The Company records the total rent expense on a straight-line basis over the lease term. When lease agreements provide allowances for leasehold improvements, the Company capitalizes the leasehold improvement assets and recognizes the related depreciation expense on a straight-line basis over the lesser of the lease term or the estimated useful life of the asset, and reduces rent expense on a straight-line basis over the term of the lease by the amount of the allowances provided. The Company classifies the cash payments for the leasehold improvements within investing activities while reimbursements from the landlords are classified within operating activities. The Company records a liability for the estimated fair value for any asset retirement obligation (ARO) associated with its leases, with an offsetting asset. In the determination of the fair value of AROs, the Company uses various assumptions and judgments, including such factors as the existence of a legal obligation, estimated amounts and timing of settlements, and discount and inflation rates. The liability is subsequently accreted while the asset is depreciated. As of December 31, 2016, the Company had a liability for ARO, gross of accretion, of $3.2 million and an associated asset, net of depreciation, of $2.6 million . Business Combinations The purchase price of an acquisition is allocated to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the acquisition dates. The excess of total consideration over the fair values of the assets acquired and the liabilities assumed is recorded as goodwill. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments would be recorded on the consolidated statements of operations. Long-Lived Assets, including Goodwill and Acquired Intangibles The Company evaluates the recoverability of property and equipment and finite lived intangible assets for impairment whenever events or circumstances indicate that the carrying amounts of such assets may not be recoverable. Recoverability is measured by comparing the carrying amount of an asset or an asset group to estimate undiscounted future net cash flows expected to be generated. If the carrying amount of the long–lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values, and third–part independent appraisals, as considered necessary. For the periods presented, the Company had recorded no impairment charges. Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in a business combination. The Company performs a goodwill impairment test annually on December 31 and more frequently if events and circumstances indicate that the asset might be impaired. An impairment loss is recognized to the extent that the carrying amount exceeds the reporting unit’s fair value. The Company has the option to first assess qualitative factors to determine whether events or circumstances indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying amount and determine whether further action is needed. If, after assessing the totality of events or circumstances, the Company determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. For the periods presented, the Company had recorded no impairment charges. Acquired intangibles consist of acquired technology and customer relationships associated with various acquisitions. Acquired technology is amortized over its estimated useful life on a straight-line basis within cost of revenue. Customer relationships acquired are amortized on a straight-line basis over their estimated useful lives within operating expenses. The Company evaluates the remaining estimated useful life of its intangible assets being amortized on an ongoing basis to determine whether events and circumstances warrant a revision to the remaining period of amortization. Customers Payable Customers payable represents the transaction amounts, less revenue earned by the Company, owed to sellers. The payable amount comprises amounts owed to customers due to timing differences as we typically settle within one business day, amounts held by the Company in accordance with its risk management policies, and amounts held for customers who have not yet linked a bank account. Accrued Transaction Losses The Company establishes a reserve for estimated transaction losses due to chargebacks, which represent a potential loss due to disputes between a seller and their customer or due to a fraudulent transaction. The reserve is estimated based on available data as of the reporting date, including expectations of future chargebacks, and historical trends related to loss rates. Additions to the reserve are reflected in current operating results, while charges to the reserve are made when losses are recognized. These amounts are classified within transaction and advance losses on the consolidated statements of operations. Recent Accounting Pronouncements In May 2014, the

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS The Company’s financial assets and liabilities that are measured at fair value on a recurring basis are classified as follows (in thousands): December 31, 2016 December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash and cash equivalents: Money market funds $ 207,168 $ — $ — $ 337,234 $ — $ — Commercial paper — 7,496 — — — — Municipal securities — 1,000 — — — — Short-term securities: U.S. agency securities — 9,055 — — — — Corporate bonds — 6,980 — — — — Commercial paper — 17,298 — — — — Municipal securities — 8,028 — U.S. government securities 18,540 — — — — — Long-term securities: U.S. agency securities — 3,502 — — — — Corporate bonds — 12,914 — — — — Municipal securities — 2,492 — — — — U.S. government securities 8,458 — — — — — Total $ 234,166 $ 68,765 $ — $ 337,234 $ — $ — The carrying amounts of certain financial instruments, including cash equivalents, settlements receivable, customer funds held, merchant cash advance receivable, accounts payable, customers payable, customer funds obligation, and settlements payable, approximate their fair values due to their short-term nature. Loans held for sale are recorded at the lower of cost or fair value. To determine the fair value of loans, the Company utilizes industry-standard valuation modeling, such as discounted cash flow models, to arrive at an estimate of fair value. A summary of loans disclosed at fair value on a recurring basis is as follows (in thousands): December 31, 2016 Carrying Value Fair Value (Level 3) Loans held for sale $ 42,144 $ 42,633 Total $ 42,144 $ 42,633 As of December 31, 2015 , the difference between the fair value of loans and the carrying value was insignificant. If applicable, the Company will recognize transfers into and out of levels within the fair value hierarchy at the end of the reporting period in which the actual event or change in circumstance occurs. During the years ended December 31, 2016 , 2015 and 2014 , the Company did not have any transfers between Level 2 or Level 3 assets.

INVESTMENTS

INVESTMENTS	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS The Company determines the appropriate classification of its investments in marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified and accounted for its marketable securities as available-for-sale. The Company's short-term and long-term investments as of December 31, 2016 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term securities: U.S. agency securities $ 9,048 $ 7 $ — $ 9,055 Corporate bonds 17,318 — (20 ) 17,298 Commercial paper 6,980 — — 6,980 Municipal securities 8,037 — (9 ) 8,028 U.S. government securities 18,537 3 — 18,540 Total $ 59,920 $ 10 $ (29 ) $ 59,901 Long-term securities: U.S. agency securities $ 3,502 $ — $ — $ 3,502 Corporate bonds 12,939 — (25 ) 12,914 Municipal securities 2,505 — (13 ) 2,492 U.S. government securities 8,478 — (20 ) 8,458 Total $ 27,424 $ — $ (58 ) $ 27,366 For the year ended December 31, 2016 , gains or losses realized on the sale of investments were not material. Investments are reviewed periodically to identify possible other-than-temporary impairments. As the Company has the ability and intent to hold these investments with unrealized losses until a recovery of fair value, or for a reasonable period of time sufficient for the recovery of fair value, which may be maturity, the Company does not consider these investments to be other-than-temporarily impaired as of December 31, 2016 . The contractual maturities of the Company's short-term and long-term investments as of December 31, 2016 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 59,920 $ 59,901 Due in one to five years 27,424 27,366 Total $ 87,344 $ 87,267

MERCHANT CASH ADVANCE RECEIVABL

MERCHANT CASH ADVANCE RECEIVABLE, NET	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
MERCHANT CASH ADVANCE RECEIVABLE, NET	MERCHANT CASH ADVANCE RECEIVABLE, NET The following table summarizes the activities of the Company’s allowance for uncollectible receivables (in thousands): Year Ended December 31, Year Ended December 31, 2016 2015 Allowance for uncollectible MCA receivables, beginning of the period $ 7,443 $ 2,431 Provision for uncollectible MCA receivables 1,159 6,240 MCA receivables charged off (4,039 ) (1,228 ) Allowance for uncollectible MCA receivables, end of the period $ 4,563 $ 7,443 During the first quarter of 2016, the Company had fully transitioned from offering MCAs to loans.

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT, NET	PROPERTY AND EQUIPMENT, NET The following is a summary of property, equipment, and internally-developed software at cost, less accumulated depreciation and amortization (in thousands): December 31, December 31, Computer equipment $ 52,915 $ 43,531 Office furniture and equipment 10,737 9,339 Leasehold improvements 73,366 65,298 Capitalized software 24,642 14,533 Construction in process — 490 Total 161,660 133,191 Less: Accumulated depreciation and amortization (73,332 ) (45,969 ) Property and equipment, net $ 88,328 $ 87,222 Depreciation and amortization expense on property and equipment was $28.7 million , $20.1 million , and $16.5 million , for the years ended December 31, 2016 , 2015 , and 2014 , respectively.

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Fiscal 2016 During the year ended December 31, 2016, the Company completed an acquisition for a total consideration of $ 1.6 million in cash. This acquisition was accounted for as a business combination. This method requires, among other things, that assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. Of the total purchase consideration, $ 1.1 million was allocated to acquired intangible assets and $ 0.5 million was allocated to goodwill. Intangible assets and goodwill generated from this acquisition is deductible for tax purposes. Goodwill is primarily attributable to expected synergies from future growth opportunities. The results of operations from this acquisition have been consolidated with those of the Company as of the acquisition date. The acquisition's impact on revenue and net earnings for the year ended December 31, 2016 was not material. There was also no material impact on the Company’s revenue and net earnings on a pro forma basis for all periods presented. Fiscal 2015 During the year ended December 31, 2015, the Company completed acquisitions for a total consideration of $32.0 million , consisting of 2,923,881 shares of common stock, options to purchase 26,173 shares of common stock, and $4.5 million in cash. These acquisitions were accounted for as business combinations. This method requires, among other things, that assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. Of the total purchase consideration of $32.0 million , $16.4 million has been allocated to goodwill, $14.9 million to acquired intangible assets, $0.8 million to property and equipment, and $0.2 million to deferred tax liabilities. Goodwill from these acquisitions is primarily attributable to expected synergies and cost reductions. $29.8 million of the intangible assets and goodwill generated from these acquisitions is deductible for tax purposes. Acquisition-related costs of $0.6 million were recognized in general and administrative expenses. Of the total purchase price, 355,284 shares of common stock and 22,818 options have been accounted for as post-combination compensation expense. As of December 31, 2016 , 292,813 shares of the total share consideration remain withheld for indemnification purposes. Additionally, the Company completed an acquisition of certain assets for a total purchase consideration of $ 9.5 million , consisting of 667,133 shares of common stock, and $ 1.0 million in cash. This transaction was accounted for as a purchase of assets, which consists of $ 9.0 million in intangible assets and $ 0.5 million of other assets. Fiscal 2014 During the year ended December 31, 2014, the Company completed acquisitions for a total consideration of $ 59.6 million , consisting of 8,552,990 shares of common stock and options to purchase 168,834 shares of common stock. These acquisitions were accounted for as business combinations. This method requires, among other things, that assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. Of the total purchase consideration $ 39.7 million was allocated to goodwill, $ 11.4 million to acquired intangible assets, and $ 8.5 million to net tangible assets. Goodwill from these acquisitions was primarily attributable to expected synergies and cost reductions. No ne of the goodwill was deductible for tax. Acquisition-related costs of $ 0.5 million were recognized in general and administrative expenses. As of December 31, 2016 , 1,291,979 shares of the total share consideration remain withheld for indemnification purposes.

GOODWILL

GOODWILL	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL	GOODWILL Goodwill is recorded when the consideration paid for an acquisition of a business exceeds the fair value of identifiable net tangible and intangible assets acquired. The following table summarizes activities related to the carrying value of goodwill (in thousands): Balance at December 31, 2014 40,267 Acquisitions completed during the year ended December 31, 2015 $ 16,432 Balance at December 31, 2015 $ 56,699 Acquisitions completed during the year ended December 31, 2016 $ 474 Balance at December 31, 2016 $ 57,173 The Company performed its annual goodwill impairment test as of December 31, 2016 . The Company determined that the consolidated business is represented by a single reporting unit and concluded that it was more likely than not that the fair value of the reporting unit was greater than its carrying amount. As a result, the two-step goodwill impairment test was not required, and no impairments of goodwill were recognized during the year ended December 31, 2016 .

ACQUIRED INTANGIBLE ASSETS

ACQUIRED INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
ACQUIRED INTANGIBLE ASSETS	ACQUIRED INTANGIBLE ASSETS The following table presents the detail of acquired intangible assets as of the periods presented (in thousands): Balance at December 31, 2016 Cost Accumulated Amortization Net Patents $ 1,285 $ (454 ) $ 831 Technology Assets 29,075 (14,702 ) 14,373 Customer Assets 7,745 (3,657 ) 4,088 Total $ 38,105 $ (18,813 ) $ 19,292 Balance at December 31, 2015 Cost Accumulated Amortization Net Patents $ 1,285 $ (348 ) $ 937 Technology Assets 28,645 (6,644 ) 22,001 Customer Assets 6,645 (2,807 ) 3,838 Total $ 36,575 $ (9,799 ) $ 26,776 The weighted average amortization periods for acquired patents, acquired technology, and customer intangible assets are approximately 13 years , 3 years , and 7 years , respectively. Amortization expense associated with other intangible assets was $9.0 million , $7.5 million , and $2.1 million for the years ended December 31, 2016 , 2015 , and 2014 , respectively. The total estimated annual future amortization expense of these intangible assets as of December 31, 2016 , are as follows (in thousands): 2017 $ 7,380 2018 5,881 2019 3,097 2020 1,140 2021 696 Thereafter 1,098 Total $ 19,292

OTHER CONSOLIDATED BALANCE SHEE

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT)	OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) Other Current Assets The following table presents the detail of other current assets (in thousands): December 31, December 31, Inventory $ 13,724 $ 11,864 Accounts receivable 6,191 4,808 Prepaid expenses 7,365 7,101 Deferred magstripe reader costs 3,911 4,018 Tenant improvement reimbursement receivable 1,189 1,788 Deferred hardware costs 4,546 1,709 Processing costs receivable 8,593 7,847 Other 10,812 2,312 Total $ 56,331 $ 41,447 Accrued Expenses The following table presents the detail of accrued expenses (in thousands): December 31, December 31, Accrued hardware costs $ 3,148 $ 11,622 Processing costs payable 9,655 11,417 Accrued professional fees 5,788 7,642 Accrued payroll 5,799 2,660 Accrued marketing 3,972 2,443 Other accrued liabilities 11,181 8,617 Total $ 39,543 $ 44,401 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): December 31, December 31, Settlements payable $ 51,151 $ 13,105 Employee early exercised stock options 674 2,141 Accrued redemptions 1,628 1,066 Current portion of deferred rent 2,862 2,393 Deferred revenue 5,407 6,623 Other 11,901 3,617 Total $ 73,623 $ 28,945 OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) Other Non-Current Assets The following table presents the detail of other non-current assets (in thousands): December 31, December 31, Deposits $ 1,775 $ 1,993 Deferred tax assets 306 188 Other 1,113 1,645 Total $ 3,194 $ 3,826 Other Non-Current Liabilities The following table presents the detail of other non-current liabilities (in thousands): December 31, December 31, Deferred rent $ 23,119 $ 25,543 Employee early exercised stock options 66 1,128 Deferred tax liabilities 476 299 Statutory liabilities 29,497 25,492 Other 4,587 60 Total $ 57,745 $ 52,522

