Block (XYZ) 10-Q 7 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 02, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Square, Inc.
Entity Central Index Key	1,512,673
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Class A
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		308,397,662
Class B
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		105,099,942

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 721,738	$ 696,474
Short-term investments	448,986	169,576
Restricted cash	33,230	28,805
Settlements receivable	1,194,701	620,523
Customer funds	269,094	103,042
Loans held for sale	73,219	73,420
Other current assets	136,400	86,454
Total current assets	2,877,368	1,778,294
Property and equipment, net	130,145	91,496
Goodwill	259,964	58,327
Acquired intangible assets, net	81,130	14,334
Long-term investments	537,663	203,667
Restricted cash	10,102	9,802
Other non-current assets	76,996	31,350
Total assets	3,973,368	2,187,270
Current liabilities:
Accounts payable	12,448	16,763
Customers payable	1,315,108	733,736
Settlements payable	203,274	114,788
Accrued transaction losses	35,332	26,893
Accrued expenses	101,066	52,280
Current portion of long-term debt	125,971	0
Other current liabilities	70,338	28,367
Total current liabilities	1,863,537	972,827
Long-term debt, net of current portion (Note 13)	897,976	358,572
Other non-current liabilities	89,711	69,538
Total liabilities	2,851,224	1,400,937
Commitments and contingencies (Note 18)
Stockholders’ equity:
Preferred stock, $0.0000001 par value: 100,000,000 shares authorized at September 30, 2018 and December 31, 2017. None issued and outstanding at September 30, 2018 and December 31, 2017.	0	0
Additional paid-in capital	1,986,059	1,630,386
Accumulated other comprehensive loss	(6,345)	(1,318)
Accumulated deficit	(857,570)	(842,735)
Total stockholders’ equity	1,122,144	786,333
Total liabilities and stockholders’ equity	3,973,368	2,187,270
Class A
Stockholders’ equity:
Common stock	0	0
Class B
Stockholders’ equity:
Common stock	$ 0	$ 0

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
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
Class of Stock [Line Items]
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)	306,228,873	280,400,813
Common stock, shares outstanding (in shares)	306,228,873	280,400,813
Class B
Class of Stock [Line Items]
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)	106,143,959	114,793,262
Common stock, shares outstanding (in shares)	106,143,959	114,793,262

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue:
Revenue	$ 882,108	$ 585,159	$ 2,365,649	$ 1,598,218
Revenue	857,700		2,298,700
Cost of revenue:
Total cost of revenue	529,448	366,543	1,442,003	998,742
Gross profit	352,660	218,616	923,646	599,476
Operating expenses:
Product development	135,773	82,547	355,668	229,255
Sales and marketing	116,337	66,533	291,846	176,349
General and administrative	85,527	64,312	243,800	184,235
Transaction, loan and advance losses	23,596	19,893	63,603	50,185
Amortization of acquired customer assets	4,384	1,804	9,075	5,868
Total operating expenses	362,527	233,507	957,152	640,673
Operating loss	(9,867)	(14,891)	(33,506)	(41,197)
Interest expense, net	7,224	3,080	12,806	7,570
Other income, net	(37,800)	(1,226)	(37,908)	(1,951)
Income (loss) before income tax	20,709	(16,745)	(8,404)	(46,816)
Provision (benefit) for income taxes	1,066	(647)	1,845	334
Net income (loss)	$ 19,643	$ (16,098)	$ (10,249)	$ (47,150)
Net income (loss) per share:
Basic (in USD per share)	$ 0.05	$ (0.04)	$ (0.03)	$ (0.13)
Diluted (in USD per share)	$ 0.04	$ (0.04)	$ (0.03)	$ (0.13)
Weighted-average shares used to compute net income (loss) per share
Basic (in shares)	409,690	383,951	402,980	375,743
Diluted (in shares)	474,915	383,951	402,980	375,743
Technology assets
Cost of revenue:
Amortization of acquired technology	$ 2,277	$ 1,556	$ 5,714	$ 5,058
Customer assets
Operating expenses:
Amortization of acquired customer assets	1,294	222	2,235	649
Transaction-based revenue
Revenue:
Revenue	655,384	510,019	1,803,649	1,395,562
Cost of revenue:
Cost of revenue	414,456	328,043	1,137,716	896,913
Subscription and services-based revenue
Revenue:
Revenue	166,203	65,051	397,589	173,262
Revenue	141,752	65,051	330,637	173,262
Cost of revenue:
Cost of revenue	47,078	18,169	117,230	51,161
Hardware revenue
Revenue:
Revenue	17,558	10,089	50,337	29,394
Cost of revenue:
Cost of revenue	23,229	18,775	68,467	45,610
Bitcoin revenue
Revenue:
Revenue	42,963	0	114,074	0
Cost of revenue:
Cost of revenue	$ 42,408	$ 0	$ 112,876	$ 0

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 19,643	$ (16,098)	$ (10,249)	$ (47,150)
Net foreign currency translation adjustments	(946)	367	(3,341)	1,554
Net unrealized gain (loss) on revaluation of intercompany loans	(296)	(41)	(89)	362
Net unrealized gain (loss) on marketable debt securities	(647)	(200)	(1,597)	(320)
Total comprehensive income (loss)	$ 17,754	$ (15,972)	$ (15,276)	$ (45,554)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net loss	$ (10,249)	$ (47,150)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	38,323	27,647
Non-cash interest and other expense	23,554	9,969
Loss on extinguishment of long-term debt	1,625	0
Share-based compensation	157,856	111,311
Replacement stock awards issued in connection with acquisition	899	0
Gain on revaluation of equity investment	(36,908)	0
Recovery of common stock in connection with indemnification settlement agreement	(2,745)	0
Transaction, loan and advance losses	63,603	50,185
Change in deferred income taxes	(563)	133
Changes in operating assets and liabilities:
Settlements receivable	(579,769)	(271,235)
Customer funds	(156,162)	(41,899)
Purchase of loans held for sale	(1,139,142)	(874,498)
Sales and principal payments of loans held for sale	1,130,378	852,187
Other current assets	(50,060)	(6,262)
Other non-current assets	(8,875)	(1,699)
Accounts payable	(6,470)	1,223
Customers payable	581,530	295,406
Settlements payable	88,486	30,263
Charge-offs to accrued transaction losses	(40,354)	(33,081)
Accrued expenses	31,015	20,328
Other current liabilities	27,230	(1,125)
Other non-current liabilities	5,458	8,614
Net cash provided by operating activities	118,660	130,317
Cash flows from investing activities:
Purchase of marketable debt securities	(859,060)	(485,484)
Proceeds from maturities of marketable debt securities	128,603	106,079
Proceeds from sale of marketable debt securities	106,358	65,121
Purchase of property and equipment	(37,173)	(19,625)
Purchase of equity investment	0	(25,000)
Purchase of intangible assets	(1,584)	0
Business combinations, net of cash acquired	(112,399)	(1,600)
Net cash used in investing activities	(775,255)	(360,509)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net	855,663	428,250
Purchase of convertible senior note hedges	(172,586)	(92,136)
Proceeds from issuance of warrants	112,125	57,244
Principal payment on conversion of senior notes	(70,047)	0
Payment of deferred purchase consideration	(640)	0
Payment for termination of Starbucks warrant	0	(54,808)
Principal payments on capital lease obligation	(2,658)	(1,020)
Proceeds from the exercise of stock options and purchases under the employee stock purchase plan, net	94,780	111,889
Payments for tax withholding related to vesting of restricted stock units	(125,899)	(18,298)
Net cash provided by financing activities	690,738	431,121
Effect of foreign exchange rate on cash and cash equivalents	(4,154)	3,836
Net increase in cash, cash equivalents and restricted cash	29,989	204,765
Cash, cash equivalents and restricted cash, beginning of period	735,081	488,745
Cash, cash equivalents and restricted cash, end of period	$ 765,070	$ 693,510

DESCRIPTION OF BUSINESS AND SUM

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Business Square, Inc. (together with its subsidiaries, Square or the Company) creates tools that help sellers start, run, and grow their businesses. Square enables sellers to accept card payments and also provides reporting and analytics, next-day settlement, and chargeback protection. Square’s point-of-sale software and other business services help sellers manage inventory, locations, and employees; access financing; engage buyers; build a website or online store; and grow sales. The Cash App is an easy way to send, spend, and receive money, and Caviar is a food-ordering platform. Square was founded in 2009 and is headquartered in San Francisco, with offices in the United States, Canada, Japan, Australia, Ireland, and the UK. Reclassifications and Other Adjustments During the third quarter of 2018, the Company has reclassified prior period balances within interest and other (income) expense, net, to disaggregate the amounts and separately present interest (income) expense, net and other (income) expense, net on its consolidated statements of operations to conform to the current period presentation. This classification change was made to provide clarity of the balances as the activity continues to grow, particularly as a result of the impact of revaluation of an equity investment in the current period. During both the three and nine months ended September 30, 2018, the Company recorded a gain of $36.9 million to other income on the consolidated statements of operations arising from revaluation of this investment (Note 12). There was no impact to the net income (loss) on its consolidated statements of operations to any of the periods presented as result of this change. Basis of Presentation The accompanying interim condensed consolidated financial statements of the Company are unaudited. These interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and the applicable rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The December 31, 2017 condensed consolidated balance sheet was derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The accompanying unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments of a normal recurring nature considered necessary to state fairly the Company's consolidated financial position, results of operations, comprehensive income (loss), and cash flows for the interim periods. All intercompany transactions and balances have been eliminated in consolidation. The interim results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 , or for any other future annual or interim period. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Quantitative and Qualitative Disclosures About Market Risk,” and the Consolidated Financial Statements and notes thereto included in Items 7, 7A, and 8, respectively, in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 . 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. 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 the debt component of convertible senior notes, valuation of loans held for sale, goodwill, acquired intangible assets and deferred revenue, income and other taxes, and share-based compensation. Concentration of Credit Risk For the three and nine months ended September 30, 2018 and 2017 , the Company had no customer that accounted for greater than 10% of total net revenue. The Company had three third-party payment processors that represented approximately 50% , 37% , and 9% of settlements receivable as of September 30, 2018 . The same three parties represented approximately 46% , 42% , and 8% of settlements receivable as of December 31, 2017 . All other third-party processors were insignificant. Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash, marketable debt securities, settlements receivables, customer funds, and loans held for sale. The associated risk of concentration for cash and cash equivalents and restricted cash 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 debt 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 loans held for sale is partially mitigated by credit evaluations that are performed prior to facilitating the offering of loans and ongoing performance monitoring of the Company’s loan customers. Accounting Policies Except for the adoption of ASC 606, Revenue from Contracts with Customers (ASC 606) , described in Note 2, and the accounting policy on cryptocurrency transactions and customer funds, both described below, there have been no material changes to the Company’s accounting policies during the nine months ended September 30, 2018 , as compared to the accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Cryptocurrency transactions During the fourth quarter of 2017, the Company started offering its Cash App customers the ability to purchase bitcoin, a cryptocurrency denominated asset, from the Company. The Company purchases bitcoin from private broker dealers or from Cash App customers. Upon purchase, the Company records the cost of bitcoin within other current assets in its consolidated balance sheets. Upon sale, the Company records the total sale amount received from customers as bitcoin revenue and the associated cost as cost of revenue. The carrying value of bitcoin held by the Company was $0.2 million and $0.3 million as of September 30, 2018 and December 31, 2017 , respectively. The Company assesses the carrying value of bitcoin held by the Company at each reporting date and records an impairment charge if the cost exceeds the fair value. Losses on bitcoin for the three and nine months ended September 30, 2018 , were insignificant. Customer funds Customer funds represent Cash App customers' stored balances that customers can later use to send money or make payments, or customers with cash in transit. As of December 31, 2017, the Company held these stored balances as short term bank deposits. During the third quarter of 2018, the Company started investing a portion of these stored balances in short-term marketable debt securities (Note 5 ). Recent Accounting Pronouncements Recently issued accounting pronouncements not yet adopted In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-02, Leases , which will require, among other items, lessees to recognize a right of use asset and a related lease liability for most leases 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 new standard should be applied on a modified retrospective basis. The Company does not plan to early adopt this guidance. The Company’s operating leases primarily comprise of office facilities, with the most significant leases relating to corporate headquarters in San Francisco and an office in New York. While the Company continues to evaluate the impact of adopting this guidance on its consolidated financial statements, it does expect to record material right to use assets and related lease liabilities on its consolidated balance sheets upon adoption, which will increase total assets and liabilities. 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. Early adoption is permitted for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The Company is currently evaluating the impact this guidance may have on the consolidated financial statements and related disclosures. In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment . The new guidance eliminates the requirement to calculate the implied fair value of goodwill assuming a hypothetical purchase price allocation (i.e., Step 2 of the goodwill impairment test) to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value, not to exceed the carrying amount of goodwill. 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 does not expect the adoption of this guidance to have a material impact on the consolidated financial statements and related disclosures. In March 2017, the FASB issued ASU No. 2017-08, Premium Amortization on Purchased Callable Debt Securities, which amends the amortization period for certain purchased callable debt securities held at a premium, shortening such period to the earliest call date. This standard is effective for annual periods beginning after December 15, 2018, 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 guidance may have on the consolidated financial statements and related disclosures. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . When the Tax Cuts and Jobs Act of 2017 was enacted in December 2017, there was a valuation allowance on the deferred tax assets included within the Company's accumulated other comprehensive income; therefore no tax expense resulted from the change in the federal income tax rate. This guidance allows companies to reclassify such tax effects from accumulated other comprehensive income to retained earnings. 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 expect the adoption of this guidance to have a material impact on the consolidated financial statements and related disclosures. In July 2018, the FASB issued ASU 2018-13, Changes to the Disclosure Requirements for Fair Value Measurement, which will remove, modify and add disclosure requirements for fair value measurements to improve the overall usefulness of such disclosures. 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 for any removed or modified disclosure requirements. Transition is on a prospective basis for the new and modified disclosures, and on a retrospective basis for disclosures that have been eliminated. The Company is currently evaluating the impact this guidance may have on the consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which is intended to align the requirements for capitalization of implementation costs incurred in a cloud computing arrangement that is a service contract with the existing guidance for internal-use software. 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 guidance provides flexibility in adoption, allowing for either retrospective adjustment or prospective adjustment for all implementation costs incurred after the date of adoption. The Company is currently evaluating the impact this guidance may have on the consolidated financial statements and related disclosures.

