Block (XYZ) 10-K 27 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 22, 2019	Jun. 30, 2018
Class of Stock [Line Items]
Entity Registrant Name	Square, Inc.
Entity Central Index Key	1,512,673
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 18.6
Class A
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		327,326,001
Class B
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		92,368,406

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 583,173	$ 696,474
Short-term investments	540,991	169,576
Restricted cash	33,838	28,805
Settlements receivable	364,946	620,523
Customer funds	334,017	103,042
Loans held for sale	89,974	73,420
Other current assets	164,966	86,454
Total current assets	2,111,905	1,778,294
Property and equipment, net	142,402	91,496
Goodwill	261,705	58,327
Acquired intangible assets, net	77,102	14,334
Long-term investments	464,680	203,667
Restricted cash	15,836	9,802
Build-to-suit lease asset	149,000	0
Other non-current assets	58,393	31,350
Total assets	3,281,023	2,187,270
Current liabilities:
Customers payable	749,215	733,736
Settlements payable	54,137	114,788
Accrued transaction losses	33,682	26,893
Accrued expenses	82,354	52,280
Other current liabilities	99,153	45,130
Total current liabilities	1,018,541	972,827
Long-term debt (Note 12)	899,695	358,572
Build-to-suit lease liability	149,000	0
Other non-current liabilities	93,286	69,538
Total liabilities	2,160,522	1,400,937
Commitments and contingencies (Note 17)
Stockholders’ equity:
Preferred stock, $0.0000001 par value: 100,000,000 shares authorized at December 31, 2018 and December 31, 2017. None issued and outstanding at December 31, 2018 and December 31, 2017.	0	0
Additional paid-in capital	2,012,328	1,630,386
Accumulated other comprehensive loss	(6,053)	(1,318)
Accumulated deficit	(885,774)	(842,735)
Total stockholders’ equity	1,120,501	786,333
Total liabilities and stockholders’ equity	3,281,023	2,187,270
Class A
Stockholders’ equity:
Common stock	0	0
Class B
Stockholders’ equity:
Common stock	$ 0	$ 0

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in USD per share)	$ 0.00	$ 0.00
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A
Common stock, par value (in USD per share)	$ 0.00	$ 0.00
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	323,546,864	280,400,813
Common stock, shares outstanding (in shares)	323,546,864	280,400,813
Class B
Common stock, par value (in USD per share)	$ 0.00	$ 0.00
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	93,501,142	114,793,262
Common stock, shares outstanding (in shares)	93,501,142	114,793,262

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue:
Revenue	$ 3,205,500
Revenues	3,298,177	$ 2,214,253	$ 1,708,721
Cost of Revenue [Abstract]
Cost of revenue	94,114	62,393	68,562
Total cost of revenue	1,994,477	1,374,947	1,132,683
Gross profit	1,303,700	839,306	576,038
Operating expenses:
Product development	497,479	321,888	268,537
Sales and marketing	411,151	253,170	173,876
General and administrative	339,245	250,553	251,993
Transaction, loan and advance losses	88,077	67,018	51,235
Total operating expenses	1,340,314	893,512	746,491
Operating loss	(36,614)	(54,206)	(170,453)
Interest expense, net	17,982	10,053	(533)
Other income, net	(18,469)	(1,595)	(247)
Loss before income tax	(36,127)	(62,664)	(169,673)
Provision for income taxes	2,326	149	1,917
Net loss	$ (38,453)	$ (62,813)	$ (171,590)
Net loss per share:
Basic (in USD per share)	$ (0.09)	$ (0.17)	$ (0.50)
Diluted (in USD per share)	$ (0.09)	$ (0.17)	$ (0.50)
Weighted-average shares used to compute net loss per share:
Basic (in shares)	405,731	379,344	341,555
Diluted (in shares)	405,731	379,344	341,555
Transaction-based
Revenue:
Revenue	$ 2,471,451	$ 1,920,174	$ 1,456,160
Subscription and services-based revenue
Revenue:
Revenue	499,010	185,485	79,507
Revenues	591,706	252,664	129,351
Cost of Revenue [Abstract]
Cost of revenue	169,884	75,720	43,132
Hardware revenue
Revenue:
Revenue	68,503	41,415	44,307
Cost of Revenue [Abstract]
Cost of revenue	94,114
Bitcoin revenue
Revenue:
Revenue	166,517	0	0
Cost of Revenue [Abstract]
Cost of revenue	164,827	0	0
Customers Other than Starbucks | Transaction-based
Revenue:
Revenue	2,471,451	1,920,174	1,456,160
Cost of Revenue [Abstract]
Cost of revenue	1,558,562	1,230,290	943,200
Starbucks | Transaction-based
Revenue:
Revenue	0	0	78,903
Cost of Revenue [Abstract]
Cost of revenue	0	0	69,761
Acquired technology
Cost of Revenue [Abstract]
Amortization of acquired technology	7,090	6,544	8,028
Acquired customers
Operating expenses:
Amortization of acquired customer assets	$ 4,362	$ 883	$ 850

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (38,453)	$ (62,813)	$ (171,590)
Net foreign currency translation adjustments	(4,496)	1,900	(716)
Net unrealized gain (loss) on revaluation of intercompany loans	303	385	(11)
Net unrealized loss on marketable debt securities	(542)	(1,614)	(77)
Total comprehensive loss	$ (43,188)	$ (62,142)	$ (172,394)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Convertible preferred stock	Class A and B common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Beginning balance at Dec. 31, 2015	$ 508,048	$ 0	$ 0	$ 1,116,882	$ (1,185)	$ (607,649)
Beginning balance (in shares) at Dec. 31, 2015		0	334,949,445
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(171,590)					(171,590)
Shares issued in connection with:
Exercise of stock options and warrants (in shares)			24,413,821
Exercise of stock options and warrants	82,438			82,438
Purchases under employee stock purchase plan (in shares)			1,852,900
Purchases under employee stock purchase plan	14,201			14,201
Vesting of restricted stock units (in shares)			3,392,726
Vesting of restricted stock units	0
Vesting of early exercised stock options and other	2,313			2,313
Cancellation of shares related to business combinations (in shares)			(228)
Cancellation of shares related to business combinations	0
Repurchase of common stock (in shares)			(61,288)
Repurchase of common stock	0
Change in other comprehensive loss	(804)				(804)
Share-based compensation	141,547			141,547
Ending balance at Dec. 31, 2016	576,153	$ 0	$ 0	1,357,381	(1,989)	(779,239)
Ending balance (in shares) at Dec. 31, 2016		0	364,547,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(62,813)					(62,813)
Shares issued in connection with:
Exercise of stock options (in shares)			24,510,745
Exercise of stock options	144,774			144,774
Purchases under employee stock purchase plan (in shares)			1,670,045
Purchases under employee stock purchase plan	17,859			17,859
Vesting of restricted stock units (in shares)			5,964,153
Vesting of restricted stock units	0
Vesting of early exercised stock options and other	661			661
Repurchase of common stock (in shares)			(24,209)
Repurchase of common stock	0
Change in other comprehensive loss	671				671
Share-based compensation	159,509			159,509
Tax withholding related to vesting of restricted stock units (in shares)			(1,474,035)
Tax withholding related to vesting of restricted stock units	(44,682)			(44,682)
Conversion feature of convertible senior notes, due 2022, net of allocated debt issuance costs	83,901			83,901
Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2022	(92,136)			(92,136)
Sale of warrants in conjunction with issuance of convertible senior notes, due 2022	57,244			57,244
Payment for termination of Starbucks warrant	(54,808)			(54,808)
Ending balance at Dec. 31, 2017	786,333	$ 0	$ 0	1,630,386	(1,318)	(842,735)
Ending balance (in shares) at Dec. 31, 2017		0	395,194,075
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (38,453)					(38,453)
Shares issued in connection with:
Exercise of stock options (in shares)	13,402,680		13,402,680
Exercise of stock options	$ 106,962			106,962
Purchases under employee stock purchase plan (in shares)			826,356
Purchases under employee stock purchase plan	26,888			26,888
Vesting of restricted stock units (in shares)			8,046,640
Vesting of early exercised stock options and other	177			177
Issuance of common stock in connection with business combination (shares)			2,649,590
Issuance of common stock in connection with business combination	140,107			140,107
Replacement stock awards issued in connection with acquisition (in shares)			24,613
Replacement stock awards issued in connection with acquisition	899			899
Change in other comprehensive loss	(4,735)				(4,735)
Share-based compensation	226,182			226,182
Tax withholding related to vesting of restricted stock units (in shares)			(3,013,394)
Tax withholding related to vesting of restricted stock units	(189,124)			(189,124)
Conversion feature of convertible senior notes, due 2022, net of allocated debt issuance costs	154,019			154,019
Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2022	(172,586)			(172,586)
Sale of warrants in conjunction with issuance of convertible senior notes, due 2022	112,125			112,125
Issuance of common stock in conjunction with the conversion of senior notes, due 2022 (in shares)			7,288,907
Issuance of common stock in conjunction with the conversion of senior notes, due 2022	(20,962)			(20,962)
Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022 (in shares)			(6,901,567)
Recovery of common stock in connection with indemnification settlement agreement (in shares)			(469,894)
Recovery of common stock in connection with indemnification settlement agreement	(2,745)			(2,745)
Ending balance at Dec. 31, 2018	$ 1,120,501	$ 0	$ 0	$ 2,012,328	$ (6,053)	$ (885,774)
Ending balance (in shares) at Dec. 31, 2018		0	417,048,006

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (38,453)	$ (62,813)	$ (171,590)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	60,961	37,279	37,745
Non-cash interest and other expense	31,257	14,421	(49)
Loss on extinguishment of long-term debt	5,047	0	0
Share-based compensation	216,881	155,836	138,786
Replacement stock awards issued in connection with acquisition	899	0	0
Gain on revaluation of equity investment	(20,342)	0	0
Recovery of common stock in connection with indemnification settlement agreement	(2,745)	0	0
Transaction, loan and advance losses	88,077	67,018	51,235
Change in deferred income taxes	(646)	(1,385)	58
Changes in operating assets and liabilities:
Settlements receivable	245,795	(305,831)	(177,662)
Customer funds	(131,004)	(59,468)	(34,128)
Purchase of loans held for sale	(1,609,611)	(1,184,630)	(668,976)
Sales and principal payments of loans held for sale	1,579,834	1,145,314	627,627
Other current assets	(77,405)	(26,119)	16,116
Other non-current assets	(6,641)	(3,274)	631
Customers payable	15,597	301,778	206,574
Settlements payable	(60,651)	63,637	38,046
Charge-offs to accrued transaction losses	(58,192)	(46,148)	(47,931)
Accrued expenses	7,190	12,207	(409)
Other current liabilities	35,294	8,198	3,909
Other non-current liabilities	13,938	11,691	3,149
Net cash provided by operating activities	295,080	127,711	23,131
Cash flows from investing activities:
Purchase of marketable debt securities	(1,000,346)	(544,910)	(164,766)
Proceeds from maturities of marketable debt securities	197,454	168,224	43,200
Proceeds from sale of marketable debt securities	171,992	89,087	34,222
Purchase of marketable debt securities from customer funds	(148,096)	0	0
Proceeds from sale of marketable debt securities from customer funds	48,334	0	0
Purchase of property and equipment	(61,203)	(26,097)	(25,433)
Proceeds from sale of property and equipment	0	0	296
Purchase of equity investment	0	(25,000)	0
Purchase of intangible assets	(1,584)	0	(400)
Business combinations, net of cash acquired	(112,399)	(1,915)	(1,360)
Net cash used in investing activities:	(905,848)	(340,611)	(114,241)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net	855,663	428,250	0
Purchase of convertible senior note hedges	(172,586)	(92,136)	0
Proceeds from issuance of warrants	112,125	57,244	0
Principal payment on conversion of senior notes	(219,384)	0	0
Payment of deferred purchase consideration	(848)	0	0
Payment for termination of Starbucks warrant	0	(54,808)	0
Payments of offering costs related to initial public offering	0	0	(5,530)
Principal payments on capital lease obligation	(3,941)	(1,439)	(168)
Proceeds from the exercise of stock options and purchases under the employee stock purchase plan, net	133,850	162,504	96,439
Payments for tax withholding related to vesting of restricted stock units	(189,124)	(44,682)	0
Net cash provided by financing activities	515,755	454,933	90,741
Effect of foreign exchange rate on cash and cash equivalents	(7,221)	4,303	(438)
Net increase (decrease) in cash, cash equivalents and restricted cash	(102,234)	246,336	(807)
Cash, cash equivalents and restricted cash, beginning of the year	735,081	488,745	489,552
Cash, cash equivalents and restricted cash, end of the year	$ 632,847	$ 735,081	$ 488,745