OTHER CONSOLIDATED BALANCE SH17

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT)	OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) Other Current Assets The following table presents the detail of other current assets (in thousands): December 31, December 31, Inventory $ 13,724 $ 11,864 Accounts receivable 6,191 4,808 Prepaid expenses 7,365 7,101 Deferred magstripe reader costs 3,911 4,018 Tenant improvement reimbursement receivable 1,189 1,788 Deferred hardware costs 4,546 1,709 Processing costs receivable 8,593 7,847 Other 10,812 2,312 Total $ 56,331 $ 41,447 Accrued Expenses The following table presents the detail of accrued expenses (in thousands): December 31, December 31, Accrued hardware costs $ 3,148 $ 11,622 Processing costs payable 9,655 11,417 Accrued professional fees 5,788 7,642 Accrued payroll 5,799 2,660 Accrued marketing 3,972 2,443 Other accrued liabilities 11,181 8,617 Total $ 39,543 $ 44,401 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): December 31, December 31, Settlements payable $ 51,151 $ 13,105 Employee early exercised stock options 674 2,141 Accrued redemptions 1,628 1,066 Current portion of deferred rent 2,862 2,393 Deferred revenue 5,407 6,623 Other 11,901 3,617 Total $ 73,623 $ 28,945 OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) Other Non-Current Assets The following table presents the detail of other non-current assets (in thousands): December 31, December 31, Deposits $ 1,775 $ 1,993 Deferred tax assets 306 188 Other 1,113 1,645 Total $ 3,194 $ 3,826 Other Non-Current Liabilities The following table presents the detail of other non-current liabilities (in thousands): December 31, December 31, Deferred rent $ 23,119 $ 25,543 Employee early exercised stock options 66 1,128 Deferred tax liabilities 476 299 Statutory liabilities 29,497 25,492 Other 4,587 60 Total $ 57,745 $ 52,522

DEBT

DEBT	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
DEBT	DEBT In November 2015 , the Company entered into a revolving credit agreement with certain lenders, which extinguished the prior revolving credit agreement and provided for a $375.0 million revolving secured credit facility maturing in November 2020 . This revolving credit agreement is secured by certain tangible and intangible assets. Loans under the credit facility bear interest, at the Company’s option of (i) a base rate based on the highest of the prime rate, the federal funds rate plus 0.50% and an adjusted LIBOR rate for a one-month interest period in each case plus a margin ranging from 0.00% to 1.00% , or (ii) an adjusted LIBOR rate plus a margin ranging from 1.00% to 2.00% . This margin is determined based on the Company’s total leverage ratio for the preceding four fiscal quarters. The Company is obligated to pay other customary fees for a credit facility of this size and type including an annual administrative agent fee of $0.1 million and an unused commitment fee of 0.15% . To date no funds were drawn under the credit facility, with $375.0 million remaining available. The Company paid $0.6 million and $0.5 million in unused commitment fees during the years ended December 31, 2016 and 2015, respectively.

ACCRUED TRANSACTION LOSSES

ACCRUED TRANSACTION LOSSES	12 Months Ended
	Dec. 31, 2016
Product Warranties Disclosures [Abstract]
ACCRUED TRANSACTION LOSSES	ACCRUED TRANSACTION LOSSES The Company is exposed to transaction losses due to chargebacks as a result of fraud or uncollectibility. The following table summarizes the activities of the Company’s reserve for transaction losses (in thousands): Year Ended December 31, 2016 2015 2014 Accrued transaction losses, beginning of the year $ 17,176 $ 8,452 $ 7,488 Provision for transaction losses 50,819 43,379 18,478 Charge-offs and recoveries to accrued transaction losses (47,931 ) (34,655 ) (17,514 ) Accrued transaction losses, end of the year $ 20,064 $ 17,176 $ 8,452

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The domestic and foreign components of loss before income taxes are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Domestic $ (145,499 ) $ (157,229 ) $ (139,675 ) Foreign (24,174 ) (18,842 ) (12,978 ) Loss before income taxes $ (169,673 ) $ (176,071 ) $ (152,653 ) The components of the provision for income taxes are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Current: Federal $ 63 $ 1,662 $ 2,746 State 527 836 531 Foreign 1,269 1,222 827 Total current provision for income taxes 1,859 3,720 4,104 Deferred: Federal 173 67 (2,503 ) State 18 11 (161 ) Foreign (133 ) (52 ) — Total deferred provision for income taxes 58 26 (2,664 ) Total provision for income taxes $ 1,917 $ 3,746 $ 1,440 The following is a reconciliation of the statutory federal income tax rate to the Company's effective tax rate: Balance at December 31, 2016 2015 2014 Tax at federal statutory rate 34.0 % 34.0 % 34.0 % State taxes, net of federal benefit (0.1 ) (0.2 ) (0.1 ) Foreign rate differential (2.4 ) (1.8 ) (1.5 ) Nondeductible expenses (3.3 ) (3.3 ) (1.8 ) Credits 8.5 8.2 2.7 Other items (0.4 ) (0.4 ) 0.7 Change in valuation allowance (37.4 ) (38.6 ) (35.0 ) Total (1.1 )% (2.1 )% (1.0 )% The tax effects of temporary differences and related deferred tax assets and liabilities are as follows (in thousands): Balance at December 31, 2016 2015 2014 Deferred tax assets: Capitalized costs $ 61,897 $ 67,051 $ 28,102 Accrued expenses 29,421 27,964 19,714 Net operating loss carryforwards 65,507 36,633 54,528 Tax credit carryforwards 38,927 25,349 11,662 Property, equipment and intangible assets 5,721 — — Share-based compensation 52,091 36,689 13,153 Other 1,640 1,469 542 Total deferred tax assets 255,204 195,155 127,701 Valuation allowance (254,898 ) (195,103 ) (125,368 ) Total deferred tax assets, net of valuation allowance 306 52 2,333 Deferred tax liabilities: Property, equipment and intangible assets (476 ) (163 ) (2,333 ) Total deferred tax liabilities (476 ) (163 ) (2,333 ) Net deferred tax liabilities $ (170 ) $ (111 ) $ — Realization of deferred tax assets is dependent upon the generation of future taxable income, the timing and amount of which are uncertain. Due to the history of losses generated in the U.S. and certain foreign jurisdictions, the Company believes that it is more likely than not that its deferred tax assets in these jurisdictions will not be realized as of December 31, 2016 . Accordingly, the Company retained a full valuation allowance on its deferred tax assets in these jurisdictions. The amount of deferred tax assets considered realizable in future periods may change as management continues to reassess the underlying factors it uses in estimating future taxable income. The valuation allowance increased by approximately $59.8 million , $69.7 million , and $50.5 million during the years ended December 31, 2016 , 2015 , and 2014 , respectively. As of December 31, 2016 , the Company had $261.1 million of federal, $272.4 million of state, and $76.2 million of foreign net operating loss carryforwards, which will begin to expire in 2035 for federal and 2021 for state tax purposes. The foreign net operating loss carryforwards do not expire. The benefit of stock options will only be recorded to stockholders’ equity when cash taxes payable is reduced. As of December 31, 2016 , approximately $252.8 million of net operating loss is attributable to certain employee stock option deductions. This amount will be credited to stockholders’ equity when it is realized on the tax return. As of December 31, 2016 , the Company had $26.7 million of federal, $17.9 million of state, and $0.7 million of Canadian research credit carryforwards. The federal credit carryforward will begin to expire in 2029, the state credit carryforward has no expiration date, and the Canadian credit carryforward will begin to expire in 2035. The Company also has a federal AMT credit carryforward of $2.6 million that has no expiration date and California Enterprise Zone credit carryforwards of $2.7 million , which will begin to expire in 2023. Utilization of the net operating loss carryforwards and credits may be subject to annual limitations due to the ownership change limitations provided by the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitations may result in the expiration of net operating losses and credits before they are able to be utilized. The Company does not expect any previous ownership changes, as defined under Section 382 and 383 of the Internal Revenue Code, to result in a limitation that will reduce the total amount of net operating loss carryforwards and credits that can be utilized. As of December 31, 2016 , the unrecognized tax benefit was $92.1 million , of which $2.8 million would impact the annual effective tax rate if recognized and the remainder of which would result in a corresponding adjustment to the valuation allowance. A reconciliation of the beginning and ending amount of unrecognized tax benefit is presented below (in thousands): Year Ended December 31, 2016 2015 2014 Balance at the beginning of the year $ 90,372 $ 78,031 $ 14,152 Gross increases and decreases related to prior period tax positions 5,190 — 26,690 Gross increases and decreases related to current period tax positions (3,428 ) 12,341 37,189 Balance at the end of the year $ 92,134 $ 90,372 $ 78,031 The Company recognizes interest and penalties related to income tax matters as a component of income tax expense. As of December 31, 2016 , there were no significant accrued interest and penalties related to uncertain tax positions. The Company does not believe that its unrecognized tax benefits will significantly change within the next 12 months. The Company is subject to taxation in the United States and various state and foreign jurisdictions. The Company is currently under examination in Japan for tax year 2015, California for tax years 2013 and 2014, and New York State for tax years 2013, 2014, and 2015. The Company’s various tax years starting with 2009 to 2016 remain open in various taxing jurisdictions. As of December 31, 2016 , the Company has not provided deferred U.S. income taxes or foreign withholding taxes on temporary differences resulting from earnings for certain non-U.S. subsidiaries, which are permanently reinvested outside the U.S. Cumulative undistributed earnings for these non-U.S. subsidiaries as of December 31, 2016 are $3.9 million . It is not practicable to determine the income tax liability that might be incurred if these earnings were to be repatriated.