REVENUE

REVENUE	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
REVENUE	REVENUE Adoption of ASC 606, Revenue from Contracts with Customers On January 1, 2018, the Company adopted ASC 606 using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with the Company's historic revenue recognition methodology under ASC 605, Revenue Recognition . The Company recorded a net reduction to retained earnings of $4.6 million as of January 1, 2018, due to the cumulative impact of adopting ASC 606, primarily related to the effect on revenue and associated cost of revenue from hardware sold through the retail distribution channels and hardware installment sales. The impact to revenue for the three and nine months ended September 30, 2018 was an increase of $1.6 million and $5.3 million , respectively, as a result of applying ASC 606. For the three months ended September 30, 2018 , the revenue recognized from contracts with customers was $857.7 million and revenue from other sources was $24.5 million . For the nine months ended September 30, 2018 , the revenue recognized from contracts with customers was $2,298.7 million and revenue from other sources was $67.0 million . Impairment losses arising from contracts with customers were $0.9 million and $2.7 million for the three and nine months ended September 30, 2018 , respectively. The impact of adoption of ASC 606 on the Company's condensed consolidated statement of operations was as follows (in thousands): Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 As reported Balances without adoption Effect of change As reported Balances without adoption Effect of change Impact on the Condensed Consolidated Statement of Operations: Subscription and services-based revenue $ 166,203 $ 166,037 $ 166 $ 397,589 $ 397,272 $ 317 Hardware revenue 17,558 16,145 1,413 50,337 45,378 4,959 Subscription and services-based costs 47,078 47,078 — 117,230 117,230 — Hardware costs $ 23,229 $ 21,969 $ 1,260 $ 68,467 $ 63,665 $ 4,802 The impact of adoption of ASC 606 on the Company's condensed consolidated balance sheets was as follows (in thousands): September 30, 2018 As reported Balances without adoption Effect of change Impact on the Condensed Consolidated Balance Sheets: Other current assets $ 136,400 $ 148,491 $ (12,091 ) Other current liabilities 70,338 78,260 (7,922 ) Other non-current assets 76,996 78,584 (1,588 ) Other non-current liabilities $ 89,711 $ 91,311 $ (1,600 ) Revenue Recognition Revenue is recognized when control of the promised goods or services is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company's contracts with customers generally do not include multiple performance obligations with differing patterns of revenue recognition, except for domain name registration offered with website hosting services sold after May 31, 2018 following the acquisition of Weebly (Note 8 ). The following table presents the Company's revenue from contracts with customers disaggregated by revenue source (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue from Contracts with Customers: Transaction-based revenue $ 655,384 $ 510,019 $ 1,803,649 $ 1,395,562 Subscription and services-based revenue 141,752 65,051 330,637 173,262 Hardware revenue 17,558 10,089 50,337 29,394 Bitcoin revenue $ 42,963 $ — $ 114,074 $ — 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 certain sellers. The Company collects the transaction amount from the seller's customer's bank, net of acquiring interchange and assessment fees, processing fees, and bank settlement fees paid to third-party payment processors and financial institutions. The Company retains its fees and remits the net amount to the 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. The Company satisfies its performance obligations and therefore recognizes the transaction fees 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 transaction fees collected from sellers are recognized as revenue on a gross basis as the Company is the principal in the delivery of the managed payments solutions to the sellers. The Company has concluded it is the principal because as the merchant of record, it controls the services before delivery to the seller, it is primarily responsible for the delivery of the services to its sellers, and it has discretion in setting prices charged to sellers. The Company also has the unilateral ability to accept or reject a transaction based on criteria established by the Company. As the merchant of record, Square is liable for the costs of processing the transactions for its sellers, and records such costs within cost of revenue. Subscription and services-based revenue Subscription and services-based revenue is primarily comprised of revenue the Company generates from Instant Deposit and Cash Card, Caviar, website hosting and domain name registration services, and various other software as a service (SaaS) products. Instant Deposit is a functionality within the Cash App and the Company's managed payments solution that enables customers, including individuals and sellers, to instantly deposit funds into their bank accounts. The Company charges a per transaction fee which is recognized as revenue when customers instantly deposit funds to their bank account. The Company also offers Cash App customers the ability to use funds stored in the Cash App via a Visa debit card, for which the Company charges a per transaction fee that is recorded as revenue. Caviar is a food ordering platform that facilitates food delivery services. The Company's performance obligations are the delivery of food orders from restaurants to customers and the provision of catered meals to corporate customers. For delivery of food orders, the Company charges fees to restaurants, as sellers, and also charges delivery and service fees to individuals. For provision of catered meals the Company charges corporate customers a fee. All fees are billed upon delivery of food orders or catered meals, when the Company considers that it has satisfied its performance obligations. Revenue is recognized upon delivery of the food orders or catered meals, net of refunds. Refunds are estimated based on historical experience. Following the acquisition of Weebly, the Company offers customers website hosting services for a fee that is generally billed at inception. The Company also acts as a reseller of domain names registration services for a registrar for a fee, which is also generally billed at inception. The Company considers that it satisfies its performance obligations over time and as such recognizes revenue ratably over the term of the relevant arrangements, which vary from one month to twenty four months for website hosting, and one year to ten years for domain name registration. SaaS represents software products and solutions that provide customers with access to various technologies for a fee which is recognized as revenue ratably as the service is provided. The Company's contracts with customers are generally for a term of one month and renew automatically each month. The Company invoices its customers monthly. The Company considers that it satisfies its performance obligations over time each month as it provides the SaaS services to customers and hence recognizes revenue ratably over the month. Hardware revenue The Company generates revenue through the sale of hardware through e-commerce and through its retail distribution channels. The Company satisfies its performance obligation upon delivery of hardware to its customers who include end user customers, distributors, and retailers. The Company may at times offer concessions to customers and also allow for customer returns, which are accounted for as variable consideration. The Company estimates these amounts based on historical experience and reduces revenue recognized. The Company invoices end user customers upon delivery of the products to customers, and payments from such customers are due upon invoicing. Distributors and retailers have payment terms that range from 30 to 90 days after delivery. The Company offers hardware installment sales to customers with terms ranging from three to twenty four months. The Company allocates a portion of the consideration received from these arrangements to a financing component when it determines that a significant financing component exists. The financing component is subsequently recognized as financing revenue separate from hardware revenue, within subscription and services-based revenue, over the terms of the arrangement with the customer. Bitcoin revenue During the fourth quarter of 2017, the Company started offering its Cash App customers the ability to purchase bitcoin, a cryptocurrency denominated asset, from the Company. The Company satisfies its performance obligation and records revenue when bitcoin is transferred to the customer's account. Arrangements with Multiple Performance Obligations The Company also offers its customers the option to buy website hosting bundled with domain name registration, and infrequently the Company has offered its hardware customers free managed payments solutions with the purchase of its hardware as part of a marketing promotion. For such arrangements, the Company allocates revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling prices based on the prices charged to customers since the Company's products and services are normally sold on a stand alone basis. Deferred Revenue Deferred revenue is primarily comprised of payments for website hosting and domain name registration received from customers at inception of the arrangements prior to the services being rendered. Deferred revenue also includes unearned revenue related to managed payments services offered in conjunction with hardware sales for which the cash payments from customers are received and due upon the sale of the hardware. The deferred revenue balances were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Deferred revenue, beginning of the period $ 27,155 $ 4,523 $ 5,893 $ 5,407 Less: accumulative adjustment for adoption of ASC 606 — — (4,303 ) — Deferred revenue, beginning of the period, as adjusted 27,155 4,523 1,590 5,407 Deferred revenue, end of the period 33,614 3,424 33,614 3,424 Deferred revenue arising from business combination 22,800 — 22,800 — Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period $ 10,165 $ 2,060 $ 1,539 $ 5,312 Practical Expedients The Company does not recognize a financing component for hardware installment sales that have a term of one year or less.

RESTRICTED CASH

RESTRICTED CASH	9 Months Ended
	Sep. 30, 2018
Cash and Cash Equivalents [Abstract]
RESTRICTED CASH	RESTRICTED CASH As of September 30, 2018 and December 31, 2017 , restricted cash of $33.2 million and $28.8 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. Additionally, this balance includes certain amounts held as collateral pursuant to multi-year lease agreements, discussed in the paragraph below, which we expect to become unrestricted within the next year. As of September 30, 2018 and December 31, 2017 , the remaining restricted cash of $10.1 million and $9.8 million , respectively, is primarily related to cash deposited into money market funds that is used as collateral pursuant to multi-year lease agreements (Note 18 ). 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.

INVESTMENTS

INVESTMENTS	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS The Company determines the appropriate classification of its investments in marketable debt securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified and accounted for its marketable debt securities as available-for-sale. The Company's short-term and long-term investments as of September 30, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 48,206 $ 11 $ (27 ) $ 48,190 Corporate bonds 83,647 135 (64 ) 83,718 Municipal securities 28,904 37 (49 ) 28,892 U.S. government securities 270,094 70 (372 ) 269,792 Non-U.S. government securities 18,433 — (39 ) 18,394 Total $ 449,284 $ 253 $ (551 ) $ 448,986 Long-term debt securities: U.S. agency securities $ 132,013 $ 1 $ (244 ) $ 131,770 Corporate bonds 160,777 178 (75 ) 160,880 Municipal securities 20,203 82 (45 ) 20,240 U.S. government securities 221,751 202 (419 ) 221,534 Non-U.S. government securities 3,251 — (12 ) 3,239 Total $ 537,995 $ 463 $ (795 ) $ 537,663 The Company's short-term and long-term investments as of December 31, 2017 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 15,122 $ — $ (39 ) $ 15,083 Corporate bonds 57,855 22 (79 ) 57,798 Commercial paper 17,428 — — 17,428 Municipal securities 23,743 8 (51 ) 23,700 U.S. government securities 55,729 1 (163 ) 55,567 Total $ 169,877 $ 31 $ (332 ) $ 169,576 Long-term debt securities: U.S. agency securities $ 20,288 $ 2 $ (121 ) $ 20,169 Corporate bonds 91,959 25 (571 ) 91,413 Municipal securities 26,371 13 (160 ) 26,224 U.S. government securities 66,362 19 (520 ) 65,861 Total $ 204,980 $ 59 $ (1,372 ) $ 203,667 For the periods presented, 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 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 for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's short-term and long-term investments as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 449,284 $ 448,986 Due in one to five years 537,995 537,663 Total $ 987,279 $ 986,649 CUSTOMER FUNDS The following table presents the assets underlying customer funds (in thousands): September 30, December 31, Cash $ 219,087 $ 103,042 Cash Equivalents: Money market funds 1,884 — U.S. agency securities 8,335 — U.S. government securities 29,898 — Short-term debt securities: U.S. government securities $ 9,890 $ — Total $ 269,094 $ 103,042 The Company determines the appropriate classification of the investments in marketable debt securities within customer funds at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified and accounted for its marketable debt securities within customer funds as available-for-sale. The Company's investments within customer funds as of September 30, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. government securities 9,891 — (1 ) 9,890 Total $ 9,891 $ — $ (1 ) $ 9,890 For the periods presented, 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 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 for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's investments within customer funds as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 9,891 $ 9,890 Due in one to five years — — Total $ 9,891 $ 9,890

CUSTOMER FUNDS

CUSTOMER FUNDS	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
CUSTOMER FUNDS	INVESTMENTS The Company determines the appropriate classification of its investments in marketable debt securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified and accounted for its marketable debt securities as available-for-sale. The Company's short-term and long-term investments as of September 30, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 48,206 $ 11 $ (27 ) $ 48,190 Corporate bonds 83,647 135 (64 ) 83,718 Municipal securities 28,904 37 (49 ) 28,892 U.S. government securities 270,094 70 (372 ) 269,792 Non-U.S. government securities 18,433 — (39 ) 18,394 Total $ 449,284 $ 253 $ (551 ) $ 448,986 Long-term debt securities: U.S. agency securities $ 132,013 $ 1 $ (244 ) $ 131,770 Corporate bonds 160,777 178 (75 ) 160,880 Municipal securities 20,203 82 (45 ) 20,240 U.S. government securities 221,751 202 (419 ) 221,534 Non-U.S. government securities 3,251 — (12 ) 3,239 Total $ 537,995 $ 463 $ (795 ) $ 537,663 The Company's short-term and long-term investments as of December 31, 2017 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 15,122 $ — $ (39 ) $ 15,083 Corporate bonds 57,855 22 (79 ) 57,798 Commercial paper 17,428 — — 17,428 Municipal securities 23,743 8 (51 ) 23,700 U.S. government securities 55,729 1 (163 ) 55,567 Total $ 169,877 $ 31 $ (332 ) $ 169,576 Long-term debt securities: U.S. agency securities $ 20,288 $ 2 $ (121 ) $ 20,169 Corporate bonds 91,959 25 (571 ) 91,413 Municipal securities 26,371 13 (160 ) 26,224 U.S. government securities 66,362 19 (520 ) 65,861 Total $ 204,980 $ 59 $ (1,372 ) $ 203,667 For the periods presented, 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 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 for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's short-term and long-term investments as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 449,284 $ 448,986 Due in one to five years 537,995 537,663 Total $ 987,279 $ 986,649 CUSTOMER FUNDS The following table presents the assets underlying customer funds (in thousands): September 30, December 31, Cash $ 219,087 $ 103,042 Cash Equivalents: Money market funds 1,884 — U.S. agency securities 8,335 — U.S. government securities 29,898 — Short-term debt securities: U.S. government securities $ 9,890 $ — Total $ 269,094 $ 103,042 The Company determines the appropriate classification of the investments in marketable debt securities within customer funds at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified and accounted for its marketable debt securities within customer funds as available-for-sale. The Company's investments within customer funds as of September 30, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. government securities 9,891 — (1 ) 9,890 Total $ 9,891 $ — $ (1 ) $ 9,890 For the periods presented, 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 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 for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's investments within customer funds as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 9,891 $ 9,890 Due in one to five years — — Total $ 9,891 $ 9,890

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS The Company measures its cash equivalents, customer funds, short-term and long-term marketable debt securities, and equity investments at fair value. The Company classifies these investments within Level 1 or Level 2 of the fair value hierarchy because the Company values these investments using quoted market prices or alternative pricing sources and models utilizing market observable inputs. The Company’s financial assets and liabilities that are measured at fair value on a recurring basis are classified as follows (in thousands): September 30, 2018 December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash Equivalents: Money market funds $ 311,158 $ — $ — $ 387,698 $ — $ — U.S. agency securities — 123,202 — — — — Commercial paper — — — — 24,695 — U.S. government securities 20,065 — — — — — Customer funds: Money market funds 1,884 — — — — — U.S. agency securities — 8,335 — — — — U.S. government securities 39,788 — — — — — Short-term debt securities: U.S. agency securities — 48,190 — — 15,083 — Corporate bonds — 83,718 — — 57,798 — Commercial paper — — — — 17,428 — Municipal securities — 28,892 — — 23,700 — U.S. government securities 269,792 — — 55,567 — — Non-U.S. government securities — 18,394 — — — — Long-term debt securities: U.S. agency securities — 131,770 — — 20,169 — Corporate bonds — 160,880 — — 91,413 — Municipal securities — 20,240 — — 26,224 — U.S. government securities 221,534 — — 65,861 — — Non-U.S. government securities — 3,239 — — — — Other: Equity investment 61,908 — — — — — Total $ 926,129 $ 626,860 $ — $ 509,126 $ 276,510 $ — The carrying amounts of certain financial instruments, including settlements receivable, accounts payable, customers payable, and settlements payable, approximate their fair values due to their short-term nature. The Company estimates the fair value of its convertible senior notes based on their last actively traded prices (Level 1) or market observable inputs (Level 2). The estimated fair value and carrying value of the convertible senior notes were as follows (in thousands): September 30, 2018 December 31, 2017 Carrying Value Fair Value (Level 2) Carrying Value Fair Value (Level 2) 2023 Notes $ 711,229 $ 1,234,496 $ — $ — 2022 Notes 312,718 1,599,954 358,572 719,356 Total $ 1,023,947 $ 2,834,450 $ 358,572 $ 719,356 Loans held for sale are recorded at the lower of amortized cost or fair value determined on an individual loan basis. To determine the fair value the Company utilizes industry-standard valuation modeling, such as discounted cash flow models, taking into account the estimated timing and amounts of periodic repayments. The estimated fair value and carrying value of loans held for sale is as follows (in thousands): September 30, 2018 December 31, 2017 Carrying Value Fair Value (Level 3) Carrying Value Fair Value (Level 3) Loans held for sale $ 73,219 $ 76,302 $ 73,420 $ 76,070 Total $ 73,219 $ 76,302 $ 73,420 $ 76,070 The Company recognizes a charge within transaction, loan and advance losses on the consolidated statement of operations whenever the amortized cost of a loan exceeds its fair value, with such charges being reversed for subsequent increases in fair value, but only to the extent that such reversals do not result in the amortized cost of a loan exceeding its fair value. For the three and nine months ended September 30, 2018 , the Company recorded a charge for the excess of amortized cost over fair value of the loans of $3.3 million and $9.0 million , respectively. For the three and nine months ended September 30, 2017 , the Company recorded a charge for the excess of amortized cost over fair value of the loans of $3.4 million and $6.1 million , respectively. 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 three and nine months ended September 30, 2018 and 2017 , the Company did not have any transfers in or out of Level 1, Level 2, or Level 3 assets or liabilities.

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT, NET	PROPERTY AND EQUIPMENT, NET The following is a summary of property and equipment, less accumulated depreciation and amortization (in thousands): September 30, December 31, Leasehold improvements $ 99,722 $ 77,073 Computer equipment 90,218 66,186 Capitalized software 51,177 35,063 Office furniture and equipment 18,773 14,490 259,890 192,812 Less: Accumulated depreciation and amortization (129,745 ) (101,316 ) Property and equipment, net $ 130,145 $ 91,496 Depreciation and amortization expense on property and equipment was $11.7 million and $29.2 million for the three and nine months ended September 30, 2018 , respectively. Depreciation and amortization expense on property and equipment was $7.3 million and $21.8 million for the three and nine months ended September 30, 2017 , respectively.