DESCRIPTION OF BUSINESS AND SUM

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 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 store money, and Caviar is a food-ordering service. 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 year ended December 31, 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 the year ended December 31, 2018 , the Company recorded a gain of $20.3 million to other income on the consolidated statements of operations arising from revaluation of this investment (Note 11 ). 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. Litigation Settlement On June 8, 2016, a final, definitive settlement agreement (Settlement Agreement) was entered into by Robert E. Morley, REM Holdings 3, LLC, Jack Dorsey, Jim McKelvey, and the Company. The Settlement Agreement required an aggregate total payment of $50.0 million to plaintiffs, including meaningful contributions by Mr. Dorsey and Mr. McKelvey. The Company made a payment of $48.0 million to plaintiffs and met its obligations under the Settlement Agreement. This amount was classified within general and administrative expenses on the consolidated statements of operations for the year ended December 31, 2016. On June 17, 2016, the Court entered an Order dismissing the complaints in their entirety, with prejudice. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, as well as related disclosure of contingent assets and liabilities. Actual results could differ from the Company’s estimates. To the extent that there are material differences between these estimates and actual results, the Company’s financial condition or operating results will be materially affected. The Company bases its estimates on past experience and other assumptions that the Company believes are reasonable under the circumstances, and the Company evaluates these estimates on an ongoing basis. 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, build-to-suit lease asset and liability, and share-based compensation. Revenue Recognition On January 1, 2018, the Company adopted Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers, 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. Refer to Note 2 for the impact of this adoption. 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. 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, Square Capital, 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 (Cash 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. Square Capital facilitates a loan that is offered through a partnership with an industrial bank that is either repaid through withholding a percentage of the collections of the seller's receivables processed by the Company or a specified monthly amount. The Company generally facilitates loans to its sellers pre-qualified through an analysis of the aggregated data of the seller’s business which includes, but is not limited to, the seller’s historical processing volumes, transaction count, chargebacks, growth, and length of time as a Square customer. The Company also facilitates loans to the customers of certain sellers as well as to the sellers of its partners who do not process payments through the Company. The loans are generally originated by a bank partner, from whom the Company purchases the loans obtaining all rights, title, and interest. The loans have no stated coupon rate but the seller is charged a one-time origination fee by the bank partner based upon their risk rating, which is derived primarily from processing activity. It is the Company’s intent to sell all of its rights, title, and interest of these loans to third-party investors for an upfront fee when the loans are sold. The Company records the net amounts paid to the bank as the cost of the loans purchased and subsequently records a gain on sale of the loans to the third-party investors as revenue upon transfer of title. The Company is retained by the third-party investors to service the loans and earns a servicing fee for facilitating the repayment of these receivables through its managed payments solutions. The Company records servicing revenue as servicing is delivered. For the loans which are not immediately sold to third-party investors, the Company recognizes a portion of the expected seller repayments over the cost of the loans as revenue in proportion to the loan principal reduction. 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. Pursuant to practical expedients afforded under ASC 606, the Company does not recognize a financing component for hardware installment sales that have a term of one year or less. 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'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 7 ). The Company 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. The Company determines 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. Cost of Revenue Transaction-based costs Transaction-based costs consist primarily of interchange and assessment fees, processing fees and bank settlement fees paid to third-party payment processors and financial institutions. Subscription and services-based costs Subscription and services-based costs consist primarily of Caviar-related costs, which include processing fees, payments to third-party couriers for deliveries and the cost of equipment provided to sellers. Caviar-related costs for catered meals also includes food costs and personnel costs. These costs also include costs associated with Cash Card and Instant Deposit. Hardware costs Hardware costs consist of all product costs associated with contactless and chip readers, chip card readers, Square Stand, Square Register, Square Terminal and third-party peripherals. Product costs consist of third-party manufacturing costs. Bitcoin costs Bitcoin cost of revenue comprises of the amounts the Company pays to purchase bitcoin, which will fluctuate in line with the price of bitcoin in the market. Advertising Costs Advertising costs are expensed as incurred and included in sales and marketing expense on the consolidated statements of operations. Total advertising costs for the years ended December 31, 2018 , 2017 , and 2016 were $101.9 million , $81.9 million , and $58.3 million , respectively. Share-based Compensation Share-based compensation expense relates to stock options, restricted stock awards (RSAs), restricted stock units (RSUs), and purchases under the Company’s 2015 Employee Stock Purchase Plan (ESPP) which is measured based on the grant-date fair value. The 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 and ESPP shares granted to employees is estimated on the date of grant using the Black-Scholes-Merton option valuation model. This share-based compensation expense valuation model requires the Company to make assumptions and judgments regarding the variables used in the calculation. These variables include the expected term (weighted average period of time that the options granted are expected to be outstanding), the expected volatility of the Company’s stock, expected risk-free interest rate and expected dividends. The Company uses the simplified calculation of expected term, as the Company does not have sufficient historical data to use any other method to estimate expected term. Expected volatility is based on a weighted average of the historical volatilities of the Company's common stock along with several entities with characteristics similar to those of the Company. The Company will continue to weight its own volatility more heavily as more of its own historical stock price information becomes available. Once its own historical data is equal to that of the expected term of option grants a peer group is no longer considered necessary. The expected risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. Share-based compensation expense is recorded on a straight-line basis over the requisite service period. For the year ended December 31, 2016 and prior, the Company recorded share-based compensation expense net of estimated forfeitures. On January 1, 2017, as a result of the Company's adoption of ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting , the Company elected to account for forfeitures as they occur. Income and Other Taxes The Company reports income taxes under the asset and liability approach. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, as well as net operating loss and tax credit carryforwards. Deferred tax amounts are determined by using the enacted tax rates expected to be in effect when the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance reduces the deferred tax assets to the amount that is more likely than not to be realized. The Company uses financial projections to support its net deferred tax assets, which contain significant assumptions and estimates of future operations. If such assumptions were to differ significantly from actual future results of operations, it may have a material impact on the Company’s ability to realize its deferred tax assets. At the end of each period, the Company assesses the ability to realize the deferred tax assets. If it is more likely than not that the Company would not realize the deferred tax assets, then the Company would establish a valuation allowance for all or a portion of the deferred tax assets. The Company recognizes the effect of uncertain income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that has a greater than 50% likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to uncertain tax positions in the provision for income tax expense on the consolidated statements of operations. Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments, including money market funds, with an original maturity of three months or less when purchased to be cash equivalents. As of December 31, 2018 and 2017 , restricted cash of $33.8 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 that we expect to become unrestricted within the next year. As of December 31, 2018 and 2017 , the remaining restricted cash of $15.8 million and $9.8 million , respectively, is primarily related to cash held as collateral pursuant to multi-year lease agreements (Note 17 ). The Company has recorded this amount as a non-current asset on the consolidated balance sheets as the terms of the related leases extend beyond one year. Concentration of Credit Risk For the years ended December 31, 2018 , 2017 and 2016 , the Company had no customer who accounted for greater than 10% of total net revenue. The Company had three third-party payment processors that represented approximately 45% , 33% , and 9% of settlements receivable as of December 31, 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. Investments The Company's short-term and long-term investments include marketable debt securities such as government and agency securities, corporate bonds, commercial paper and municipal securities. 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. Investments are reviewed periodically to identify possible other-than-temporary impairments. If any impairment is considered other-than-temporary, the Company writes down the investment to its fair value and record the corresponding charge through other income (expense), net on its consolidated statements of operations. Customer funds Customer funds held in deposit represent Cash App customers' stored balances that customers would later use to send money or make payments, or customers cash in transit. As of December 31, 2017 , the Company held these stored balances as short term bank deposits. During the year ended December 31, 2018 , the Company started investing a portion of these stored balances in short-term marketable debt securities (Note 4 ). 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. Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value accounting establishes a three-level hierarchy priority for disclosure of assets and liabilities recorded at fair value. The ordering of priority reflects the degree to which objective prices in external active markets are available to measure fair value. The classification of assets and liabilities within the hierarchy is based on whether the inputs to the valuation methodology used for measurement are observable or unobservable. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: • Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date. • Level 2 Inputs: Other than quoted prices included in Level 1 Inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date. Loans Held for Sale The Company classifies customer loans as held for sale upon purchase from an industrial bank partner, as there is an available market for such loans and it is the Company’s intent to sell all of its rights, title, and interest in these loans to third-party investors. 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 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. A loan that is initially designated as held for sale may be reclassified to held for investment if and when the Company's intent for that loan changes. There have been no reclassifications made to date. Settlements Receivable Settlements receivable represents amounts due from third-party payment processors for customer transactions. Settlements receivable are typically received within one or two business days of the transaction date. No valuation allowances have been established, as funds are due from large, well-established financial institutions with no historical collections issue. Inventory Inventory is comprised of contactless and chip readers, chip card readers, Square Stand, Square Register, Square Terminal and third-party peripherals, as well as component parts that are used to manufacture these products. Inventory is stated at the lower of cost (generally on a first-in, first-out basis) or net realizable value. Inventory that is obsolete or in excess of forecasted usage is written down to its net realizable value based on the estimated selling prices in the ordinary course of business. The Company's inventory is held at the Company's warehouses as well as at third party contract manufacturer premises. 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. 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 December 31, 2018 and 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 carrying value exceeds the fair value. Losses on bitcoin for the years ended December 31, 2018 and 2017 , were insignificant. Property and Equipment Property and equipment are recorded at historical cost less accumulated depreciation, which is computed on a straight-line basis over the asset’s estimated useful life. The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Two to three years Furniture and fixtures Seven years Leasehold improvements Lesser of ten years or remaining lease term When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from their respective accounts, and any gain or loss on such sale or disposal is reflected in operating expenses. Capitalized Software The Company capitalizes certain cost incurred in developing internal-use software when capitalization requirements have been met. Costs prior to meeting the capitalization requirements are expensed as incurred. Capitalized costs are included in property and equipment, net, and amortized on a straight-lined basis over the estimated useful life of the software and included in product development costs on the consolidated statements of operations. The Company capitalized $24.0 million , $9.8 million and $7.9 million of internally developed software during the years ended December 31, 2018 , 2017 and 2016 , respectively, and recognized $10.6 million , $6.6 million and $7.1 million of amortization expense during the years ended December 31, 2018 , 2017 and 2016 , respectively. Leases The Company leases office space and equipment under non-cancellable capital and operating leases with various expiration dates. The Company records the total rent expense on a straight-line basis over the lease term. When lease agreements provide allowances for leasehold improvements, the Company capitalizes the leasehold improvement assets and recognizes the related depreciation expense on a straight-line basis over the lesser of the lease term or the estimated useful life of the asset, and reduces rent expense on a straight-line basis over the term of the lease by the amount of the allowances provided. The Company classifies the cash payments for the leasehold improvements within investing activities while reimbursements from the landlords are classified within operating activities. The Company records a liability for the estimated fair value for any asset retirement obligation (ARO) associated with its leases, with an offsetting asset. In the determination of the fair value of AROs, the Company uses various assumptions and judgments, including such factors as the existence of a legal obligation, estimated amounts and timing of settlements, and discount and inflation rates. The liability is subsequently accreted while the asset is depreciated. As of December 31, 2018 , the Company had a liability for ARO, gross of accretion, of $3.6 million and an associated asset, net of depreciation, of $2.1 million . Under ASC 840, Leases , the Company is deemed to be the owner, for accounting purposes, during the construction phase of a certain long-lived asset under a build-to-suit lease arrangement because of its involvement with the construc

REVENUE

REVENUE	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
REVENUE	REVENUE Adoption of ASC 606, Revenue from Contracts with Customers 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 year ended December 31, 2018 was an increase of $6.4 million as a result of applying ASC 606. For the year ended December 31, 2018 , the revenue recognized from contracts with customers was $3,205.5 million and revenue from other sources was $92.7 million . Impairment losses arising from contracts with customers were $3.7 million for the year ended December 31, 2018 . Practical Expedients The Company does not recognize a financing component for hardware installment sales that have a term of one year or less. The impact of adoption of ASC 606 on the Company's consolidated statement of operations was as follows (in thousands): Year Ended December 31, 2018 As reported Balances without adoption Effect of change Impact on the Consolidated Statement of Operations: Subscription and services-based revenue $ 591,706 $ 591,220 $ 486 Hardware revenue 68,503 62,572 5,931 Subscription and services-based costs 169,884 169,884 — Hardware costs $ 94,114 $ 88,625 $ 5,489 The impact of adoption of ASC 606 on the Company's consolidated balance sheets was as follows (in thousands): December 31, 2018 As reported Balances without adoption Effect of change Impact on the Consolidated Balance Sheets: Other current assets $ 164,966 $ 178,101 $ (13,135 ) Other current liabilities 99,153 108,334 (9,181 ) Other non-current assets 58,393 59,768 (1,375 ) Other non-current liabilities $ 93,286 $ 94,717 $ (1,431 ) The following table presents the Company's revenue from contracts with customers (i.e. excluding revenue from other sources) disaggregated by revenue source (in thousands): Year Ended December 31, 2018 2017 2016 Revenue from Contracts with Customers: Transaction-based revenue $ 2,471,451 $ 1,920,174 $ 1,456,160 Starbucks transaction-based revenue — — 78,903 Subscription and services-based revenue 499,010 185,485 79,507 Hardware revenue 68,503 41,415 44,307 Bitcoin revenue $ 166,517 $ — $ — The deferred revenue balances were as follows (in thousands): Year Ended December 31, 2018 2017 Deferred revenue, beginning of the period $ 5,893 $ 5,407 Less: accumulative adjustment for adoption of ASC 606 (4,303 ) — Deferred revenue, beginning of the period, as adjusted 1,590 5,407 Deferred revenue, end of the period 36,451 5,893 Deferred revenue arising from business combination 22,800 — Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period $ 1,590 $ 5,257

INVESTMENTS

INVESTMENTS	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS The Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term securities: U.S. agency securities $ 80,160 $ 32 $ (70 ) $ 80,122 Corporate bonds 109,807 80 (368 ) 109,519 Municipal securities 27,839 52 (59 ) 27,832 U.S. government securities 292,615 161 (509 ) 292,267 Non-U.S. government securities 31,263 4 (16 ) 31,251 Total $ 541,684 $ 329 $ (1,022 ) $ 540,991 Long-term securities: U.S. agency securities $ 114,444 $ 194 $ (78 ) $ 114,560 Corporate bonds 159,783 419 (950 ) 159,252 Municipal securities 28,453 167 (26 ) 28,594 U.S. government securities 153,743 553 (172 ) 154,124 Non-U.S. government securities 8,122 28 — 8,150 Total $ 464,545 $ 1,361 $ (1,226 ) $ 464,680 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 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 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 as cash equivalents are excluded from the table since the amortized cost approximated the fair value due to the short term nature of these investments. For the years ended December 31, 2018 , 2017 and 2016 , gains or losses realized on the sale of investments were not material. Investments are reviewed periodically to identify possible other-than-temporary impairments. As the Company has the ability and intent to hold these investments with unrealized losses 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 contractual maturities of the Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 541,684 $ 540,991 Due in one to five years 464,545 464,680 Total $ 1,006,229 $ 1,005,671 CUSTOMER FUNDS The following table presents the assets underlying customer funds (in thousands): December 31, December 31, Cash $ 158,697 $ 103,042 Cash Equivalents: Money market funds 18 — U.S. agency securities 39,991 — U.S. government securities 35,349 — Short-term debt securities: U.S. agency securities 27,291 — U.S. government securities 72,671 — Total $ 334,017 $ 103,042 The Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 27,293 $ 2 $ (4 ) $ 27,291 U.S. government securities 72,662 12 (3 ) 72,671 Total $ 99,955 $ 14 $ (7 ) $ 99,962 Investments within customer funds classified as cash equivalents are excluded from the table since the amortized cost approximated the fair value due to the short term nature of these investments. 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 contractual maturities of the Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 99,955 $ 99,962 Due in one to five years — — Total $ 99,955 $ 99,962

CUSTOMER FUNDS

CUSTOMER FUNDS	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
CUSTOMER FUNDS	INVESTMENTS The Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term securities: U.S. agency securities $ 80,160 $ 32 $ (70 ) $ 80,122 Corporate bonds 109,807 80 (368 ) 109,519 Municipal securities 27,839 52 (59 ) 27,832 U.S. government securities 292,615 161 (509 ) 292,267 Non-U.S. government securities 31,263 4 (16 ) 31,251 Total $ 541,684 $ 329 $ (1,022 ) $ 540,991 Long-term securities: U.S. agency securities $ 114,444 $ 194 $ (78 ) $ 114,560 Corporate bonds 159,783 419 (950 ) 159,252 Municipal securities 28,453 167 (26 ) 28,594 U.S. government securities 153,743 553 (172 ) 154,124 Non-U.S. government securities 8,122 28 — 8,150 Total $ 464,545 $ 1,361 $ (1,226 ) $ 464,680 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 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 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 as cash equivalents are excluded from the table since the amortized cost approximated the fair value due to the short term nature of these investments. For the years ended December 31, 2018 , 2017 and 2016 , gains or losses realized on the sale of investments were not material. Investments are reviewed periodically to identify possible other-than-temporary impairments. As the Company has the ability and intent to hold these investments with unrealized losses 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 contractual maturities of the Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 541,684 $ 540,991 Due in one to five years 464,545 464,680 Total $ 1,006,229 $ 1,005,671 CUSTOMER FUNDS The following table presents the assets underlying customer funds (in thousands): December 31, December 31, Cash $ 158,697 $ 103,042 Cash Equivalents: Money market funds 18 — U.S. agency securities 39,991 — U.S. government securities 35,349 — Short-term debt securities: U.S. agency securities 27,291 — U.S. government securities 72,671 — Total $ 334,017 $ 103,042 The Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 27,293 $ 2 $ (4 ) $ 27,291 U.S. government securities 72,662 12 (3 ) 72,671 Total $ 99,955 $ 14 $ (7 ) $ 99,962 Investments within customer funds classified as cash equivalents are excluded from the table since the amortized cost approximated the fair value due to the short term nature of these investments. 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 contractual maturities of the Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 99,955 $ 99,962 Due in one to five years — — Total $ 99,955 $ 99,962

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 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): December 31, 2018 December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash and cash equivalents: Money market funds $ 218,109 $ — $ — $ 387,698 $ — $ — U.S. agency securities — 46,423 — — — — Commercial paper — — — — 24,695 — U.S. government securities 86,239 — — — — — Non-U.S. government securities — 23,981 — — — — Customer Funds: Money market funds 18 — — — — — U.S. agency securities — 67,282 — — — — U.S. government securities 108,020 — — — — — Short-term securities: U.S. agency securities — 80,122 — — 15,083 — Corporate bonds — 109,519 — — 57,798 — Commercial paper — — — — 17,428 — Municipal securities — 27,832 — — 23,700 — U.S. government securities 292,267 — — 55,567 — — Non-U.S. government securities — 31,251 — — — — Long-term securities: U.S. agency securities — 114,560 — — 20,169 — Corporate bonds — 159,252 — — 91,413 — Municipal securities — 28,594 — — 26,224 — U.S. government securities 154,124 — — 65,861 — — Non-U.S. government securities — 8,150 — — — — Other: Equity investment 45,342 — — — — — Total $ 904,119 $ 696,966 $ — $ 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): December 31, 2018 December 31, 2017 Carrying Value Fair Value (Level 2) Carrying Value Fair Value (Level 2) 2023 Notes $ 718,522 $ 901,468 $ — $ — 2022 Notes 181,173 515,693 358,572 719,356 Total $ 899,695 $ 1,417,161 $ 358,572 $ 719,356 The estimated fair value and carrying value of loans held for sale is as follows (in thousands): December 31, 2018 December 31, 2017 Carrying Value Fair Value (Level 3) Carrying Value Fair Value (Level 3) Loans held for sale $ 89,974 $ 93,064 $ 73,420 $ 76,070 Total $ 89,974 $ 93,064 $ 73,420 $ 76,070 For the years ended December 31, 2018 and 2017 , the Company recorded a charge for the excess of amortized cost over fair value of the loans of $13.2 million and $8.0 million , respectively. No charges were recorded for the year ended December 31, 2016 . If applicable, the Company will recognize transfers into and out of levels within the fair value hierarchy at the end of the reporting period in which the actual event or change in circumstance occurs. During the years ended December 31, 2018 , 2017 and 2016 , 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	12 Months Ended
	Dec. 31, 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): December 31, December 31, Leasehold improvements $ 107,611 $ 77,073 Computer equipment 80,093 66,186 Capitalized software 58,908 35,063 Office furniture and equipment 20,699 14,490 Total 267,311 192,812 Less: Accumulated depreciation and amortization (124,909 ) (101,316 ) Property and equipment, net $ 142,402 $ 91,496 Depreciation and amortization expense on property and equipment was $46.8 million , $29.7 million , and $28.7 million , for the years ended December 31, 2018 , 2017 , and 2016 , respectively.