STOCKHOLDER'S EQUITY

STOCKHOLDER'S EQUITY	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
STOCKHOLDER'S EQUITY	STOCKHOLDERS' EQUITY Initial Public Offering In November 2015 , the Company completed its IPO in which it issued and sold 29,700,000 shares of Class A common stock at a public offering price of $9.00 per share. The total net proceeds received from the IPO were $245.7 million after deducting underwriting discounts and commissions of $14.7 million and other offering expenses of approximately $6.9 million . Convertible Preferred Stock As of December 31, 2016 , the Company is authorized to issue 100,000,000 shares of preferred stock, with a $0.0000001 par value. No shares of preferred stock are outstanding as of December 31, 2016 . Deemed Dividend on Series E Preferred Stock On November 24, 2015, upon the closing of the IPO, certain holders of Series E preferred stock were issued an incremental 10,299,696 shares of Class B common stock pursuant to the Company's Restated Certificate of Incorporation dated as of September 8, 2014, as amended (the 2014 Certificate). The 2014 Certificate allowed for an adjustment to the Series E original conversion price based on a prescribed formula upon the Company's IPO. The conversion of the Series E preferred stock resulted in a beneficial conversion feature, analogous to a deemed dividend. The beneficial conversion feature was calculated as the difference between fair value of the Company's common stock ultimately issued, based on the commitment date fair value of the Company's common stock, and the initial proceeds received for the Series E preferred stock. As a result, the Company recorded a one-time $32.2 million deemed stock dividend that resulted in an increase to net loss to arrive at net loss attributable to common stockholders. Common Stock The Company has authorized the issuance of Class A common stock and Class B common stock. Holders of the Company's Class A common stock and Class B common stock are entitled to dividends when, as and if, declared by the Company's board of directors, subject to the rights of the holders of all classes of stock outstanding having priority rights to dividends. As of December 31, 2016 , the Company did not declare any dividends. Holders of shares of Class A common stock are entitled to one vote per share, while holders of shares of Class B common stock are entitled to ten votes per share. Shares of the Company's Class B common stock are convertible into an equivalent number of shares of its Class A common stock and generally convert into shares of its Class A common stock upon transfer. Class A common stock and Class B common stock are referred to as common stock throughout these Notes to the Consolidated Financial Statements, unless otherwise noted. The holders of Class A common stock and Class B common stock have no preemptive or other subscription rights and there are no redemption or sinking fund provisions with respect to such shares. As of December 31, 2016 , the Company was authorized to issue 1,000,000,000 shares of Class A common stock and 500,000,000 shares of Class B common stock, each with a par value of $0.0000001 per share. As of December 31, 2016 , the Company had outstanding 198,746,620 shares of Class A common stock and 165,800,756 shares of Class B common stock, each with a par value of $0.0000001 per share. Warrants On August 7, 2012, the Company entered into a processing agreement with Starbucks and issued warrants to purchase 15,761,575 shares of common stock that would become exercisable if certain performance conditions, specified in the agreement as subsequently amended between 2012 and 2015, were achieved. In 2015, warrants to purchase 6,304,620 shares of common stock were canceled. As of December 31, 2016 , the Company had outstanding warrants to purchase an aggregate of 9,456,955 shares of its capital stock, with a weighted average exercise price of approximately $11.01 per share. Stock Plans The Company maintains two share-based employee compensation plans: the 2009 Stock Option Plan (2009 Plan) and the 2015 Equity Incentive Plan (2015 Plan). The 2015 Plan serves as the successor to its 2009 Plan. The 2015 Plan became effective as of November 17, 2015. Outstanding awards under the 2009 Plan continue to be subject to the terms and conditions of the 2009 Plan. Under the 2015 Plan, shares of common stock are reserved for the issuance of incentive stock options (ISOs), non-statutory stock options (NSOs), restricted stock awards, RSUs, performance shares and stock bonuses to qualified employees, directors and consultants. The shares may be granted at a price per share not less than the fair market value at the date of grant. Initially, 30,000,000 shares were reserved under the 2015 Plan and any shares subject to options or other similar awards granted under the 2009 Plan that expire, are forfeited, are repurchased by the Company or otherwise terminate unexercised will become available under the 2015 Plan. The number of shares available for issuance under the 2015 Plan will be increased on the first day of each fiscal year, in an amount equal to the least of (i) 40,000,000 shares, (ii) 5% of the outstanding shares on the last day of the immediately preceding fiscal year, or (iii) such number of shares determined by the Company’s board of directors. As of December 31, 2016 , the total number of options and RSUs outstanding under the 2015 Plan was 19,295,512 million shares, and 36,282,753 million shares were available for future issuance. Under the 2009 Plan, shares of common stock are reserved for the issuance of ISOs or NSOs to eligible participants. The options may be granted at a price per share not less than the fair market value at the date of grant. Options granted generally vest over a four -year term from the date of grant, at a rate of 25% after one year, then monthly on a straight-line basis thereafter. Generally, options granted are exercisable for up to 10 years from the date of grant. The Plan allows for early exercise of employee stock options whereby the option holder is allowed to exercise prior to vesting. Any unvested shares are subject to repurchase by the Company at their original exercise prices. As of December 31, 2016 , the total number of options and RSUs outstanding under the 2009 Plan was 69,409,441 million shares. No additional shares will be issued under 2009 Plan, effective November 17, 2015. In January 2015, the Company’s Chief Executive Officer contributed 5,068,238 shares of common stock back to the Company for no consideration. The purpose of the contribution was to retire such shares in order to offset stock ownership dilution to existing investors in connection with future issuances under the 2009 Plan. A summary of stock option activity for the year ended December 31, 2016 is as follows (in thousands, except share and per share data): Number of stock options outstanding Weighted Weighted Aggregate Balance at December 31, 2015 107,515,554 $ 6.99 7.87 $ 656,194 Granted 1,767,320 13.49 Exercised (24,328,414 ) 3.39 Forfeited and canceled (11,692,898 ) 10.98 Balance at December 31, 2016 73,261,562 $ 7.70 7.28 $ 443,711 Options vested and expected to vest at December 31, 2016 69,467,073 $ 7.51 6.95 $ 433,756 Options exercisable at December 31, 2016 69,936,089 $ 7.54 7.19 $ 434,962 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. Aggregate intrinsic value for stock options exercised through December 31, 2016 , 2015 and 2014 was $202.6 million , $49.8 million and $47.8 million , respectively. The total weighted average grant-date fair value of options granted was $5.80 , $5.87 and $3.84 per share for the years ended December 31, 2016 , 2015 and 2014 , respectively. Restricted Stock Activity The Company issues restricted stock units (RSUs) under the 2015 Plan, which typically vest over a term of four years. On December 18, 2015, the Company granted an aggregate of 1,854,145 RSUs, which vested within one year of their grant date. Activity related to RSUs during the year ended December 31, 2016 is set forth below: Number of Weighted Unvested at December 31, 2015 3,632,765 $ 13.14 Granted 17,060,055 12.08 Vested (3,392,726 ) 12.58 Forfeited (1,856,703 ) 13.15 Unvested at December 31, 2016 15,443,391 $ 12.09 Employee Stock Purchase Plan On November 17, 2015 , the Company’s 2015 Employee Stock Purchase Plan (ESPP) became effective. 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 ESPP provides for 12 -month offering periods. The offering periods are scheduled to start on the first trading day on or after May 15 and November 15 of each year, except for the first offering period, which commenced on November 19, 2015 and ended on November 15, 2016. Each offering period includes two purchase periods, which begin on the first trading day on or after November 15 and May 15, and ending on the last trading day on or before May 15 and November 15, respectively. 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 the last trading day of the purchase period. The number of shares available for sale under the ESPP will be increased annually on the first day of each fiscal year, equal to the least of (i) 8,400,000 million shares, (ii) 1% of the outstanding shares of the Company’s common stock as of the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by the administrator. As of December 31, 2016 , 1,852,900 shares had been purchased under the ESPP and 5,696,594 shares were available for future issuance under the ESPP. The Company recorded $5.1 million and $0.7 million of share-based compensation expense related to the ESPP during the year ended December 31, 2016 and 2015 , respectively. Share-Based Compensation The fair value of RSUs is based on the market value of the Company's common stock on grant date. The fair value of stock options and employee stock purchase plan shares granted to employees is estimated on the date of grant using the Black-Scholes-Merton option valuation model. This share-based compensation expense valuation model requires the Company to make assumptions and judgments regarding the variables used in the calculation. These variables include the expected term (weighted average period of time that the options granted are expected to be outstanding), the expected volatility of the Company’s stock, expected risk-free interest rate, expected dividends, and the estimated forfeitures of unvested stock options. To the extent actual forfeiture results differ from the estimates, the difference will be recorded as a cumulative adjustment in the period estimates are revised. The Company uses the simplified calculation of expected term, as the Company does not have sufficient historical data to use any other method to estimate expected term. Expected volatility is based on an average of the historical volatilities of the common stock of several entities with characteristics similar to those of the Company. The expected risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. Expected forfeitures are based on the Company’s historical experience. Share-based compensation expense is recorded net of estimated forfeitures on a straight-line basis over the requisite service period. The fair value of stock options granted to non-employees, including consultants, is initially measured upon the date of grant and remeasured over the vesting period using the same methodology described above. These non-employees provide service to the Company on an ongoing basis, therefore, the performance commitment for each non-employee grant is not considered probable until the award is earned over time. The expected term for non-employee grants is the contractual term and share-based compensation expense is recognized on a straight-line basis over this term. Share-based compensation expense related to non-employees has not been material for any of the periods presented. Effective August 31, 2015 , the Company modified all of its nonstatutory stock option grants to extend the exercise term for terminated employees who have completed two years of service. During the year ended December 31, 2016 and 2015 , share-based compensation expense includes $2.6 million and $3.3 million , respectively, related to the vested portion of the impacted options as a result of the modification. The Company will incur an additional $4.2 million of share-based compensation expense over the remaining vesting periods of the impacted options. The fair value of stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2016 2015 2014 Fair value of common stock $8.37 - $15.48 $10.06 - $15.39 $7.25 - $10.06 Dividend yield — % — % — % Risk-free interest rate 1.54 % 1.73 % 1.85 % Expected volatility 42.74 % 47.68 % 46.95 % Expected term (years) 6.08 6.02 6.06 The following table summarizes the effects of share-based compensation on the Company's consolidated statements of operations (in thousands): Year Ended December 31, 2016 2015 2014 Product development $ 91,404 $ 54,738 $ 24,758 Sales and marketing 14,122 7,360 3,738 General and administrative 33,260 20,194 7,604 Total $ 138,786 $ 82,292 $ 36,100 The Company capitalized $2.8 million of share-based compensation expense related to capitalized software during the year ended December 31, 2016 . There was no similar activity during the year ended December 31, 2015 . As of December 31, 2016 , there was $257.6 million of total unrecognized compensation cost related to outstanding stock options and restricted stock awards that is expected to be recognized over a weighted average period of 2.82 years .

NET LOSS PER SHARE

NET LOSS PER SHARE	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE Basic net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. For the year ended December 31, 2015, net loss attributable to common stockholders includes the impact of the issuance of 10,299,696 shares of the Company's common stock to certain holders of Series E preferred stock, in the form of a deemed stock dividend of $ 32.2 million . Diluted loss per share is the same as basic loss per share for all years presented because the effects of potentially dilutive items were anti-dilutive given the Company’s net loss attributable to common stockholders. The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Net loss $ (171,590 ) $ (179,817 ) $ (154,093 ) Deemed dividend on Series E preferred stock — (32,200 ) — Net loss attributable to common stockholders $ (171,590 ) $ (212,017 ) $ (154,093 ) Basic shares: Weighted-average common shares outstanding 344,393 175,139 148,876 Weighted-average unvested shares (2,838 ) (4,641 ) (6,834 ) Weighted-average shares used to compute basic net loss per share 341,555 170,498 142,042 Diluted shares: Weighted-average shares used to compute diluted net loss per share 341,555 170,498 142,042 Loss per share attributable to common stockholders: Basic $ (0.50 ) $ (1.24 ) $ (1.08 ) Diluted $ (0.50 ) $ (1.24 ) $ (1.08 ) The following potential common shares 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): Year Ended December 31, 2016 2015 2014 Stock options and restricted stock units 88,705 111,148 87,471 Common stock warrants 9,457 9,544 15,762 Preferred stock warrants — — 87 Convertible preferred stock — — 135,253 Unvested shares 1,892 3,420 6,443 Employee stock purchase plan 216 172 — Total anti-dilutive securities 100,270 124,284 245,016

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Operating and Capital Leases The Company has entered into various non-cancelable operating leases for certain offices with contractual lease periods expiring between 2017 and 2025 . The Company recognized total rental expenses under operating leases of $11.3 million , $12.8 million , and $11.4 million during the years ended December 31, 2016 , 2015 , and 2014 , respectively. Future minimum lease payments under non-cancelable operating leases (with initial or remaining lease terms in excess of one year) and future minimum capital lease payments as of December 31, 2016 are as follows (in thousands): Capital Operating Year: 2017 $ 694 $ 16,639 2018 651 16,519 2019 536 15,673 2020 1 15,757 2021 — 16,172 Thereafter — 35,943 Total $ 1,882 $ 116,703 Less amount representing interest (4 ) Present value of capital lease obligations 1,878 Less current portion of capital lease obligation (691 ) Non-current portion of capital lease obligation $ 1,187 The Company recognized sublease income of $3.1 million and $0.6 million during the years ended December 31, 2016 and 2015 , respectively, under non-cancelable sublease arrangements expiring in 2018 . Litigation The Company is currently a party to, and may in the future be involved in, various litigation matters (including intellectual property litigation), legal claims, and government investigations. The Company is involved in a class action lawsuit concerning independent contractors in connection with the Company’s Caviar business. On March 19, 2015, Jeffry Levin, on behalf of a putative nationwide class, filed a lawsuit in the United States District Court for the Northern District of California against the Company’s wholly owned subsidiary, Caviar, Inc., which, as amended, alleges that Caviar misclassified Mr. Levin and other similarly situated couriers as independent contractors and, in doing so, violated various provisions of the California Labor Code and California Business and Professions Code by requiring them to pay various business expenses that should have been borne by Caviar. The Court compelled arbitration of Mr. Levin’s individual claims on November 16, 2015 and dismissed the lawsuit in its entirety with prejudice on May 2, 2016. On June 1, 2016, Mr. Levin filed a Notice of Appeal of the Court’s order compelling arbitration with the United States Court of Appeals for the Ninth Circuit. Mr. Levin filed his opening appellate brief regarding the order compelling arbitration of his individual claims on October 7, 2016. The Company filed its answering brief on December 7, 2016, and Mr. Levin filed his reply on December 21, 2016. The parties now await notice of a hearing date from the Ninth Circuit. Mr. Levin also sought an award of penalties pursuant to the Labor Code Private Attorneys General Act of 2004 (PAGA). The parties stipulated that Mr. Levin would no longer pursue this PAGA claim but that it may instead be pursued by a different courier. Subsequently, couriers Nadezhda Rosen and La’Dell Brewster filed a new PAGA-only claim in California state court on November 7, 2016. Plaintiffs claim that Caviar misclassified its couriers as independent contractors resulting in numerous violations of the California Labor Code, pursuant to which plaintiffs seek statutory penalties for those violations. The parties have stipulated to extend the time for Caviar to respond to the complaint until March 17, 2017. In February 2017, the Company participated in a mediation with the parties in these Caviar misclassification suits to explore resolution of the matters at hand; however, an agreement on all the material terms has not been reached. In addition, from time to time, the Company is involved in various other litigation matters and disputes arising in the ordinary course of business. The Company cannot at this time fairly estimate a reasonable range of exposure, if any, of the potential liability with respect to these other matters. While the Company does not believe, at this time, that any ultimate liability resulting from any of these other matters will have a material adverse effect on the Company's results of operations, financial position, or liquidity, the Company cannot give any assurance regarding the ultimate outcome of these other matters, and their resolution could be material to the Company's operating results for any particular period, depending on the level of income for the period.

SEGMENT AND GEOGRAPHICAL INFORM

SEGMENT AND GEOGRAPHICAL INFORMATION	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
SEGMENT AND GEOGRAPHICAL INFORMATION	SEGMENT AND GEOGRAPHICAL INFORMATION Operating segments are defined as components of an enterprise for which discrete financial information is available that is evaluated regularly by the chief operating decision maker (CODM) for purposes of allocating resources and evaluating financial performance. The Company’s CODM reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. As such, the Company’s operations constitute a single operating segment and one reportable segment. Revenue Revenue by geography is based on the billing addresses of the merchants. The following table sets forth revenue by geographic area (in thousands): Year Ended December 31, 2016 2015 2014 Revenue United States $ 1,643,852 $ 1,224,566 $ 825,578 International 64,869 42,552 24,614 Total net revenue $ 1,708,721 $ 1,267,118 $ 850,192 No individual country from the international markets contributed in excess of 10% of total revenue for the years ended December 31, 2016 , 2015 and 2014 . Long-Lived Assets The following table sets forth long-lived assets by geographic area (in thousands): December 31, 2016 2015 Long-lived assets United States $ 162,118 $ 168,583 International 2,675 2,114 Total long-lived assets $ 164,793 $ 170,697

SUPPLEMENTAL CASH FLOW INFORMAT

SUPPLEMENTAL CASH FLOW INFORMATION	12 Months Ended
	Dec. 31, 2016
Supplemental Cash Flow Elements [Abstract]
SUPPLEMENTAL CASH FLOW INFORMATION	SUPPLEMENTAL CASH FLOW INFORMATION The supplemental disclosures of cash flow information consist of the following (in thousands): Year Ended December 31, 2016 2015 2014 Supplemental Cash Flow Data: Cash paid for interest $ 570 $ 981 $ 940 Cash paid for income taxes 395 1,916 2,442 Supplemental disclosures of non-cash investing and financing activities: Purchases of property and equipment in accounts payable and accrued expenses 2,554 5,593 — Unpaid business acquisition purchase price 240 — — Conversion of Series A, B, C, D & E preferred stock upon initial public offering to common stock — 544,897 — Unpaid offering costs related to initial public offering — 5,530 — Deemed dividend on Series E preferred stock — 32,200 — Fair value of shares issued related to acquisitions — 35,776 59,576

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On February 24, 2017 , the Company and Starbucks entered into a Warrant Cancellation and Payment Agreement pursuant to which the Company is to pay Starbucks a cash consideration of approximately $54.8 million in return for the termination of the Warrant to Purchase Stock dated August 7, 2012 , as amended, that provides for the right to purchase an aggregate of 9,456,955 shares of the Company’s common stock.