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Weebly, Inc. On May 31, 2018 , the Company acquired 100% of the outstanding shares of Weebly, a technology company that offers customers website hosting and domain name registration solutions. The acquisition of Weebly enables the Company to combine Weebly’s web presence tools with the Company's in-person and online offerings to create a cohesive solution for sellers to start or grow an omnichannel business. The acquisition will also expand the Company’s customer base globally and add a new recurring revenue stream. The purchase consideration was comprised of $132.4 million in cash and 2,418,271 shares of the Company’s Class A common stock with an aggregate fair value of $140.1 million based on the closing price of the Company’s Class A common stock on the acquisition date. As part of the acquisition, the Company paid an aggregate of $17.7 million in cash and shares to settle outstanding vested and unvested employee options, of which $2.6 million was accounted for as post-combination compensation expense and is excluded from the purchase consideration. Third-party acquisition-related costs were insignificant. The results of Weebly's operations have been included in the consolidated financial statements since the closing date. The 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 and that the difference between the fair value of the consideration paid for the acquired entity and the fair value of the net assets acquired be recorded as goodwill, which is not amortized but is tested at least annually for impairment. The table below summarizes the consideration paid for Weebly and the preliminary assessment of the fair value of the assets acquired and liabilities assumed at the closing date (in thousands, except share data). Consideration: Cash $ 132,432 Stock (2,418,271 shares of Class A common stock) 140,107 $ 272,539 Recognized amounts of identifiable assets acquired and liabilities assumed: Current assets (inclusive of cash acquired of $25,758) $ 44,685 Intangible customer assets 42,700 Intangible technology assets 14,900 Intangible trade name 11,300 Intangible other assets 961 Total liabilities assumed (including deferred revenue of $22,800) (35,849 ) Total identifiable net assets acquired 78,697 Goodwill 193,842 Total $ 272,539 The Company prepared an initial determination of the fair value of the assets acquired and liabilities assumed as of the acquisition date using preliminary information. During the third quarter of 2018, the Company has recognized measurement period adjustments to the purchase consideration and the fair value of certain liabilities assumed as a result of further refinements in the Company’s estimates. These adjustments were prospectively applied. The effect of these adjustments on the preliminary purchase price allocation was an increase in goodwill and tax liabilities assumed of $4.3 million and $3.0 million , respectively. There was no impact to the consolidated statements of operations as result of these adjustments. The Company continues the process of completing the valuation of the acquired intangible assets and deferred revenue and evaluating contingencies and tax effects related to the acquisition. Accordingly, the preliminary values reflected in the table above are subject to change. As of September 30, 2018, $19.9 million of cash and 372,578 shares of the total consideration were withheld as security for indemnification obligations related to general representations and warranties, in addition to certain potential tax exposures. Goodwill from the Weebly acquisition is primarily attributable to the value of expected synergies created by incorporating Weebly solutions into the Company's technology platform and the value of the assembled workforce. None of the goodwill generated from the Weebly acquisition or the acquired intangible assets are expected to be deductible for tax purposes. Additionally the acquisition would have resulted in recognition of deferred tax assets arising mainly from the net of deferred tax assets from acquired net operating losses (NOLs) and research and development credits, and deferred tax liabilities associated with intangible assets and deferred revenue. However, the realization of such deferred tax assets depends primarily on the Company's post-acquisition ability to generate taxable income in future periods. Accordingly, a valuation allowance was recorded against the net acquired deferred tax asset in accounting for the acquisition. The acquisition of Weebly did not have a material impact on the Company's reported revenue or net loss amounts for any period presented. Accordingly, pro forma financial information has not been presented. Other acquisitions The Company also spent an aggregate of $9.9 million , net of cash acquired, in connection with other immaterial acquisitions during the nine months ended September 30, 2018, which resulted in the recognition of additional intangible assets and goodwill. Pro forma financial information has not been presented for any of our acquisitions as the impact to our consolidated financial statements was not material.

GOODWILL

GOODWILL	9 Months Ended
	Sep. 30, 2018
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 change in carrying value of goodwill in the period was as follows (in thousands): Balance at December 31, 2017 $ 58,327 Acquisitions completed during the nine months ended September 30, 2018 201,637 Balance at September 30, 2018 $ 259,964 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. For the periods presented, the Company had recorded no impairment charges.

ACQUIRED INTANGIBLE ASSETS

ACQUIRED INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
ACQUIRED INTANGIBLE ASSETS	ACQUIRED INTANGIBLE ASSETS The Company entered into two transactions accounted for as business combinations during the quarter ended June 30, 2018, that involved the acquisition of intangible assets. Refer to Note 8 for further details. The following table presents the detail of acquired intangible assets as of the periods presented (in thousands): Balance at September 30, 2018 Cost Accumulated Amortization Net Patents $ 1,285 $ (638 ) $ 647 Technology assets 45,978 (27,043 ) 18,935 Customer assets 57,109 (6,775 ) 50,334 Trade name 11,300 (942 ) 10,358 Other 961 (105 ) 856 Total $ 116,633 $ (35,503 ) $ 81,130 Balance at December 31, 2017 Cost Accumulated Amortization Net Patents $ 1,285 $ (559 ) $ 726 Technology assets 29,158 (21,329 ) 7,829 Customer assets 10,319 (4,540 ) 5,779 Total $ 40,762 $ (26,428 ) $ 14,334 The weighted average amortization periods for acquired patents, acquired technology, customer intangible assets, and acquired trade name are approximately 13 years , 5 years , 11 years and 4 years , respectively. All intangible assets are amortized over their estimated useful lives. The changes to the carrying value of intangible assets were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Acquired intangible assets, net, beginning of the period $ 85,514 $ 16,452 $ 14,334 $ 19,292 Acquisitions — — 75,871 1,224 Amortization expense 4,384 1,804 9,075 5,868 Acquired intangible assets, net, end of the period $ 81,130 $ 14,648 $ 81,130 $ 14,648 The total estimated future amortization expense of these intangible assets as of September 30, 2018 is as follows (in thousands): 2018 (remaining 3 months) $ 4,069 2019 13,702 2020 11,496 2021 10,299 2022 8,369 Thereafter 33,195 Total $ 81,130

OTHER CONSOLIDATED BALANCE SHEE

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT)	9 Months Ended
	Sep. 30, 2018
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): September 30, December 31, Inventory, net $ 25,294 $ 16,777 Processing costs receivable 36,747 21,083 Prepaid expenses 12,666 14,473 Accounts receivable, net 18,980 8,606 Deferred hardware costs (i) — 7,931 Deferred magstripe reader costs (ii) 6,996 2,469 Prepaid compensation, current (iii) 5,487 — Other 30,230 15,115 Total $ 136,400 $ 86,454 (i) The deferred hardware costs represented costs associated with hardware sold through the retail distribution channels. The adoption of ASC 606 on January 1, 2018, has resulted in the recognition of such costs upon delivery of the hardware to the distribution channel. (ii) The Company capitalizes the cost of its magstripe 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. (iii) Prepaid compensation relates to cash transferred by the Company to an escrow agent in connection with a business combination that will be paid to officers of the acquiree over time as they provide services to the Company. Accrued Expenses The following table presents the detail of accrued expenses (in thousands): September 30, December 31, Accrued payroll $ 17,691 $ 9,103 Accrued professional fees 6,903 5,638 Accrued advertising and other marketing 16,391 6,723 Processing costs payable 11,150 10,145 Accrued non income tax liabilities 6,390 6,155 Accrued hardware costs 10,232 2,496 Other accrued liabilities 32,309 12,020 Total $ 101,066 $ 52,280 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): September 30, December 31, Deferred revenue, current $ 29,285 $ 5,893 Square Capital payable (iv) 12,762 7,671 Square Payroll payable (v) 6,707 2,850 Deferred rent, current 3,844 3,311 Accrued redemptions 1,052 1,036 Other 16,688 7,606 Total $ 70,338 $ 28,367 (iv) Square Capital payable represents unpaid amounts arising from the purchase of loans or loan repayments collected on behalf of third parties. (v) Square Payroll payable represents amounts received from Square Payroll product customers that will be utilized to settle the customers employee payroll and related obligations. OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) Other Non-Current Assets The following table presents the detail of other non-current assets (in thousands): September 30, December 31, Equity investment (i) $ 61,908 $ 25,000 Prepaid compensation, non-current (ii) 6,959 — Deposits 2,544 2,738 Debt issuance costs 580 788 Deferred tax assets 540 519 Other 4,465 2,305 Total $ 76,996 $ 31,350 (i) In August, 2017, the Company invested $25.0 million for preferred shares of Eventbrite, Inc. (Eventbrite) which was carried at cost. In September, 2018, upon Eventbrite's initial public offering, the preferred shares held by the Company converted into Class B common shares of Eventbrite. The Company revalued this investment and will subsequently carry it at fair value, with changes in fair value being recorded within other income or expense on the consolidated statement of operations. During the three and nine months ended September 30, 2018, the Company recorded a gain of $36.9 million to other income on the consolidated statements of operations arising from revaluation of this investment. (ii) Prepaid compensation relates to cash transferred by the Company to an escrow agent in connection with a business combination that will be paid to officers of the acquiree over time as they provide services to the Company. Other Non-Current Liabilities The following table presents the detail of other non-current liabilities (in thousands): September 30, December 31, Statutory liabilities (iii) $ 51,134 $ 40,768 Deferred rent, non-current 22,243 20,349 Deferred purchase consideration 3,900 — Deferred revenue, non-current 4,329 432 Deferred tax liabilities 147 644 Other 7,958 7,345 Total $ 89,711 $ 69,538 (iii) Statutory liabilities represent loss contingencies that may arise from the Company's interpretation and application of certain guidelines and rules issued by various federal, state, local, and foreign regulatory authorities.

OTHER CONSOLIDATED BALANCE SH_2

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT)	9 Months Ended
	Sep. 30, 2018
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): September 30, December 31, Inventory, net $ 25,294 $ 16,777 Processing costs receivable 36,747 21,083 Prepaid expenses 12,666 14,473 Accounts receivable, net 18,980 8,606 Deferred hardware costs (i) — 7,931 Deferred magstripe reader costs (ii) 6,996 2,469 Prepaid compensation, current (iii) 5,487 — Other 30,230 15,115 Total $ 136,400 $ 86,454 (i) The deferred hardware costs represented costs associated with hardware sold through the retail distribution channels. The adoption of ASC 606 on January 1, 2018, has resulted in the recognition of such costs upon delivery of the hardware to the distribution channel. (ii) The Company capitalizes the cost of its magstripe 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. (iii) Prepaid compensation relates to cash transferred by the Company to an escrow agent in connection with a business combination that will be paid to officers of the acquiree over time as they provide services to the Company. Accrued Expenses The following table presents the detail of accrued expenses (in thousands): September 30, December 31, Accrued payroll $ 17,691 $ 9,103 Accrued professional fees 6,903 5,638 Accrued advertising and other marketing 16,391 6,723 Processing costs payable 11,150 10,145 Accrued non income tax liabilities 6,390 6,155 Accrued hardware costs 10,232 2,496 Other accrued liabilities 32,309 12,020 Total $ 101,066 $ 52,280 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): September 30, December 31, Deferred revenue, current $ 29,285 $ 5,893 Square Capital payable (iv) 12,762 7,671 Square Payroll payable (v) 6,707 2,850 Deferred rent, current 3,844 3,311 Accrued redemptions 1,052 1,036 Other 16,688 7,606 Total $ 70,338 $ 28,367 (iv) Square Capital payable represents unpaid amounts arising from the purchase of loans or loan repayments collected on behalf of third parties. (v) Square Payroll payable represents amounts received from Square Payroll product customers that will be utilized to settle the customers employee payroll and related obligations. OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) Other Non-Current Assets The following table presents the detail of other non-current assets (in thousands): September 30, December 31, Equity investment (i) $ 61,908 $ 25,000 Prepaid compensation, non-current (ii) 6,959 — Deposits 2,544 2,738 Debt issuance costs 580 788 Deferred tax assets 540 519 Other 4,465 2,305 Total $ 76,996 $ 31,350 (i) In August, 2017, the Company invested $25.0 million for preferred shares of Eventbrite, Inc. (Eventbrite) which was carried at cost. In September, 2018, upon Eventbrite's initial public offering, the preferred shares held by the Company converted into Class B common shares of Eventbrite. The Company revalued this investment and will subsequently carry it at fair value, with changes in fair value being recorded within other income or expense on the consolidated statement of operations. During the three and nine months ended September 30, 2018, the Company recorded a gain of $36.9 million to other income on the consolidated statements of operations arising from revaluation of this investment. (ii) Prepaid compensation relates to cash transferred by the Company to an escrow agent in connection with a business combination that will be paid to officers of the acquiree over time as they provide services to the Company. Other Non-Current Liabilities The following table presents the detail of other non-current liabilities (in thousands): September 30, December 31, Statutory liabilities (iii) $ 51,134 $ 40,768 Deferred rent, non-current 22,243 20,349 Deferred purchase consideration 3,900 — Deferred revenue, non-current 4,329 432 Deferred tax liabilities 147 644 Other 7,958 7,345 Total $ 89,711 $ 69,538 (iii) Statutory liabilities represent loss contingencies that may arise from the Company's interpretation and application of certain guidelines and rules issued by various federal, state, local, and foreign regulatory authorities.