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 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 expanded the Company’s customer base globally and added 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) (37,592 ) Total identifiable net assets acquired 76,954 Goodwill 195,585 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. Subsequently, 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 $6.1 million and $4.8 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 evaluation of contingencies and tax effects related to the acquisition. Accordingly, the preliminary values reflected in the table above are subject to change. As of December 31, 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 year ended December 31, 2018 , which resulted in the recognition of additional intangible assets and goodwill. Pro forma financial information has not been presented for any of these acquisitions as the impact to our consolidated financial statements was not material.

GOODWILL

GOODWILL	12 Months Ended
	Dec. 31, 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, 2016 $ 57,173 Acquisitions completed during the year ended December 31, 2017 1,154 Balance at December 31, 2017 58,327 Acquisitions completed during the year ended December 31, 2018 203,378 Balance at December 31, 2018 $ 261,705 The Company performed its annual goodwill impairment test as of December 31, 2018 . The Company determined that the business operations as a whole is represented by a single reporting unit and through qualitative analysis concluded that it was more likely than not that the fair value of the reporting unit was greater than its carrying amount. As a result, the two-step goodwill impairment test was not required, and no impairments of goodwill were recognized during the year ended December 31, 2018 .

ACQUIRED INTANGIBLE ASSETS

ACQUIRED INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
ACQUIRED INTANGIBLE ASSETS	ACQUIRED INTANGIBLE ASSETS The Company entered into various transactions accounted for as business combinations during the year ended December 31, 2018 , that involved the acquisition of intangible assets. Refer to Note 7 for further details. During the year ended December 31, 2017 , the Company did not make any material acquisitions. The following table presents the detail of acquired intangible assets as of the periods presented (in thousands): Balance at December 31, 2018 Cost Accumulated Amortization Net Patents $ 1,285 $ (664 ) $ 621 Technology Assets 45,978 (28,420 ) 17,558 Customer Assets 57,109 (8,068 ) 49,041 Trade Name 11,300 (1,648 ) 9,652 Other 961 (731 ) 230 Total $ 116,633 $ (39,531 ) $ 77,102 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): Year Ended December 31, 2018 2017 2016 Acquired intangible assets, net, beginning of the period $ 14,334 $ 19,292 $ 26,776 Acquisitions 75,871 2,657 1,529 Amortization expense 13,104 7,615 9,013 Acquired intangible assets, net, end of the period $ 77,102 $ 14,334 $ 19,292 The total estimated annual future amortization expense of these intangible assets as of December 31, 2018 , is as follows (in thousands): 2019 $ 13,744 2020 11,496 2021 10,299 2022 8,369 2023 6,839 Thereafter 26,355 Total $ 77,102

OTHER CONSOLIDATED BALANCE SHEE

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT)	12 Months Ended
	Dec. 31, 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): December 31, December 31, Inventory, net $ 28,627 $ 16,777 Processing costs receivable 46,102 21,083 Prepaid expenses 21,782 14,473 Accounts receivable, net 22,393 8,606 Deferred hardware costs (i) — 7,931 Deferred magstripe reader costs (ii) 9,361 2,469 Prepaid compensation, current (iii) 4,995 — Other 31,706 15,115 Total $ 164,966 $ 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 and recognized as compensation expense over time as they provide services to the Company. Accrued Expenses The following table presents the detail of accrued expenses (in thousands): December 31, December 31, Accrued facilities expenses $ 13,040 $ 568 Accrued payroll 9,612 9,103 Accrued professional fees 5,232 5,638 Accrued advertising and other marketing 12,201 6,723 Processing costs payable 12,683 10,145 Accrued non income tax liabilities 9,503 6,155 Accrued hardware costs 5,125 2,496 Other accrued liabilities 14,958 11,452 Total $ 82,354 $ 52,280 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): December 31, December 31, Accounts payable $ 36,416 $ 16,763 Square Capital payable (iv) 6,092 7,671 Square Payroll payable (v) 7,534 2,850 Deferred revenue, current 31,474 5,893 Deferred rent, current 3,842 3,311 Accrued redemptions 1,305 1,036 Other 12,490 7,606 Total $ 99,153 $ 45,130 (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): December 31, December 31, Equity investment (i) $ 45,342 $ 25,000 Prepaid compensation, non-current (ii) 5,915 — Deposits 2,747 2,738 Other 4,389 3,612 Total $ 58,393 $ 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 year ended December 31, 2018 , the Company recorded a gain of $20.3 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 and recognized as compensation expense 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): December 31, December 31, Statutory liabilities (iii) $ 54,748 $ 40,768 Deferred rent, non-current 23,003 20,349 Deferred purchase consideration 3,900 — Deferred revenue, non-current 4,977 432 Other 6,658 7,989 Total $ 93,286 $ 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)	12 Months Ended
	Dec. 31, 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): December 31, December 31, Inventory, net $ 28,627 $ 16,777 Processing costs receivable 46,102 21,083 Prepaid expenses 21,782 14,473 Accounts receivable, net 22,393 8,606 Deferred hardware costs (i) — 7,931 Deferred magstripe reader costs (ii) 9,361 2,469 Prepaid compensation, current (iii) 4,995 — Other 31,706 15,115 Total $ 164,966 $ 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 and recognized as compensation expense over time as they provide services to the Company. Accrued Expenses The following table presents the detail of accrued expenses (in thousands): December 31, December 31, Accrued facilities expenses $ 13,040 $ 568 Accrued payroll 9,612 9,103 Accrued professional fees 5,232 5,638 Accrued advertising and other marketing 12,201 6,723 Processing costs payable 12,683 10,145 Accrued non income tax liabilities 9,503 6,155 Accrued hardware costs 5,125 2,496 Other accrued liabilities 14,958 11,452 Total $ 82,354 $ 52,280 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): December 31, December 31, Accounts payable $ 36,416 $ 16,763 Square Capital payable (iv) 6,092 7,671 Square Payroll payable (v) 7,534 2,850 Deferred revenue, current 31,474 5,893 Deferred rent, current 3,842 3,311 Accrued redemptions 1,305 1,036 Other 12,490 7,606 Total $ 99,153 $ 45,130 (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): December 31, December 31, Equity investment (i) $ 45,342 $ 25,000 Prepaid compensation, non-current (ii) 5,915 — Deposits 2,747 2,738 Other 4,389 3,612 Total $ 58,393 $ 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 year ended December 31, 2018 , the Company recorded a gain of $20.3 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 and recognized as compensation expense 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): December 31, December 31, Statutory liabilities (iii) $ 54,748 $ 40,768 Deferred rent, non-current 23,003 20,349 Deferred purchase consideration 3,900 — Deferred revenue, non-current 4,977 432 Other 6,658 7,989 Total $ 93,286 $ 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	12 Months Ended
	Dec. 31, 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 $0.6 million in unused commitment fees for both the years ended December 31, 2018 and 2017 . As of December 31, 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 $862.5 million of convertible senior notes (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 2023 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 $440.0 million of convertible senior notes (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 and continued to be met through December 31, 2018. During the year ended December 31, 2018, certain holders of the 2022 Notes converted an aggregate principal amount of $228.3 million of their 2022 Notes. The Company settled certain of the 2022 Notes through a combination of cash of $219.4 million for the principal amount and the issuance of 6.9 million 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, and expects to settle future conversions in shares of the Company's Class A common stock. Subsequently, the Company settled $8.9 million principal of the 2022 Notes entirely in shares of the Company's Class A common stock. The Company will reevaluate its settlement 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 2022 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 $5.0 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 $21.0 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 December 31, 2018 2023 Notes $ 862,500 $ (138,924 ) $ (5,054 ) $ 718,522 2022 Notes 211,728 (27,569 ) (2,986 ) 181,173 Total 1,074,228 (166,493 ) (8,040 ) 899,695 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 December 31, 2018 2023 Notes $ 155,250 $ (1,231 ) $ 154,019 2022 Notes 41,481 (1,108 ) 40,373 Total 196,731 (2,339 ) 194,392 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): Year Ended December 31, 2018 2017 Contractual interest expense $ 4,023 $ 1,351 Amortization of debt discount and issuance costs 32,855 14,223 Total $ 36,878 $ 15,574 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 (2018 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 2018 Counterparties whereby the 2018 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 (2017 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 2017 Counterparties whereby the 2017 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 consolidated balance sheets. During the year ended December 31, 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 6.9 million shares of the Company's Class A common stock from the 2017 Counterparties.

ACCRUED TRANSACTION LOSSES

ACCRUED TRANSACTION LOSSES	12 Months Ended
	Dec. 31, 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): Year Ended December 31, 2018 2017 Accrued transaction losses, beginning of the year $ 26,893 $ 20,064 Provision for transaction losses 64,981 52,977 Charge-offs to accrued transaction losses (58,192 ) (46,148 ) Accrued transaction losses, end of the year $ 33,682 $ 26,893

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The domestic and foreign components of loss before income taxes are as follows (in thousands): Year Ended December 31, 2018 2017 2016 Domestic $ 44,538 $ (10,900 ) $ (145,499 ) Foreign (80,665 ) (51,764 ) (24,174 ) Loss before income taxes $ (36,127 ) $ (62,664 ) $ (169,673 ) The components of the provision for income taxes are as follows (in thousands): Year Ended December 31, 2018 2017 2016 Current: Federal $ (4 ) $ (1,192 ) $ 63 State 752 739 527 Foreign 2,224 1,987 1,269 Total current provision for income taxes 2,972 1,534 1,859 Deferred: Federal (404 ) (1,169 ) 173 State 35 57 18 Foreign (277 ) (273 ) (133 ) Total deferred provision for income taxes (646 ) (1,385 ) 58 Total provision for income taxes $ 2,326 $ 149 $ 1,917 The following is a reconciliation of the statutory federal income tax rate to the Company's effective tax rate: Balance at December 31, 2018 2017 2016 Tax at federal statutory rate 21.0 % 34.0 % 34.0 % State taxes, net of federal benefit (1.1 ) (0.4 ) (0.1 ) Foreign rate differential (14.7 ) (14.9 ) (2.4 ) Non-deductible meals (i) (3.4 ) (0.3 ) (0.1 ) Other non-deductible expenses (1.7 ) (0.7 ) (0.8 ) Credits 164.8 41.5 8.5 Other items 2.3 (1.2 ) 0.2 Change in valuation allowance (718.5 ) (119.5 ) (37.4 ) Impact of U.S. tax reform — (209.1 ) — Share-based compensation (ii) 549.0 243.5 (2.4 ) Change in uncertain tax positions (4.1 ) (2.4 ) (0.6 ) Termination of warrant — 29.3 — Total (6.4 )% (0.2 )% (1.1 )% (i) This item was previously included in other non-deductible expenses in 2016 and 2017. (ii) Starting in 2017, excess tax benefits from share-based award activity are reflected in the provision for income taxes. The tax effects of temporary differences and related deferred tax assets and liabilities are as follows (in thousands): Balance at December 31, 2018 2017 2016 Deferred tax assets: Capitalized costs $ 30,131 $ 35,608 $ 61,897 Accrued expenses 31,494 23,553 29,421 Net operating loss carryforwards 485,562 244,197 65,507 Tax credit carryforwards 133,275 60,567 38,927 Property, equipment and intangible assets — 7,390 5,721 Share-based compensation 38,265 35,728 52,091 Deferred Interest 8,290 — — Other 105 2,519 1,640 Total deferred tax assets 727,122 409,562 255,204 Valuation allowance (719,040 ) (409,043 ) (254,898 ) Total deferred tax assets, net of valuation allowance 8,082 519 306 Deferred tax liabilities: Property, equipment and intangible assets (7,361 ) — — Indefinite-lived intangibles (275 ) (644 ) (476 ) Total deferred tax liabilities (7,636 ) (644 ) (476 ) Net deferred tax assets (liabilities) $ 446 $ (125 ) $ (170 ) On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act ("2017 Tax Act"). The 2017 Tax Act makes broad and complex changes to the U.S. tax code, including, but not limited to, (1) reducing the U.S. federal corporate tax rate from 35% to 21%; (2) requiring companies to pay a one-time transition tax on certain unrepatriated earnings of foreign subsidiaries; (3) in part eliminating U.S. federal income taxes on dividends from foreign subsidiaries; (4) requiring a current inclusion in U.S. federal taxable income of certain unrepatriated earnings of controlled foreign corporations; (5) eliminating the corporate alternative minimum tax ("AMT") and changing how existing AMT credits can be realized; (6) creating the base erosion anti-abuse tax ("BEAT"), a new minimum tax; (7) creating a new limitation on deductible interest expense; and (8) changing rules related to uses and limitations of net operating loss carryforwards created in tax years beginning after December 31, 2017. In connection with the Company's analysis of the impact of the 2017 Tax Act, it recorded no tax benefit or expense for the year ended December 31, 2018 and recorded a benefit of $1.3 million for the year ended December 31, 2017. The net benefit for 2017 consisted of the release of the valuation allowance on the Company's AMT credit carryforward, which will be refunded in tax years 2018-2021. In addition, the 2017 Tax Act reduces the corporate tax rate to 21%, effective January 1, 2018. Consequently, the Company recorded no change to its U.S. federal and state deferred tax assets for the year ended December 31, 2018 and recorded a $63.6 million decrease, with an offset to the valuation allowance, for the year ended December 31, 2017. The Company has also completed its analysis of the deemed repatriation transition tax and has concluded that it will not owe any transition tax. Additionally, on December 22, 2017, the SEC staff 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 2017 Tax Act. The Company has recognized the tax impacts related to refundable AMT credits and revaluation of deferred tax assets, offset by the valuation allowance, and included these amounts in its consolidated financial statements for the year ended December 31, 2017. 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. Realization of deferred tax assets is dependent upon the generation of future taxable income, the timing and amount of which are uncertain. Due to the history of losses generated in the U.S. and certain foreign jurisdictions, the Company believes that it is more likely than not that its deferred tax assets in these jurisdictions will not be realized as of December 31, 2018 . Accordingly, the Company retained a full valuation allowance on its deferred tax assets in these jurisdictions. The amount of deferred tax assets considered realizable in future periods may change as management continues to reassess the underlying factors it uses in estimating future taxable income. The valuation allowance increased by approximately $310.0 million , $154.1 million , and $59.8 million during the years ended December 31, 2018 , 2017 , and 2016 , respectively. As of December 31, 2018 , the Company had $1,709.8 million of federal, $1,903.8 million of state, and $215.1 million of foreign net operating loss carryforwards, which will begin to expire in 2031 for federal and 2021 for state tax purposes. The foreign net operating loss carryforwards do not expire. As of December 31, 2018 , the Company had $107.3 million of federal, $65.6 million of state, and $2.7 million of Canadian research credit carryforwards. The federal credit carryforward will begin to expire in 2029, the state credit carryforward has no expiration date, and the Canadian credit carryforward will begin to expire in 2036. The Company has federal AMT credit carryforwards of $1.3 million that will be refunded over the 2018-2021 tax years under the 2017 Tax Act. The Company has California Enterprise Zone credit carryforwards of $2.8 million , which will begin to expire in 2023. Utilization of the net operating loss carryforwards and credits may be subject to annual limitations due to the ownership change limitations provided by the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitations may result in the expiration of net operating losses and credits before they are able to be utilized. The Company does not expect any previous ownership changes, as defined under Section 382 and 383 of the Internal Revenue Code, to result in a limitation that will reduce the total amount of net operating loss carryforwards and credits that can be utilized. As of December 31, 2018 , the unrecognized tax benefit was $198.5 million , of which $5.7 million would impact the annual effective tax rate if recognized and the remainder of which would result in a corresponding adjustment to the valuation allowance. A reconciliation of the beginning and ending amount of unrecognized tax benefit is presented below (in thousands): Year Ended December 31, 2018 2017 2016 Balance at the beginning of the year $ 70,799 $ 92,134 $ 90,372 Gross increases and decreases related to prior period tax positions 513 — 5,190 Gross increases and decreases related to current period tax positions 119,261 4,193 (3,428 ) Reductions related to lapse of statute of limitations (142 ) (91 ) — Gross increases and decreases related to U.S. tax reform — (25,437 ) — Gross increases and decreases related to acquisition 8,109 — — Balance at the end of the year $ 198,540 $ 70,799 $ 92,134 The Company recognizes interest and penalties related to income tax matters as a component of income tax expense. As of December 31, 2018 , there were no significant accrued interest and penalties related to uncertain tax positions. It is reasonably possible that over the next 12-month period the Company may experience a decrease in its unrecognized tax benefits as a result of tax examinations or lapses of statute of limitations. The estimated decrease in unrecognized tax benefits may range up to $ 13 million . The Company is subject to taxation in the United States and various state and foreign jurisdictions. The Company is currently under examination in California for tax years 2013 and 2014. The Company’s various tax years starting with 2009 to 2017 remain open in various taxing jurisdictions. As of December 31, 2018 , the Company has not provided deferred U.S. income taxes or foreign withholding taxes on temporary differences resulting from earnings for certain non-U.S. subsidiaries, which are permanently reinvested outside the U.S. Cumulative undistributed earnings for these non-U.S. subsidiaries as of December 31, 2018 are $4.2 million .