DESCRIPTION OF BUSINESS AND S27

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) and include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, as well as related disclosure of contingent assets and liabilities. Actual results could differ from the Company’s estimates. To the extent that there are material differences between these estimates and actual results, the Company’s financial condition or operating results will be materially affected. The Company bases its estimates on past experience and other assumptions that the Company believes are reasonable under the circumstances, and the Company evaluates these estimates on an ongoing basis. Significant estimates, judgments, and assumptions in these consolidated financial statements include, but are not limited to, those related to revenue recognition, accrued transaction losses, valuation of loans held for sale, business combinations, goodwill and intangible assets, income taxes, and share-based compensation.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery of obligations to its customers has occurred, the related fees are fixed or determinable, and collectibility is reasonably assured. Revenue is generated from the following: Transaction-based revenue and Starbucks transaction-based revenue The Company charges its sellers a transaction fee for managed payments solutions that is generally calculated as a percentage of the total transaction amount processed. The Company selectively offers custom pricing for larger sellers. The Company had a processing agreement with Starbucks, for certain Starbucks-owned stores in the United States. As of December 31, 2016 , Starbucks has completed its previously announced transition to another payments solution provider. The Company recognizes the transaction fees a seller pays to the Company as revenue upon authorization of a transaction by the seller's customer's bank. Revenue is recognized net of refunds, which arise from reversals of transactions initiated by sellers. The Company acts as the merchant of record for its sellers and works directly with payment card networks and banks so that its sellers do not need to manage the complex systems, rules, and requirements of the payments industry. As the merchant of record, Square is liable for settlement of the transactions the Company processes for its sellers. The gross transaction fees collected from sellers are recognized as revenue on a gross basis as the Company is the primary obligor to the seller and is responsible for processing the payment, has latitude in establishing pricing with respect to the sellers and other terms of service, has sole discretion in selecting the third party to perform the settlement, and assumes the credit risk for the transaction processed. Subscription and services-based revenue Subscription and services-based revenue primarily consists of revenue related to services provided through software offerings or deriving from the use of underlying data. Subscription and services-based revenue is primarily generated by Square Capital, Caviar, and other software as a service. Square Capital facilitates a loan that is offered through a partnership with a Utah-chartered, member FDIC industrial bank that is generally repaid through withholding a percentage of the collections of the seller's receivables processed by the Company. During the first quarter of 2016, the Company fully transitioned from offering merchant cash advances (MCAs) to loans. The Company facilitates loans to sellers pre-qualified through an analysis of the aggregated data of the seller’s business which includes, but is not limited to, the seller’s historical processing volumes, transaction count, chargebacks, growth, and length of time as a Square customer. The loans are originated by a bank partner, from whom the Company purchases the loans obtaining all rights, title, and interest. The loans have no stated coupon rate but the seller is charged a one-time origination fee by the bank partner based upon their risk rating, which is derived primarily from processing activity. It is the Company’s intent to sell all of its rights, title, and interest in certain of these loans to third-party investors for an upfront fee when the loans are sold. The Company records the net amounts paid to the bank as the cost of the loans purchased and subsequently records a gain on sale of the loans to the third-party investors. The Company is retained by the third-party investors to service the loans and earns a servicing fee for facilitating the repayment of these receivables through its payments solutions. The Company recognizes the gain on sale of the loans to the investors as revenue upon transfer of title to investors. The Company records servicing revenue as servicing is delivered. For the loans which are not sold to third-party investors, the Company recognizes a portion of the expected seller repayments over the cost of the loans as revenue in proportion to the loan principal reduction. Caviar is a courier order management app that facilitates food delivery services for restaurants. Caviar revenue consists of seller fees charged to restaurants, delivery fees, and service fees from consumers. All fees are recognized upon delivery of the food, net of refunds. Software as a service provides the use of software on a stand-alone basis for a fee which is recognized ratably as service is provided.
Hardware revenue	Hardware revenue Hardware revenue is generated from sales of contactless and chip readers, chip card readers, Square Stand, and third-party peripherals. Hardware revenue is recorded net of returns and is recognized upon delivery of hardware to the end customer. The Company considers delivery to have occurred once title and risk of loss has been transferred to the end customer. The Company records deferred revenue when it receives payments in advance of the delivery of products.
Cost of Revenue	Cost of Revenue Transaction-based costs and Starbucks transaction-based costs Transaction-based costs and Starbucks transaction-based costs consist primarily of interchange fees set by payment card networks that are paid to the card-issuing financial institution, assessment fees paid to payment networks, fees paid to third-party payment card processors, and bank settlement fees. Contracts with third-party payment processors are typically for a term of two to four years. Subscription and services-based costs Subscription and services-based costs consist primarily of Caviar-related costs, which include payments to third-party couriers for deliveries and seller-facing equipment. Cost of revenue for other subscription and services-based costs consists primarily of the amortization related to the development of certain subscription and services-based products. Hardware costs Hardware costs consist of all product costs associated with contactless and chip readers, chip card readers, Square Stand, and third-party peripherals. Product costs include manufacturing-related overhead and personnel costs, certain royalties, packaging, and fulfillment costs.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred and included in sales and marketing expense on the consolidated statements of operations.
Share-based Compensation	Share-based Compensation Share-based compensation expense relates to stock options, restricted stock units (RSUs), and purchases under the Company’s 2015 Employee Stock Purchase Plan (ESPP) which is measured based on the grant-date fair value. The Company estimates the fair value of stock options and employee stock purchase plan shares granted to employees on the date of grant using the Black-Scholes-Merton option valuation model. The fair value of RSUs is based on the market value of the Company's common stock on grant date. The Company recognizes compensation expense net of estimated forfeitures over the vesting period of the applicable award using the straight-line method. Forfeiture rates are estimated based on historical forfeitures of share-based awards and are adjusted to reflect changes in facts and circumstances, if any. There are unvested restricted shares issued to employees of certain acquired companies. A portion of these awards is generally subject to continued post-acquisition employment, which is accounted for as post-acquisition share-based compensation expense. The shares are measured based on the grant-date fair value and recognized as compensation expense on a straight-line basis over the required service period.
Income Taxes	Income Taxes The Company reports income taxes under the asset and liability approach. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, as well as net operating loss and tax credit carryforwards. Deferred tax amounts are determined by using the enacted tax rates expected to be in effect when the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance reduces the deferred tax assets to the amount that is more likely than not to be realized. The Company uses financial projections to support its net deferred tax assets, which contain significant assumptions and estimates of future operations. If such assumptions were to differ significantly from actual future results of operations, it may have a material impact on the Company’s ability to realize its deferred tax assets. At the end of each period, the Company assesses the ability to realize the deferred tax assets. If it is more likely than not that the Company would not realize the deferred tax assets, then the Company would establish a valuation allowance for all or a portion of the deferred tax assets. The Company recognizes the effect of uncertain income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that has a greater than 50% likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to uncertain tax positions in the provision for income tax expense on the consolidated statements of operations.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments, including money market funds, with an original maturity of three months or less when purchased to be cash equivalents. As of December 31, 2016 and 2015 , restricted cash of $22.1 million and $13.5 million , respectively, is related to pledged cash deposited into savings accounts at the financial institutions that process the Company's sellers' payment transactions and as collateral pursuant to an agreement with the originating bank for the Company's loan product. The Company uses the restricted cash to secure letters of credit with the financial institution to provide collateral for cash flow timing differences in the processing of these payments. The Company has recorded this amount as a current asset on the consolidated balance sheets due to the short-term nature of these cash flow timing differences and that there is no minimum time frame during which the cash must remain restricted. As of December 31, 2016 and 2015 , the remaining restricted cash of $14.6 million and $14.7 million , respectively, is primarily related to cash deposited into money market funds that is used as collateral pursuant to multi-year lease agreements entered into in 2012 and 2014 (Note 16 ). The Company has recorded this amount as a non-current asset on the consolidated balance sheets as the terms of the related leases extend beyond one year.
Concentration of Credit Risk	Concentration of Credit Risk For the year ended December 31, 2016 , the Company had no customer who accounted for greater than 10% of total net revenue. For the years ended December 31, 2015 and 2014 , the Company had no customer other than Starbucks who accounted for greater than 10% of total net revenue. The Company terminated its relationship with Starbucks during the year ended December 31, 2016. The Company had three third-party processors that represented approximately 52% , 35% , and 10% of settlements receivable as of December 31, 2016 . The Company had three third-party processors that represented approximately 56% , 23% , and 16% of settlements receivable as of December 31, 2015 . Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities, settlements receivables, customer funds held, merchant cash advance receivables, and loans held for sale. The associated risk of concentration for cash and cash equivalents is mitigated by banking with creditworthy institutions. At certain times, amounts on deposit exceed federal deposit insurance limits. The associated risk of concentration for marketable securities is mitigated by holding a diversified portfolio of highly rated investments. Settlements receivable are amounts due from well established payment processing companies and normally take one or two business days to settle which mitigates the associated risk of concentration. The associated risk of concentration for merchant cash advance receivables and loans held for sale is mitigated by ongoing credit evaluations of the Company’s customers.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value accounting establishes a three-level hierarchy priority for disclosure of assets and liabilities recorded at fair value. The ordering of priority reflects the degree to which objective prices in external active markets are available to measure fair value. The classification of assets and liabilities within the hierarchy is based on whether the inputs to the valuation methodology used for measurement are observable or unobservable. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: • Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date. • Level 2 Inputs: Other than quoted prices included in Level 1 Inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date.
Loans Held for Sale	Loans Held for Sale The Company facilitates the offering of loans by its bank partner to sellers pre-qualified through an analysis of the aggregated data of the seller’s business which includes, but is not limited to, the seller’s historical processing volumes, transaction count, chargebacks, growth, and length of time as a Square customer. The loans are originated by a bank partner, from whom the Company purchases the loans obtaining all rights, title, and interest. Loans are classified as held for sale upon purchase, as it is the Company’s intent to sell all of its rights, title, and interest in certain of these loans to third-party investors for an agreed-upon purchase price when the loans are sold. A loan that is initially designated as held for sale may be reclassified to held for investment if and when the Company's intent for that loan changes. There have been no reclassifications made to date. Loans are recorded at the lower of cost or fair value. To determine the fair value of loans, the Company utilizes industry standard modeling, such as discounted cash flow models, to arrive at an estimate of fair value.
Settlement Receivable	Settlements Receivable Settlements receivable represents amounts due from third-party payment processors for customer transactions. Settlements receivable are typically received within one or two business days of the transaction date. No valuation allowances have been established, as funds are due from large, well-established financial institutions with no historical collections issue.
Provision for Uncollectible Receivables Related to MCAs	Provision for Uncollectible Receivables Related to MCAs Merchant cash advance receivable, net, represents the aggregate amount of advances to merchants outstanding as of the balance sheet date, net of an allowance for potential uncollectible amounts. The Company estimates the allowance based on an assessment of various factors, including historical experience, merchants’ current processing volume, and other factors that may affect the merchants’ ability to generate future receivables. Additions to the allowance are reflected in current operating results, while charges against the allowance are made when charge-offs are recognized. The additions are classified within transaction and advance losses on the consolidated statements of operations. During the first quarter of 2016, the Company had fully transitioned from offering MCAs to loans. Activity subsequent to this transition relates primarily to updates to the Company's provision estimates for historical balances, write-offs or recoveries. The Company is not exposed to losses for the merchant cash advance receivables that are sold to third-party investors in accordance with the Company’s arrangements with them.
Inventory	Inventory Inventory is comprised of contactless and chip readers, chip card readers, Square Stand, and third-party peripherals. Inventory is stated at the lower of cost (generally on a first-in, first-out basis) or market. Inventory that is obsolete or in excess of forecasted usage is written down to its estimated net realizable value based on assumptions about future demand and market conditions.
Deferred Magstripe Reader Costs	Deferred Magstripe Reader Costs The Company capitalizes the cost of its magstripe readers, which are included in other current assets on the consolidated balance sheets. The amount capitalized represents the cost of the readers, including packaging and shipping costs, held on-hand by the Company as of each consolidated balance sheet date. Once the readers are shipped to a third-party distributor or an end-customer, they are recorded as marketing expense on the consolidated statements of operations.
Property and Equipment	Property and Equipment Property and equipment are recorded at historical cost less accumulated depreciation, which is computed on a straight-line basis over the asset’s estimated useful life. The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Three years Furniture and fixtures Seven years Leasehold improvements Lesser of estimated useful life or remaining lease term When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from their respective accounts, and any gain or loss on such sale or disposal is reflected in operating expenses.
Capitalized Software	Capitalized Software The Company capitalizes certain cost incurred in developing internal-use software when capitalization requirements have been met. Costs prior to meeting the capitalization requirements are expensed as incurred. Capitalized costs are included in property and equipment, net, and amortized on a straight-lined basis over the estimated useful life of the software and included in product development costs or allocated to subscription and service-based costs on the consolidated statements of operations.
Leases	Leases The Company leases office space and equipment under non-cancellable capital and operating leases with various expiration dates. The Company records the total rent expense on a straight-line basis over the lease term. When lease agreements provide allowances for leasehold improvements, the Company capitalizes the leasehold improvement assets and recognizes the related depreciation expense on a straight-line basis over the lesser of the lease term or the estimated useful life of the asset, and reduces rent expense on a straight-line basis over the term of the lease by the amount of the allowances provided. The Company classifies the cash payments for the leasehold improvements within investing activities while reimbursements from the landlords are classified within operating activities.
Asset Retirement Obligations	The Company records a liability for the estimated fair value for any asset retirement obligation (ARO) associated with its leases, with an offsetting asset. In the determination of the fair value of AROs, the Company uses various assumptions and judgments, including such factors as the existence of a legal obligation, estimated amounts and timing of settlements, and discount and inflation rates. The liability is subsequently accreted while the asset is depreciated.
Business Combinations	Business Combinations The purchase price of an acquisition is allocated to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the acquisition dates. The excess of total consideration over the fair values of the assets acquired and the liabilities assumed is recorded as goodwill. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments would be recorded on the consolidated statements of operations.
Long-lived Assets, including Goodwill and Acquired Intangibles	Long-Lived Assets, including Goodwill and Acquired Intangibles The Company evaluates the recoverability of property and equipment and finite lived intangible assets for impairment whenever events or circumstances indicate that the carrying amounts of such assets may not be recoverable. Recoverability is measured by comparing the carrying amount of an asset or an asset group to estimate undiscounted future net cash flows expected to be generated. If the carrying amount of the long–lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values, and third–part independent appraisals, as considered necessary. For the periods presented, the Company had recorded no impairment charges. Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in a business combination. The Company performs a goodwill impairment test annually on December 31 and more frequently if events and circumstances indicate that the asset might be impaired. An impairment loss is recognized to the extent that the carrying amount exceeds the reporting unit’s fair value. The Company has the option to first assess qualitative factors to determine whether events or circumstances indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying amount and determine whether further action is needed. If, after assessing the totality of events or circumstances, the Company determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. For the periods presented, the Company had recorded no impairment charges. Acquired intangibles consist of acquired technology and customer relationships associated with various acquisitions. Acquired technology is amortized over its estimated useful life on a straight-line basis within cost of revenue. Customer relationships acquired are amortized on a straight-line basis over their estimated useful lives within operating expenses. The Company evaluates the remaining estimated useful life of its intangible assets being amortized on an ongoing basis to determine whether events and circumstances warrant a revision to the remaining period of amortization.
Customers Funds and Payables	Customer Funds Customer funds held represent cash stored by customers within the Square Cash App that the customers would later use to send money or make payments, or customer cash in transit. As of December 31, 2016 and 2015 , the Company held these stored balances as short term deposits within a bank account. Customers Payable Customers payable represents the transaction amounts, less revenue earned by the Company, owed to sellers. The payable amount comprises amounts owed to customers due to timing differences as we typically settle within one business day, amounts held by the Company in accordance with its risk management policies, and amounts held for customers who have not yet linked a bank account.
Accrued Transaction Losses	Accrued Transaction Losses The Company establishes a reserve for estimated transaction losses due to chargebacks, which represent a potential loss due to disputes between a seller and their customer or due to a fraudulent transaction. The reserve is estimated based on available data as of the reporting date, including expectations of future chargebacks, and historical trends related to loss rates. Additions to the reserve are reflected in current operating results, while charges to the reserve are made when losses are recognized. These amounts are classified within transaction and advance losses on the consolidated statements of operations.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers , and issued subsequent amendments to the initial guidance within ASU 2015-04, ASU 2016-08, ASU 2016-10, ASU 2016-12, and ASU 2016-20. The new guidance will replace all current U.S. GAAP guidance on this topic and eliminate all industry specific guidance. The core principal of this new guidance is that revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration for which the Company expects to be entitled in exchange for those goods or services. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The Company does not plan to early adopt the guidance. The guidance can be adopted either through the full retrospective approach which requires restatement of all periods presented or through a modified retrospective approach which requires a cumulative effect adjustment as of the date of adoption. The modified retrospective approach also requires additional disclosures of the impact of the new guidance to each of the financial statements line items and qualitative explanation of the significant changes between the reported results under the new revenue guidance and the previous revenue guidance. The Company plans to apply the modified retrospective approach in the year of adoption of this guidance and is currently assessing the impact that the adoption of the guidance would have on the consolidated financial statements and related disclosures. The Company is also assessing any financial reporting system changes that would be necessary to implement the new guidance. In July 2015, the FASB issued ASU No. 2015-11, Simplifying the Measurement of Inventory, as part of its simplification initiative. The current guidance requires an entity to measure inventory at the lower of cost or market. Market could be replacement cost, net realizable value, or net realizable value less an approximately normal profit margin. Under the new guidance, inventory is measured at the lower of cost and net realizable value, which would eliminate the other two options that currently exist for market replacement cost and net realizable value less an approximately normal profit margin. The amendment is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes. The new guidance eliminates the current requirement to present deferred tax assets and liabilities as current and noncurrent on the consolidated balance sheets. Instead, organizations will be required to classify all deferred tax assets and liabilities as noncurrent. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with early adoption permitted. The Company early adopted this new guidance on a prospective basis as a change in accounting policy and therefore prior periods were not retrospectively adjusted. In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities. This guidance is intended to improve the recognition, measurement, presentation, and disclosure of financial instruments. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted with certain restrictions. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases , which will require, among other items, lessees to recognize most leases as assets and liabilities on the balance sheet. Qualitative and quantitative disclosures will be enhanced to better understand the amount, timing and uncertainty of cash flows arising from leases. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with early adoption permitted. The Company does not plan to early adopt this guidance. The Company’s operating leases primarily comprise of office spaces, with the most significant leases relating to corporate headquarters in San Francisco and an office in New York. Based on the Company's initial assessment of its current leases and potential, the Company does not anticipate the adoption of this guidance to have a material impact on its operating results. The Company will continue to evaluate the impact of recording right to use assets and related liabilities on its consolidated balance sheets. In March 2016, the FASB issued ASU No. 2016-04, Recognition of Breakage for Certain Prepaid Stored-Value Products. This guidance specifies how prepaid stored-value product liabilities should be derecognized, thereby eliminating the current and potential future diversity in practice. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting , which is intended to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments , which requires measurement and recognition of expected credit losses for financial assets held. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments. This guidance addresses several specific cash flow issues with the objective of reducing the existing diversity in practice. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory , which amends existing guidance on the recognition of current and deferred income tax impacts for intra-entity asset transfers other than inventory. This standard is effective for annual periods beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The amendments in this guidance should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Restricted Cash , which provides guidance on the classification of restricted cash to be included with cash and cash equivalents when reconciling the beginning of period and end of period total amounts on the statement of cash flows. This standard is effective for annual periods beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. For the years ended December 31, 2016 , 2015 and 2014 , $36.7 million , $28.2 million and $26.3 million , respectively, of restricted cash would have been included in cash and cash equivalents in the consolidated statements of cash flows if this new guidance had been adopted as of the respective dates. In December 2016, the FASB issued ASU No. 2016-19, Technical Corrections and Improvements . The amendments cover a wide range of topics in the Accounting Standards Codification, covering differences between original guidance and the Accounting Standards Codification, guidance clarification and reference corrections, simplification and minor improvements. Most of the amendments in this update do not require transition guidance and are effective upon issuance of this update. Early adoption is permitted for the amendments that require transition guidance. The Company is currently evaluating the impact this new update may have on the consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business . The amendment seeks to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill and consolidation. This standard is effective for annual periods beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The amendments should be applied prospectively on or after the effective dates. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-03, Amendments to SEC Paragraphs Pursuant to Staff Announcements . The amendment provides guidance to the Company in relation to the disclosure of the impact that ASU 2014-09, ASU 2016-02 and ASU 2016-13 will have on the Company’s financial statements when adopted. Specifically, registrants should consider additional qualitative disclosures if the impact of an issued but not yet adopted ASU is unknown or cannot be reasonably estimated and to include a description of the effect of the accounting policies that the registrant expects. The Company has implemented this guidance within its current disclosures. In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment . This amendment modified the concept of impairment assessment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. This standard should be adopted when the Company performs its annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019, with early adoption permitted. The amendments should be applied on a prospective basis. The Company is currently evaluating the impact this new guidance may have on the consolidated financial statements.