INDEBTEDNESS

INDEBTEDNESS	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
INDEBTEDNESS	INDEBTEDNESS Revolving Credit Facility 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 have been drawn under the credit facility, with $375.0 million remaining available. The Company paid $0.1 million and $0.4 million in unused commitment fees during both the three and nine months ended September 30, 2018 and 2017 , respectively. As of September 30, 2018 , the Company was in compliance with all financial covenants associated with this credit facility. Convertible Senior Notes due in 2023 On May 25, 2018, the Company issued an aggregate principal amount of $750.0 million of convertible senior notes and an additional 15% or $112.5 million pursuant to the exercise in full of the option to the initial purchaser to cover over-allotments (2023 Notes). The 2023 Notes mature on May 15, 2023, unless earlier converted or repurchased, and bear interest at a rate of 0.50% payable semi-annually on May 15 and November 15 of each year. The 2023 Notes are convertible at an initial conversion rate of 12.8456 shares of the Company's Class A common stock per $1,000 principal amount of 2023 Notes, which is equivalent to an initial conversion price of approximately $77.85 per share of Class A common stock. Holders may convert their 2023 Notes at any time prior to the close of business on the business day immediately preceding February 15, 2023 only under the following circumstances: (1) during any calendar quarter commencing after September 30, 2018 (and only during such calendar quarter), if the last reported sale price of the Company’s Class A common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period (the measurement period) in which the trading price (as defined in the indenture governing the 2023 Notes) per $1,000 principal amount of 2023 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s Class A common stock and the conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events, including certain distributions, the occurrence of a fundamental change (as defined in the indenture governing the 2023 Notes) or a transaction resulting in the Company’s Class A common stock converting into other securities or property or assets. On or after February 15, 2023, up until the close of business on the second scheduled trading day immediately preceding the maturity date, a holder may convert all or any portion of its 2023 Notes regardless of the foregoing circumstances. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of its Class A common stock, or a combination of cash and shares of its Class A common stock, at the Company’s election. Effective October 2018, the Company revised its prior stated policy of settling conversions through combination settlement with a specified dollar amount of $1,000 per $1,000 principal amount of 2023 Notes, and currently expects to settle future conversions entirely in shares of the Company's Class A common stock. The Company will reevaluate this policy from time to time as conversion notices are received from holders of the 2023 Notes. In accounting for the issuance of the 2023 Notes, the Company separated the 2023 Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was $155.3 million and was determined by deducting the fair value of the liability component from the par value of the 2023 Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount ("debt discount") is amortized to interest expense over the term of the 2023 Notes at an effective interest rate of 4.69% over the contractual terms of the Notes. Debt issuance costs related to the 2023 Notes comprised of discounts and commissions payable to the initial purchasers of $6.0 million and third party offering costs of $0.8 million . The Company allocated the total amount incurred to the liability and equity components of the 2023 Notes based on their relative values. Issuance costs attributable to the liability component were $5.6 million and will be amortized to interest expense using the effective interest method over the contractual term. Issuance costs attributable to the equity component were netted with the equity component in stockholders’ equity. Convertible Senior Notes due in 2022 On March 6, 2017, the Company issued an aggregate principal amount of $400.0 million of convertible senior notes and an additional 10% or $40.0 million pursuant to the exercise in full of the option to the initial purchasers to cover over-allotments (2022 Notes). The 2022 Notes mature on March 1, 2022, unless earlier converted or repurchased, and bear interest at a rate of 0.375% payable semi-annually on March 1 and September 1 of each year. The 2022 Notes are convertible at an initial conversion rate of 43.5749 shares of the Company's Class A common stock per $1,000 principal amount of 2022 Notes, which is equivalent to an initial conversion price of approximately $22.95 per share of Class A common stock. Holders may convert their 2022 Notes at any time prior to the close of business on the business day immediately preceding December 1, 2021 only under the following circumstances: (1) during any calendar quarter (and only during such calendar quarter), if the last reported sale price of the Company’s Class A common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period (the measurement period) in which the trading price (as defined in the indenture governing the 2022 Notes) per $1,000 principal amount of 2022 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s Class A common stock and the conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events, including certain distributions, the occurrence of a fundamental change (as defined in the indenture governing the 2022 Notes) or a transaction resulting in the Company’s Class A common stock converting into other securities or property or assets. On or after December 1, 2021, up until the close of business on the second scheduled trading day immediately preceding the maturity date, a holder may convert all or any portion of its 2022 Notes regardless of the foregoing circumstances. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of its Class A common stock, or a combination of cash and shares of its Class A common stock, at the Company’s election. The circumstances required to allow the holders to convert their 2022 Notes were met starting January 1, 2018. During the third quarter of 2018, certain holders of the 2022 Notes converted an aggregate principal amount of $70.0 million of their Notes. The Company settled the principal amount in cash and the balance by issuing 2.2 million shares of the Company's Class A common stock. Additionally, as of September 30, 2018, the Company had received notification from certain holders of the 2022 Notes of their intention to convert an aggregate principal amount of $149.0 million of 2022 Notes, that are expected to be settled in the fourth quarter of 2018 through a combination of cash and shares of the Company's Class A common stock. Effective October 2018, the Company revised its prior stated policy of settling conversions through combination settlement with a specified dollar amount of $1,000 per $1,000 principal amount of 2022 Notes. The Company currently expects to settle future conversions in shares of the Company's Class A common stock. The Company will reevaluate this policy from time to time as conversion notices are received from holders of the 2022 Notes. In accounting for the issuance of the 2022 Notes, the Company separated the 2022 Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was $86.2 million and was determined by deducting the fair value of the liability component from the par value of the 2022 Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The debt discount is amortized to interest expense over the term of the 2022 Notes at an effective interest rate of 5.34% over the contractual terms of the Notes. Debt issuance costs related to the 2022 Notes comprised of discounts and commissions payable to the initial purchasers of $11.0 million and third party offering costs of $0.8 million . The Company allocated the total amount incurred to the liability and equity components of the 2022 Notes based on their relative values. Issuance costs attributable to the liability component were $9.4 million and will be amortized to interest expense using the effective interest method over the contractual term. Issuance costs attributable to the equity component were netted with the equity component in stockholders’ equity. The debt component associated with the 2022 Notes that were converted was accounted for as an extinguishment of debt, with the Company recording loss on extinguishment of $1.6 million , as the difference between the estimated fair value and the carrying value of such 2022 Notes. The equity component associated with the 2022 Notes that were converted was accounted for as a reacquisition of equity upon the conversion of such 2022 Notes. Accordingly, the excess of the fair value of the consideration issued to settle the conversion over the fair value of the debt component of $9.3 million was accounted for as a reduction to the additional paid in capital. The net carrying amount of the Notes were as follows (in thousands): Principal outstanding Unamortized debt discount Unamortized debt issuance costs Net carrying value September 30, 2018 2023 Notes $ 862,500 $ (145,998 ) $ (5,273 ) $ 711,229 2022 Notes 369,953 (51,581 ) (5,654 ) 312,718 Total 1,232,453 (197,579 ) (10,927 ) 1,023,947 December 31, 2017 2022 Notes $ 440,000 $ (73,384 ) $ (8,044 ) $ 358,572 The net carrying amount of the equity component of the Notes were as follows (in thousands): Amount allocated to conversion option Less: allocated issuance costs Equity component, net September 30, 2018 2023 Notes $ 155,250 $ (1,231 ) $ 154,019 2022 Notes 72,480 (1,936 ) 70,544 Total 227,730 (3,167 ) 224,563 December 31, 2017 2022 Notes $ 86,203 $ (2,302 ) $ 83,901 The Company recognized interest expense on the Notes as follows (in thousands, except for percentages): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Contractual interest expense $ 1,469 $ 413 $ 2,732 $ 938 Amortization of debt discount and issuance costs 11,627 4,277 22,850 9,889 Total $ 13,096 $ 4,690 $ 25,582 $ 10,827 The effective interest rate of the liability component is 4.69% and 5.34% for the 2023 Notes and 2022 Notes, respectively. Convertible Note Hedge and Warrant Transactions In connection with the offering of the 2023 Notes, the Company entered into convertible note hedge transactions (2023 convertible note hedges) with certain financial institution counterparties whereby the Company has the option to purchase a total of approximately 11.1 million shares of its Class A common stock at a price of approximately $77.85 per share. The total cost of the 2023 convertible note hedge transactions was $172.6 million . In addition, the Company sold warrants (2023 warrants) to the counterparties whereby the counterparties have the option to purchase a total of 11.1 million shares of the Company’s Class A common stock at a price of approximately $109.26 per share. The Company received $112.1 million in cash proceeds from the sale of the 2023 warrants. Taken together, the purchase of the 2023 convertible note hedges and sale of the 2023 warrants are intended to reduce dilution from the conversion of the 2023 Notes and/or offset any cash payments the Company is required to make in excess of the principal amount of the converted 2023 Notes, as the case may be, and to effectively increase the overall conversion price from approximately $77.85 per share to approximately $109.26 per share. As these instruments are considered indexed to the Company's own stock and are considered equity classified, the 2023 convertible note hedges and 2023 warrants are recorded in stockholders’ equity, are not accounted for as derivatives and are not remeasured each reporting period. The net costs incurred in connection with the 2023 convertible note hedge and 2023 warrant transactions were recorded as a reduction to additional paid-in capital on the condensed consolidated balance sheets. In connection with the offering of the 2022 Notes, the Company entered into convertible note hedge transactions (2022 convertible note hedges) with certain financial institution counterparties whereby the Company has the option to purchase a total of approximately 19.2 million shares of its Class A common stock at a price of approximately $22.95 per share. The total cost of the 2022 convertible note hedge transactions was $92.1 million . In addition, the Company sold warrants (2022 warrants) to the counterparties whereby the counterparties have the option to purchase a total of 19.2 million shares of the Company’s Class A common stock at a price of approximately $31.18 per share. The Company received $57.2 million in cash proceeds from the sale of the 2022 warrants. Taken together, the purchase of the 2022 convertible note hedges and sale of the 2022 warrants are intended to reduce dilution from the conversion of the 2022 Notes and/or offset any cash payments the Company is required to make in excess of the principal amount of the converted 2022 Notes, as the case may be, and to effectively increase the overall conversion price from approximately $22.95 per share to approximately $31.18 per share. As these instruments are considered indexed to the Company's own stock and are considered equity classified, the 2022 convertible note hedges and 2022 warrants are recorded in stockholders’ equity, are not accounted for as derivatives and are not remeasured each reporting period. The net costs incurred in connection with the 2022 convertible note hedge and 2022 warrant transactions were recorded as a reduction to additional paid-in capital on the condensed consolidated balance sheets. During the third quarter of 2018, the Company exercised a pro-rata portion of the 2022 convertible note hedges to offset the shares of the Company's Class A common stock issued to settle the conversion of the 2022 Notes discussed above. The 2022 convertible note hedges were net share settled, and the Company received 2.2 million shares of the Company's Class A common stock from the counterparties.

ACCRUED TRANSACTION LOSSES

ACCRUED TRANSACTION LOSSES	9 Months Ended
	Sep. 30, 2018
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): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Accrued transaction losses, beginning of the period $ 29,207 $ 22,455 $ 26,893 $ 20,064 Provision for transaction losses 20,449 15,102 48,794 39,737 Charge-offs to accrued transaction losses (14,324 ) (10,837 ) (40,355 ) (33,081 ) Accrued transaction losses, end of the period $ 35,332 $ 26,720 $ 35,332 $ 26,720

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company recorded an income tax expense of $1.1 million and $1.8 million for the three and nine months ended September 30, 2018 , respectively, compared to income tax (benefit) expense of $(0.6) million and $0.3 million for the three and nine months ended September 30, 2017 , respectively. The income tax expense recorded for the three and nine months ended September 30, 2018 was primarily due to state and foreign income tax expense offset by a release in the U.S. valuation allowance. The Company’s effective tax rate was 5.1% and (22.0)% for the three and nine months ended September 30, 2018 , respectively, compared to an effective tax rate of 3.9% and (0.7)% for the three and nine months ended September 30, 2017 , respectively. The difference between the effective tax rate and the federal statutory tax rate for the three and nine months ended September 30, 2018 and September 30, 2017 primarily relates to the valuation allowance on the Company’s deferred tax assets and the income tax benefit of the monetization of its alternative minimum tax (AMT) credit in 2017. The Company’s effective tax rate may be subject to fluctuation during the year as new information is obtained, which may affect the assumptions used to estimate the annual effective tax rate, including factors such as the mix of forecasted pre-tax earnings in the various jurisdictions in which the Company operates, valuation allowances against deferred tax assets, the recognition and de-recognition of tax benefits related to uncertain tax positions, and changes in or the interpretation of tax laws in jurisdictions where the Company conducts business. As of September 30, 2018 , the Company retains a full valuation allowance on its deferred tax assets in the U.S. and certain foreign jurisdictions. The realization of the Company’s deferred tax assets depends primarily on its ability to generate taxable income in future periods. 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 tax provision for the three and nine months ended September 30, 2018 and September 30, 2017 , was calculated on a jurisdictional basis. The Company estimated the foreign income tax provision using the effective income tax rate expected to be applicable for the full year. On December 22, 2017, the SEC issued Staff Accounting Bulletin No. 118 (SAB 118) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act of 2017 (Tax Act). During the third quarter of 2018, the Company finalized its federal and state income tax returns, making no material adjustments to provisional amounts previously recorded. If additional guidance clarifying aspects of the Tax Act is released, any subsequent adjustment to these amounts will be recorded to current tax expense as a change in tax law.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS’ EQUITY The changes in total stockholders’ equity were as follows (in thousands): Total stockholders’ equity Balance at December 31, 2017 $ 786,333 Net loss (10,249 ) Exercise of stock options 82,202 Purchases under the employee stock purchase plan 12,578 Vesting of early exercised stock options and other 136 Issuance of common stock in connection with business combination 140,107 Replacement stock awards issued in connection with acquisition 899 Conversion feature of convertible senior notes, due 2023, net of allocated costs 154,019 Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2023 (172,586 ) Sale of warrants in conjunction with issuance of convertible senior notes, due 2023 112,125 Issuance of common stock in conjunction with the conversion of senior notes, due 2022 (9,305 ) Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022 — Share-based compensation 164,142 Tax withholding related to vesting of restricted stock units (125,899 ) Cumulative adjustment for adoption of ASC 606 (4,586 ) Recovery of common stock in connection with indemnification settlement agreement (2,745 ) Change in other comprehensive loss (5,027 ) Balance at September 30, 2018 $ 1,122,144 Common Stock The Company has authorized the issuance of Class A common stock and Class B common stock. Class A common stock and Class B common stock are referred to as "common stock" throughout these Notes to the Condensed Consolidated Financial Statements, unless otherwise noted. As of September 30, 2018 , 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 September 30, 2018 , there were 306,228,873 shares of Class A common stock and 106,143,959 shares of Class B common stock outstanding. Options and awards granted following the Company's initial public offering are related to underlying Class A common stock. Additionally, holders of Class B common stock are able to convert such shares into Class A common stock. Warrants In conjunction with the 2023 Notes offering, the Company sold the 2023 warrants whereby the counterparties have the option to purchase a total of approximately 11.1 million shares of the Company’s Class A common stock at a price of $109.26 per share. The Company received $112.1 million in cash proceeds from the sale of the 2023 warrants. See Note 13 , Indebtedness , for more details on this transaction. Release of Caviar Shares Held Back In 2014, in conjunction with the Company's acquisition of Caviar, Inc. (Caviar), 1,291,979 shares of the purchase consideration issuable were withheld for indemnification purposes. In April 2018, the Company reached an agreement with the former owners of Caviar whereby 822,085 of the shares held back were released to the former owners and 469,894 shares were forfeited back to the Company as indemnification against liabilities related to Caviar preacquisition matters. Upon reaching the agreement, the Company recorded an indemnification asset of $2.8 million and a corresponding credit to expense to compensate for the costs previously incurred in connection with Caviar preacquisition claims. The remaining value of the forfeited shares was treated as an equity repurchase. Conversion of 2022 Notes and Exercise of the 2022 Convertible Note Hedges In connection with the conversion of certain of the 2022 Notes, the Company issued 2.2 million shares of Class A common stock. The Company also exercised a pro-rata portion of the 2022 convertible note hedges and received 2.2 million shares of Class A common stock from the counterparties to offset the shares issued. Stock Plans The Company maintains two share-based employee compensation plans: the 2009 Stock Plan (2009 Plan) and the 2015 Equity Incentive Plan (2015 Plan). The 2015 Plan serves as the successor to the 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. Since November 17, 2015, no additional awards have been nor will be in the future granted under the 2009 Plan. Under the 2015 Plan, shares of the Company's Class A common stock are reserved for the issuance of incentive and nonstatutory stock options, restricted stock awards (RSAs), restricted stock units (RSUs), performance shares, and stock bonuses to qualified employees, directors, and consultants. The awards must 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 or a committee thereof. As of September 30, 2018 , the total number of shares subject to stock options, RSAs and RSUs outstanding under the 2015 Plan was 25,272,110 , and 63,264,588 shares were available for future issuance. As of September 30, 2018 , the total number of shares subject to stock options, RSAs and RSUs outstanding under the 2009 Plan was 31,343,565 . A summary of stock option activity for the nine months ended September 30, 2018 is as follows (in thousands, except share and per share data): Number of Stock Options Outstanding Weighted Weighted Aggregate Balance at December 31, 2017 47,270,091 $ 8.67 6.52 $ 1,229,103 Granted 783,625 44.75 Exercised (10,661,450 ) 7.71 Forfeited (674,525 ) 12.97 Balance at September 30, 2018 36,717,741 $ 9.64 5.94 $ 3,281,558 Options exercisable as of September 30, 2018 33,952,212 $ 8.64 5.75 $ 3,068,274 Restricted Stock Activity Activity related to RSAs and RSUs during the nine months ended September 30, 2018 is set forth below: Number of Weighted Unvested as of December 31, 2017 21,317,525 $ 17.84 Granted 6,408,650 52.93 Vested (5,796,657 ) 18.30 Forfeited (2,031,584 ) 18.56 Unvested as of September 30, 2018 19,897,934 $ 28.94 Share-Based Compensation The fair value of stock options and employee stock purchase plan rights are estimated on the date of grant using the Black-Scholes-Merton option valuation model. The fair value of RSAs and RSUs is determined by the closing price of the Company’s common stock on each grant date. The fair value of stock options granted was estimated using the following weighted-average assumptions: Nine Months Ended September 30, 2018 2017 Dividend yield — % — % Risk-free interest rate 2.92 % 1.88 % Expected volatility 30.87 % 32.22 % Expected term (years) 6.19 6.02 The following table summarizes the effects of share-based compensation on the Company's condensed consolidated statements of operations (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Cost of revenue $ 18 $ 29 $ 79 $ 47 Product development 39,525 25,254 103,813 69,746 Sales and marketing 6,108 4,579 16,703 12,869 General and administrative 13,262 10,186 37,261 28,649 Total $ 58,913 $ 40,048 $ 157,856 $ 111,311 The Company recorded $2.0 million and $6.3 million of share-based compensation expense related to the Company's 2015 Employee Stock Purchase Plan during the three and nine months ended September 30, 2018 , respectively, compared to $1.3 million and $4.4 million for the three and nine months ended September 30, 2017 , respectively, which are included in the table above. The Company capitalized $2.0 million and $6.3 million of share-based compensation expense related to capitalized software costs during the three and nine months ended September 30, 2018 , respectively, compared to $1.3 million and $2.5 million for the three and nine months ended September 30, 2017 , respectively. As of September 30, 2018 , there was $588.5 million of total unrecognized compensation cost related to outstanding awards that are expected to be recognized over a weighted-average period of 2.90 years .

INCOME (LOSS) PER SHARE

INCOME (LOSS) PER SHARE	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
INCOME (LOSS) PER SHARE	INCOME (LOSS) PER SHARE Basic net income (loss) per share is computed by dividing the net income (loss) by the weighted-average number of shares of common stock outstanding during the period. Diluted net income per share is computed by dividing net income by the weighted-average number of shares of common stock outstanding adjusted for the dilutive effect of all potential shares of common stock. Diluted net loss per share is the same as basic net loss per share because the effects of potentially dilutive items were anti-dilutive given the Company’s net loss. The following table presents the calculation of basic and diluted net income (loss) per share (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Net income (loss) $ 19,643 $ (16,098 ) $ (10,249 ) $ (47,150 ) Denominator: Basic shares: Weighted-average common shares outstanding 410,095 385,409 403,577 377,374 Weighted-average unvested shares (405 ) (1,458 ) (597 ) (1,631 ) Weighted-average shares used to compute basic net income (loss) per share 409,690 383,951 402,980 375,743 Diluted shares: Stock options and restricted stock units 47,175 — — — Convertible senior notes 6,409 — — — Common stock warrants 11,422 — — — Employee stock purchase plan 219 — — — Weighted-average shares used to compute diluted net income (loss) per share 474,915 383,951 402,980 375,743 Net income (loss) per share: Basic $ 0.05 $ (0.04 ) $ (0.03 ) $ (0.13 ) Diluted $ 0.04 $ (0.04 ) $ (0.03 ) $ (0.13 ) Additionally, since the Company has revised its policy and now intends to settle future conversions of its outstanding 2022 Notes and 2023 Notes entirely in shares of its Class A common stock, the Company will consider the number of shares expected to be issued in calculating any potential dilutive effect of the conversions, if applicable. In the periods that the Company has reported a net loss the diluted loss per share is the same as basic loss per share for those periods. The following potential common shares were excluded from the calculation of diluted net income (loss) per share because their effect would have been anti-dilutive for the periods presented (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Stock options and restricted stock units 12,079 76,618 62,822 81,118 Common stock warrants 18,830 19,173 24,387 16,539 Convertible senior notes 23,415 — 24,276 — Unvested shares 405 1,458 597 1,631 Employee stock purchase plan 26 517 207 412 Total anti-dilutive securities 54,755 97,766 112,289 99,700

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2018
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 2018 and 2025 . The Company recognized total rental expenses under operating leases of $6.4 million and $16.2 million for the three and nine months ended September 30, 2018 , respectively, compared to $3.7 million and $9.6 million for the three and nine months ended September 30, 2017 , respectively. Future minimum lease payments under non-cancelable operating leases (with initial lease terms in excess of one year) and future minimum capital lease payments as of September 30, 2018 are as follows (in thousands): Capital Operating Year: 2018 (remaining 3 months) $ 1,284 $ 7,687 2019 5,029 29,454 2020 2,446 30,657 2021 — 30,598 2022 — 31,051 Thereafter — 32,747 Total $ 8,759 $ 162,194 Less amount representing interest — Present value of capital lease obligations 8,759 Less current portion of capital lease obligation (5,135 ) Non-current portion of capital lease obligation $ 3,624 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 Treasurer & Tax Collector of the City and County of San Francisco (Tax Collector) has issued a decision for fiscal years 2014 and 2015, that the Tax Collector believes the Company’s primary business activity is financial services rather than information services, and accordingly, the Company would be liable for the Gross Receipts Tax and Payroll Expense Tax under the rules for financial services business activities. The Company paid the liability for fiscal years 2014 and 2015 in the first quarter of 2018, as assessed by the Tax Collector. The Company intends to vigorously defend its position, which it believes has merit. Should the Company not prevail, the Company could be obligated to pay additional taxes together with any associated penalties and interest for subsequent years that together, in aggregate, could be material. The Company is currently unable to estimate the range of possible loss given the uncertainties associated with this matter, including uncertainties about the Tax Collector’s rationale for its position and about the amounts that may ultimately be subject to such taxes. On May 14, 2018, Joshua Woodle, on behalf of a class of couriers who have delivered with Caviar in California, filed a lawsuit in San Francisco County Superior Court against the Company doing business as Caviar, which alleges that Caviar misclassified Mr. Woodle 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. Plaintiffs seek damages and injunctive relief. The Court compelled arbitration of Mr. Woodle’s arbitrable claims on November 5, 2018. On August 24, 2018, Mervyn Cole, on behalf of the State of California and similarly situated couriers who have delivered with Caviar in California filed a lawsuit in Los Angeles County Superior Court against the Company doing business as Caviar. The complaint alleges that Caviar misclassified Mr. Cole and other similarly situated couriers as independent contractors and, in doing so, violated certain provisions of the California Labor Code. The action is being brought as a representative action under the Private Attorneys General Act (“PAGA”). Plaintiffs seek civil penalties and injunctive relief. Given the early stage of these proceedings, it is not yet possible to reliably determine any potential liability that could result from these matters. 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.