STOCKHOLDER'S EQUITY

STOCKHOLDER'S EQUITY	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
STOCKHOLDER'S EQUITY	STOCKHOLDERS' EQUITY Convertible Preferred Stock As of December 31, 2018 , the Company is authorized to issue 100,000,000 shares of preferred stock, with a $0.0000001 par value. No shares of preferred stock are outstanding as of December 31, 2018 . Common Stock The Company has authorized the issuance of Class A common stock and Class B common stock. Holders of the Company's Class A common stock and Class B common stock are entitled to dividends when, as and if, declared by the Company's board of directors, subject to the rights of the holders of all classes of stock outstanding having priority rights to dividends. As of December 31, 2018 , the Company did not declare any dividends. Holders of shares of Class A common stock are entitled to one vote per share, while holders of shares of Class B common stock are entitled to ten votes per share. Shares of the Company's Class B common stock are convertible into an equivalent number of shares of its Class A common stock and generally convert into shares of its Class A common stock upon transfer. Class A common stock and Class B common stock are referred to as common stock throughout these Notes to the Consolidated Financial Statements, unless otherwise noted. The holders of Class A common stock and Class B common stock have no preemptive or other subscription rights and there are no redemption or sinking fund provisions with respect to such shares. As of December 31, 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 December 31, 2018 , there were 323,546,864 shares of Class A common stock and 93,501,142 shares of Class B common stock outstanding. Options and awards granted following the Company's November 2015 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 On February 24, 2017, the Company and Starbucks entered into a Warrant Cancellation and Payment Agreement pursuant to which the Company paid Starbucks cash consideration of approximately $54.8 million in return for the termination of the Warrant to Purchase Stock dated August 7, 2012, as amended, that provided Starbucks with the right to purchase an aggregate of approximately 9.5 million shares of the Company’s common stock. In conjunction with the 2022 Notes offering, the Company sold warrants whereby the Counterparties have the option to purchase a total of approximately 19.2 million shares of the Company’s Class A common stock at a price of $31.18 per share. None of the warrants were exercised as of December 31, 2018. 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. None of the warrants were exercised as of December 31, 2018. 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 $2.7 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 7.3 million shares of Class A common stock. The Company also exercised a pro-rata portion of the 2022 convertible note hedges and received 6.9 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. Effective November 17, 2015, no additional awards will be granted under the 2009 Plan. Under the 2015 Plan, shares of shares of the Company's Class A common stock are reserved for the issuance of incentive and nonstatutory stock options (ISOs and NSOs, respectively), 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 administrator. As of December 31, 2018 , the total number of shares subject to stock options, RSAs and RSUs outstanding under the 2015 Plan was 22,666,464 shares, and 64,851,998 shares were available for future issuance. Under the 2009 Plan, shares of common stock are reserved for the issuance of ISOs or NSOs to eligible participants. The options may be granted at a price per share not less than the fair market value at the date of grant. Options granted generally vest over a four -year term from the date of grant, at a rate of 25% after one year, then monthly on a straight-line basis thereafter. Generally, options granted are exercisable for up to 10 years from the date of grant. The Plan allows for early exercise of employee stock options whereby the option holder is allowed to exercise prior to vesting. Any unvested shares are subject to repurchase by the Company at their original exercise prices. As of December 31, 2018 , the total number of options and RSUs outstanding under the 2009 Plan was 28,421,145 shares. A summary of stock option activity for the year ended December 31, 2018 is as follows (in thousands, except share and per share data): Number of 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 (13,402,680 ) 7.98 Forfeited and canceled (1,498,155 ) 14.75 Balance at December 31, 2018 33,152,881 $ 9.52 5.45 $ 1,543,793 Options vested and expected to vest at December 31, 2018 33,152,881 $ 9.52 5.45 $ 1,543,793 Options exercisable at December 31, 2018 31,066,578 $ 8.63 5.27 $ 1,474,339 Aggregate intrinsic value represents the difference between the Company’s estimated fair value of its common stock and the exercise price of outstanding, “in-the-money” options. Aggregate intrinsic value for stock options exercised through December 31, 2018 , 2017 , and 2016 was $720.1 million , $464.1 million , and $202.6 million , respectively. The total weighted average grant-date fair value of options granted was $16.25 , $5.97 and $5.80 per share for the years ended December 31, 2018 , 2017 and 2016 , respectively. Restricted Stock Activity The Company issues RSAs and RSUs under the 2015 Plan, which typically vest over a term of four years. Activity related to RSAs and RSUs during the year ended December 31, 2018 is set forth below: Number of Weighted Unvested at December 31, 2017 21,317,525 $ 17.84 Granted 7,147,541 54.43 Vested (7,786,561 ) 19.62 Forfeited (2,743,777 ) 19.88 Unvested at December 31, 2018 17,934,728 $ 31.34 Employee Stock Purchase Plan On November 17, 2015 , the Company’s 2015 Employee Stock Purchase Plan (ESPP) became effective. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP provides for 12 -month offering periods. The offering periods are scheduled to start on the first trading day on or after May 15 and November 15 of each year, except for the first offering period, which commenced on November 19, 2015 and ended on November 15, 2016. Each offering period includes two purchase periods, which begin on the first trading day on or after November 15 and May 15, and ending on the last trading day on or before May 15 and November 15, respectively. Employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or the last trading day of the purchase period. The number of shares available for sale under the ESPP will be increased annually on the first day of each fiscal year, equal to the least of (i) 8,400,000 shares, (ii) 1% of the outstanding shares of the Company’s common stock as of the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by the administrator. As of December 31, 2018 , 4,349,301 shares had been purchased under the ESPP and 10,797,606 shares were available for future issuance under the ESPP. The Company recorded $9.0 million and $6.0 million of share-based compensation expense related to the ESPP during the year ended December 31, 2018 and 2017 , respectively. Share-Based Compensation The fair value of stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2018 2017 2016 Dividend yield — % — % — % Risk-free interest rate 2.92 % 1.88 % 1.54 % Expected volatility 30.87 % 32.22 % 42.74 % Expected term (years) 6.19 6.02 6.08 The following table summarizes the effects of share-based compensation on the Company's consolidated statements of operations (in thousands): Year Ended December 31, 2018 2017 2016 Cost of revenue $ 97 $ 77 $ — Product development 144,601 98,310 91,404 Sales and marketing 22,797 17,568 14,122 General and administrative 49,386 39,881 33,260 Total $ 216,881 $ 155,836 $ 138,786 The Company capitalized $9.3 million , $3.7 million , and $2.8 million of share-based compensation expense related to capitalized software during the year ended December 31, 2018 , 2017 and 2016 , respectively. As of December 31, 2018 , there was $564.5 million of total unrecognized compensation cost related to outstanding stock options and restricted stock awards that are expected to be recognized over a weighted average period of 2.76 years .

NET LOSS PER SHARE

NET LOSS PER SHARE	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted loss per share is the same as basic loss per share for all years presented because the effects of potentially dilutive items were anti-dilutive given the Company’s net loss. The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Year Ended December 31, 2018 2017 2016 Net loss $ (38,453 ) $ (62,813 ) $ (171,590 ) Basic shares: Weighted-average common shares outstanding 406,313 380,921 344,393 Weighted-average unvested shares (582 ) (1,577 ) (2,838 ) Weighted-average shares used to compute basic net loss per share 405,731 379,344 341,555 Diluted shares: Weighted-average shares used to compute diluted net loss per share 405,731 379,344 341,555 Loss per share: Basic $ (0.09 ) $ (0.17 ) $ (0.50 ) Diluted $ (0.09 ) $ (0.17 ) $ (0.50 ) Since the Company 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 loss per share because their effect would have been anti-dilutive for the periods presented (in thousands): Year Ended December 31, 2018 2017 2016 Stock options and restricted stock units 60,589 68,588 88,705 Common stock warrants 25,798 19,173 9,457 Convertible senior notes 23,820 — — Unvested shares 582 1,300 1,892 Employee stock purchase plan 140 157 216 Total anti-dilutive securities 110,929 89,218 100,270

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 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 2019 and 2031 . The Company recognized total rental expenses under operating leases of $23.3 million , $12.9 million , and $11.3 million during the years ended December 31, 2018 , 2017 , and 2016 , 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 December 31, 2018 are as follows (in thousands): Capital Operating Year: 2019 $ 5,029 $ 28,405 2020 2,446 38,131 2021 — 52,319 2022 — 53,430 2023 — 47,222 Thereafter — 209,959 Total $ 7,475 $ 429,466 Less amount representing interest — Present value of capital lease obligations 7,475 Less current portion of capital lease obligation (5,029 ) Non-current portion of capital lease obligation $ 2,446 Build-to-Suit Lease Arrangement In December 2018, the Company entered into a lease arrangement for 355,762 square feet of office space in Oakland, California for a term of 12 years with options to renew for two five year terms. The lease commencement date is expected to be in November 2019 with total lease payments over the term of approximately $272 million . Due to the Company’s involvement with the construction of the property and its exposure to any potential cost overruns, the Company is deemed to be the owner of the property for accounting purposes during the construction phase. Accordingly, as of December 31, 2018, the Company recorded a non-cash build-to-suit lease asset under construction of $149 million , and a corresponding build-to-suit lease liability on the consolidated balance sheets. 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. Caviar filed a Motion to Compel Arbitration on December 12, 2018. 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	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
SEGMENT AND GEOGRAPHICAL INFORMATION	SEGMENT AND GEOGRAPHICAL INFORMATION Operating segments are defined as components of an enterprise for which discrete financial information is available that is evaluated regularly by the chief operating decision maker (CODM) for purposes of allocating resources and evaluating financial performance. The Company’s CODM 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 merchants. The following table sets forth revenue by geographic area (in thousands): Year Ended December 31, 2018 2017 2016 Revenue United States $ 3,138,859 $ 2,120,088 $ 1,643,852 International 159,318 94,165 64,869 Total net revenue $ 3,298,177 $ 2,214,253 $ 1,708,721 No individual country from the international markets contributed in excess of 10% of total revenue for the years ended December 31, 2018 , 2017 , and 2016 . Long-Lived Assets The following table sets forth long-lived assets by geographic area (in thousands): December 31, 2018 2017 Long-lived assets United States $ 471,970 $ 158,820 International 9,239 5,337 Total long-lived assets $ 481,209 $ 164,157

SUPPLEMENTAL CASH FLOW INFORMAT

SUPPLEMENTAL CASH FLOW INFORMATION	12 Months Ended
	Dec. 31, 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): Year Ended December 31, 2018 2017 2016 Supplemental Cash Flow Data: Cash paid for interest $ 4,125 $ 1,374 $ 570 Cash paid for income taxes 1,622 1,254 395 Supplemental disclosures of non-cash investing and financing activities: Change in purchases of property and equipment in accounts payable and accrued expenses 15,067 143 2,554 Unpaid business acquisition purchase price 3,995 2,115 240 Fair value of shares 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 (571,408 ) — — Fair value of shares received to settle senior note hedges, due 2022 $ 544,276 $ — $ —