DESCRIPTION OF BUSINESS AND S28

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Estimated Useful Lives of Property and Equipment	The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Three years Furniture and fixtures Seven years Leasehold improvements Lesser of estimated useful life or remaining lease term The following is a summary of property, equipment, and internally-developed software at cost, less accumulated depreciation and amortization (in thousands): December 31, December 31, Computer equipment $ 52,915 $ 43,531 Office furniture and equipment 10,737 9,339 Leasehold improvements 73,366 65,298 Capitalized software 24,642 14,533 Construction in process — 490 Total 161,660 133,191 Less: Accumulated depreciation and amortization (73,332 ) (45,969 ) Property and equipment, net $ 88,328 $ 87,222

FAIR VALUE OF FINANCIAL INSTR29

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of the Fair Value of Financial Instruments	The Company’s financial assets and liabilities that are measured at fair value on a recurring basis are classified as follows (in thousands): December 31, 2016 December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash and cash equivalents: Money market funds $ 207,168 $ — $ — $ 337,234 $ — $ — Commercial paper — 7,496 — — — — Municipal securities — 1,000 — — — — Short-term securities: U.S. agency securities — 9,055 — — — — Corporate bonds — 6,980 — — — — Commercial paper — 17,298 — — — — Municipal securities — 8,028 — U.S. government securities 18,540 — — — — — Long-term securities: U.S. agency securities — 3,502 — — — — Corporate bonds — 12,914 — — — — Municipal securities — 2,492 — — — — U.S. government securities 8,458 — — — — — Total $ 234,166 $ 68,765 $ — $ 337,234 $ — $ — A summary of loans disclosed at fair value on a recurring basis is as follows (in thousands): December 31, 2016 Carrying Value Fair Value (Level 3) Loans held for sale $ 42,144 $ 42,633 Total $ 42,144 $ 42,633

INVESTMENTS (Tables)

INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Short-term and Long-term Investments	The Company's short-term and long-term investments as of December 31, 2016 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term securities: U.S. agency securities $ 9,048 $ 7 $ — $ 9,055 Corporate bonds 17,318 — (20 ) 17,298 Commercial paper 6,980 — — 6,980 Municipal securities 8,037 — (9 ) 8,028 U.S. government securities 18,537 3 — 18,540 Total $ 59,920 $ 10 $ (29 ) $ 59,901 Long-term securities: U.S. agency securities $ 3,502 $ — $ — $ 3,502 Corporate bonds 12,939 — (25 ) 12,914 Municipal securities 2,505 — (13 ) 2,492 U.S. government securities 8,478 — (20 ) 8,458 Total $ 27,424 $ — $ (58 ) $ 27,366
Investments Classified by Contractual Maturity Date	The contractual maturities of the Company's short-term and long-term investments as of December 31, 2016 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 59,920 $ 59,901 Due in one to five years 27,424 27,366 Total $ 87,344 $ 87,267

MERCHANT CASH ADVANCE RECEIVA31

MERCHANT CASH ADVANCE RECEIVABLE, NET (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Summary of Activities of the Company's Allowance for Uncollectible Receivables	The following table summarizes the activities of the Company’s allowance for uncollectible receivables (in thousands): Year Ended December 31, Year Ended December 31, 2016 2015 Allowance for uncollectible MCA receivables, beginning of the period $ 7,443 $ 2,431 Provision for uncollectible MCA receivables 1,159 6,240 MCA receivables charged off (4,039 ) (1,228 ) Allowance for uncollectible MCA receivables, end of the period $ 4,563 $ 7,443

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Summary of Property, Equipment and Internally-Developed Software	The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Three years Furniture and fixtures Seven years Leasehold improvements Lesser of estimated useful life or remaining lease term The following is a summary of property, equipment, and internally-developed software at cost, less accumulated depreciation and amortization (in thousands): December 31, December 31, Computer equipment $ 52,915 $ 43,531 Office furniture and equipment 10,737 9,339 Leasehold improvements 73,366 65,298 Capitalized software 24,642 14,533 Construction in process — 490 Total 161,660 133,191 Less: Accumulated depreciation and amortization (73,332 ) (45,969 ) Property and equipment, net $ 88,328 $ 87,222

GOODWILL (Tables)

GOODWILL (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Activities Related to the Carrying Value of Goodwill	The following table summarizes activities related to the carrying value of goodwill (in thousands): Balance at December 31, 2014 40,267 Acquisitions completed during the year ended December 31, 2015 $ 16,432 Balance at December 31, 2015 $ 56,699 Acquisitions completed during the year ended December 31, 2016 $ 474 Balance at December 31, 2016 $ 57,173

ACQUIRED INTANGIBLE ASSETS (Tab

ACQUIRED INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Detail of Acquired Intangible Assets	The following table presents the detail of acquired intangible assets as of the periods presented (in thousands): Balance at December 31, 2016 Cost Accumulated Amortization Net Patents $ 1,285 $ (454 ) $ 831 Technology Assets 29,075 (14,702 ) 14,373 Customer Assets 7,745 (3,657 ) 4,088 Total $ 38,105 $ (18,813 ) $ 19,292 Balance at December 31, 2015 Cost Accumulated Amortization Net Patents $ 1,285 $ (348 ) $ 937 Technology Assets 28,645 (6,644 ) 22,001 Customer Assets 6,645 (2,807 ) 3,838 Total $ 36,575 $ (9,799 ) $ 26,776
Estimated Annual Future Amortization Expense of Intangible Assets	The total estimated annual future amortization expense of these intangible assets as of December 31, 2016 , are as follows (in thousands): 2017 $ 7,380 2018 5,881 2019 3,097 2020 1,140 2021 696 Thereafter 1,098 Total $ 19,292