SEGMENT AND GEOGRAPHICAL INFORM

SEGMENT AND GEOGRAPHICAL INFORMATION	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
SEGMENT AND GEOGRAPHIC 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 is the chief executive officer who 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 sellers or customers. The following table sets forth revenue by geographic area (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue United States $ 838,149 $ 559,053 $ 2,255,657 $ 1,533,960 International 43,959 26,106 109,992 64,258 Total net revenue $ 882,108 $ 585,159 $ 2,365,649 $ 1,598,218 No individual country from the international markets contributed in excess of 10% of total revenue for the three and nine months ended September 30, 2018 and 2017 . Long-Lived Assets The following table sets forth long-lived assets by geographic area (in thousands): September 30, December 31, Long-lived assets United States $ 464,455 $ 158,820 International 6,784 5,337 Total long-lived assets $ 471,239 $ 164,157

SUPPLEMENTAL CASH FLOW INFORMAT

SUPPLEMENTAL CASH FLOW INFORMATION	9 Months Ended
	Sep. 30, 2018
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): Nine Months Ended September 30, 2018 2017 Supplemental Cash Flow Data: Cash paid for interest $ 1,945 $ 1,230 Cash paid for income taxes 1,265 1,117 Supplemental disclosures of non-cash investing and financing activities: Change in purchases of property and equipment in accounts payable and accrued expenses 11,004 (123 ) Unpaid business combination purchase price 3,995 644 Fair value of common stock issued related to business combination (140,107 ) — Recovery of common stock in connection with indemnification settlement agreement 2,745 — Fair value of common stock issued to settle the conversion of senior notes, due 2022 (189,916 ) — Fair value of shares received to settle senior note hedges, due 2022 189,916 —

DESCRIPTION OF BUSINESS AND S_2

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reclassifications and Other Adjustments	During the third quarter of 2018, the Company has reclassified prior period balances within interest and other (income) expense, net, to disaggregate the amounts and separately present interest (income) expense, net and other (income) expense, net on its consolidated statements of operations to conform to the current period presentation. This classification change was made to provide clarity of the balances as the activity continues to grow, particularly as a result of the impact of revaluation of an equity investment in the current period.
Basis of Presentation	The accompanying interim condensed consolidated financial statements of the Company are unaudited. These interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and the applicable rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The December 31, 2017 condensed consolidated balance sheet was derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The accompanying unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments of a normal recurring nature considered necessary to state fairly the Company's consolidated financial position, results of operations, comprehensive income (loss), and cash flows for the interim periods. All intercompany transactions and balances have been eliminated in consolidation. The interim results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 , or for any other future annual or interim period. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Quantitative and Qualitative Disclosures About Market Risk,” and the Consolidated Financial Statements and notes thereto included in Items 7, 7A, and 8, respectively, in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 .
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. 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 the debt component of convertible senior notes, valuation of loans held for sale, goodwill, acquired intangible assets and deferred revenue, income and other taxes, and share-based compensation.
Concentration of Credit Risk	Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash, marketable debt securities, settlements receivables, customer funds, and loans held for sale. The associated risk of concentration for cash and cash equivalents and restricted cash 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 debt 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 loans held for sale is partially mitigated by credit evaluations that are performed prior to facilitating the offering of loans and ongoing performance monitoring of the Company’s loan customers.
Cryptocurrency transactions	During the fourth quarter of 2017, the Company started offering its Cash App customers the ability to purchase bitcoin, a cryptocurrency denominated asset, from the Company. The Company purchases bitcoin from private broker dealers or from Cash App customers. Upon purchase, the Company records the cost of bitcoin within other current assets in its consolidated balance sheets. Upon sale, the Company records the total sale amount received from customers as bitcoin revenue and the associated cost as cost of revenue. The carrying value of bitcoin held by the Company was $0.2 million and $0.3 million as of September 30, 2018 and December 31, 2017 , respectively. The Company assesses the carrying value of bitcoin held by the Company at each reporting date and records an impairment charge if the cost exceeds the fair value. Losses on bitcoin for the three and nine months ended September 30, 2018 , were insignificant.
Customer funds	Customer funds represent Cash App customers' stored balances that customers can later use to send money or make payments, or customers with cash in transit. As of December 31, 2017, the Company held these stored balances as short term bank deposits. During the third quarter of 2018, the Company started investing a portion of these stored balances in short-term marketable debt securities (Note 5 ).
Recent Accounting Pronouncements	Recently issued accounting pronouncements not yet adopted In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-02, Leases , which will require, among other items, lessees to recognize a right of use asset and a related lease liability for most leases 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 new standard should be applied on a modified retrospective basis. The Company does not plan to early adopt this guidance. The Company’s operating leases primarily comprise of office facilities, with the most significant leases relating to corporate headquarters in San Francisco and an office in New York. While the Company continues to evaluate the impact of adopting this guidance on its consolidated financial statements, it does expect to record material right to use assets and related lease liabilities on its consolidated balance sheets upon adoption, which will increase total assets and liabilities. 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. Early adoption is permitted for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The Company is currently evaluating the impact this guidance may have on the consolidated financial statements and related disclosures. In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment . The new guidance eliminates the requirement to calculate the implied fair value of goodwill assuming a hypothetical purchase price allocation (i.e., Step 2 of the goodwill impairment test) to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value, not to exceed the carrying amount of goodwill. 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 does not expect the adoption of this guidance to have a material impact on the consolidated financial statements and related disclosures. In March 2017, the FASB issued ASU No. 2017-08, Premium Amortization on Purchased Callable Debt Securities, which amends the amortization period for certain purchased callable debt securities held at a premium, shortening such period to the earliest call date. This standard is effective for annual periods beginning after December 15, 2018, 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 guidance may have on the consolidated financial statements and related disclosures. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . When the Tax Cuts and Jobs Act of 2017 was enacted in December 2017, there was a valuation allowance on the deferred tax assets included within the Company's accumulated other comprehensive income; therefore no tax expense resulted from the change in the federal income tax rate. This guidance allows companies to reclassify such tax effects from accumulated other comprehensive income to retained earnings. 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 expect the adoption of this guidance to have a material impact on the consolidated financial statements and related disclosures. In July 2018, the FASB issued ASU 2018-13, Changes to the Disclosure Requirements for Fair Value Measurement, which will remove, modify and add disclosure requirements for fair value measurements to improve the overall usefulness of such disclosures. 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 for any removed or modified disclosure requirements. Transition is on a prospective basis for the new and modified disclosures, and on a retrospective basis for disclosures that have been eliminated. The Company is currently evaluating the impact this guidance may have on the consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which is intended to align the requirements for capitalization of implementation costs incurred in a cloud computing arrangement that is a service contract with the existing guidance for internal-use software. 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 guidance provides flexibility in adoption, allowing for either retrospective adjustment or prospective adjustment for all implementation costs incurred after the date of adoption. The Company is currently evaluating the impact this guidance may have on the consolidated financial statements and related disclosures.

REVENUE (Tables)

REVENUE (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Schedule of Impact of Adoption of ASC 606	The impact of adoption of ASC 606 on the Company's condensed consolidated statement of operations was as follows (in thousands): Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 As reported Balances without adoption Effect of change As reported Balances without adoption Effect of change Impact on the Condensed Consolidated Statement of Operations: Subscription and services-based revenue $ 166,203 $ 166,037 $ 166 $ 397,589 $ 397,272 $ 317 Hardware revenue 17,558 16,145 1,413 50,337 45,378 4,959 Subscription and services-based costs 47,078 47,078 — 117,230 117,230 — Hardware costs $ 23,229 $ 21,969 $ 1,260 $ 68,467 $ 63,665 $ 4,802 The impact of adoption of ASC 606 on the Company's condensed consolidated balance sheets was as follows (in thousands): September 30, 2018 As reported Balances without adoption Effect of change Impact on the Condensed Consolidated Balance Sheets: Other current assets $ 136,400 $ 148,491 $ (12,091 ) Other current liabilities 70,338 78,260 (7,922 ) Other non-current assets 76,996 78,584 (1,588 ) Other non-current liabilities $ 89,711 $ 91,311 $ (1,600 )
Schedule of Disaggregation of Revenue	The following table presents the Company's revenue from contracts with customers disaggregated by revenue source (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue from Contracts with Customers: Transaction-based revenue $ 655,384 $ 510,019 $ 1,803,649 $ 1,395,562 Subscription and services-based revenue 141,752 65,051 330,637 173,262 Hardware revenue 17,558 10,089 50,337 29,394 Bitcoin revenue $ 42,963 $ — $ 114,074 $ —
Schedule of Deferred Revenue	The deferred revenue balances were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Deferred revenue, beginning of the period $ 27,155 $ 4,523 $ 5,893 $ 5,407 Less: accumulative adjustment for adoption of ASC 606 — — (4,303 ) — Deferred revenue, beginning of the period, as adjusted 27,155 4,523 1,590 5,407 Deferred revenue, end of the period 33,614 3,424 33,614 3,424 Deferred revenue arising from business combination 22,800 — 22,800 — Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period $ 10,165 $ 2,060 $ 1,539 $ 5,312

INVESTMENTS (Tables)

INVESTMENTS (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Short-term and Long-term Investments	The Company's short-term and long-term investments as of September 30, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 48,206 $ 11 $ (27 ) $ 48,190 Corporate bonds 83,647 135 (64 ) 83,718 Municipal securities 28,904 37 (49 ) 28,892 U.S. government securities 270,094 70 (372 ) 269,792 Non-U.S. government securities 18,433 — (39 ) 18,394 Total $ 449,284 $ 253 $ (551 ) $ 448,986 Long-term debt securities: U.S. agency securities $ 132,013 $ 1 $ (244 ) $ 131,770 Corporate bonds 160,777 178 (75 ) 160,880 Municipal securities 20,203 82 (45 ) 20,240 U.S. government securities 221,751 202 (419 ) 221,534 Non-U.S. government securities 3,251 — (12 ) 3,239 Total $ 537,995 $ 463 $ (795 ) $ 537,663 The Company's short-term and long-term investments as of December 31, 2017 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 15,122 $ — $ (39 ) $ 15,083 Corporate bonds 57,855 22 (79 ) 57,798 Commercial paper 17,428 — — 17,428 Municipal securities 23,743 8 (51 ) 23,700 U.S. government securities 55,729 1 (163 ) 55,567 Total $ 169,877 $ 31 $ (332 ) $ 169,576 Long-term debt securities: U.S. agency securities $ 20,288 $ 2 $ (121 ) $ 20,169 Corporate bonds 91,959 25 (571 ) 91,413 Municipal securities 26,371 13 (160 ) 26,224 U.S. government securities 66,362 19 (520 ) 65,861 Total $ 204,980 $ 59 $ (1,372 ) $ 203,667
Investments Classified by Contractual Maturity Date	The contractual maturities of the Company's short-term and long-term investments as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 449,284 $ 448,986 Due in one to five years 537,995 537,663 Total $ 987,279 $ 986,649 The contractual maturities of the Company's investments within customer funds as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 9,891 $ 9,890 Due in one to five years — — Total $ 9,891 $ 9,890

CUSTOMER FUNDS (Tables)

CUSTOMER FUNDS (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Assets Underlying Customer Funds	The following table presents the assets underlying customer funds (in thousands): September 30, December 31, Cash $ 219,087 $ 103,042 Cash Equivalents: Money market funds 1,884 — U.S. agency securities 8,335 — U.S. government securities 29,898 — Short-term debt securities: U.S. government securities $ 9,890 $ — Total $ 269,094 $ 103,042
Investments within Customer Funds	The Company's investments within customer funds as of September 30, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. government securities 9,891 — (1 ) 9,890 Total $ 9,891 $ — $ (1 ) $ 9,890
Investments within Customer Funds Classified by Contractual Maturity Date	The contractual maturities of the Company's short-term and long-term investments as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 449,284 $ 448,986 Due in one to five years 537,995 537,663 Total $ 987,279 $ 986,649 The contractual maturities of the Company's investments within customer funds as of September 30, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 9,891 $ 9,890 Due in one to five years — — Total $ 9,891 $ 9,890

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The estimated fair value and carrying value of the convertible senior notes were as follows (in thousands): September 30, 2018 December 31, 2017 Carrying Value Fair Value (Level 2) Carrying Value Fair Value (Level 2) 2023 Notes $ 711,229 $ 1,234,496 $ — $ — 2022 Notes 312,718 1,599,954 358,572 719,356 Total $ 1,023,947 $ 2,834,450 $ 358,572 $ 719,356 The estimated fair value and carrying value of loans held for sale is as follows (in thousands): September 30, 2018 December 31, 2017 Carrying Value Fair Value (Level 3) Carrying Value Fair Value (Level 3) Loans held for sale $ 73,219 $ 76,302 $ 73,420 $ 76,070 Total $ 73,219 $ 76,302 $ 73,420 $ 76,070 The Company’s financial assets and liabilities that are measured at fair value on a recurring basis are classified as follows (in thousands): September 30, 2018 December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash Equivalents: Money market funds $ 311,158 $ — $ — $ 387,698 $ — $ — U.S. agency securities — 123,202 — — — — Commercial paper — — — — 24,695 — U.S. government securities 20,065 — — — — — Customer funds: Money market funds 1,884 — — — — — U.S. agency securities — 8,335 — — — — U.S. government securities 39,788 — — — — — Short-term debt securities: U.S. agency securities — 48,190 — — 15,083 — Corporate bonds — 83,718 — — 57,798 — Commercial paper — — — — 17,428 — Municipal securities — 28,892 — — 23,700 — U.S. government securities 269,792 — — 55,567 — — Non-U.S. government securities — 18,394 — — — — Long-term debt securities: U.S. agency securities — 131,770 — — 20,169 — Corporate bonds — 160,880 — — 91,413 — Municipal securities — 20,240 — — 26,224 — U.S. government securities 221,534 — — 65,861 — — Non-U.S. government securities — 3,239 — — — — Other: Equity investment 61,908 — — — — — Total $ 926,129 $ 626,860 $ — $ 509,126 $ 276,510 $ —

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	The following is a summary of property and equipment, less accumulated depreciation and amortization (in thousands): September 30, December 31, Leasehold improvements $ 99,722 $ 77,073 Computer equipment 90,218 66,186 Capitalized software 51,177 35,063 Office furniture and equipment 18,773 14,490 259,890 192,812 Less: Accumulated depreciation and amortization (129,745 ) (101,316 ) Property and equipment, net $ 130,145 $ 91,496