DESCRIPTION OF BUSINESS AND S_2

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reclassifications and Other Adjustments	Reclassifications and Other Adjustments During the year ended December 31, 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 the year ended December 31, 2018 , the Company recorded a gain of $20.3 million to other income on the consolidated statements of operations arising from revaluation of this investment (Note 11 ). 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	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, as well as related disclosure of contingent assets and liabilities. Actual results could differ from the Company’s estimates. To the extent that there are material differences between these estimates and actual results, the Company’s financial condition or operating results will be materially affected. The Company bases its estimates on past experience and other assumptions that the Company believes are reasonable under the circumstances, and the Company evaluates these estimates on an ongoing basis. 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, build-to-suit lease asset and liability, and share-based compensation.
Revenue Recognition and Cost of Revenue	Revenue Recognition On January 1, 2018, the Company adopted Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers, 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. Refer to Note 2 for the impact of this adoption. 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. 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, Square Capital, 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 (Cash 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. Square Capital facilitates a loan that is offered through a partnership with an industrial bank that is either repaid through withholding a percentage of the collections of the seller's receivables processed by the Company or a specified monthly amount. The Company generally facilitates loans to its sellers pre-qualified through an analysis of the aggregated data of the seller’s business which includes, but is not limited to, the seller’s historical processing volumes, transaction count, chargebacks, growth, and length of time as a Square customer. The Company also facilitates loans to the customers of certain sellers as well as to the sellers of its partners who do not process payments through the Company. The loans are generally originated by a bank partner, from whom the Company purchases the loans obtaining all rights, title, and interest. The loans have no stated coupon rate but the seller is charged a one-time origination fee by the bank partner based upon their risk rating, which is derived primarily from processing activity. It is the Company’s intent to sell all of its rights, title, and interest of these loans to third-party investors for an upfront fee when the loans are sold. The Company records the net amounts paid to the bank as the cost of the loans purchased and subsequently records a gain on sale of the loans to the third-party investors as revenue upon transfer of title. The Company is retained by the third-party investors to service the loans and earns a servicing fee for facilitating the repayment of these receivables through its managed payments solutions. The Company records servicing revenue as servicing is delivered. For the loans which are not immediately sold to third-party investors, the Company recognizes a portion of the expected seller repayments over the cost of the loans as revenue in proportion to the loan principal reduction. 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. Pursuant to practical expedients afforded under ASC 606, the Company does not recognize a financing component for hardware installment sales that have a term of one year or less. 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'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 7 ). The Company 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. The Company determines 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. Cost of Revenue Transaction-based costs Transaction-based costs consist primarily of interchange and assessment fees, processing fees and bank settlement fees paid to third-party payment processors and financial institutions. Subscription and services-based costs Subscription and services-based costs consist primarily of Caviar-related costs, which include processing fees, payments to third-party couriers for deliveries and the cost of equipment provided to sellers. Caviar-related costs for catered meals also includes food costs and personnel costs. These costs also include costs associated with Cash Card and Instant Deposit. Hardware costs Hardware costs consist of all product costs associated with contactless and chip readers, chip card readers, Square Stand, Square Register, Square Terminal and third-party peripherals. Product costs consist of third-party manufacturing costs. Bitcoin costs Bitcoin cost of revenue comprises of the amounts the Company pays to purchase bitcoin, which will fluctuate in line with the price of bitcoin in the market.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred and included in sales and marketing expense on the consolidated statements of operations.
Share-based Compensation	Share-based Compensation Share-based compensation expense relates to stock options, restricted stock awards (RSAs), restricted stock units (RSUs), and purchases under the Company’s 2015 Employee Stock Purchase Plan (ESPP) which is measured based on the grant-date fair value. The 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 and ESPP shares granted to employees is estimated on the date of grant using the Black-Scholes-Merton option valuation model. This share-based compensation expense valuation model requires the Company to make assumptions and judgments regarding the variables used in the calculation. These variables include the expected term (weighted average period of time that the options granted are expected to be outstanding), the expected volatility of the Company’s stock, expected risk-free interest rate and expected dividends. The Company uses the simplified calculation of expected term, as the Company does not have sufficient historical data to use any other method to estimate expected term. Expected volatility is based on a weighted average of the historical volatilities of the Company's common stock along with several entities with characteristics similar to those of the Company. The Company will continue to weight its own volatility more heavily as more of its own historical stock price information becomes available. Once its own historical data is equal to that of the expected term of option grants a peer group is no longer considered necessary. The expected risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. Share-based compensation expense is recorded on a straight-line basis over the requisite service period. For the year ended December 31, 2016 and prior, the Company recorded share-based compensation expense net of estimated forfeitures. On January 1, 2017, as a result of the Company's adoption of ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting , the Company elected to account for forfeitures as they occur.
Income and Other Taxes	Income and Other Taxes The Company reports income taxes under the asset and liability approach. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, as well as net operating loss and tax credit carryforwards. Deferred tax amounts are determined by using the enacted tax rates expected to be in effect when the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance reduces the deferred tax assets to the amount that is more likely than not to be realized. The Company uses financial projections to support its net deferred tax assets, which contain significant assumptions and estimates of future operations. If such assumptions were to differ significantly from actual future results of operations, it may have a material impact on the Company’s ability to realize its deferred tax assets. At the end of each period, the Company assesses the ability to realize the deferred tax assets. If it is more likely than not that the Company would not realize the deferred tax assets, then the Company would establish a valuation allowance for all or a portion of the deferred tax assets. The Company recognizes the effect of uncertain income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that has a greater than 50% likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to uncertain tax positions in the provision for income tax expense on the consolidated statements of operations.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments, including money market funds, with an original maturity of three months or less when purchased to be cash equivalents. As of December 31, 2018 and 2017 , restricted cash of $33.8 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 that we expect to become unrestricted within the next year. As of December 31, 2018 and 2017 , the remaining restricted cash of $15.8 million and $9.8 million , respectively, is primarily related to cash held as collateral pursuant to multi-year lease agreements (Note 17 ).
Concentration of Credit Risk	Concentration of Credit Risk For the years ended December 31, 2018 , 2017 and 2016 , the Company had no customer who accounted for greater than 10% of total net revenue. The Company had three third-party payment processors that represented approximately 45% , 33% , and 9% of settlements receivable as of December 31, 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.
Investments	Investments The Company's short-term and long-term investments include marketable debt securities such as government and agency securities, corporate bonds, commercial paper and municipal securities. 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. Investments are reviewed periodically to identify possible other-than-temporary impairments. If any impairment is considered other-than-temporary, the Company writes down the investment to its fair value and record the corresponding charge through other income (expense), net on its consolidated statements of operations.
Customer Funds	Customer funds Customer funds held in deposit represent Cash App customers' stored balances that customers would later use to send money or make payments, or customers cash in transit. As of December 31, 2017 , the Company held these stored balances as short term bank deposits. During the year ended December 31, 2018 , the Company started investing a portion of these stored balances in short-term marketable debt securities (Note 4 ). 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.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value accounting establishes a three-level hierarchy priority for disclosure of assets and liabilities recorded at fair value. The ordering of priority reflects the degree to which objective prices in external active markets are available to measure fair value. The classification of assets and liabilities within the hierarchy is based on whether the inputs to the valuation methodology used for measurement are observable or unobservable. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: • Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date. • Level 2 Inputs: Other than quoted prices included in Level 1 Inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date.
Loans Held for Sale	Loans Held for Sale The Company classifies customer loans as held for sale upon purchase from an industrial bank partner, as there is an available market for such loans and it is the Company’s intent to sell all of its rights, title, and interest in these loans to third-party investors. 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 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. A loan that is initially designated as held for sale may be reclassified to held for investment if and when the Company's intent for that loan changes. There have been no reclassifications made to date.
Settlement Receivable	Settlements Receivable Settlements receivable represents amounts due from third-party payment processors for customer transactions. Settlements receivable are typically received within one or two business days of the transaction date. No valuation allowances have been established, as funds are due from large, well-established financial institutions with no historical collections issue.
Inventory	Inventory Inventory is comprised of contactless and chip readers, chip card readers, Square Stand, Square Register, Square Terminal and third-party peripherals, as well as component parts that are used to manufacture these products. Inventory is stated at the lower of cost (generally on a first-in, first-out basis) or net realizable value. Inventory that is obsolete or in excess of forecasted usage is written down to its net realizable value based on the estimated selling prices in the ordinary course of business. The Company's inventory is held at the Company's warehouses as well as at third party contract manufacturer premises.
Deferred Revenue	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.
Cryptocurrency transactions	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 December 31, 2018 and 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 carrying value exceeds the fair value. Losses on bitcoin for the years ended December 31, 2018 and 2017 , were insignificant.
Property and Equipment	Property and Equipment Property and equipment are recorded at historical cost less accumulated depreciation, which is computed on a straight-line basis over the asset’s estimated useful life. The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Two to three years Furniture and fixtures Seven years Leasehold improvements Lesser of ten years or remaining lease term When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from their respective accounts, and any gain or loss on such sale or disposal is reflected in operating expenses.
Capitalized Software	Capitalized Software The Company capitalizes certain cost incurred in developing internal-use software when capitalization requirements have been met. Costs prior to meeting the capitalization requirements are expensed as incurred. Capitalized costs are included in property and equipment, net, and amortized on a straight-lined basis over the estimated useful life of the software and included in product development costs on the consolidated statements of operations.
Leases	Leases The Company leases office space and equipment under non-cancellable capital and operating leases with various expiration dates. The Company records the total rent expense on a straight-line basis over the lease term. When lease agreements provide allowances for leasehold improvements, the Company capitalizes the leasehold improvement assets and recognizes the related depreciation expense on a straight-line basis over the lesser of the lease term or the estimated useful life of the asset, and reduces rent expense on a straight-line basis over the term of the lease by the amount of the allowances provided. The Company classifies the cash payments for the leasehold improvements within investing activities while reimbursements from the landlords are classified within operating activities. The Company records a liability for the estimated fair value for any asset retirement obligation (ARO) associated with its leases, with an offsetting asset. In the determination of the fair value of AROs, the Company uses various assumptions and judgments, including such factors as the existence of a legal obligation, estimated amounts and timing of settlements, and discount and inflation rates. The liability is subsequently accreted while the asset is depreciated. As of December 31, 2018 , the Company had a liability for ARO, gross of accretion, of $3.6 million and an associated asset, net of depreciation, of $2.1 million . Under ASC 840, Leases , the Company is deemed to be the owner, for accounting purposes, during the construction phase of a certain long-lived asset under a build-to-suit lease arrangement because of its involvement with the construction and its exposure to any potential cost overruns under the arrangement. In these cases, the Company recognizes a build-to-suit lease asset and a corresponding build-to-suit lease liability on the consolidated balance sheets. Refer to Note 17 for further details.
Asset Retirement Obligations	The Company records a liability for the estimated fair value for any asset retirement obligation (ARO) associated with its leases, with an offsetting asset. In the determination of the fair value of AROs, the Company uses various assumptions and judgments, including such factors as the existence of a legal obligation, estimated amounts and timing of settlements, and discount and inflation rates. The liability is subsequently accreted while the asset is depreciated.
Business Combinations	Business Combinations The purchase price of an acquisition is allocated to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the acquisition dates. The excess of total consideration over the fair values of the assets acquired and the liabilities assumed is recorded as goodwill. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments would be recorded on the consolidated statements of operations.
Long-lived Assets, including Goodwill and Acquired Intangibles	Long-Lived Assets, including Goodwill and Acquired Intangibles The Company evaluates the recoverability of property and equipment and finite lived intangible assets for impairment whenever events or circumstances indicate that the carrying amounts of such assets may not be recoverable. Recoverability is measured by comparing the carrying amount of an asset or an asset group to estimated undiscounted future net cash flows expected to be generated. If the carrying amount of the long–lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values, and third–part independent appraisals, as considered necessary. For the periods presented, the Company had recorded no impairment charges. Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in a business combination. The Company performs a goodwill impairment test annually on December 31 and more frequently if events and circumstances indicate that the asset might be impaired. An impairment loss is recognized to the extent that the carrying amount exceeds the reporting unit’s fair value. The Company has concluded that its business operations as a whole comprise one reporting unit. The Company has the option to first assess qualitative factors to determine whether events or circumstances indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying amount and determine whether further action is needed. If, after assessing the totality of events or circumstances, the Company determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. For the periods presented, the Company had recorded no impairment charges. Acquired intangibles consist of acquired technology and customer relationships associated with various acquisitions. Acquired technology is amortized over its estimated useful life on a straight-line basis within cost of revenue. Customer relationships acquired are amortized on a straight-line basis over their estimated useful lives within operating expenses. The Company evaluates the remaining estimated useful life of its intangible assets being amortized on an ongoing basis to determine whether events and circumstances warrant a revision to the remaining period of amortization.
Customers Payable	Customers Payable Customers payable represents the transaction amounts, less revenue earned by the Company, owed to sellers or Cash App customers. The payable amount comprises amounts owed to customers due to timing differences as the Company typically settles within one business day, amounts held by the Company in accordance with its risk management policies, and amounts held for customers who have not yet linked a bank account. This balance also includes the Company's liability for customer funds held on deposit in the Cash App.
Accrued Transaction Losses	Accrued Transaction Losses The Company establishes a reserve for estimated transaction losses due to chargebacks, which represent a potential loss due to disputes between a seller and their customer or due to a fraudulent transaction. This also includes estimated transactions losses on Cash App activity related to peer-to-peer payments sent from a credit card, Cash for Business and Cash Card. The reserve is estimated based on available data as of the reporting date, including expectations of future chargebacks, and historical trends related to loss rates. Additions to the reserve are reflected in current operating results, while realized losses are offset against the reserve. These amounts are classified within transaction and advance losses on the consolidated statements of operations.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently issued accounting pronouncements not yet adopted 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 intends to adopt this guidance effective January 1, 2020. 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 intends to adopt this guidance effective with its 2019 annual goodwill impairment test. 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 currently does not intend to early adopt any portion of this disclosure guidance. 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 whether to early adopt this guidance as well as the impact it may have on the consolidated financial statements and related disclosures. Recently adopted accounting pronouncements 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. The Company adopted this new guidance on January 1, 2019, using the modified retrospective approach. Based on the Company's current portfolio of leases, approximately $96.6 million of lease assets and approximately $123.4 million of lease liabilities is expected to be recognized on its consolidated balance sheet. 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. Additionally, the Company will derecognize $149 million related to the build-to-suit asset and liability upon adoption of this standard. The Company is in the process of finalizing changes to its systems and processes in conjunction with its review of lease agreements and will disclose the actual impact of adopting ASU 2016–02 in its interim report on Form 10–Q for the quarter ended March 31, 2019. 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. 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 adopted this new guidance on January 1, 2019, and it did not have a material impact 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 . This guidance allows companies to reclassify such tax effects from accumulated other comprehensive income to retained earnings. 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. No tax expense resulted from the change in the federal income tax rate.

REVENUE (Tables)

REVENUE (Tables)	12 Months Ended
	Dec. 31, 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 consolidated statement of operations was as follows (in thousands): Year Ended December 31, 2018 As reported Balances without adoption Effect of change Impact on the Consolidated Statement of Operations: Subscription and services-based revenue $ 591,706 $ 591,220 $ 486 Hardware revenue 68,503 62,572 5,931 Subscription and services-based costs 169,884 169,884 — Hardware costs $ 94,114 $ 88,625 $ 5,489 The impact of adoption of ASC 606 on the Company's consolidated balance sheets was as follows (in thousands): December 31, 2018 As reported Balances without adoption Effect of change Impact on the Consolidated Balance Sheets: Other current assets $ 164,966 $ 178,101 $ (13,135 ) Other current liabilities 99,153 108,334 (9,181 ) Other non-current assets 58,393 59,768 (1,375 ) Other non-current liabilities $ 93,286 $ 94,717 $ (1,431 )
Schedule of Disaggregation of Revenue	The following table presents the Company's revenue from contracts with customers (i.e. excluding revenue from other sources) disaggregated by revenue source (in thousands): Year Ended December 31, 2018 2017 2016 Revenue from Contracts with Customers: Transaction-based revenue $ 2,471,451 $ 1,920,174 $ 1,456,160 Starbucks transaction-based revenue — — 78,903 Subscription and services-based revenue 499,010 185,485 79,507 Hardware revenue 68,503 41,415 44,307 Bitcoin revenue $ 166,517 $ — $ —
Schedule of Deferred Revenue	The deferred revenue balances were as follows (in thousands): Year Ended December 31, 2018 2017 Deferred revenue, beginning of the period $ 5,893 $ 5,407 Less: accumulative adjustment for adoption of ASC 606 (4,303 ) — Deferred revenue, beginning of the period, as adjusted 1,590 5,407 Deferred revenue, end of the period 36,451 5,893 Deferred revenue arising from business combination 22,800 — Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period $ 1,590 $ 5,257

DESCRIPTION OF BUSINESS AND S_3

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Estimated Useful Lives of Property and Equipment	The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Two to three years Furniture and fixtures Seven years Leasehold improvements Lesser of ten years or remaining lease term The following is a summary of property and equipment, less accumulated depreciation and amortization (in thousands): December 31, December 31, Leasehold improvements $ 107,611 $ 77,073 Computer equipment 80,093 66,186 Capitalized software 58,908 35,063 Office furniture and equipment 20,699 14,490 Total 267,311 192,812 Less: Accumulated depreciation and amortization (124,909 ) (101,316 ) Property and equipment, net $ 142,402 $ 91,496

INVESTMENTS (Tables)

INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Short-term and Long-term Investments	The Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term securities: U.S. agency securities $ 80,160 $ 32 $ (70 ) $ 80,122 Corporate bonds 109,807 80 (368 ) 109,519 Municipal securities 27,839 52 (59 ) 27,832 U.S. government securities 292,615 161 (509 ) 292,267 Non-U.S. government securities 31,263 4 (16 ) 31,251 Total $ 541,684 $ 329 $ (1,022 ) $ 540,991 Long-term securities: U.S. agency securities $ 114,444 $ 194 $ (78 ) $ 114,560 Corporate bonds 159,783 419 (950 ) 159,252 Municipal securities 28,453 167 (26 ) 28,594 U.S. government securities 153,743 553 (172 ) 154,124 Non-U.S. government securities 8,122 28 — 8,150 Total $ 464,545 $ 1,361 $ (1,226 ) $ 464,680 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 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 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 The Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 27,293 $ 2 $ (4 ) $ 27,291 U.S. government securities 72,662 12 (3 ) 72,671 Total $ 99,955 $ 14 $ (7 ) $ 99,962
Investments Classified by Contractual Maturity Date	The contractual maturities of the Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 541,684 $ 540,991 Due in one to five years 464,545 464,680 Total $ 1,006,229 $ 1,005,671 The contractual maturities of the Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 99,955 $ 99,962 Due in one to five years — — Total $ 99,955 $ 99,962

CUSTOMER FUNDS (Tables)

CUSTOMER FUNDS (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Assets Underlying Customer Funds	The following table presents the assets underlying customer funds (in thousands): December 31, December 31, Cash $ 158,697 $ 103,042 Cash Equivalents: Money market funds 18 — U.S. agency securities 39,991 — U.S. government securities 35,349 — Short-term debt securities: U.S. agency securities 27,291 — U.S. government securities 72,671 — Total $ 334,017 $ 103,042
Investments within Customer Funds	The Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term securities: U.S. agency securities $ 80,160 $ 32 $ (70 ) $ 80,122 Corporate bonds 109,807 80 (368 ) 109,519 Municipal securities 27,839 52 (59 ) 27,832 U.S. government securities 292,615 161 (509 ) 292,267 Non-U.S. government securities 31,263 4 (16 ) 31,251 Total $ 541,684 $ 329 $ (1,022 ) $ 540,991 Long-term securities: U.S. agency securities $ 114,444 $ 194 $ (78 ) $ 114,560 Corporate bonds 159,783 419 (950 ) 159,252 Municipal securities 28,453 167 (26 ) 28,594 U.S. government securities 153,743 553 (172 ) 154,124 Non-U.S. government securities 8,122 28 — 8,150 Total $ 464,545 $ 1,361 $ (1,226 ) $ 464,680 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 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 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 The Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 27,293 $ 2 $ (4 ) $ 27,291 U.S. government securities 72,662 12 (3 ) 72,671 Total $ 99,955 $ 14 $ (7 ) $ 99,962
Investments within Customer Funds Classified by Contractual Maturity Date	The contractual maturities of the Company's short-term and long-term investments as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 541,684 $ 540,991 Due in one to five years 464,545 464,680 Total $ 1,006,229 $ 1,005,671 The contractual maturities of the Company's investments within customer funds as of December 31, 2018 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 99,955 $ 99,962 Due in one to five years — — Total $ 99,955 $ 99,962