OTHER CONSOLIDATED BALANCE SH35

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) (Tables)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Current Assets	The following table presents the detail of other current assets (in thousands): December 31, December 31, Inventory $ 13,724 $ 11,864 Accounts receivable 6,191 4,808 Prepaid expenses 7,365 7,101 Deferred magstripe reader costs 3,911 4,018 Tenant improvement reimbursement receivable 1,189 1,788 Deferred hardware costs 4,546 1,709 Processing costs receivable 8,593 7,847 Other 10,812 2,312 Total $ 56,331 $ 41,447
Accrued Expenses	The following table presents the detail of accrued expenses (in thousands): December 31, December 31, Accrued hardware costs $ 3,148 $ 11,622 Processing costs payable 9,655 11,417 Accrued professional fees 5,788 7,642 Accrued payroll 5,799 2,660 Accrued marketing 3,972 2,443 Other accrued liabilities 11,181 8,617 Total $ 39,543 $ 44,401
Other Current Liabilities	The following table presents the detail of other current liabilities (in thousands): December 31, December 31, Settlements payable $ 51,151 $ 13,105 Employee early exercised stock options 674 2,141 Accrued redemptions 1,628 1,066 Current portion of deferred rent 2,862 2,393 Deferred revenue 5,407 6,623 Other 11,901 3,617 Total $ 73,623 $ 28,945

OTHER CONSOLIDATED BALANCE SH36

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) (Tables)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Non-Current Assets	The following table presents the detail of other non-current assets (in thousands): December 31, December 31, Deposits $ 1,775 $ 1,993 Deferred tax assets 306 188 Other 1,113 1,645 Total $ 3,194 $ 3,826
Other Non-Current Liabilities	The following table presents the detail of other non-current liabilities (in thousands): December 31, December 31, Deferred rent $ 23,119 $ 25,543 Employee early exercised stock options 66 1,128 Deferred tax liabilities 476 299 Statutory liabilities 29,497 25,492 Other 4,587 60 Total $ 57,745 $ 52,522

ACCRUED TRANSACTION LOSSES (Tab

ACCRUED TRANSACTION LOSSES (Tables)	12 Months Ended
	Dec. 31, 2016
Product Warranties Disclosures [Abstract]
Summary of Reserve for Transaction Losses	The following table summarizes the activities of the Company’s reserve for transaction losses (in thousands): Year Ended December 31, 2016 2015 2014 Accrued transaction losses, beginning of the year $ 17,176 $ 8,452 $ 7,488 Provision for transaction losses 50,819 43,379 18,478 Charge-offs and recoveries to accrued transaction losses (47,931 ) (34,655 ) (17,514 ) Accrued transaction losses, end of the year $ 20,064 $ 17,176 $ 8,452

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Domestic and Foreign Components of Loss Before Income Taxes	The domestic and foreign components of loss before income taxes are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Domestic $ (145,499 ) $ (157,229 ) $ (139,675 ) Foreign (24,174 ) (18,842 ) (12,978 ) Loss before income taxes $ (169,673 ) $ (176,071 ) $ (152,653 )
Components of Provision for Income Taxes	The components of the provision for income taxes are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Current: Federal $ 63 $ 1,662 $ 2,746 State 527 836 531 Foreign 1,269 1,222 827 Total current provision for income taxes 1,859 3,720 4,104 Deferred: Federal 173 67 (2,503 ) State 18 11 (161 ) Foreign (133 ) (52 ) — Total deferred provision for income taxes 58 26 (2,664 ) Total provision for income taxes $ 1,917 $ 3,746 $ 1,440
Reconciliation of Statutory Federal Income Tax Rate to Company's Effective Tax Rate	The following is a reconciliation of the statutory federal income tax rate to the Company's effective tax rate: Balance at December 31, 2016 2015 2014 Tax at federal statutory rate 34.0 % 34.0 % 34.0 % State taxes, net of federal benefit (0.1 ) (0.2 ) (0.1 ) Foreign rate differential (2.4 ) (1.8 ) (1.5 ) Nondeductible expenses (3.3 ) (3.3 ) (1.8 ) Credits 8.5 8.2 2.7 Other items (0.4 ) (0.4 ) 0.7 Change in valuation allowance (37.4 ) (38.6 ) (35.0 ) Total (1.1 )% (2.1 )% (1.0 )%
Tax Effects of Temporary Differences and Related Deferred Tax Assets and Liabilities	The tax effects of temporary differences and related deferred tax assets and liabilities are as follows (in thousands): Balance at December 31, 2016 2015 2014 Deferred tax assets: Capitalized costs $ 61,897 $ 67,051 $ 28,102 Accrued expenses 29,421 27,964 19,714 Net operating loss carryforwards 65,507 36,633 54,528 Tax credit carryforwards 38,927 25,349 11,662 Property, equipment and intangible assets 5,721 — — Share-based compensation 52,091 36,689 13,153 Other 1,640 1,469 542 Total deferred tax assets 255,204 195,155 127,701 Valuation allowance (254,898 ) (195,103 ) (125,368 ) Total deferred tax assets, net of valuation allowance 306 52 2,333 Deferred tax liabilities: Property, equipment and intangible assets (476 ) (163 ) (2,333 ) Total deferred tax liabilities (476 ) (163 ) (2,333 ) Net deferred tax liabilities $ (170 ) $ (111 ) $ —
Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefit	A reconciliation of the beginning and ending amount of unrecognized tax benefit is presented below (in thousands): Year Ended December 31, 2016 2015 2014 Balance at the beginning of the year $ 90,372 $ 78,031 $ 14,152 Gross increases and decreases related to prior period tax positions 5,190 — 26,690 Gross increases and decreases related to current period tax positions (3,428 ) 12,341 37,189 Balance at the end of the year $ 92,134 $ 90,372 $ 78,031

STOCKHOLDER'S EQUITY (Tables)

STOCKHOLDER'S EQUITY (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Summary of Stock Option Activity	A summary of stock option activity for the year ended December 31, 2016 is as follows (in thousands, except share and per share data): Number of stock options outstanding Weighted Weighted Aggregate Balance at December 31, 2015 107,515,554 $ 6.99 7.87 $ 656,194 Granted 1,767,320 13.49 Exercised (24,328,414 ) 3.39 Forfeited and canceled (11,692,898 ) 10.98 Balance at December 31, 2016 73,261,562 $ 7.70 7.28 $ 443,711 Options vested and expected to vest at December 31, 2016 69,467,073 $ 7.51 6.95 $ 433,756 Options exercisable at December 31, 2016 69,936,089 $ 7.54 7.19 $ 434,962
Activity Related to RSUs	Activity related to RSUs during the year ended December 31, 2016 is set forth below: Number of Weighted Unvested at December 31, 2015 3,632,765 $ 13.14 Granted 17,060,055 12.08 Vested (3,392,726 ) 12.58 Forfeited (1,856,703 ) 13.15 Unvested at December 31, 2016 15,443,391 $ 12.09
Weighted Average Assumptions Used to Determine the Fair Value of Stock Options	The fair value of stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2016 2015 2014 Fair value of common stock $8.37 - $15.48 $10.06 - $15.39 $7.25 - $10.06 Dividend yield — % — % — % Risk-free interest rate 1.54 % 1.73 % 1.85 % Expected volatility 42.74 % 47.68 % 46.95 % Expected term (years) 6.08 6.02 6.06
Effects of Share-Based Compensation on Consolidated Statements of Operations	The following table summarizes the effects of share-based compensation on the Company's consolidated statements of operations (in thousands): Year Ended December 31, 2016 2015 2014 Product development $ 91,404 $ 54,738 $ 24,758 Sales and marketing 14,122 7,360 3,738 General and administrative 33,260 20,194 7,604 Total $ 138,786 $ 82,292 $ 36,100

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Calculation of Basic and Diluted Net Loss Per Share	The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Net loss $ (171,590 ) $ (179,817 ) $ (154,093 ) Deemed dividend on Series E preferred stock — (32,200 ) — Net loss attributable to common stockholders $ (171,590 ) $ (212,017 ) $ (154,093 ) Basic shares: Weighted-average common shares outstanding 344,393 175,139 148,876 Weighted-average unvested shares (2,838 ) (4,641 ) (6,834 ) Weighted-average shares used to compute basic net loss per share 341,555 170,498 142,042 Diluted shares: Weighted-average shares used to compute diluted net loss per share 341,555 170,498 142,042 Loss per share attributable to common stockholders: Basic $ (0.50 ) $ (1.24 ) $ (1.08 ) Diluted $ (0.50 ) $ (1.24 ) $ (1.08 )
Potential Common Shares Excluded from the Calculation of Diluted Net Loss Per Share Attributable to Common Stockholders	The following potential common shares 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): Year Ended December 31, 2016 2015 2014 Stock options and restricted stock units 88,705 111,148 87,471 Common stock warrants 9,457 9,544 15,762 Preferred stock warrants — — 87 Convertible preferred stock — — 135,253 Unvested shares 1,892 3,420 6,443 Employee stock purchase plan 216 172 — Total anti-dilutive securities 100,270 124,284 245,016

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments Under Operating and Capital Leases	Future minimum lease payments under non-cancelable operating leases (with initial or remaining lease terms in excess of one year) and future minimum capital lease payments as of December 31, 2016 are as follows (in thousands): Capital Operating Year: 2017 $ 694 $ 16,639 2018 651 16,519 2019 536 15,673 2020 1 15,757 2021 — 16,172 Thereafter — 35,943 Total $ 1,882 $ 116,703 Less amount representing interest (4 ) Present value of capital lease obligations 1,878 Less current portion of capital lease obligation (691 ) Non-current portion of capital lease obligation $ 1,187

SEGMENT AND GEOGRAPHICAL INFO42

SEGMENT AND GEOGRAPHICAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Revenue by Geographic Area	Revenue by geography is based on the billing addresses of the merchants. The following table sets forth revenue by geographic area (in thousands): Year Ended December 31, 2016 2015 2014 Revenue United States $ 1,643,852 $ 1,224,566 $ 825,578 International 64,869 42,552 24,614 Total net revenue $ 1,708,721 $ 1,267,118 $ 850,192
Long-Lived Assets by Geographic Area	The following table sets forth long-lived assets by geographic area (in thousands): December 31, 2016 2015 Long-lived assets United States $ 162,118 $ 168,583 International 2,675 2,114 Total long-lived assets $ 164,793 $ 170,697

SUPPLEMENTAL CASH FLOW INFORM43

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures of Cash Flow Information	The supplemental disclosures of cash flow information consist of the following (in thousands): Year Ended December 31, 2016 2015 2014 Supplemental Cash Flow Data: Cash paid for interest $ 570 $ 981 $ 940 Cash paid for income taxes 395 1,916 2,442 Supplemental disclosures of non-cash investing and financing activities: Purchases of property and equipment in accounts payable and accrued expenses 2,554 5,593 — Unpaid business acquisition purchase price 240 — — Conversion of Series A, B, C, D & E preferred stock upon initial public offering to common stock — 544,897 — Unpaid offering costs related to initial public offering — 5,530 — Deemed dividend on Series E preferred stock — 32,200 — Fair value of shares issued related to acquisitions — 35,776 59,576

DESCRIPTION OF BUSINESS AND S44

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)	Jun. 08, 2016USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2016customer	Jun. 30, 2015customer	Dec. 31, 2016USD ($)customerthird_party_processor	Dec. 31, 2015USD ($)third_party_processor	Dec. 31, 2014USD ($)customer	Dec. 31, 2013USD ($)
Concentration Risk [Line Items]
Transaction, loan and advance losses					$ 51,235,000	$ 54,009,000	$ 24,081,000
Cash and cash equivalents					452,030,000	461,329,000	222,315,000	$ 166,176,000
Customer funds held					43,574,000	9,446,000
Net cash (used in) provided by operating activities					23,131,000	21,123,000	(112,379,000)
Change in cash and cash equivalents					(9,299,000)	239,014,000	56,139,000
Settlement agreement amount	$ 50,000,000
Payment for settlement agreement	$ 48,000,000
Advertising costs					58,300,000	58,300,000	45,100,000
Pledged cash					22,131,000	13,537,000
Collateral					14,584,000	14,686,000
Capitalized internally developed software					7,900,000	4,500,000	6,400,000
Amortization expense related to capitalized internally developed software					7,100,000	3,200,000	2,700,000
Asset retirement obligation					3,200,000
Asset retirement obligation, associated asset net of depreciation					$ 88,328,000	87,222,000
Measurement period for business combinations					1 year
Impairment charges					$ 0	0	0
Settlement period for customers payable					1 day
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2016-18 | Pro Forma
Concentration Risk [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents					$ 36,700,000	$ 28,200,000	$ 26,300,000
Leasehold Improvements Under Asset Retirement Obligation
Concentration Risk [Line Items]
Asset retirement obligation, associated asset net of depreciation					$ 2,600,000
Customer Concentration Risk | Net Revenue
Concentration Risk [Line Items]
Number of customers | customer			0	1	0		1
Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Number of third party processors | third_party_processor					3	3
Third Party Processor One | Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Concentration risk, percentage					52.00%	56.00%
Third Party Processor Two | Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Concentration risk, percentage					35.00%	23.00%
Third Party Processor Three | Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Concentration risk, percentage					10.00%	16.00%
Minimum
Concentration Risk [Line Items]
Contracts with third-party payment processors, period					2 years
Maximum
Concentration Risk [Line Items]
Contracts with third-party payment processors, period					4 years
Out of Period Adjustment | Restatement Adjustment
Concentration Risk [Line Items]
Transaction, loan and advance losses		$ 6,000,000
Out of Period Adjustment, Related to Three Months Ended March 31, 2016 | Restatement Adjustment
Concentration Risk [Line Items]
Transaction, loan and advance losses		500,000
Out of Period Adjustment, Related to Year Ended December 31, 2015 | Restatement Adjustment
Concentration Risk [Line Items]
Transaction, loan and advance losses		2,600,000
Out of Period Adjustment, Related to Year Ended December 31, 2014 | Restatement Adjustment
Concentration Risk [Line Items]
Transaction, loan and advance losses		1,600,000
Out of Period Adjustment, Related to Historical Periods | Restatement Adjustment
Concentration Risk [Line Items]
Transaction, loan and advance losses		$ 1,300,000
Adjustments to Cash and Cash Equivalents | Restatement Adjustment
Concentration Risk [Line Items]
Cash and cash equivalents						$ (9,500,000)
Customer funds held						9,500,000
Net cash (used in) provided by operating activities						(6,500,000)
Change in cash and cash equivalents						$ 6,500,000