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Assets Acquired and Liabilities Assumed	The table below summarizes the consideration paid for Weebly and the preliminary assessment of the fair value of the assets acquired and liabilities assumed at the closing date (in thousands, except share data). Consideration: Cash $ 132,432 Stock (2,418,271 shares of Class A common stock) 140,107 $ 272,539 Recognized amounts of identifiable assets acquired and liabilities assumed: Current assets (inclusive of cash acquired of $25,758) $ 44,685 Intangible customer assets 42,700 Intangible technology assets 14,900 Intangible trade name 11,300 Intangible other assets 961 Total liabilities assumed (including deferred revenue of $22,800) (35,849 ) Total identifiable net assets acquired 78,697 Goodwill 193,842 Total $ 272,539

GOODWILL (Tables)

GOODWILL (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The change in carrying value of goodwill in the period was as follows (in thousands): Balance at December 31, 2017 $ 58,327 Acquisitions completed during the nine months ended September 30, 2018 201,637 Balance at September 30, 2018 $ 259,964

ACQUIRED INTANGIBLE ASSETS (Tab

ACQUIRED INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite Lived Intangible Assets	The changes to the carrying value of intangible assets were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Acquired intangible assets, net, beginning of the period $ 85,514 $ 16,452 $ 14,334 $ 19,292 Acquisitions — — 75,871 1,224 Amortization expense 4,384 1,804 9,075 5,868 Acquired intangible assets, net, end of the period $ 81,130 $ 14,648 $ 81,130 $ 14,648 The following table presents the detail of acquired intangible assets as of the periods presented (in thousands): Balance at September 30, 2018 Cost Accumulated Amortization Net Patents $ 1,285 $ (638 ) $ 647 Technology assets 45,978 (27,043 ) 18,935 Customer assets 57,109 (6,775 ) 50,334 Trade name 11,300 (942 ) 10,358 Other 961 (105 ) 856 Total $ 116,633 $ (35,503 ) $ 81,130 Balance at December 31, 2017 Cost Accumulated Amortization Net Patents $ 1,285 $ (559 ) $ 726 Technology assets 29,158 (21,329 ) 7,829 Customer assets 10,319 (4,540 ) 5,779 Total $ 40,762 $ (26,428 ) $ 14,334
Schedule of Annual Future Amortization Expense of Intangible Assets	The total estimated future amortization expense of these intangible assets as of September 30, 2018 is as follows (in thousands): 2018 (remaining 3 months) $ 4,069 2019 13,702 2020 11,496 2021 10,299 2022 8,369 Thereafter 33,195 Total $ 81,130

OTHER CONSOLIDATED BALANCE SH_3

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Other Current Assets	The following table presents the detail of other current assets (in thousands): September 30, December 31, Inventory, net $ 25,294 $ 16,777 Processing costs receivable 36,747 21,083 Prepaid expenses 12,666 14,473 Accounts receivable, net 18,980 8,606 Deferred hardware costs (i) — 7,931 Deferred magstripe reader costs (ii) 6,996 2,469 Prepaid compensation, current (iii) 5,487 — Other 30,230 15,115 Total $ 136,400 $ 86,454 (i) The deferred hardware costs represented costs associated with hardware sold through the retail distribution channels. The adoption of ASC 606 on January 1, 2018, has resulted in the recognition of such costs upon delivery of the hardware to the distribution channel. (ii) The Company capitalizes the cost of its magstripe 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. (iii) Prepaid compensation relates to cash transferred by the Company to an escrow agent in connection with a business combination that will be paid to officers of the acquiree over time as they provide services to the Company.
Schedule of Accrued Expenses	The following table presents the detail of accrued expenses (in thousands): September 30, December 31, Accrued payroll $ 17,691 $ 9,103 Accrued professional fees 6,903 5,638 Accrued advertising and other marketing 16,391 6,723 Processing costs payable 11,150 10,145 Accrued non income tax liabilities 6,390 6,155 Accrued hardware costs 10,232 2,496 Other accrued liabilities 32,309 12,020 Total $ 101,066 $ 52,280
Schedule of Other Current Liabilities	The following table presents the detail of other current liabilities (in thousands): September 30, December 31, Deferred revenue, current $ 29,285 $ 5,893 Square Capital payable (iv) 12,762 7,671 Square Payroll payable (v) 6,707 2,850 Deferred rent, current 3,844 3,311 Accrued redemptions 1,052 1,036 Other 16,688 7,606 Total $ 70,338 $ 28,367 (iv) Square Capital payable represents unpaid amounts arising from the purchase of loans or loan repayments collected on behalf of third parties. (v) Square Payroll payable represents amounts received from Square Payroll product customers that will be utilized to settle the customers employee payroll and related obligations.

OTHER CONSOLIDATED BALANCE SH_4

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Other Non-Current Assets	The following table presents the detail of other non-current assets (in thousands): September 30, December 31, Equity investment (i) $ 61,908 $ 25,000 Prepaid compensation, non-current (ii) 6,959 — Deposits 2,544 2,738 Debt issuance costs 580 788 Deferred tax assets 540 519 Other 4,465 2,305 Total $ 76,996 $ 31,350 (i) In August, 2017, the Company invested $25.0 million for preferred shares of Eventbrite, Inc. (Eventbrite) which was carried at cost. In September, 2018, upon Eventbrite's initial public offering, the preferred shares held by the Company converted into Class B common shares of Eventbrite. The Company revalued this investment and will subsequently carry it at fair value, with changes in fair value being recorded within other income or expense on the consolidated statement of operations. During the three and nine months ended September 30, 2018, the Company recorded a gain of $36.9 million to other income on the consolidated statements of operations arising from revaluation of this investment. (ii) Prepaid compensation relates to cash transferred by the Company to an escrow agent in connection with a business combination that will be paid to officers of the acquiree over time as they provide services to the Company.
Schedule of Other Non-Current Liabilities	The following table presents the detail of other non-current liabilities (in thousands): September 30, December 31, Statutory liabilities (iii) $ 51,134 $ 40,768 Deferred rent, non-current 22,243 20,349 Deferred purchase consideration 3,900 — Deferred revenue, non-current 4,329 432 Deferred tax liabilities 147 644 Other 7,958 7,345 Total $ 89,711 $ 69,538 (iii) Statutory liabilities represent loss contingencies that may arise from the Company's interpretation and application of certain guidelines and rules issued by various federal, state, local, and foreign regulatory authorities.

INDEBTEDNESS (Tables)

INDEBTEDNESS (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Convertible Notes	The net carrying amount of the Notes were as follows (in thousands): Principal outstanding Unamortized debt discount Unamortized debt issuance costs Net carrying value September 30, 2018 2023 Notes $ 862,500 $ (145,998 ) $ (5,273 ) $ 711,229 2022 Notes 369,953 (51,581 ) (5,654 ) 312,718 Total 1,232,453 (197,579 ) (10,927 ) 1,023,947 December 31, 2017 2022 Notes $ 440,000 $ (73,384 ) $ (8,044 ) $ 358,572 The net carrying amount of the equity component of the Notes were as follows (in thousands): Amount allocated to conversion option Less: allocated issuance costs Equity component, net September 30, 2018 2023 Notes $ 155,250 $ (1,231 ) $ 154,019 2022 Notes 72,480 (1,936 ) 70,544 Total 227,730 (3,167 ) 224,563 December 31, 2017 2022 Notes $ 86,203 $ (2,302 ) $ 83,901
Interest Expense on Convertible Notes	The Company recognized interest expense on the Notes as follows (in thousands, except for percentages): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Contractual interest expense $ 1,469 $ 413 $ 2,732 $ 938 Amortization of debt discount and issuance costs 11,627 4,277 22,850 9,889 Total $ 13,096 $ 4,690 $ 25,582 $ 10,827

ACCRUED TRANSACTION LOSSES (Tab

ACCRUED TRANSACTION LOSSES (Tables)	9 Months Ended
	Sep. 30, 2018
Product Warranties Disclosures [Abstract]
Schedule of Reserve for Transaction Losses	The following table summarizes the activities of the Company’s reserve for transaction losses (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Accrued transaction losses, beginning of the period $ 29,207 $ 22,455 $ 26,893 $ 20,064 Provision for transaction losses 20,449 15,102 48,794 39,737 Charge-offs to accrued transaction losses (14,324 ) (10,837 ) (40,355 ) (33,081 ) Accrued transaction losses, end of the period $ 35,332 $ 26,720 $ 35,332 $ 26,720

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Changes in Stockholder's Equity	The changes in total stockholders’ equity were as follows (in thousands): Total stockholders’ equity Balance at December 31, 2017 $ 786,333 Net loss (10,249 ) Exercise of stock options 82,202 Purchases under the employee stock purchase plan 12,578 Vesting of early exercised stock options and other 136 Issuance of common stock in connection with business combination 140,107 Replacement stock awards issued in connection with acquisition 899 Conversion feature of convertible senior notes, due 2023, net of allocated costs 154,019 Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2023 (172,586 ) Sale of warrants in conjunction with issuance of convertible senior notes, due 2023 112,125 Issuance of common stock in conjunction with the conversion of senior notes, due 2022 (9,305 ) Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022 — Share-based compensation 164,142 Tax withholding related to vesting of restricted stock units (125,899 ) Cumulative adjustment for adoption of ASC 606 (4,586 ) Recovery of common stock in connection with indemnification settlement agreement (2,745 ) Change in other comprehensive loss (5,027 ) Balance at September 30, 2018 $ 1,122,144
Summary of Stock Option Activity	A summary of stock option activity for the nine months ended September 30, 2018 is as follows (in thousands, except share and per share data): Number of Stock Options Outstanding Weighted Weighted Aggregate Balance at December 31, 2017 47,270,091 $ 8.67 6.52 $ 1,229,103 Granted 783,625 44.75 Exercised (10,661,450 ) 7.71 Forfeited (674,525 ) 12.97 Balance at September 30, 2018 36,717,741 $ 9.64 5.94 $ 3,281,558 Options exercisable as of September 30, 2018 33,952,212 $ 8.64 5.75 $ 3,068,274
Schedule of RSU Activity	Activity related to RSAs and RSUs during the nine months ended September 30, 2018 is set forth below: Number of Weighted Unvested as of December 31, 2017 21,317,525 $ 17.84 Granted 6,408,650 52.93 Vested (5,796,657 ) 18.30 Forfeited (2,031,584 ) 18.56 Unvested as of September 30, 2018 19,897,934 $ 28.94
Schedule of Fair Value Assumptions for Options	The fair value of stock options granted was estimated using the following weighted-average assumptions: Nine Months Ended September 30, 2018 2017 Dividend yield — % — % Risk-free interest rate 2.92 % 1.88 % Expected volatility 30.87 % 32.22 % Expected term (years) 6.19 6.02
Summary of the Effect of Share-Based Compensation on the Condensed Consolidated Statements of Operations	The following table summarizes the effects of share-based compensation on the Company's condensed consolidated statements of operations (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Cost of revenue $ 18 $ 29 $ 79 $ 47 Product development 39,525 25,254 103,813 69,746 Sales and marketing 6,108 4,579 16,703 12,869 General and administrative 13,262 10,186 37,261 28,649 Total $ 58,913 $ 40,048 $ 157,856 $ 111,311

INCOME (LOSS) PER SHARE (Tables

INCOME (LOSS) PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share	The following table presents the calculation of basic and diluted net income (loss) per share (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Net income (loss) $ 19,643 $ (16,098 ) $ (10,249 ) $ (47,150 ) Denominator: Basic shares: Weighted-average common shares outstanding 410,095 385,409 403,577 377,374 Weighted-average unvested shares (405 ) (1,458 ) (597 ) (1,631 ) Weighted-average shares used to compute basic net income (loss) per share 409,690 383,951 402,980 375,743 Diluted shares: Stock options and restricted stock units 47,175 — — — Convertible senior notes 6,409 — — — Common stock warrants 11,422 — — — Employee stock purchase plan 219 — — — Weighted-average shares used to compute diluted net income (loss) per share 474,915 383,951 402,980 375,743 Net income (loss) per share: Basic $ 0.05 $ (0.04 ) $ (0.03 ) $ (0.13 ) Diluted $ 0.04 $ (0.04 ) $ (0.03 ) $ (0.13 )
Schedule of Antidilutive Securities Excluded from Calculation of Diluted Net Income (Loss) Per Share	The following potential common shares were excluded from the calculation of diluted net income (loss) per share because their effect would have been anti-dilutive for the periods presented (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Stock options and restricted stock units 12,079 76,618 62,822 81,118 Common stock warrants 18,830 19,173 24,387 16,539 Convertible senior notes 23,415 — 24,276 — Unvested shares 405 1,458 597 1,631 Employee stock purchase plan 26 517 207 412 Total anti-dilutive securities 54,755 97,766 112,289 99,700

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Payments Under Operating and Capital Leases	Future minimum lease payments under non-cancelable operating leases (with initial lease terms in excess of one year) and future minimum capital lease payments as of September 30, 2018 are as follows (in thousands): Capital Operating Year: 2018 (remaining 3 months) $ 1,284 $ 7,687 2019 5,029 29,454 2020 2,446 30,657 2021 — 30,598 2022 — 31,051 Thereafter — 32,747 Total $ 8,759 $ 162,194 Less amount representing interest — Present value of capital lease obligations 8,759 Less current portion of capital lease obligation (5,135 ) Non-current portion of capital lease obligation $ 3,624

SEGMENT AND GEOGRAPHICAL INFO_2

SEGMENT AND GEOGRAPHICAL INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Revenue from External Customers by Geographic Areas	Revenue by geography is based on the billing addresses of the sellers or customers. The following table sets forth revenue by geographic area (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue United States $ 838,149 $ 559,053 $ 2,255,657 $ 1,533,960 International 43,959 26,106 109,992 64,258 Total net revenue $ 882,108 $ 585,159 $ 2,365,649 $ 1,598,218
Long-lived Assets by Geographic Areas	The following table sets forth long-lived assets by geographic area (in thousands): September 30, December 31, Long-lived assets United States $ 464,455 $ 158,820 International 6,784 5,337 Total long-lived assets $ 471,239 $ 164,157

SUPPLEMENTAL CASH FLOW INFORM_2

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	The supplemental disclosures of cash flow information consist of the following (in thousands): Nine Months Ended September 30, 2018 2017 Supplemental Cash Flow Data: Cash paid for interest $ 1,945 $ 1,230 Cash paid for income taxes 1,265 1,117 Supplemental disclosures of non-cash investing and financing activities: Change in purchases of property and equipment in accounts payable and accrued expenses 11,004 (123 ) Unpaid business combination purchase price 3,995 644 Fair value of common stock issued related to business combination (140,107 ) — Recovery of common stock in connection with indemnification settlement agreement 2,745 — Fair value of common stock issued to settle the conversion of senior notes, due 2022 (189,916 ) — Fair value of shares received to settle senior note hedges, due 2022 189,916 —

DESCRIPTION OF BUSINESS AND S_3

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018USD ($)customer	Sep. 30, 2017customer	Sep. 30, 2018USD ($)customerthird_party_processor	Sep. 30, 2017USD ($)customer	Dec. 31, 2017USD ($)third_party_processor
Concentration Risk [Line Items]
Gain on equity investment	$ 36,900		$ 36,908	$ 0
Cryptocurrency denominated assets	$ 200		$ 200		$ 300
Total Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Number of customers | customer	0	0	0	0
Settlements Receivable | Credit Concentration Risk
Concentration Risk [Line Items]
Number of third party processors | third_party_processor			3		3
Settlements Receivable | Credit Concentration Risk | Third Party Processor One
Concentration Risk [Line Items]
Concentration risk, percentage			50.00%		46.00%
Settlements Receivable | Credit Concentration Risk | Third Party Processor Two
Concentration Risk [Line Items]
Concentration risk, percentage			37.00%		42.00%
Settlements Receivable | Credit Concentration Risk | Third Party Processor Three
Concentration Risk [Line Items]
Concentration risk, percentage			9.00%		8.00%
Minimum
Concentration Risk [Line Items]
Settlements receivable period			1 day
Maximum
Concentration Risk [Line Items]
Settlements receivable period			2 days

REVENUE - Narrative (Details)

REVENUE - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings (accumulated deficit)	$ (857,570)		$ (857,570)			$ (842,735)
Revenue	857,700		2,298,700
Revenue, other	24,500		67,000
Impairment losses arising from contracts with customers	900		$ 2,700
Term of revenue recognition for website hosting and domain name registration			The Company considers that it satisfies its performance obligations over time and as such recognizes revenue ratably over the term of the relevant arrangements, which vary from 1 month to 24 months for website hosting, and 1 year to 10 years for domain name registration.
Effect of change | ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings (accumulated deficit)					$ (4,600)
Revenue	1,600		$ 5,300
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Distributors and retailers, payment terms			30 days
Customer installment sales, terms			3 months
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Distributors and retailers, payment terms			90 days
Customer installment sales, terms			24 months
Bitcoin revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 42,963	$ 0	$ 114,074	$ 0