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 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): December 31, 2018 December 31, 2017 Carrying Value Fair Value (Level 2) Carrying Value Fair Value (Level 2) 2023 Notes $ 718,522 $ 901,468 $ — $ — 2022 Notes 181,173 515,693 358,572 719,356 Total $ 899,695 $ 1,417,161 $ 358,572 $ 719,356 The estimated fair value and carrying value of loans held for sale is as follows (in thousands): December 31, 2018 December 31, 2017 Carrying Value Fair Value (Level 3) Carrying Value Fair Value (Level 3) Loans held for sale $ 89,974 $ 93,064 $ 73,420 $ 76,070 Total $ 89,974 $ 93,064 $ 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): December 31, 2018 December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash and cash equivalents: Money market funds $ 218,109 $ — $ — $ 387,698 $ — $ — U.S. agency securities — 46,423 — — — — Commercial paper — — — — 24,695 — U.S. government securities 86,239 — — — — — Non-U.S. government securities — 23,981 — — — — Customer Funds: Money market funds 18 — — — — — U.S. agency securities — 67,282 — — — — U.S. government securities 108,020 — — — — — Short-term securities: U.S. agency securities — 80,122 — — 15,083 — Corporate bonds — 109,519 — — 57,798 — Commercial paper — — — — 17,428 — Municipal securities — 27,832 — — 23,700 — U.S. government securities 292,267 — — 55,567 — — Non-U.S. government securities — 31,251 — — — — Long-term securities: U.S. agency securities — 114,560 — — 20,169 — Corporate bonds — 159,252 — — 91,413 — Municipal securities — 28,594 — — 26,224 — U.S. government securities 154,124 — — 65,861 — — Non-U.S. government securities — 8,150 — — — — Other: Equity investment 45,342 — — — — — Total $ 904,119 $ 696,966 $ — $ 509,126 $ 276,510 $ —

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Summary of Property, Equipment and Internally-Developed Software	The estimated useful lives of property and equipment are described below: Property and Equipment Useful Life Capitalized software 18 months Computer and data center equipment Two to three years Furniture and fixtures Seven years Leasehold improvements Lesser of ten years or remaining lease term The following is a summary of property and equipment, less accumulated depreciation and amortization (in thousands): December 31, December 31, Leasehold improvements $ 107,611 $ 77,073 Computer equipment 80,093 66,186 Capitalized software 58,908 35,063 Office furniture and equipment 20,699 14,490 Total 267,311 192,812 Less: Accumulated depreciation and amortization (124,909 ) (101,316 ) Property and equipment, net $ 142,402 $ 91,496

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Schedule of Business Acquisitions	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) (37,592 ) Total identifiable net assets acquired 76,954 Goodwill 195,585 Total $ 272,539

GOODWILL (Tables)

GOODWILL (Tables)	12 Months Ended
	Dec. 31, 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, 2016 $ 57,173 Acquisitions completed during the year ended December 31, 2017 1,154 Balance at December 31, 2017 58,327 Acquisitions completed during the year ended December 31, 2018 203,378 Balance at December 31, 2018 $ 261,705

ACQUIRED INTANGIBLE ASSETS (Tab

ACQUIRED INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite Lived Intangible Assets	All intangible assets are amortized over their estimated useful lives. The changes to the carrying value of intangible assets were as follows (in thousands): Year Ended December 31, 2018 2017 2016 Acquired intangible assets, net, beginning of the period $ 14,334 $ 19,292 $ 26,776 Acquisitions 75,871 2,657 1,529 Amortization expense 13,104 7,615 9,013 Acquired intangible assets, net, end of the period $ 77,102 $ 14,334 $ 19,292 The following table presents the detail of acquired intangible assets as of the periods presented (in thousands): Balance at December 31, 2018 Cost Accumulated Amortization Net Patents $ 1,285 $ (664 ) $ 621 Technology Assets 45,978 (28,420 ) 17,558 Customer Assets 57,109 (8,068 ) 49,041 Trade Name 11,300 (1,648 ) 9,652 Other 961 (731 ) 230 Total $ 116,633 $ (39,531 ) $ 77,102 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 annual future amortization expense of these intangible assets as of December 31, 2018 , is as follows (in thousands): 2019 $ 13,744 2020 11,496 2021 10,299 2022 8,369 2023 6,839 Thereafter 26,355 Total $ 77,102

OTHER CONSOLIDATED BALANCE SH_3

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Current Assets	The following table presents the detail of other current assets (in thousands): December 31, December 31, Inventory, net $ 28,627 $ 16,777 Processing costs receivable 46,102 21,083 Prepaid expenses 21,782 14,473 Accounts receivable, net 22,393 8,606 Deferred hardware costs (i) — 7,931 Deferred magstripe reader costs (ii) 9,361 2,469 Prepaid compensation, current (iii) 4,995 — Other 31,706 15,115 Total $ 164,966 $ 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 and recognized as compensation expense over time as they provide services to the Company.
Accrued Expenses	The following table presents the detail of accrued expenses (in thousands): December 31, December 31, Accrued facilities expenses $ 13,040 $ 568 Accrued payroll 9,612 9,103 Accrued professional fees 5,232 5,638 Accrued advertising and other marketing 12,201 6,723 Processing costs payable 12,683 10,145 Accrued non income tax liabilities 9,503 6,155 Accrued hardware costs 5,125 2,496 Other accrued liabilities 14,958 11,452 Total $ 82,354 $ 52,280
Other Current Liabilities	The following table presents the detail of other current liabilities (in thousands): December 31, December 31, Accounts payable $ 36,416 $ 16,763 Square Capital payable (iv) 6,092 7,671 Square Payroll payable (v) 7,534 2,850 Deferred revenue, current 31,474 5,893 Deferred rent, current 3,842 3,311 Accrued redemptions 1,305 1,036 Other 12,490 7,606 Total $ 99,153 $ 45,130 (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)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Non-Current Assets	The following table presents the detail of other non-current assets (in thousands): December 31, December 31, Equity investment (i) $ 45,342 $ 25,000 Prepaid compensation, non-current (ii) 5,915 — Deposits 2,747 2,738 Other 4,389 3,612 Total $ 58,393 $ 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 year ended December 31, 2018 , the Company recorded a gain of $20.3 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 and recognized as compensation expense 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): December 31, December 31, Statutory liabilities (iii) $ 54,748 $ 40,768 Deferred rent, non-current 23,003 20,349 Deferred purchase consideration 3,900 — Deferred revenue, non-current 4,977 432 Other 6,658 7,989 Total $ 93,286 $ 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)	12 Months Ended
	Dec. 31, 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 December 31, 2018 2023 Notes $ 862,500 $ (138,924 ) $ (5,054 ) $ 718,522 2022 Notes 211,728 (27,569 ) (2,986 ) 181,173 Total 1,074,228 (166,493 ) (8,040 ) 899,695 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 December 31, 2018 2023 Notes $ 155,250 $ (1,231 ) $ 154,019 2022 Notes 41,481 (1,108 ) 40,373 Total 196,731 (2,339 ) 194,392 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): Year Ended December 31, 2018 2017 Contractual interest expense $ 4,023 $ 1,351 Amortization of debt discount and issuance costs 32,855 14,223 Total $ 36,878 $ 15,574

ACCRUED TRANSACTION LOSSES (Tab

ACCRUED TRANSACTION LOSSES (Tables)	12 Months Ended
	Dec. 31, 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): Year Ended December 31, 2018 2017 Accrued transaction losses, beginning of the year $ 26,893 $ 20,064 Provision for transaction losses 64,981 52,977 Charge-offs to accrued transaction losses (58,192 ) (46,148 ) Accrued transaction losses, end of the year $ 33,682 $ 26,893

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic and Foreign Components of Loss Before Income Taxes	The domestic and foreign components of loss before income taxes are as follows (in thousands): Year Ended December 31, 2018 2017 2016 Domestic $ 44,538 $ (10,900 ) $ (145,499 ) Foreign (80,665 ) (51,764 ) (24,174 ) Loss before income taxes $ (36,127 ) $ (62,664 ) $ (169,673 )
Components of Provision for Income Taxes	The components of the provision for income taxes are as follows (in thousands): Year Ended December 31, 2018 2017 2016 Current: Federal $ (4 ) $ (1,192 ) $ 63 State 752 739 527 Foreign 2,224 1,987 1,269 Total current provision for income taxes 2,972 1,534 1,859 Deferred: Federal (404 ) (1,169 ) 173 State 35 57 18 Foreign (277 ) (273 ) (133 ) Total deferred provision for income taxes (646 ) (1,385 ) 58 Total provision for income taxes $ 2,326 $ 149 $ 1,917
Reconciliation of Statutory Federal Income Tax Rate to Company's Effective Tax Rate	The following is a reconciliation of the statutory federal income tax rate to the Company's effective tax rate: Balance at December 31, 2018 2017 2016 Tax at federal statutory rate 21.0 % 34.0 % 34.0 % State taxes, net of federal benefit (1.1 ) (0.4 ) (0.1 ) Foreign rate differential (14.7 ) (14.9 ) (2.4 ) Non-deductible meals (i) (3.4 ) (0.3 ) (0.1 ) Other non-deductible expenses (1.7 ) (0.7 ) (0.8 ) Credits 164.8 41.5 8.5 Other items 2.3 (1.2 ) 0.2 Change in valuation allowance (718.5 ) (119.5 ) (37.4 ) Impact of U.S. tax reform — (209.1 ) — Share-based compensation (ii) 549.0 243.5 (2.4 ) Change in uncertain tax positions (4.1 ) (2.4 ) (0.6 ) Termination of warrant — 29.3 — Total (6.4 )% (0.2 )% (1.1 )% (i) This item was previously included in other non-deductible expenses in 2016 and 2017. (ii) Starting in 2017, excess tax benefits from share-based award activity are reflected in the provision for income taxes.
Tax Effects of Temporary Differences and Related Deferred Tax Assets and Liabilities	The tax effects of temporary differences and related deferred tax assets and liabilities are as follows (in thousands): Balance at December 31, 2018 2017 2016 Deferred tax assets: Capitalized costs $ 30,131 $ 35,608 $ 61,897 Accrued expenses 31,494 23,553 29,421 Net operating loss carryforwards 485,562 244,197 65,507 Tax credit carryforwards 133,275 60,567 38,927 Property, equipment and intangible assets — 7,390 5,721 Share-based compensation 38,265 35,728 52,091 Deferred Interest 8,290 — — Other 105 2,519 1,640 Total deferred tax assets 727,122 409,562 255,204 Valuation allowance (719,040 ) (409,043 ) (254,898 ) Total deferred tax assets, net of valuation allowance 8,082 519 306 Deferred tax liabilities: Property, equipment and intangible assets (7,361 ) — — Indefinite-lived intangibles (275 ) (644 ) (476 ) Total deferred tax liabilities (7,636 ) (644 ) (476 ) Net deferred tax assets (liabilities) $ 446 $ (125 ) $ (170 )
Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefit	A reconciliation of the beginning and ending amount of unrecognized tax benefit is presented below (in thousands): Year Ended December 31, 2018 2017 2016 Balance at the beginning of the year $ 70,799 $ 92,134 $ 90,372 Gross increases and decreases related to prior period tax positions 513 — 5,190 Gross increases and decreases related to current period tax positions 119,261 4,193 (3,428 ) Reductions related to lapse of statute of limitations (142 ) (91 ) — Gross increases and decreases related to U.S. tax reform — (25,437 ) — Gross increases and decreases related to acquisition 8,109 — — Balance at the end of the year $ 198,540 $ 70,799 $ 92,134

STOCKHOLDER'S EQUITY (Tables)

STOCKHOLDER'S EQUITY (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Summary of Stock Option Activity	A summary of stock option activity for the year ended December 31, 2018 is as follows (in thousands, except share and per share data): Number of 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 (13,402,680 ) 7.98 Forfeited and canceled (1,498,155 ) 14.75 Balance at December 31, 2018 33,152,881 $ 9.52 5.45 $ 1,543,793 Options vested and expected to vest at December 31, 2018 33,152,881 $ 9.52 5.45 $ 1,543,793 Options exercisable at December 31, 2018 31,066,578 $ 8.63 5.27 $ 1,474,339
Summary of RSU Activity	Activity related to RSAs and RSUs during the year ended December 31, 2018 is set forth below: Number of Weighted Unvested at December 31, 2017 21,317,525 $ 17.84 Granted 7,147,541 54.43 Vested (7,786,561 ) 19.62 Forfeited (2,743,777 ) 19.88 Unvested at December 31, 2018 17,934,728 $ 31.34
Schedule of Fair Value Assumptions for Options	The fair value of stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2018 2017 2016 Dividend yield — % — % — % Risk-free interest rate 2.92 % 1.88 % 1.54 % Expected volatility 30.87 % 32.22 % 42.74 % Expected term (years) 6.19 6.02 6.08
Summary of the Effect of Share-Based Compensation on the Consolidated Statements of Operations	The following table summarizes the effects of share-based compensation on the Company's consolidated statements of operations (in thousands): Year Ended December 31, 2018 2017 2016 Cost of revenue $ 97 $ 77 $ — Product development 144,601 98,310 91,404 Sales and marketing 22,797 17,568 14,122 General and administrative 49,386 39,881 33,260 Total $ 216,881 $ 155,836 $ 138,786

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 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 loss per share (in thousands, except per share data): Year Ended December 31, 2018 2017 2016 Net loss $ (38,453 ) $ (62,813 ) $ (171,590 ) Basic shares: Weighted-average common shares outstanding 406,313 380,921 344,393 Weighted-average unvested shares (582 ) (1,577 ) (2,838 ) Weighted-average shares used to compute basic net loss per share 405,731 379,344 341,555 Diluted shares: Weighted-average shares used to compute diluted net loss per share 405,731 379,344 341,555 Loss per share: Basic $ (0.09 ) $ (0.17 ) $ (0.50 ) Diluted $ (0.09 ) $ (0.17 ) $ (0.50 )
Schedule of Antidilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	The following potential common shares were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive for the periods presented (in thousands): Year Ended December 31, 2018 2017 2016 Stock options and restricted stock units 60,589 68,588 88,705 Common stock warrants 25,798 19,173 9,457 Convertible senior notes 23,820 — — Unvested shares 582 1,300 1,892 Employee stock purchase plan 140 157 216 Total anti-dilutive securities 110,929 89,218 100,270

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments Under Operating and Capital Leases	Future minimum lease payments under non-cancelable operating leases (with initial lease terms in excess of one year) and future minimum capital lease payments as of December 31, 2018 are as follows (in thousands): Capital Operating Year: 2019 $ 5,029 $ 28,405 2020 2,446 38,131 2021 — 52,319 2022 — 53,430 2023 — 47,222 Thereafter — 209,959 Total $ 7,475 $ 429,466 Less amount representing interest — Present value of capital lease obligations 7,475 Less current portion of capital lease obligation (5,029 ) Non-current portion of capital lease obligation $ 2,446

SEGMENT AND GEOGRAPHICAL INFO_2

SEGMENT AND GEOGRAPHICAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Revenue by Geographic Area	Revenue by geography is based on the billing addresses of the merchants. The following table sets forth revenue by geographic area (in thousands): Year Ended December 31, 2018 2017 2016 Revenue United States $ 3,138,859 $ 2,120,088 $ 1,643,852 International 159,318 94,165 64,869 Total net revenue $ 3,298,177 $ 2,214,253 $ 1,708,721
Long-Lived Assets by Geographic Area	The following table sets forth long-lived assets by geographic area (in thousands): December 31, 2018 2017 Long-lived assets United States $ 471,970 $ 158,820 International 9,239 5,337 Total long-lived assets $ 481,209 $ 164,157