DESCRIPTION OF BUSINESS AND S45

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
Capitalized software
Property, Plant and Equipment [Line Items]
Useful Life	18 months
Computer and data center equipment
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful Life	7 years

FAIR VALUE OF FINANCIAL INSTR46

FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$ 59,901	$ 0
Long-term investments	27,366	0
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	234,166	337,234
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	68,765	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	9,055	0
Long-term investments	3,502	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
Corporate bonds | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
Corporate bonds | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	6,980	0
Long-term investments	12,914	0
Corporate bonds | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	17,298	0
Commercial paper | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Municipal securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0
Long-term investments	0	0
Municipal securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	8,028
Long-term investments	2,492	0
Municipal securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0
Long-term investments	0	0
U.S. government securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	18,540	0
Long-term investments	8,458	0
U.S. government securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
U.S. government securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
Money market funds | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	207,168	337,234
Money market funds | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Money market funds | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	7,496	0
Commercial paper | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Municipal securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Municipal securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	1,000	0
Municipal securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR47

FAIR VALUE OF FINANCIAL INSTRUMENTS - Summary of Loans Disclosed at Fair Value (Details) - Fair Value, Measurements, Recurring - Level 3 $ in Thousands	Dec. 31, 2016USD ($)
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 42,144
Fair Value (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 42,633

INVESTMENTS - Short-term and L

INVESTMENTS - Short-term and Long-term Investments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 87,344
Fair Value	87,267
Gains or losses realized on the sale of investments	0
Short-term Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	59,920
Gross Unrealized Gains	10
Gross Unrealized Losses	(29)
Fair Value	59,901
Short-term Securities | U.S. agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,048
Gross Unrealized Gains	7
Gross Unrealized Losses	0
Fair Value	9,055
Short-term Securities | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,318
Gross Unrealized Gains	0
Gross Unrealized Losses	(20)
Fair Value	17,298
Short-term Securities | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,980
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	6,980
Short-term Securities | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,037
Gross Unrealized Gains	0
Gross Unrealized Losses	(9)
Fair Value	8,028
Short-term Securities | U.S. government securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,537
Gross Unrealized Gains	3
Gross Unrealized Losses	0
Fair Value	18,540
Long-term Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,424
Gross Unrealized Gains	0
Gross Unrealized Losses	(58)
Fair Value	27,366
Long-term Securities | U.S. agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,502
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	3,502
Long-term Securities | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,939
Gross Unrealized Gains	0
Gross Unrealized Losses	(25)
Fair Value	12,914
Long-term Securities | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,505
Gross Unrealized Gains	0
Gross Unrealized Losses	(13)
Fair Value	2,492
Long-term Securities | U.S. government securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,478
Gross Unrealized Gains	0
Gross Unrealized Losses	(20)
Fair Value	$ 8,458

INVESTMENTS - Maturity of Avail

INVESTMENTS - Maturity of Available for Sale Securities (Details) $ in Thousands	Dec. 31, 2016USD ($)
Amortized Cost
Due in one year or less	$ 59,920
Due in one to five years	27,424
Amortized Cost	87,344
Fair Value
Due in one year or less	59,901
Due in one to five years	27,366
Total	$ 87,267

MERCHANT CASH ADVANCE RECEIVA50

MERCHANT CASH ADVANCE RECEIVABLE, NET - Summary of Activities of the Company's Allowance for Uncollectible Receivables(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Merchant Cash Advance Receivable [Roll Forward]
Allowance for uncollectible MCA receivables, beginning of the period	$ 7,443	$ 2,431
Provision for uncollectible MCA receivables	1,159	6,240	$ 2,431
MCA receivables charged off	(4,039)	(1,228)
Allowance for uncollectible MCA receivables, end of the period	$ 4,563	$ 7,443	$ 2,431

PROPERTY AND EQUIPMENT, NET -

PROPERTY AND EQUIPMENT, NET - Summary of Property, Equipment and Internally-Developed Software (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total	$ 161,660	$ 133,191
Less: Accumulated depreciation and amortization	(73,332)	(45,969)
Property and equipment, net	88,328	87,222
Computer equipment
Property, Plant and Equipment [Line Items]
Total	52,915	43,531
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Total	10,737	9,339
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total	73,366	65,298
Capitalized software
Property, Plant and Equipment [Line Items]
Total	24,642	14,533
Construction in process
Property, Plant and Equipment [Line Items]
Total	$ 0	$ 490

PROPERTY AND EQUIPMENT, NET - N

PROPERTY AND EQUIPMENT, NET - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense on property and equipment	$ 28.7	$ 20.1	$ 16.5

ACQUISITIONS - Narrative (Deta

ACQUISITIONS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Consideration allocated to goodwill	$ 57,173,000	$ 56,699,000	$ 40,267,000
2016 Acquisition
Business Acquisition [Line Items]
Total consideration	1,600,000
Consideration allocated to intangible assets	1,100,000
Consideration allocated to goodwill	$ 500,000
2015 Acquisitions
Business Acquisition [Line Items]
Total consideration		32,000,000
Consideration allocated to intangible assets		14,900,000
Consideration allocated to goodwill		16,400,000
Consideration, cash		4,500,000
Consideration allocated to property and equipment		800,000
Consideration allocated to deferred tax liabilities		200,000
Goodwill and intangible assets generated from acquisition deductible for tax purposes		29,800,000
Acquisition-related costs		600,000
Shares of the total share consideration remaining withheld for indemnification purposes (in shares)	292,813
Total purchase consideration for acquisition of certain assets		$ 9,500,000
Purchase consideration, shares, for acquisition of certain assets (in shares)		667,133
Purchase consideration, cash, for acquisition of certain assets		$ 1,000,000
Purchase consideration allocated to intangible assets for acquisition of certain assets		9,000,000
Purchase consideration allocated to other assets for acquisition of certain assets		$ 500,000
2015 Acquisitions | Shares of Common Stock
Business Acquisition [Line Items]
Business Acquisitions, Equity Interest Issues or Issuable, Including Separately Recognized Equity Interest Issuable, Number of Shares		2,923,881
2015 Acquisitions | Non-Employee Stock Option [Member]
Business Acquisition [Line Items]
Business Acquisitions, Equity Interest Issues or Issuable, Including Separately Recognized Equity Interest Issuable, Number of Shares		26,173
Shares accounted for as post-combination compensation expense (in shares)		22,818
2014 Acquisitions
Business Acquisition [Line Items]
Total consideration			59,600,000
Consideration allocated to intangible assets			11,400,000
Consideration allocated to goodwill			39,700,000
Acquisition-related costs			500,000
Shares of the total share consideration remaining withheld for indemnification purposes (in shares)	1,291,979
Consideration allocated to tangible assets, net			8,500,000
Goodwill deductible for tax purposes			$ 0
2014 Acquisitions | Shares of Common Stock
Business Acquisition [Line Items]
Consideration (in shares)			8,552,990
2014 Acquisitions | Non-Employee Stock Option [Member]
Business Acquisition [Line Items]
Consideration (in shares)			168,834
Common Stock | 2015 Acquisitions
Business Acquisition [Line Items]
Shares accounted for as post-combination compensation expense (in shares)		355,284

GOODWILL - Summary of Activiti

GOODWILL - Summary of Activities Related to the Carrying Value of Goodwill(Details)	12 Months Ended
	Dec. 31, 2016USD ($)reporting_unit	Dec. 31, 2015USD ($)
Goodwill [Roll Forward]
Goodwill beginning balance	$ 56,699,000	$ 40,267,000
Acquisitions	474,000	16,432,000
Goodwill ending balance	57,173,000	$ 56,699,000
Impairment of goodwill	$ 0
Number of reporting units | reporting_unit	1

ACQUIRED INTANGIBLE ASSETS - D

ACQUIRED INTANGIBLE ASSETS - Detail of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 38,105	$ 36,575
Accumulated Amortization	(18,813)	(9,799)
Net	19,292	26,776
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,285	1,285
Accumulated Amortization	(454)	(348)
Net	831	937
Technology Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	29,075	28,645
Accumulated Amortization	(14,702)	(6,644)
Net	14,373	22,001
Customer Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	7,745	6,645
Accumulated Amortization	(3,657)	(2,807)
Net	$ 4,088	$ 3,838

ACQUIRED INTANGIBLE ASSETS - Na

ACQUIRED INTANGIBLE ASSETS - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 9	$ 7.5	$ 2.1
Weighted Average | Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average amortization periods	13 years
Weighted Average | Technology Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average amortization periods	3 years
Weighted Average | Customer Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average amortization periods	7 years

ACQUIRED INTANGIBLE ASSETS - Es

ACQUIRED INTANGIBLE ASSETS - Estimated Future Amortization Expense of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
2,017	$ 7,380
2,018	5,881
2,019	3,097
2,020	1,140
2,021	696
Thereafter	1,098
Net	$ 19,292	$ 26,776

OTHER CONSOLIDATED BALANCE SH58

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventory	$ 13,724	$ 11,864
Accounts receivable	6,191	4,808
Prepaid expenses	7,365	7,101
Deferred magstripe reader costs	3,911	4,018
Tenant improvement reimbursement receivable	1,189	1,788
Deferred hardware costs	4,546	1,709
Processing costs receivable	8,593	7,847
Other	10,812	2,312
Total	$ 56,331	$ 41,447

OTHER CONSOLIDATED BALANCE SH59

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued hardware costs	$ 3,148	$ 11,622
Processing costs payable	9,655	11,417
Accrued professional fees	5,788	7,642
Accrued payroll	5,799	2,660
Accrued marketing	3,972	2,443
Other accrued liabilities	11,181	8,617
Total	$ 39,543	$ 44,401

OTHER CONSOLIDATED BALANCE SH60

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Settlements payable	$ 51,151	$ 13,105
Employee early exercised stock options	674	2,141
Accrued redemptions	1,628	1,066
Current portion of deferred rent	2,862	2,393
Deferred revenue	5,407	6,623
Other	11,901	3,617
Total	$ 73,623	$ 28,945

OTHER CONSOLIDATED BALANCE SH61

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) - Other Non-Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deposits	$ 1,775	$ 1,993
Deferred tax assets	306
Deferred tax assets		188
Other	1,113	1,645
Total	$ 3,194	$ 3,826

OTHER CONSOLIDATED BALANCE SH62

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) - Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred rent	$ 23,119	$ 25,543
Employee early exercised stock options	66	1,128
Deferred tax liabilities	476
Deferred tax liabilities		299
Statutory liabilities	29,497	25,492
Other	4,587	60
Total	$ 57,745	$ 52,522

DEBT (Details)

DEBT (Details) - Revolving Secured Credit Facility - Revolving Secured Credit Facility - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Nov. 30, 2015
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 375,000,000
Annual administrative agent fee	$ 100,000
Unused commitment fee, percent	0.15%
Remaining borrowing capacity	$ 375,000,000
Unused commitment fees	$ 600,000	$ 500,000
Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
One-Month LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.00%
One-Month LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%

ACCRUED TRANSACTION LOSSES - S

ACCRUED TRANSACTION LOSSES - Summary of Reserve for Transaction Losses(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss Contingency Accrual [Roll Forward]
Accrued transaction losses, beginning of the year	$ 17,176
Provision for transaction losses	50,819	$ 43,379	$ 18,478
Accrued transaction losses, end of the year	20,064	17,176
Transaction Losses
Loss Contingency Accrual [Roll Forward]
Accrued transaction losses, beginning of the year	17,176	8,452	7,488
Provision for transaction losses	50,819	43,379	18,478
Charge-offs and recoveries to accrued transaction losses	(47,931)	(34,655)	(17,514)
Accrued transaction losses, end of the year	$ 20,064	$ 17,176	$ 8,452

INCOME TAXES - Domestic and Fo

INCOME TAXES - Domestic and Foreign Components of Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Domestic	$ (145,499)	$ (157,229)	$ (139,675)
Foreign	(24,174)	(18,842)	(12,978)
Loss before income tax	$ (169,673)	$ (176,071)	$ (152,653)

INCOME TAXES - Components of Pr

INCOME TAXES - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 63	$ 1,662	$ 2,746
State	527	836	531
Foreign	1,269	1,222	827
Total current provision for income taxes	1,859	3,720	4,104
Deferred:
Federal	173	67	(2,503)
State	18	11	(161)
Foreign	(133)	(52)	0
Total deferred provision for income taxes	58	26	(2,664)
Total provision for income taxes	$ 1,917	$ 3,746	$ 1,440

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Statutory Federal Income Tax Rate to Company's Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Tax at federal statutory rate	34.00%	34.00%	34.00%
State taxes, net of federal benefit	(0.10%)	(0.20%)	(0.10%)
Foreign rate differential	(2.40%)	(1.80%)	(1.50%)
Nondeductible expenses	(3.30%)	(3.30%)	(1.80%)
Credits	8.50%	8.20%	2.70%
Other items	(0.40%)	(0.40%)	0.70%
Change in valuation allowance	(37.40%)	(38.60%)	(35.00%)
Total	(1.10%)	(2.10%)	(1.00%)