REVENUE - Adoption of ASC 606 o

REVENUE - Adoption of ASC 606 on the Condensed Consolidated Statement of Operation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 882,108	$ 585,159	$ 2,365,649	$ 1,598,218
Revenue	857,700		2,298,700
ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	1,600		5,300
Subscription and services-based revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	166,203	65,051	397,589	173,262
Revenue	141,752	65,051	330,637	173,262
Cost of revenue	47,078	18,169	117,230	51,161
Subscription and services-based revenue | Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	166,037		397,272
Cost of revenue	47,078		117,230
Subscription and services-based revenue | ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	166		317
Cost of revenue	0		0
Hardware revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	17,558	10,089	50,337	29,394
Cost of revenue	23,229	$ 18,775	68,467	$ 45,610
Hardware revenue | Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	16,145		45,378
Cost of revenue	21,969		63,665
Hardware revenue | ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	1,413		4,959
Cost of revenue	$ 1,260		$ 4,802

REVENUE - Adoption of ASC 606_2

REVENUE - Adoption of ASC 606 on the Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets	$ 136,400	$ 86,454
Other current liabilities	70,338	28,367
Other non-current assets	76,996	31,350
Other non-current liabilities	89,711	$ 69,538
Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets	148,491
Other current liabilities	78,260
Other non-current assets	78,584
Other non-current liabilities	91,311
ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets	(12,091)
Other current liabilities	(7,922)
Other non-current assets	(1,588)
Other non-current liabilities	$ (1,600)

REVENUE - Revenue from Contract

REVENUE - Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue, contracts from customers	$ 857,700		$ 2,298,700
Transaction-based revenue
Disaggregation of Revenue [Line Items]
Revenue, contracts from customers	655,384	$ 510,019	1,803,649	$ 1,395,562
Subscription and services-based revenue
Disaggregation of Revenue [Line Items]
Revenue, contracts from customers	141,752	65,051	330,637	173,262
Hardware revenue
Disaggregation of Revenue [Line Items]
Revenue, contracts from customers	17,558	10,089	50,337	29,394
Bitcoin revenue
Disaggregation of Revenue [Line Items]
Revenue, contracts from customers	$ 42,963	$ 0	$ 114,074	$ 0

REVENUE - Deferred Revenue (Det

REVENUE - Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue, beginning of the period	$ 27,155	$ 4,523	$ 1,590	$ 5,407
Deferred revenue, end of the period	33,614	3,424	33,614	3,424
Deferred revenue arising from business combination	22,800	0	22,800	0
Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period	10,165	2,060	1,539	5,312
Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue, beginning of the period	27,155	4,523	5,893	5,407
ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue, beginning of the period	$ 0	$ 0	$ (4,303)	$ 0

RESTRICTED CASH (Details)

RESTRICTED CASH (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Pledged cash	$ 33,230	$ 28,805
Collateral	$ 10,102	$ 9,802

INVESTMENTS - Available for Sa

INVESTMENTS - Available for Sale Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 987,279
Fair Value	986,649
Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	449,284	$ 169,877
Gross Unrealized Gains	253	31
Gross Unrealized Losses	(551)	(332)
Fair Value	448,986	169,576
Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	537,995	204,980
Gross Unrealized Gains	463	59
Gross Unrealized Losses	(795)	(1,372)
Fair Value	537,663	203,667
U.S. agency securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	48,206	15,122
Gross Unrealized Gains	11	0
Gross Unrealized Losses	(27)	(39)
Fair Value	48,190	15,083
U.S. agency securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	132,013	20,288
Gross Unrealized Gains	1	2
Gross Unrealized Losses	(244)	(121)
Fair Value	131,770	20,169
Corporate bonds | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	83,647	57,855
Gross Unrealized Gains	135	22
Gross Unrealized Losses	(64)	(79)
Fair Value	83,718	57,798
Corporate bonds | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	160,777	91,959
Gross Unrealized Gains	178	25
Gross Unrealized Losses	(75)	(571)
Fair Value	160,880	91,413
Commercial paper | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		17,428
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		17,428
Municipal securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	28,904	23,743
Gross Unrealized Gains	37	8
Gross Unrealized Losses	(49)	(51)
Fair Value	28,892	23,700
Municipal securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	20,203	26,371
Gross Unrealized Gains	82	13
Gross Unrealized Losses	(45)	(160)
Fair Value	20,240	26,224
U.S. government securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	270,094	55,729
Gross Unrealized Gains	70	1
Gross Unrealized Losses	(372)	(163)
Fair Value	269,792	55,567
U.S. government securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	221,751	66,362
Gross Unrealized Gains	202	19
Gross Unrealized Losses	(419)	(520)
Fair Value	221,534	$ 65,861
Non-U.S. government securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,433
Gross Unrealized Gains	0
Gross Unrealized Losses	(39)
Fair Value	18,394
Non-U.S. government securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,251
Gross Unrealized Gains	0
Gross Unrealized Losses	(12)
Fair Value	$ 3,239

INVESTMENTS - Maturity of Avai

INVESTMENTS - Maturity of Available for Sale Debt Securities (Details) $ in Thousands	Sep. 30, 2018USD ($)
Amortized Cost
Due in one year or less	$ 449,284
Due in one to five years	537,995
Amortized Cost	987,279
Fair Value
Due in one year or less	448,986
Due in one to five years	537,663
Fair Value	$ 986,649

CUSTOMER FUNDS - Assets Underly

CUSTOMER FUNDS - Assets Underlying Customer Funds (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Customer funds	$ 269,094	$ 103,042
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	9,890	0
Cash
Debt Securities, Available-for-sale [Line Items]
Customer funds	219,087	103,042
Cash Equivalents | Money market funds
Debt Securities, Available-for-sale [Line Items]
Customer funds	1,884	0
Cash Equivalents | U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	8,335	0
Cash Equivalents | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	$ 29,898	$ 0

CUSTOMER FUNDS - Investments wi

CUSTOMER FUNDS - Investments within Customer Funds (Details) $ in Thousands	Sep. 30, 2018USD ($)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 987,279
Fair Value	986,649
Customer funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,891
Gross Unrealized Gains	0
Gross Unrealized Losses	(1)
Fair Value	9,890
Customer funds | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,891
Gross Unrealized Gains	0
Gross Unrealized Losses	(1)
Fair Value	$ 9,890

CUSTOMER FUNDS - Maturity of Av

CUSTOMER FUNDS - Maturity of Available for Sale Securities within Customer Funds (Details) $ in Thousands	Sep. 30, 2018USD ($)
Amortized Cost
Due in one year or less	$ 449,284
Due in one to five years	537,995
Amortized Cost	987,279
Fair Value
Due in one year or less	448,986
Due in one to five years	537,663
Fair Value	986,649
Customer funds
Amortized Cost
Due in one year or less	9,891
Due in one to five years	0
Amortized Cost	9,891
Fair Value
Due in one year or less	9,890
Due in one to five years	0
Fair Value	$ 9,890

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	$ 269,094	$ 103,042
Short-term debt securities	448,986	169,576
Long-term debt securities	537,663	203,667
Equity investment	61,908	25,000
U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	9,890	0
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment	61,908	0
Total	926,129	509,126
Fair Value, Measurements, Recurring | Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	1,884	0
Fair Value, Measurements, Recurring | Level 1 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	39,788	0
Short-term debt securities	269,792	55,567
Long-term debt securities	221,534	65,861
Fair Value, Measurements, Recurring | Level 1 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	311,158	387,698
Fair Value, Measurements, Recurring | Level 1 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	20,065	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment	0	0
Total	626,860	276,510
Fair Value, Measurements, Recurring | Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	8,335	0
Short-term debt securities	48,190	15,083
Long-term debt securities	131,770	20,169
Fair Value, Measurements, Recurring | Level 2 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	83,718	57,798
Long-term debt securities	160,880	91,413
Fair Value, Measurements, Recurring | Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	17,428
Fair Value, Measurements, Recurring | Level 2 | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	28,892	23,700
Long-term debt securities	20,240	26,224
Fair Value, Measurements, Recurring | Level 2 | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	18,394	0
Long-term debt securities	3,239	0
Fair Value, Measurements, Recurring | Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	123,202	0
Fair Value, Measurements, Recurring | Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	24,695
Fair Value, Measurements, Recurring | Level 2 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment	0	0
Total	0	0
Fair Value, Measurements, Recurring | Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Convertible Senior Notes (Details) - Level 2 - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	$ 1,023,947	$ 358,572
Fair Value (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	2,834,450	719,356
Convertible Senior Notes due in 2023 | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	711,229	0
Convertible Senior Notes due in 2023 | Fair Value (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	1,234,496	0
Convertible Senior Notes due in 2022 | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	312,718	358,572
Convertible Senior Notes due in 2022 | Fair Value (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	$ 1,599,954	$ 719,356

FAIR VALUE OF FINANCIAL INSTR_5

FAIR VALUE OF FINANCIAL INSTRUMENTS - Loans Disclosed at Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Carrying Value | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, fair value	$ 73,219		$ 73,219		$ 73,420
Fair Value (Level 3) | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, fair value	76,302		76,302		$ 76,070
Loans Receivable Held-For-Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Excess amortized cost over fair value of loans charge	$ 3,300	$ 3,400	$ 9,000	$ 6,100

PROPERTY AND EQUIPMENT, NET (De

PROPERTY AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 259,890		$ 259,890		$ 192,812
Less: Accumulated depreciation and amortization	(129,745)		(129,745)		(101,316)
Property and equipment, net	130,145		130,145		91,496
Depreciation	11,700	$ 7,300	29,200	$ 21,800
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	99,722		99,722		77,073
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	90,218		90,218		66,186
Capitalized software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	51,177		51,177		35,063
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 18,773		$ 18,773		$ 14,490

ACQUISITIONS - Narrative (Detai

ACQUISITIONS - Narrative (Details) - USD ($) $ in Thousands	May 31, 2018	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Payment for acquisitions, net of cash acquired			$ 112,399	$ 1,600
Weebly, Inc.
Business Acquisition [Line Items]
Percent of outstanding shares acquired	100.00%
Cash consideration	$ 132,432
Equity consideration (in shares)	2,418,271
Equity consideration fair value	$ 140,107
Payment to settle outstanding vested and unvested employee options	17,700
Post-combination compensation expense	$ 2,600
Goodwill adjustment to purchase price allocation		$ 4,300
Tax liabilities adjustment to purchase price allocation		3,000
Cash withheld for indemnification		$ 19,900	$ 19,900
Shares withheld for indemnification (in shares)		372,578	372,578
Immaterial acquisitions
Business Acquisition [Line Items]
Payment for acquisitions, net of cash acquired			$ 9,900

ACQUISITIONS - Schedule of Asse

ACQUISITIONS - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	May 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill		$ 259,964	$ 58,327
Weebly, Inc.
Consideration:
Cash	$ 132,432
Stock (2,418,271 shares of Class A common stock)	$ 140,107
Stock (in shares)	2,418,271
Total consideration	$ 272,539
Recognized amounts of identifiable assets acquired and liabilities assumed:
Current assets (inclusive of cash acquired of $25,758)	44,685
Cash acquired	25,758
Total liabilities assumed (including deferred revenue of $22,800)	(35,849)
Deferred revenue	22,800
Total identifiable net assets acquired	78,697
Goodwill	193,842
Total	272,539
Weebly, Inc. | Customer assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	42,700
Weebly, Inc. | Technology assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	14,900
Weebly, Inc. | Trade name
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	11,300
Weebly, Inc. | Intangible other assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	$ 961

GOODWILL (Details)

GOODWILL (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Goodwill [Roll Forward]
Goodwill, beginning balance			$ 58,327,000
Acquisitions completed during the nine months ended September 30, 2018			201,637,000
Goodwill, ending balance	$ 259,964,000		259,964,000
Goodwill, impairment charges	$ 0	$ 0	$ 0	$ 0

ACQUIRED INTANGIBLE ASSETS - N

ACQUIRED INTANGIBLE ASSETS - Narrative (Details) - business	3 Months Ended	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Number of businesses acquired involving intangible assets	2
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period		13 years
Technology assets
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period		5 years
Customer assets
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period		11 years
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period		4 years

ACQUIRED INTANGIBLE ASSETS - S

ACQUIRED INTANGIBLE ASSETS - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 116,633		$ 40,762
Accumulated Amortization	(35,503)		(26,428)
Net	81,130	$ 85,514	14,334	$ 14,648	$ 16,452	$ 19,292
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,285		1,285
Accumulated Amortization	(638)		(559)
Net	647		726
Technology assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	45,978		29,158
Accumulated Amortization	(27,043)		(21,329)
Net	18,935		7,829
Customer assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	57,109		10,319
Accumulated Amortization	(6,775)		(4,540)
Net	50,334		$ 5,779
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	11,300
Accumulated Amortization	(942)
Net	10,358
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	961
Accumulated Amortization	(105)
Net	$ 856

ACQUIRED INTANGIBLE ASSETS - Ch

ACQUIRED INTANGIBLE ASSETS - Change in Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Finite-lived Intangible Assets [Roll Forward]
Acquired intangible assets, net, beginning of the period	$ 85,514	$ 16,452	$ 14,334	$ 19,292
Acquisitions	0	0	75,871	1,224
Amortization expense	4,384	1,804	9,075	5,868
Acquired intangible assets, net, end of the period	$ 81,130	$ 14,648	$ 81,130	$ 14,648

ACQUIRED INTANGIBLE ASSETS - F

ACQUIRED INTANGIBLE ASSETS - Future Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
2018 (remaining 3 months)	$ 4,069
2,019	13,702
2,020	11,496
2,021	10,299
2,022	8,369
Thereafter	33,195
Net	$ 81,130	$ 85,514	$ 14,334	$ 14,648	$ 16,452	$ 19,292

OTHER CONSOLIDATED BALANCE SH_5

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventory, net	$ 25,294	$ 16,777
Processing costs receivable	36,747	21,083
Prepaid expenses	12,666	14,473
Accounts receivable, net	18,980	8,606
Deferred hardware costs	0	7,931
Deferred magstripe reader costs	6,996	2,469
Prepaid compensation, current	5,487	0
Other	30,230	15,115
Total	$ 136,400	$ 86,454

OTHER CONSOLIDATED BALANCE SH_6

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued payroll	$ 17,691	$ 9,103
Accrued professional fees	6,903	5,638
Accrued advertising and other marketing	16,391	6,723
Processing costs payable	11,150	10,145
Accrued non income tax liabilities	6,390	6,155
Accrued hardware costs	10,232	2,496
Other accrued liabilities	32,309	12,020
Total	$ 101,066	$ 52,280

OTHER CONSOLIDATED BALANCE SH_7

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred revenue, current	$ 29,285	$ 5,893
Square Capital payable	12,762	7,671
Square Payroll payable	6,707	2,850
Deferred rent, current	3,844	3,311
Accrued redemptions	1,052	1,036
Other	16,688	7,606
Total	$ 70,338	$ 28,367

OTHER CONSOLIDATED BALANCE SH_8

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) - Other Non-Current Assets (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Aug. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Equity investment	$ 61,908	$ 61,908		$ 25,000
Prepaid compensation, non-current	6,959	6,959		0
Deposits	2,544	2,544		2,738
Debt issuance costs	580	580		788
Deferred tax assets	540	540		519
Other	4,465	4,465		2,305
Total	76,996	76,996		$ 31,350
Investment in privately held entity at cost					$ 25,000
Gain on equity investment	$ 36,900	$ 36,908	$ 0

OTHER CONSOLIDATED BALANCE SH_9

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) - Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Statutory liabilities	$ 51,134	$ 40,768
Deferred rent, non-current	22,243	20,349
Deferred purchase consideration	3,900	0
Deferred revenue, non-current	4,329	432
Deferred tax liabilities	147	644
Other	7,958	7,345
Total	$ 89,711	$ 69,538

INDEBTEDNESS - Revolving Credi

INDEBTEDNESS - Revolving Credit Facility, Narrative (Details) - Revolving Credit Facility - Line of Credit - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 2015	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 375,000,000
Administrative agent fee	$ 100,000
Unused commitment fee percentage	0.15%
Remaining borrowing capacity		$ 375,000,000		$ 375,000,000
Unused commitment fees		$ 100,000	$ 100,000	$ 400,000	$ 400,000
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 | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%