SUPPLEMENTAL CASH FLOW INFORM_2

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures of Cash Flow Information	The supplemental disclosures of cash flow information consist of the following (in thousands): Year Ended December 31, 2018 2017 2016 Supplemental Cash Flow Data: Cash paid for interest $ 4,125 $ 1,374 $ 570 Cash paid for income taxes 1,622 1,254 395 Supplemental disclosures of non-cash investing and financing activities: Change in purchases of property and equipment in accounts payable and accrued expenses 15,067 143 2,554 Unpaid business acquisition purchase price 3,995 2,115 240 Fair value of shares 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 (571,408 ) — — Fair value of shares received to settle senior note hedges, due 2022 $ 544,276 $ — $ —

REVENUE - Narrative (Details)

REVENUE - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings (accumulated deficit)	$ (885,774)		$ (842,735)
Hardware revenue	3,205,500
Revenue, other	92,700
Impairment losses arising from contracts with customers	3,700
Effect of change | ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings (accumulated deficit)		$ (4,600)
Hardware revenue	$ 6,400

DESCRIPTION OF BUSINESS AND S_4

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	Jan. 01, 2019USD ($)	Jun. 08, 2016USD ($)	Dec. 31, 2018USD ($)customerthird_party_processor	Dec. 31, 2017USD ($)customerthird_party_processor	Dec. 31, 2016USD ($)customer
Concentration Risk [Line Items]
Gain from revaluation of investment			$ 20,342	$ 0	$ 0
Settlement agreement amount		$ 50,000
Payment for settlement agreement		$ 48,000
Advertising costs			101,900	81,900	58,300
Pledged cash			33,838	28,805
Collateral			15,836	9,802
Carrying value of bitcoin held by the Company			200	300
Capitalized internally developed software during the period			24,000	9,800	7,900
Amortization expense related to capitalized internally developed software			10,600	6,600	$ 7,100
Asset retirement obligation			3,600
Asset retirement obligation, associated asset net of depreciation			$ 142,402	$ 91,496
Measurement period for business combinations			1 year
Settlement period for customers payable			1 day
Leasehold Improvements Under Asset Retirement Obligation
Concentration Risk [Line Items]
Asset retirement obligation, associated asset net of depreciation			$ 2,100
Customer Concentration Risk | Net Revenue
Concentration Risk [Line Items]
Number of customers | customer			0	0	0
Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Number of third party processors | third_party_processor			3	3
Third Party Processor One | Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			45.00%	46.00%
Third Party Processor Two | Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			33.00%	42.00%
Third Party Processor Three | Credit Concentration Risk | Settlements Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			9.00%	8.00%
Scenario, Forecast | Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Lease assets	$ 96,600
Lease liabilities	123,400
Derecognition of build-to-suit lease asset	149,000
Derecognition of build-to-suit lease liability	$ 149,000
Subscription and services-based revenue
Concentration Risk [Line Items]
Description of timing			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.
Hardware revenue
Concentration Risk [Line Items]
Description of timing			The Company offers hardware installment sales to customers with terms ranging from three to twenty four months.

REVENUE - Adoption of ASC 606 o

REVENUE - Adoption of ASC 606 on the Condensed Consolidated Statement of Operation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Subscription and services-based revenue	$ 3,298,177	$ 2,214,253	$ 1,708,721
Hardware revenue	3,205,500
Cost of revenue	94,114	62,393	68,562
ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Hardware revenue	6,400
Subscription and services-based revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Subscription and services-based revenue	591,706	252,664	129,351
Hardware revenue	499,010	185,485	79,507
Cost of revenue	169,884	75,720	43,132
Subscription and services-based revenue | Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Subscription and services-based revenue	591,220
Cost of revenue	169,884
Subscription and services-based revenue | ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Subscription and services-based revenue	486
Cost of revenue	0
Hardware revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Hardware revenue	68,503	$ 41,415	$ 44,307
Cost of revenue	94,114
Hardware revenue | Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Hardware revenue	62,572
Cost of revenue	88,625
Hardware revenue | ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Hardware revenue	5,931
Cost of revenue	$ 5,489

DESCRIPTION OF BUSINESS AND S_5

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2018
Capitalized software
Property, Plant and Equipment [Line Items]
Useful Life	18 months
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful Life	7 years
Minimum | Computer and data center equipment
Property, Plant and Equipment [Line Items]
Useful Life	2 years
Maximum | Computer and data center equipment
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Maximum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Useful Life	10 years

REVENUE - Adoption of ASC 606_2

REVENUE - Adoption of ASC 606 on the Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets	$ 164,966	$ 86,454
Other current liabilities	99,153	45,130
Other non-current assets	58,393	31,350
Other non-current liabilities	93,286	$ 69,538
Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets	178,101
Other current liabilities	108,334
Other non-current assets	59,768
Other non-current liabilities	94,717
ASU 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets	(13,135)
Other current liabilities	(9,181)
Other non-current assets	(1,375)
Other non-current liabilities	$ (1,431)

REVENUE - Revenue from Contract

REVENUE - Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers:	$ 3,205,500
Transaction-based revenue
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers:	2,471,451	$ 1,920,174	$ 1,456,160
Subscription and services-based revenue
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers:	499,010	185,485	79,507
Hardware revenue
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers:	68,503	41,415	44,307
Bitcoin revenue
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers:	166,517	0	0
Starbucks | Transaction-based revenue
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers:	$ 0	$ 0	$ 78,903

REVENUE - Deferred Revenue (Det

REVENUE - Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Movement in Deferred Revenue [Roll Forward]
Deferred revenue, beginning of the period	$ 1,590	$ 5,407
Deferred revenue, end of the period	36,451	1,590
Deferred revenue arising from business combination	22,800	0
Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period	1,590	5,257
Balances without adoption of ASC 606
Movement in Deferred Revenue [Roll Forward]
Deferred revenue, beginning of the period	5,893	5,407
Deferred revenue, end of the period		5,893
ASU 2014-09 | Effect of change
Movement in Deferred Revenue [Roll Forward]
Deferred revenue, beginning of the period	$ (4,303)	0
Deferred revenue, end of the period		$ (4,303)

INVESTMENTS Investments - Shor

INVESTMENTS Investments - Short-term and Long-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,006,229
Fair Value	1,005,671
Short-term Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	541,684	$ 169,877
Gross Unrealized Gains	329	31
Gross Unrealized Losses	(1,022)	(332)
Fair Value	540,991	169,576
Short-term Securities | U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	80,160	15,122
Gross Unrealized Gains	32	0
Gross Unrealized Losses	(70)	(39)
Fair Value	80,122	15,083
Short-term Securities | Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	109,807	57,855
Gross Unrealized Gains	80	22
Gross Unrealized Losses	(368)	(79)
Fair Value	109,519	57,798
Short-term Securities | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		17,428
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		17,428
Short-term Securities | Municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	27,839	23,743
Gross Unrealized Gains	52	8
Gross Unrealized Losses	(59)	(51)
Fair Value	27,832	23,700
Short-term Securities | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	292,615	55,729
Gross Unrealized Gains	161	1
Gross Unrealized Losses	(509)	(163)
Fair Value	292,267	55,567
Short-term Securities | Non-U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	31,263
Gross Unrealized Gains	4
Gross Unrealized Losses	(16)
Fair Value	31,251
Long-term Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	464,545	204,980
Gross Unrealized Gains	1,361	59
Gross Unrealized Losses	(1,226)	(1,372)
Fair Value	464,680	203,667
Long-term Securities | U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	114,444	20,288
Gross Unrealized Gains	194	2
Gross Unrealized Losses	(78)	(121)
Fair Value	114,560	20,169
Long-term Securities | Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	159,783	91,959
Gross Unrealized Gains	419	25
Gross Unrealized Losses	(950)	(571)
Fair Value	159,252	91,413
Long-term Securities | Municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	28,453	26,371
Gross Unrealized Gains	167	13
Gross Unrealized Losses	(26)	(160)
Fair Value	28,594	26,224
Long-term Securities | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	153,743	66,362
Gross Unrealized Gains	553	19
Gross Unrealized Losses	(172)	(520)
Fair Value	154,124	$ 65,861
Long-term Securities | Non-U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,122
Gross Unrealized Gains	28
Gross Unrealized Losses	0
Fair Value	$ 8,150

INVESTMENTS Investments - Matur

INVESTMENTS Investments - Maturity of Available for Sale Securities (Details) $ in Thousands	Dec. 31, 2018USD ($)
Amortized Cost
Due in one year or less	$ 541,684
Due in one to five years	464,545
Total	1,006,229
Fair Value
Due in one year or less	540,991
Due in one to five years	464,680
Total	$ 1,005,671

CUSTOMER FUNDS - Assets Underly

CUSTOMER FUNDS - Assets Underlying Customer Funds (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Customer funds	$ 334,017	$ 103,042
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	27,291	0
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	72,671	0
Cash Equivalents: | U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	39,991	0
Cash Equivalents: | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	35,349	0
Cash
Debt Securities, Available-for-sale [Line Items]
Customer funds	158,697	103,042
Cash | Money market funds
Debt Securities, Available-for-sale [Line Items]
Customer funds	$ 18	$ 0

CUSTOMER FUNDS - Investments wi

CUSTOMER FUNDS - Investments within Customer Funds (Details) $ in Thousands	Dec. 31, 2018USD ($)
Debt Securities, Available-for-sale [Line Items]
Total	$ 1,006,229
Fair Value	1,005,671
Customer funds
Debt Securities, Available-for-sale [Line Items]
Total	99,955
Gross Unrealized Gains	14
Gross Unrealized Losses	(7)
Fair Value	99,962
Customer funds | U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Total	27,293
Gross Unrealized Gains	2
Gross Unrealized Losses	(4)
Fair Value	27,291
Customer funds | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Total	72,662
Gross Unrealized Gains	12
Gross Unrealized Losses	(3)
Fair Value	$ 72,671

CUSTOMER FUNDS - Maturity of Av

CUSTOMER FUNDS - Maturity of Available for Sale Securities within Customer Funds (Details) $ in Thousands	Dec. 31, 2018USD ($)
Amortized Cost
Due in one year or less	$ 541,684
Due in one to five years	464,545
Total	1,006,229
Fair Value
Due in one year or less	540,991
Due in one to five years	464,680
Total	1,005,671
Customer funds
Amortized Cost
Due in one year or less	99,955
Due in one to five years	0
Total	99,955
Fair Value
Due in one year or less	99,962
Due in one to five years	0
Total	$ 99,962

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value of Financial Instruments - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	$ 334,017	$ 103,042
Short-term investments	540,991	169,576
Long-term investments	464,680	203,667
Equity investment	45,342	25,000
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment	45,342	0
Total	904,119	509,126
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment	0	0
Total	696,966	276,510
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
Money market funds | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	18	0
Money market funds | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Money market funds | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	27,291	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Short-term investments	0	0
Long-term investments	0	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	67,282	0
Short-term investments	80,122	15,083
Long-term investments	114,560	20,169
U.S. agency securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	0	0
Short-term investments	0	0
Long-term investments	0	0
Corporate bonds | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
Corporate bonds | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	109,519	57,798
Long-term investments	159,252	91,413
Corporate bonds | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	17,428
Commercial paper | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Municipal securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
Municipal securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	27,832	23,700
Long-term investments	28,594	26,224
Municipal securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0	0
U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	72,671	0
U.S. government securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	86,239	0
Customer funds	108,020	0
Short-term investments	292,267	55,567
Long-term investments	154,124	65,861
U.S. government securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Customer funds	0	0
Short-term investments	0	0
Long-term investments	0	0
U.S. government securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Customer funds	0	0
Short-term investments	0	0
Long-term investments	0	0
Non-U.S. government securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Short-term investments	0	0
Long-term investments	0	0
Non-U.S. government securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	23,981	0
Short-term investments	31,251	0
Long-term investments	8,150	0
Non-U.S. government securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Short-term investments	0	0
Long-term investments	0	0
Money market funds | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	218,109	387,698
Money market funds | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Money market funds | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	46,423	0
U.S. agency securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Commercial paper | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	24,695
Commercial paper | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value of Financial Instruments - Fair Value of Convertible Senior Notes (Details) - Fair Value, Measurements, Recurring - Level 2 - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 899,695	$ 358,572
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	1,417,161	719,356
2023 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	718,522	0
2023 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	901,468	0
2022 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	181,173	358,572
2022 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 515,693	$ 719,356

FAIR VALUE OF FINANCIAL INSTR_5

FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value of Financial Instruments - Summary of Loans Disclosed at Fair Value (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Carrying Value | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 89,974,000	$ 73,420,000
Fair Value | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	93,064,000	76,070,000
Loans 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	$ 13,200,000	$ 8,000,000	$ 0

PROPERTY AND EQUIPMENT, NET Pro

PROPERTY AND EQUIPMENT, NET Property and Equipment, Net - Summary of Property, Equipment and Internally-Developed Software (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 267,311	$ 192,812
Less: Accumulated depreciation and amortization	(124,909)	(101,316)
Property and equipment, net	142,402	91,496
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	107,611	77,073
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	80,093	66,186
Capitalized software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	58,908	35,063
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 20,699	$ 14,490

PROPERTY AND EQUIPMENT, NET P_2

PROPERTY AND EQUIPMENT, NET Property and Equipment, Net - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense on property and equipment	$ 46.8	$ 29.7	$ 28.7

ACQUISITIONS Acquisitions - Na

ACQUISITIONS Acquisitions - Narrative (Details) - USD ($) $ in Thousands	May 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Consideration, net of cash acquired		$ 112,399	$ 1,915	$ 1,360
Weebly, Inc
Business Acquisition [Line Items]
Percent acquired of outstanding shares	100.00%
Cash	$ 132,432
Consideration (in shares)	2,418,271
Stock (2,418,271 shares of Class A common stock)	$ 140,107
Amount paid to pay outstanding and unvested options	17,700
Post combination compensation expense	$ 2,600
Purchase price adjustment to goodwill		6,100
Purchase price adjustment to liabilities assumed		4,800
Cash withheld as security for indemnification obligations		$ 19,900
Shares of the total share consideration remaining withheld for indemnification purposes (in shares)		372,578
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Consideration, net of cash acquired		$ 9,900

ACQUISITIONS Acquisitions - Ass

ACQUISITIONS Acquisitions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	May 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 261,705	$ 58,327	$ 57,173
Weebly, Inc
Business Acquisition [Line Items]
Cash	$ 132,432
Stock (2,418,271 shares of Class A common stock)	$ 140,107
Consideration (in shares)	2,418,271
Consideration	$ 272,539
Current assets (inclusive of cash acquired of $25,758)	44,685
Cash acquired	25,758
Total liabilities assumed (including deferred revenue of $22,800)	(37,592)
Deferred revenue	22,800
Total identifiable net assets acquired	76,954
Goodwill	195,585
Total	272,539
Customer Assets | Weebly, Inc
Business Acquisition [Line Items]
Intangible assets	42,700
Technology Assets | Weebly, Inc
Business Acquisition [Line Items]
Intangible assets	14,900
Trade Name | Weebly, Inc
Business Acquisition [Line Items]
Intangible assets	11,300
Other | Weebly, Inc
Business Acquisition [Line Items]
Intangible assets	$ 961

GOODWILL (Details)

GOODWILL (Details)	12 Months Ended
	Dec. 31, 2018USD ($)reporting_unit	Dec. 31, 2017USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 58,327,000	$ 57,173,000
Acquisitions completed during the year	203,378,000	1,154,000
Ending balance	$ 261,705,000	$ 58,327,000
Number of reporting units | reporting_unit	1
Impairment of goodwill	$ 0

ACQUIRED INTANGIBLE ASSETS Acqu

ACQUIRED INTANGIBLE ASSETS Acquired Intangible Assets - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 116,633	$ 40,762
Accumulated Amortization	(39,531)	(26,428)
Net	77,102	14,334	$ 19,292	$ 26,776
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,285	1,285
Accumulated Amortization	(664)	(559)
Net	621	726
Technology Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	45,978	29,158
Accumulated Amortization	(28,420)	(21,329)
Net	17,558	7,829
Customer Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	57,109	10,319
Accumulated Amortization	(8,068)	(4,540)
Net	49,041	$ 5,779
Trade Name
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	11,300
Accumulated Amortization	(1,648)
Net	9,652
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	961
Accumulated Amortization	(731)
Net	$ 230