INCOME TAXES - Tax Effects of T

INCOME TAXES - Tax Effects of Temporary Differences and Related Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Capitalized costs	$ 61,897	$ 67,051	$ 28,102
Accrued expenses	29,421	27,964	19,714
Net operating loss carryforwards	65,507	36,633	54,528
Tax credit carryforwards	38,927	25,349	11,662
Property, equipment and intangible assets	5,721	0	0
Share-based compensation	52,091	36,689	13,153
Other	1,640	1,469	542
Total deferred tax assets	255,204	195,155	127,701
Valuation allowance	(254,898)	(195,103)	(125,368)
Total deferred tax assets, net of valuation allowance	306	52	2,333
Deferred tax liabilities:
Property, equipment and intangible assets	(476)	(163)	(2,333)
Total deferred tax liabilities	(476)	(163)	(2,333)
Net deferred tax liabilities	$ (170)	$ (111)	$ 0

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance	$ 59,800	$ 69,700	$ 50,500
Net operating loss attributable to certain employee stock option deductions	252,800
Unrecognized tax benefits	92,134	$ 90,372	$ 78,031	$ 14,152
Unrecognized tax benefit that would impact annual effective tax rate	2,800
Significant accrued interest and penalties related to uncertain tax positions	0
Undistributed earnings of non-U.S. subsidiaries	3,900
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	261,100
Federal | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	26,700
Federal | AMT Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	2,600
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	272,400
State | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	17,900
State | California Enterprise Zone Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	2,700
Foreign
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	76,200
Foreign | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 700

INCOME TAXES - Reconciliation70

INCOME TAXES - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at the beginning of the year	$ 90,372	$ 78,031	$ 14,152
Gross increases and decreases related to prior period tax positions	5,190	0	26,690
Gross increases and decreases related to current period tax positions	(3,428)	12,341	37,189
Balance at the end of the year	$ 92,134	$ 90,372	$ 78,031

STOCKHOLDER'S EQUITY - Common

STOCKHOLDER'S EQUITY - Common Stock, Preferred Stock and Warrants Narrative (Details) $ / shares in Units, $ in Thousands	Nov. 24, 2015USD ($)shares	Nov. 30, 2015USD ($)$ / sharesshares	Dec. 31, 2016vote$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Aug. 07, 2012shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)			100,000,000	100,000,000
Preferred stock, par value (in USD per share) | $ / shares			$ 0.00	$ 0.00
Preferred stock, shares outstanding (in shares)			0	0
Series E preferred stock issued (in shares)				10,299,696
Deemed dividend on Series E preferred stock | $				$ 0
Common Stock Warrants
Class of Stock [Line Items]
Warrants to purchase shares of common, canceled (in shares)				6,304,620
Outstanding warrants to purchase aggregate shares of capital stock (in shares)			9,456,955		15,761,575
Weighted Average | Common Stock Warrants
Class of Stock [Line Items]
Exercise price of warrants (in USD per share) | $ / shares			$ 11.01
Class A Common Stock
Class of Stock [Line Items]
Number of votes per share | vote			1
Common stock, shares authorized (in shares)			1,000,000,000	1,000,000,000
Common stock, par value (in USD per share) | $ / shares			$ 0.00	$ 0.00
Common stock, shares outstanding (in shares)			198,746,620	31,717,133
Class B Common Stock
Class of Stock [Line Items]
Number of votes per share | vote			10
Common stock, shares authorized (in shares)			500,000,000	500,000,000
Common stock, par value (in USD per share) | $ / shares			$ 0.00	$ 0.00
Common stock, shares outstanding (in shares)			165,800,756	303,232,312
IPO
Class of Stock [Line Items]
Net proceeds received from the IPO | $				$ 245,726
IPO | Class A Common Stock
Class of Stock [Line Items]
Issuance of stock (in shares)		29,700,000
Public offering price (in USD per share) | $ / shares		$ 9
Net proceeds received from the IPO | $		$ 245,700
Underwriting discounts and commissions | $		14,700
Other offering expenses | $		$ 6,900
Common Stock
Class of Stock [Line Items]
Series E preferred stock issued (in shares)	10,299,696			10,299,696
Common Stock | IPO
Class of Stock [Line Items]
Issuance of stock (in shares)				29,700,000
Net Loss to Arrive at Net Loss Attributable to Common Stockholders
Class of Stock [Line Items]
Deemed dividend on Series E preferred stock | $	$ 32,200			$ (32,200)

STOCKHOLDER'S EQUITY - Share-Ba

STOCKHOLDER'S EQUITY - Share-Based Compensation Narrative (Details)	Dec. 18, 2015shares	Aug. 31, 2015	Jan. 31, 2015shares	Dec. 31, 2016USD ($)payment_planplan$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / shares	Dec. 31, 2016USD ($)shares	Nov. 17, 2015shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based compensation plans | plan				2
Aggregate intrinsic value for options exercised | $				$ 202,600,000	$ 49,800,000	$ 47,800,000
Weighted average grant-date fair value of options granted (in USD per share) | $ / shares				$ 5.80	$ 5.87	$ 3.84
Share-based compensation expense | $				$ 138,786,000	$ 82,292,000	$ 36,100,000
Share-based compensation expense related to capitalized software | $				2,800,000	$ 0
Unrecognized compensation cost related to outstanding stock options and restricted stock awards | $				$ 257,600,000			$ 257,600,000
Unrecognized compensation cost related to outstanding stock options and restricted stock awards, recognition period				2 years 9 months 26 days
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share contributed for consideration and retired (in shares)			5,068,238		5,068,238
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Required service period		2 years
Plan modification, incremental share-based compensation cost | $				$ 2,600,000	$ 3,300,000
Plan modification, incremental share-based compensation cost not yet recognized | $				$ 4,200,000			$ 4,200,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting term	1 year			4 years
Awards granted (in shares)	1,854,145			17,060,055
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $				$ 5,100,000	$ 700,000
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved (in shares)								30,000,000
Shares reserved for issuance, percent				5.00%
Number of shares available for future issuance (in shares)				36,282,753			36,282,753
2015 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of number of shares reserved (in shares)				40,000,000			40,000,000
2015 Equity Incentive Plan | Options and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options and RSU outstanding (in shares)				19,295,512			19,295,512
2009 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares)								0
2009 Stock Option Plan | Options and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options and RSU outstanding (in shares)				69,409,441			69,409,441
2009 Stock Option Plan | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting term				4 years
Expiration period				10 years
2009 Stock Option Plan | Options | Vesting Year One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting rate				25.00%
2015 Employee Stock Purchase Plan | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance, percent				1.00%
Number of shares available for future issuance (in shares)				5,696,594			5,696,594
Discount through payroll deductions as a percentage of eligible compensation				15.00%
Offering period				12 months
Number of purchase periods | payment_plan				2
Purchase price of common stock as a percentage of fair market value				85.00%
Shares purchased under the plan (in shares)							1,852,900
2015 Employee Stock Purchase Plan | Employee Stock Purchase Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of number of shares reserved (in shares)				8,400,000			8,400,000

STOCKHOLDER'S EQUITY - Summary

STOCKHOLDER'S EQUITY - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Number of stock options outstanding
Beginning balance (in shares)	107,515,554
Granted (in shares)	1,767,320
Exercised (in shares)	(24,328,414)
Forfeited and canceled (in shares)	(11,692,898)
Ending balance (in shares)	73,261,562	107,515,554
Weighted average exercise price
Beginning balance (in USD per share)	$ 6.99
Granted (in USD per share)	13.49
Exercised (in USD per share)	3.39
Forfeited and canceled (in USD per share)	10.98
Ending balance (in USD per share)	$ 7.70	$ 6.99
Options Vested and Expected to Vest
Number of stock options outstanding (in shares)	69,467,073
Weighted average exercise price (in USD per share)	$ 7.51
Weighted average remaining contractual term (in years)	6 years 11 months 12 days
Aggregate intrinsic value	$ 433,756
Additional Disclosures
Weighted average remaining contractual term (in years)	7 years 3 months 11 days	7 years 10 months 13 days
Aggregate intrinsic value	$ 443,711	$ 656,194
Options exercisable, number of stock options outstanding (in shares)	69,936,089
Options exercisable, weighted average exercise price (in USD per share)	$ 7.54
Options exercisable, weighted average remaining contractual term (in years)	7 years 2 months 9 days
Options exercisable, aggregate intrinsic value	$ 434,962

STOCKHOLDER'S EQUITY - Activity

STOCKHOLDER'S EQUITY - Activity Related to RSUs (Details) - RSUs - $ / shares	Dec. 18, 2015	Dec. 31, 2016
Number of RSUs
Beginning balance (in shares)		3,632,765
Granted (in shares)	1,854,145	17,060,055
Vested (in shares)		(3,392,726)
Forfeited (in shares)		(1,856,703)
Ending balance (in shares)		15,443,391
Weighted average grant date fair value
Beginning balance (in USD per share)		$ 13.14
Granted (in USD per share)		12.08
Vested (in USD per share)		12.58
Forfeited (in USD per share)		13.15
Ending balance (in USD per share)		$ 12.09

STOCKHOLDER'S EQUITY - Schedule

STOCKHOLDER'S EQUITY - Schedule of Fair Value Assumptions for Options (Details) - Options - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Risk-free interest rate	1.54%	1.73%	1.85%
Expected volatility	42.74%	47.68%	46.95%
Expected term (years)	6 years 29 days	6 years 7 days	6 years 22 days
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock	$ 8.37	$ 10.06	$ 7.25
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock	$ 15.48	$ 15.39	$ 10.06

STOCKHOLDER'S EQUITY - Effects

STOCKHOLDER'S EQUITY - Effects of Share-Based Compensation on Consolidated Statements of Operations(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 138,786	$ 82,292	$ 36,100
Product development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	91,404	54,738	24,758
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	14,122	7,360	3,738
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 33,260	$ 20,194	$ 7,604

NET LOSS PER SHARE - Calculati

NET LOSS PER SHARE - Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Deemed dividend on Series E preferred stock (in shares)		10,299,696
Net loss	$ (171,590)	$ (179,817)	$ (154,093)
Deemed dividend on Series E preferred stock	0	(32,200)	0
Net loss attributable to common stockholders	$ (171,590)	$ (212,017)	$ (154,093)
Basic shares:
Weighted-average common shares outstanding (in shares)	344,393,000	175,139,000	148,876,000
Weighted-average unvested shares (in shares)	(2,838,000)	(4,641,000)	(6,834,000)
Weighted-average shares used to compute basic net loss per share (in shares)	341,555,000	170,498,000	142,042,000
Diluted shares:
Weighted-average shares used to compute diluted net loss per share (in shares)	341,555,000	170,498,000	142,042,000
Loss per share attributable to common stockholders:
Basic (in USD per share)	$ (0.50)	$ (1.24)	$ (1.08)
Diluted (in USD per share)	$ (0.50)	$ (1.24)	$ (1.08)

NET LOSS PER SHARE - Potential

NET LOSS PER SHARE - Potential Common Shares Excluded from the Calculation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	100,270	124,284	245,016
Stock options and restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	88,705	111,148	87,471
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	0	0	135,253
Unvested shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	1,892	3,420	6,443
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	216	172	0
Common stock warrants | Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	9,457	9,544	15,762
Preferred stock warrants | Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	0	0	87

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Rental expenses under operating leases	$ 11.3	$ 12.8	$ 11.4
Sublease income	$ 3.1	$ 0.6

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Future Minimum Lease Payments Under Operating and Capital Leases (Details) $ in Thousands	Dec. 31, 2016USD ($)
Capital
2,017	$ 694
2,018	651
2,019	536
2,020	1
2,021	0
Thereafter	0
Total	1,882
Less amount representing interest	(4)
Present value of capital lease obligations	1,878
Less current portion of capital lease obligation	(691)
Non-current portion of capital lease obligation	1,187
Operating
2,017	16,639
2,018	16,519
2,019	15,673
2,020	15,757
2,021	16,172
Thereafter	35,943
Total	$ 116,703

SEGMENT AND GEOGRAPHICAL INFO81

SEGMENT AND GEOGRAPHICAL INFORMATION - Narrative (Details)	12 Months Ended
	Dec. 31, 2016segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

SEGMENT AND GEOGRAPHICAL INFO82

SEGMENT AND GEOGRAPHICAL INFORMATION - Revenue by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	$ 1,708,721	$ 1,267,118	$ 850,192
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	1,643,852	1,224,566	825,578
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	$ 64,869	$ 42,552	$ 24,614

SEGMENT AND GEOGRAPHICAL INFO83

SEGMENT AND GEOGRAPHICAL INFORMATION - Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 164,793	$ 170,697
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	162,118	168,583
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 2,675	$ 2,114

SUPPLEMENTAL CASH FLOW INFORM84

SUPPLEMENTAL CASH FLOW INFORMATION - Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Cash Flow Data:
Cash paid for interest	$ 570	$ 981	$ 940
Cash paid for income taxes	395	1,916	2,442
Supplemental disclosures of non-cash investing and financing activities:
Purchases of property and equipment in accounts payable and accrued expenses	2,554	5,593	0
Unpaid business acquisition purchase price	240	0	0
Conversion of Series A, B, C, D & E preferred stock upon initial public offering to common stock	0	544,897	0
Unpaid offering costs related to initial public offering	0	5,530	0
Deemed dividend on Series E preferred stock	0	32,200	0
Fair value of shares issued related to acquisitions	$ 0	$ 35,776	$ 59,576

SUBSEQUENT EVENTS - Narrative

SUBSEQUENT EVENTS - Narrative (Details) - Common Stock Warrants - USD ($) $ in Millions	Feb. 24, 2017	Dec. 31, 2015
Subsequent Event [Line Items]
Warrants to purchase shares of common, terminated (in shares)		6,304,620
Subsequent Event
Subsequent Event [Line Items]
Warrants to purchase shares of common, terminated (in shares)	9,456,955
Consideration paid for termination of warrants	$ 54.8