INDEBTEDNESS - Convertible Seni

INDEBTEDNESS - Convertible Senior Notes, Narrative (Details) $ / shares in Units, shares in Millions	May 25, 2018USD ($)day$ / shares	Mar. 06, 2017USD ($)day$ / shares	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)shares	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Oct. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Loss on extinguishment of long-term debt					$ 1,625,000	$ 0
Convertible Debt
Debt Instrument [Line Items]
Conversion price (in USD per share) | $ / shares	$ 77.85	$ 22.95
Carrying amount of equity component				$ 224,563,000	224,563,000
Issuance costs attributable to the liability component				10,927,000	10,927,000
Convertible Debt | Convertible Senior Notes due in 2023
Debt Instrument [Line Items]
Aggregate principal amount	$ 750,000,000
Over-allotment option as a percentage of a principal amount	15.00%
Over-allotment option	$ 112,500,000
Interest rate	0.50%
Conversion rate	0.0128456
Conversion price (in USD per share) | $ / shares	$ 77.85
Conversion amount	$ 1,000
Carrying amount of equity component	155,300,000			$ 154,019,000	$ 154,019,000
Effective interest rate of the liability component				4.69%	4.69%
Discounts and commissions payable	6,000,000
Third party offering costs	800,000
Issuance costs attributable to the liability component	$ 5,600,000			$ 5,273,000	$ 5,273,000
Convertible Debt | Convertible Senior Notes due in 2023 | Debt Instrument, Conversion Term One
Debt Instrument [Line Items]
Threshold trading days | day	20
Threshold consecutive trading days | day	30
Threshold percentage of stock price trigger	130.00%
Convertible Debt | Convertible Senior Notes due in 2023 | Debt Instrument Conversion Term Two
Debt Instrument [Line Items]
Threshold trading days | day	5
Threshold consecutive trading days | day	5
Threshold percentage of stock price trigger	98.00%
Convertible Debt | Convertible Senior Notes due in 2022
Debt Instrument [Line Items]
Aggregate principal amount		$ 400,000,000
Over-allotment option as a percentage of a principal amount		10.00%
Over-allotment option		$ 40,000,000
Interest rate		0.375%
Conversion rate		0.0435749
Conversion price (in USD per share) | $ / shares		$ 22.95
Notes converted				$ 70,000,000
Shares issued upon conversion | shares				2.2
Carrying amount of equity component		$ 86,200,000		$ 70,544,000	$ 70,544,000			$ 83,901,000
Effective interest rate of the liability component				5.34%	5.34%
Discounts and commissions payable		11,000,000
Third party offering costs		800,000
Issuance costs attributable to the liability component		9,400,000		$ 5,654,000	$ 5,654,000			$ 8,044,000
Loss on extinguishment of long-term debt		1,600,000
Reduction to additional paid in capital		$ 9,300,000
Convertible Debt | Convertible Senior Notes due in 2022 | Debt Instrument, Conversion Term One
Debt Instrument [Line Items]
Threshold trading days | day		20
Threshold consecutive trading days | day		30
Threshold percentage of stock price trigger		130.00%
Convertible Debt | Convertible Senior Notes due in 2022 | Debt Instrument Conversion Term Two
Debt Instrument [Line Items]
Threshold trading days | day		5
Threshold consecutive trading days | day		5
Threshold percentage of stock price trigger		98.00%
Forecast | Convertible Debt | Convertible Senior Notes due in 2022
Debt Instrument [Line Items]
Notes converted			$ 149,000,000
Subsequent Event | Convertible Debt | Convertible Senior Notes due in 2022
Debt Instrument [Line Items]
Conversion amount							$ 1,000

INDEBTEDNESS - Components of Co

INDEBTEDNESS - Components of Convertible Notes (Details) - Convertible Debt - USD ($) $ in Thousands	Sep. 30, 2018	May 25, 2018	Dec. 31, 2017	Mar. 06, 2017
Debt Instrument [Line Items]
Principal outstanding	$ 1,232,453
Unamortized debt discount	(197,579)
Unamortized debt issuance costs	(10,927)
Net carrying value	1,023,947
Convertible Senior Notes due in 2023
Debt Instrument [Line Items]
Principal outstanding	862,500
Unamortized debt discount	(145,998)
Unamortized debt issuance costs	(5,273)	$ (5,600)
Net carrying value	711,229
Convertible Senior Notes due in 2022
Debt Instrument [Line Items]
Principal outstanding	369,953		$ 440,000
Unamortized debt discount	(51,581)		(73,384)
Unamortized debt issuance costs	(5,654)		(8,044)	$ (9,400)
Net carrying value	$ 312,718		$ 358,572

INDEBTEDNESS - Carrying Amount

INDEBTEDNESS - Carrying Amount of Equity Component of Convertible Notes (Details) - Convertible Debt - USD ($) $ in Thousands	Sep. 30, 2018	May 25, 2018	Dec. 31, 2017	Mar. 06, 2017
Debt Instrument [Line Items]
Amount allocated to conversion option	$ 227,730
Less: allocated issuance costs	(3,167)
Equity component, net	224,563
Convertible Senior Notes due in 2023
Debt Instrument [Line Items]
Amount allocated to conversion option	155,250
Less: allocated issuance costs	(1,231)
Equity component, net	154,019	$ 155,300
Convertible Senior Notes due in 2022
Debt Instrument [Line Items]
Amount allocated to conversion option	72,480		$ 86,203
Less: allocated issuance costs	(1,936)		(2,302)
Equity component, net	$ 70,544		$ 83,901	$ 86,200

INDEBTEDNESS - Interest Expense

INDEBTEDNESS - Interest Expense (Details) - Convertible Debt - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Contractual interest expense	$ 1,469	$ 413	$ 2,732	$ 938
Amortization of debt discount and issuance costs	11,627	4,277	22,850	9,889
Total	$ 13,096	$ 4,690	$ 25,582	$ 10,827
Convertible Senior Notes due in 2023
Debt Instrument [Line Items]
Effective interest rate of the liability component	4.69%		4.69%
Convertible Senior Notes due in 2022
Debt Instrument [Line Items]
Effective interest rate of the liability component	5.34%		5.34%

INDEBTEDNESS - Convertible Note

INDEBTEDNESS - Convertible Note Hedge and Warrant Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	May 25, 2018	Mar. 06, 2017	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Proceeds from issuance of warrants			$ 112,125	$ 57,244
Convertible Debt
Debt Instrument [Line Items]
Conversion price of convertible debt (in USD per share)	$ 77.85	$ 22.95
Conversion price of convertible debt after effect of warrants and note hedge (in USD per share)	$ 109.26	$ 31.18
Common Stock Warrant
Debt Instrument [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)	11.1	19.2
Warrants, weighted average exercise price (in USD per share)	$ 109.26	$ 31.18
Proceeds from issuance of warrants	$ 112,100	$ 57,200
Shares of common stock received due to exercise of note hedges (in shares)			2.2
Options
Debt Instrument [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)	11.1	19.2
Convertible note hedge, option to purchase common stock, price (in USD per share)	$ 77.85	$ 22.95
Cost of convertible note hedge	$ 172,600	$ 92,100

ACCRUED TRANSACTION LOSSES (Det

ACCRUED TRANSACTION LOSSES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Loss Contingency Accrual
Accrued transaction losses, beginning of the period			$ 26,893
Provision for transaction losses			63,603	$ 50,185
Accrued transaction losses, end of the period	$ 35,332		35,332
Transaction Losses
Loss Contingency Accrual
Accrued transaction losses, beginning of the period	29,207	$ 22,455	26,893	20,064
Provision for transaction losses	20,449	15,102	48,794	39,737
Charge-offs to accrued transaction losses	(14,324)	(10,837)	(40,355)	(33,081)
Accrued transaction losses, end of the period	$ 35,332	$ 26,720	$ 35,332	$ 26,720

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 1,066	$ (647)	$ 1,845	$ 334
Effective tax rate	5.10%	3.90%	(22.00%)	(0.70%)

STOCKHOLDERS' EQUITY - Changes

STOCKHOLDERS' EQUITY - Changes in Stockholder's Equity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			$ 786,333
Net loss	$ 19,643	$ (16,098)	(10,249)	$ (47,150)
Exercise of stock options			82,202
Purchases under the employee stock purchase plan			12,578
Vesting of early exercised stock options and other			136
Issuance of common stock in connection with business combination			140,107
Replacement stock awards issued in connection with acquisition			899
Conversion feature of convertible senior notes, due 2023, net of allocated costs			154,019
Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2023			(172,586)
Sale of warrants in conjunction with issuance of convertible senior notes, due 2023			112,125
Issuance of common stock in conjunction with the conversion of senior notes, due 2022			(9,305)
Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022			0
Share-based compensation			164,142
Tax withholding related to vesting of restricted stock units			(125,899)
Cumulative adjustment for adoption of ASC 606					$ (4,586)
Recovery of common stock in connection with indemnification settlement agreement			(2,745)
Change in other comprehensive loss			(5,027)
Balance at September 30, 2018	$ 1,122,144		$ 1,122,144

STOCKHOLDERS' EQUITY - Common

STOCKHOLDERS' EQUITY - Common Stock and Warrants Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	May 25, 2018	Mar. 06, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Apr. 30, 2018	Dec. 31, 2017	Dec. 31, 2014
Class of Stock [Line Items]
Proceeds from issuance of warrants				$ 112,125	$ 57,244
Caviar, Inc.
Class of Stock [Line Items]
Shares issued for consideration withheld for indemnification purposes (in shares)								1,291,979
Shares issued for consideration withheld for indemnification purposes, released to former owners (in shares)						822,085
Shares issued for consideration withheld for indemnification purposes, forfeited back to Company (in shares)						469,894
Indemnification asset								$ 2,800
Common Stock Warrant
Class of Stock [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)	11,100,000	19,200,000
Warrants, weighted average exercise price (in USD per share)	$ 109.26	$ 31.18
Proceeds from issuance of warrants	$ 112,100	$ 57,200
Shares of common stock received due to exercise of note hedges (in shares)			2,200,000	2,200,000
Class A
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			1,000,000,000	1,000,000,000			1,000,000,000
Common stock, par value (in USD per share)			$ 0.00	$ 0.00			$ 0.00
Common stock, shares outstanding (in shares)			306,228,873	306,228,873			280,400,813
Class B
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			500,000,000	500,000,000			500,000,000
Common stock, par value (in USD per share)			$ 0.00	$ 0.00			$ 0.00
Common stock, shares outstanding (in shares)			106,143,959	106,143,959			114,793,262
Convertible Debt | Convertible Senior Notes due in 2022
Class of Stock [Line Items]
Shares issued upon conversion			2,200,000

STOCKHOLDERS' EQUITY - Share B

STOCKHOLDERS' EQUITY - Share Based Compensation Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)shares	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)planshares	Sep. 30, 2017USD ($)	Nov. 17, 2015shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share based compensation plans | plan			2
Employee stock purchase plan, compensation expense | $	$ 58,913	$ 40,048	$ 157,856	$ 111,311
Capitalized share-based compensation expense | $	2,000	1,300	6,300	2,500
Unrecognized compensation cost, options | $	588,500		588,500
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan, compensation expense | $	$ 2,000	$ 1,300	$ 6,300	$ 4,400
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, period for recognition			2 years 10 months 24 days
2009 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	0		0
2009 Stock Option Plan | Stock options, RSAs, and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments outstanding (in shares)	31,343,565		31,343,565
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	63,264,588		63,264,588
Shares reserved for future issuance (in shares)					30,000,000
Shares reserved for future issuance, percentage of annual increase			5.00%
2015 Equity Incentive Plan | Stock options, RSAs, and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments outstanding (in shares)	25,272,110		25,272,110
2015 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance, amount of annual increase (in shares)	40,000,000		40,000,000

STOCKHOLDERS' EQUITY - Stock O

STOCKHOLDERS' EQUITY - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2018
Number of Stock Options Outstanding
Beginning balance (in shares)	47,270,091
Granted (in shares)	783,625
Exercised (in shares)	(10,661,450)
Forfeited (in shares)	(674,525)
Ending balance (in shares)	36,717,741	47,270,091
Weighted Average Exercise Price
Beginning balance (in USD per share)	$ 8.67
Granted (in USD per share)	44.75
Exercised (in USD per share)	7.71
Forfeited (in USD per share)	12.97
Ending balance (in USD per share)	$ 8.67	$ 8.67	$ 9.64
Options Exercisable
Options exercisable (in shares)			33,952,212
Options exercisable (in USD per share)			$ 8.64
Additional Disclosures
Weighted average remaining contractual term, options outstanding	5 years 11 months 9 days	6 years 6 months 7 days
Weighted average remaining contractual term, options exercisable	5 years 9 months
Aggregate intrinsic value, options outstanding		$ 1,229,103	$ 3,281,558
Aggregate intrinsic value, options exercisable			$ 3,068,274

STOCKHOLDERS' EQUITY - RSU Act

STOCKHOLDERS' EQUITY - RSU Activity (Details) - RSAs and RSUs	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Number of shares
Beginning balance (in shares) | shares	21,317,525
Granted (in shares) | shares	6,408,650
Vested (in shares) | shares	(5,796,657)
Forfeited (in shares) | shares	(2,031,584)
Ending balance (in shares) | shares	19,897,934
Weighted Average Grant Date Fair Value
Beginning balance (in USD per share) | $ / shares	$ 17.84
Granted (in USD per share) | $ / shares	52.93
Vested (in USD per share) | $ / shares	18.30
Forfeited (in USD per share) | $ / shares	18.56
Ending balance (in USD per share) | $ / shares	$ 28.94

STOCKHOLDERS' EQUITY - Stock_2

STOCKHOLDERS' EQUITY - Stock Option Fair Value Assumptions (Details) - Stock options	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%
Risk-free interest rate	2.92%	1.88%
Expected volatility	30.87%	32.22%
Expected term (years)	6 years 2 months 9 days	6 years 7 days

STOCKHOLDERS' EQUITY - Effects

STOCKHOLDERS' EQUITY - Effects of Share-Based Compensation on Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 58,913	$ 40,048	$ 157,856	$ 111,311
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	18	29	79	47
Product development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	39,525	25,254	103,813	69,746
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	6,108	4,579	16,703	12,869
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 13,262	$ 10,186	$ 37,261	$ 28,649

INCOME (LOSS) PER SHARE - Calc

INCOME (LOSS) PER SHARE - Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net income (loss)	$ 19,643	$ (16,098)	$ (10,249)	$ (47,150)
Basic shares:
Weighted-average common shares outstanding (in shares)	410,095	385,409	403,577	377,374
Weighted-average unvested shares (in shares)	(405)	(1,458)	(597)	(1,631)
Weighted-average shares used to compute basic net income (loss) per share (in shares)	409,690	383,951	402,980	375,743
Diluted shares:
Stock options and restricted stock units (in shares)	47,175	0	0	0
Convertible senior notes (in shares)	6,409	0	0	0
Common stock warrants (in shares)	11,422	0	0	0
Employee stock purchase plan (in shares)	219	0	0	0
Weighted-average shares used to compute diluted income (loss) per share (in shares)	474,915	383,951	402,980	375,743
Net income (loss) per share:
Basic (in USD per share)	$ 0.05	$ (0.04)	$ (0.03)	$ (0.13)
Diluted (in USD per share)	$ 0.04	$ (0.04)	$ (0.03)	$ (0.13)

INCOME (LOSS) PER SHARE - Anti

INCOME (LOSS) PER SHARE - Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	54,755	97,766	112,289	99,700
Stock options and restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	12,079	76,618	62,822	81,118
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	18,830	19,173	24,387	16,539
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	23,415	0	24,276	0
Unvested shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	405	1,458	597	1,631
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	26	517	207	412

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES - Operating and Capital Leases- Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Operating leases, rent expense	$ 6.4	$ 3.7	$ 16.2	$ 9.6

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Schedule of Future Payments Under Operating and Capital Leases (Details) $ in Thousands	Sep. 30, 2018USD ($)
Capital
2018 (remaining 3 months)	$ 1,284
2,019	5,029
2,020	2,446
2,021	0
2,022	0
Thereafter	0
Total	8,759
Less amount representing interest	0
Present value of capital lease obligations	8,759
Less current portion of capital lease obligation	(5,135)
Non-current portion of capital lease obligation	3,624
Operating
2018 (remaining 3 months)	7,687
2,019	29,454
2,020	30,657
2,021	30,598
2,022	31,051
Thereafter	32,747
Total	$ 162,194

SEGMENT AND GEOGRAPHICAL INFO_3

SEGMENT AND GEOGRAPHICAL INFORMATION - Narrative (Details)	9 Months Ended
	Sep. 30, 2018segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

SEGMENT AND GEOGRAPHICAL INFO_4

SEGMENT AND GEOGRAPHICAL INFORMATION - Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 882,108	$ 585,159	$ 2,365,649	$ 1,598,218
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	838,149	559,053	2,255,657	1,533,960
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 43,959	$ 26,106	$ 109,992	$ 64,258

SEGMENT AND GEOGRAPHICAL INFO_5

SEGMENT AND GEOGRAPHICAL INFORMATION - Long-lived Assets by Geography (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 471,239	$ 164,157
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	464,455	158,820
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 6,784	$ 5,337

SUPPLEMENTAL CASH FLOW INFORM_3

SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Data:
Cash paid for interest	$ 1,945	$ 1,230
Cash paid for income taxes	1,265	1,117
Supplemental disclosures of non-cash investing and financing activities:
Change in purchases of property and equipment in accounts payable and accrued expenses	11,004	(123)
Unpaid business combination purchase price	3,995	644
Fair value of common stock issued related to business combination	(140,107)	0
Recovery of common stock in connection with indemnification settlement agreement	2,745	0
Fair value of common stock issued to settle the conversion of senior notes, due 2022	(189,916)	0
Fair value of shares received to settle senior note hedges, due 2022	$ 189,916	$ 0