ACQUIRED INTANGIBLE ASSETS Ac_2

ACQUIRED INTANGIBLE ASSETS Acquired Intangible Assets - Narrative (Details) - Weighted Average	12 Months Ended
	Dec. 31, 2018
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average amortization periods	13 years
Technology Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average amortization periods	5 years
Customer Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average amortization periods	11 years
Trade Name
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average amortization periods	4 years

Acquired Intangible Assets - Ch

Acquired Intangible Assets - Change in Carrying Value of Acquired Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance	$ 14,334	$ 19,292	$ 26,776
Acquisitions	75,871	2,657	1,529
Amortization expense	13,104	7,615	9,013
Ending balance	$ 77,102	$ 14,334	$ 19,292

ACQUIRED INTANGIBLE ASSETS Ac_3

ACQUIRED INTANGIBLE ASSETS Acquired Intangible Assets - Future Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
2,019	$ 13,744
2,020	11,496
2,021	10,299
2,022	8,369
2,023	6,839
Thereafter	26,355
Net	$ 77,102	$ 14,334	$ 19,292	$ 26,776

OTHER CONSOLIDATED BALANCE SH_5

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) Other Consolidate Balance Sheet Components (Current) - Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventory, net	$ 28,627	$ 16,777
Processing costs receivable	46,102	21,083
Prepaid expenses	21,782	14,473
Accounts receivable, net	22,393	8,606
Deferred hardware costs	0	7,931
Deferred magstripe reader costs	9,361	2,469
Prepaid compensation, current	4,995	0
Other	31,706	15,115
Total	$ 164,966	$ 86,454

OTHER CONSOLIDATED BALANCE SH_6

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) Other Consolidated Balance Sheet Components (Current) - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued facilities expenses	$ 13,040	$ 568
Accrued payroll	9,612	9,103
Accrued professional fees	5,232	5,638
Accrued advertising and other marketing	12,201	6,723
Processing costs payable	12,683	10,145
Accrued non income tax liabilities	9,503	6,155
Accrued hardware costs	5,125	2,496
Other accrued liabilities	14,958	11,452
Total	$ 82,354	$ 52,280

OTHER CONSOLIDATED BALANCE SH_7

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) Other Consolidated Balance Sheet Components (Current) - Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts payable	$ 36,416	$ 16,763
Square Capital payable	6,092	7,671
Square Payroll payable	7,534	2,850
Deferred revenue, current	31,474	5,893
Deferred rent, current	3,842	3,311
Accrued redemptions	1,305	1,036
Other	12,490	7,606
Total	$ 99,153	$ 45,130

OTHER CONSOLIDATED BALANCE SH_8

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) Other Consolidated Balance Sheet Components (Non-Current) - Other Non-Current Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 31, 2017
Other Non-Current Assets [Line Items]
Equity investment	$ 45,342	$ 25,000
Prepaid compensation, non-current	5,915	0
Deposits	2,747	2,738
Other	4,389	3,612
Total	58,393	31,350
Gain from revaluation of investment	$ 20,342	$ 0	$ 0
Eventbrite
Other Non-Current Assets [Line Items]
Equity investment				$ 25,000

OTHER CONSOLIDATED BALANCE SH_9

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) Other Consolidated Balance Sheet Components (Non-Current) - Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Statutory liabilities	$ 54,748	$ 40,768
Deferred rent, non-current	23,003	20,349
Deferred purchase consideration	3,900	0
Deferred revenue, non-current	4,977	432
Other	6,658	7,989
Total	$ 93,286	$ 69,538

INDEBTEDNESS Indebtedness - Rev

INDEBTEDNESS Indebtedness - Revolving Credit Facility, Narrative (Details) - Revolving Secured Credit Facility - Revolving Secured Credit Facility - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2015	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 375,000,000
Annual administrative agent fee	$ 100,000
Unused commitment fee, percent	0.15%
Remaining borrowing capacity		$ 375,000,000
Unused commitment fees		$ 600,000	$ 600,000
Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
One-Month LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.00%
One-Month LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%

INDEBTEDNESS Indebtedness - Con

INDEBTEDNESS Indebtedness - Convertible Senior Notes, Narrative (Details) $ / shares in Units, shares in Millions	May 25, 2018USD ($)day	Mar. 06, 2017USD ($)day$ / shares	Dec. 31, 2018USD ($)day$ / sharesshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2018
Debt Instrument [Line Items]
Aggregate principal amount	$ 862,500,000
Interest rate	0.50%
Conversion price (in USD per share) | $ / shares			$ 77.85
Threshold trading days | day			20
Threshold consecutive trading days | day			30
Principal payment on conversion of senior notes			$ 219,384,000	$ 0	$ 0
Fair value of common stock issued to settle the conversion of senior notes, due 2022			571,408,000	0	0
Loss on extinguishment of long-term debt			$ 5,047,000	0	$ 0
Convertible Debt
Debt Instrument [Line Items]
Aggregate principal amount		$ 440,000,000
Interest rate		0.375%	0.375%
Conversion rate		0.0435749
Conversion price (in USD per share) | $ / shares		$ 22.95	$ 77.85
Carrying amount of equity component		$ 86,200,000	$ 194,392,000
Discounts and commissions payable		11,000,000
Third party offering costs		800,000
Issuance costs attributable to the liability component		$ 9,400,000	8,040,000
Debt Instrument, Conversion Term One | Convertible Debt
Debt Instrument [Line Items]
Threshold trading days | day		20
Threshold consecutive trading days | day		30
Threshold percentage of stock price trigger		130.00%
Debt Instrument, Conversion Term Two | Convertible Debt
Debt Instrument [Line Items]
Threshold trading days | day		5
Threshold consecutive trading days | day		5
Threshold percentage of stock price trigger		98.00%
2023 Notes | Convertible Debt
Debt Instrument [Line Items]
Conversion rate	0.0128456
Conversion amount	$ 1,000
Carrying amount of equity component	155,300,000		$ 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		$ 5,054,000
2023 Notes | Debt Instrument, Conversion Term One | Convertible Debt
Debt Instrument [Line Items]
Threshold percentage of stock price trigger	130.00%
2023 Notes | Debt Instrument, Conversion Term Two | Convertible Debt
Debt Instrument [Line Items]
Threshold trading days | day	5
Threshold consecutive trading days | day	5
Threshold percentage of stock price trigger	98.00%
2022 Notes | Convertible Debt
Debt Instrument [Line Items]
Carrying amount of equity component			$ 40,373,000	83,901,000
Effective interest rate of the liability component			5.34%
Issuance costs attributable to the liability component			$ 2,986,000	$ 8,044,000
Converted principal amount			$ 228,300,000
Shares issued in connection with conversion (in shares) | shares			6.9
Fair value of common stock issued to settle the conversion of senior notes, due 2022			$ 8,900,000
Loss on extinguishment of long-term debt			5,000,000
Reduction to additional paid-in-capital			$ 21,000,000

INDEBTEDNESS Indebtedness - Com

INDEBTEDNESS Indebtedness - Components of Convertible Notes (Details) - Convertible Debt - USD ($) $ in Thousands	Dec. 31, 2018	May 25, 2018	Dec. 31, 2017	Mar. 06, 2017
Debt Instrument [Line Items]
Principal outstanding	$ 1,074,228
Unamortized debt discount	(166,493)
Unamortized debt issuance costs	(8,040)			$ (9,400)
Net carrying amount	899,695
2023 Notes
Debt Instrument [Line Items]
Principal outstanding	862,500
Unamortized debt discount	(138,924)
Unamortized debt issuance costs	(5,054)	$ (5,600)
Net carrying amount	718,522
2022 Notes
Debt Instrument [Line Items]
Principal outstanding	211,728		$ 440,000
Unamortized debt discount	(27,569)		(73,384)
Unamortized debt issuance costs	(2,986)		(8,044)
Net carrying amount	$ 181,173		$ 358,572

INDEBTEDNESS Indebtedness - Car

INDEBTEDNESS Indebtedness - Carrying Amount of Equity Component of Convertible Notes (Details) - Convertible Debt - USD ($) $ in Thousands	Dec. 31, 2018	May 25, 2018	Dec. 31, 2017	Mar. 06, 2017
Debt Instrument [Line Items]
Amount allocated to the conversion option	$ 196,731
Less: allocated debt issuance costs	(2,339)
Equity component, net	194,392			$ 86,200
2023 Notes
Debt Instrument [Line Items]
Amount allocated to the conversion option	155,250
Less: allocated debt issuance costs	(1,231)
Equity component, net	154,019	$ 155,300
2022 Notes
Debt Instrument [Line Items]
Amount allocated to the conversion option	41,481		$ 86,203
Less: allocated debt issuance costs	(1,108)		(2,302)
Equity component, net	$ 40,373		$ 83,901

INDEBTEDNESS Indebtedness - Int

INDEBTEDNESS Indebtedness - Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	May 25, 2018	Mar. 06, 2017
Debt Instrument [Line Items]
Interest rate			0.50%
Convertible Debt
Debt Instrument [Line Items]
Contractual interest expense	$ 4,023	$ 1,351
Amortization of debt discount and issuance costs	32,855	14,223
Total	$ 36,878	$ 15,574
Interest rate	0.375%			0.375%

INDEBTEDNESS Indebtedness - C_2

INDEBTEDNESS Indebtedness - Convertible Bond Hedge and Warrant Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Mar. 06, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Proceeds from issuance of warrants		$ 112,125	$ 57,244	$ 0
Conversion price of convertible debt (in USD per share)		$ 77.85
Convertible Debt
Debt Instrument [Line Items]
Conversion price of convertible debt (in USD per share)	$ 22.95	77.85
Conversion price of convertible debt after effect of warrants and note hedge (in USD per share)	$ 31.18	$ 109.26
Common Stock Warrants
Debt Instrument [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)	19.2	11.1
Warrants, weighted average exercise price (in USD per share)	$ 31.18	$ 109.26
Proceeds from issuance of warrants	$ 57,200	$ 112,100
Shares received upon exercise of convertible notes (in shares)		6.9
Options
Debt Instrument [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)		11.1
Convertible note hedge, option to purchase common stock, price (in USD per share)	$ 22.95	$ 77.85
Cost of convertible note hedge	$ 92,100	$ 172,600

ACCRUED TRANSACTION LOSSES Accr

ACCRUED TRANSACTION LOSSES Accrued Transaction Losses - Summary of Reserve for Transaction Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loss Contingency Accrual [Roll Forward]
Accrued transaction losses, beginning of the year	$ 26,893
Provision for transaction losses	88,077	$ 67,018	$ 51,235
Accrued transaction losses, end of the year	33,682	26,893
Transaction Losses
Loss Contingency Accrual [Roll Forward]
Accrued transaction losses, beginning of the year	26,893	20,064
Provision for transaction losses	64,981	52,977
Charge-offs to accrued transaction losses	(58,192)	(46,148)
Accrued transaction losses, end of the year	$ 33,682	$ 26,893	$ 20,064

INCOME TAXES Income Taxes - Do

INCOME TAXES Income Taxes - Domestic and Foreign Components of Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Domestic	$ 44,538	$ (10,900)	$ (145,499)
Foreign	(80,665)	(51,764)	(24,174)
Loss before income tax	$ (36,127)	$ (62,664)	$ (169,673)

INCOME TAXES Income Taxes - Com

INCOME TAXES Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ (4)	$ (1,192)	$ 63
State	752	739	527
Foreign	2,224	1,987	1,269
Total current provision for income taxes	2,972	1,534	1,859
Deferred:
Federal	(404)	(1,169)	173
State	35	57	18
Foreign	(277)	(273)	(133)
Total deferred provision for income taxes	(646)	(1,385)	58
Total provision for income taxes	$ 2,326	$ 149	$ 1,917

INCOME TAXES Income Taxes - Rec

INCOME TAXES Income Taxes - Reconciliation of Statutory Federal Income Tax Rate to Company's Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Tax at federal statutory rate	21.00%	34.00%	34.00%
State taxes, net of federal benefit	(1.10%)	(0.40%)	(0.10%)
Foreign rate differential	(14.70%)	(14.90%)	(2.40%)
Non-deductible meals	(3.40%)	(0.30%)	(0.10%)
Other non-deductible expenses	(1.70%)	(0.70%)	(0.80%)
Credits	164.80%	41.50%	8.50%
Other items	2.30%	(1.20%)	0.20%
Change in valuation allowance	(718.50%)	(119.50%)	(37.40%)
Impact of U.S. tax reform	0.00%	(209.10%)	0.00%
Share-based compensation	549.00%	243.50%	(2.40%)
Change in uncertain tax positions	(4.10%)	(2.40%)	(0.60%)
Termination of warrant	0.00%	29.30%	0.00%
Total	(6.40%)	(0.20%)	(1.10%)

INCOME TAXES Income Taxes - Tax

INCOME TAXES Income Taxes - Tax Effects of Temporary Differences and Related Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Capitalized costs	$ 30,131	$ 35,608	$ 61,897
Accrued expenses	31,494	23,553	29,421
Net operating loss carryforwards	485,562	244,197	65,507
Tax credit carryforwards	133,275	60,567	38,927
Property, equipment and intangible assets	0	7,390	5,721
Share-based compensation	38,265	35,728	52,091
Deferred Interest	8,290	0	0
Other	105	2,519	1,640
Total deferred tax assets	727,122	409,562	255,204
Valuation allowance	(719,040)	(409,043)	(254,898)
Total deferred tax assets, net of valuation allowance	8,082	519	306
Deferred tax liabilities:
Property, equipment and intangible assets	(7,361)	0	0
Indefinite-lived intangibles	(275)	(644)	(476)
Total deferred tax liabilities	(7,636)	(644)	(476)
Net deferred tax asset	$ 446
Net deferred tax liabilities		$ (125)	$ (170)

INCOME TAXES Income Taxes - Nar

INCOME TAXES Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Discrete net tax benefit due to Tax Act		$ 1,300
Decrease in U.S. Federal and state DTAs due to Tax Act		63,600
Decrease in valuation allowance due to Tax Act	$ 63,600
Increase in valuation allowance	310,000	154,100	$ 59,800
Unrecognized tax benefits	198,540	$ 70,799	$ 92,134	$ 90,372
Unrecognized tax benefit that would impact annual effective tax rate	5,700
Significant accrued interest and penalties related to uncertain tax positions	0
Undistributed earnings of non-U.S. subsidiaries	4,200
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	1,709,800
Federal | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	107,300
Federal | AMT Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	1,300
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	1,903,800
State | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	65,600
State | California Enterprise Zone Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	2,800
Foreign
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	215,100
Foreign | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	2,700
Maximum | Tax examinations or lapse of applicable statute of limitations
Operating Loss Carryforwards [Line Items]
Reasonably possible decrease in unrecognized tax benefits	$ 13,000

INCOME TAXES Income Taxes - R_2

INCOME TAXES Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at the beginning of the year	$ 70,799	$ 92,134
Gross increases and decreases related to prior period tax positions	513	0	$ 5,190
Gross increases related to current period tax positions	119,261	4,193
Gross decreases related to current period tax positions			(3,428)
Reductions related to lapse of statute of limitations	(142)	(91)	0
Gross increases and decreases related to U.S. tax reform	0	(25,437)	0
Gross increases and decreases related to acquisition	8,109	0	0
Balance at the end of the year	$ 198,540	$ 70,799	$ 92,134

STOCKHOLDER'S EQUITY Stockholde

STOCKHOLDER'S EQUITY Stockholder's Equity - Common Stock and Warrants Narrative (Details) $ / shares in Units, $ in Thousands	Feb. 24, 2017USD ($)shares	Dec. 31, 2018USD ($)vote$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)	May 25, 2018$ / sharesshares	Apr. 30, 2018shares	Mar. 06, 2017$ / sharesshares	Dec. 31, 2014USD ($)shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		100,000,000	100,000,000
Preferred stock, par value (in USD per share) | $ / shares		$ 0.00	$ 0.00
Preferred stock, shares outstanding (in shares)		0	0
Warrants to purchase shares of common, canceled (in shares)	9,500,000
Consideration paid for termination of warrants | $	$ 54,800	$ 0	$ 54,808	$ 0
Common Stock Warrants
Class of Stock [Line Items]
Outstanding warrants to purchase aggregate shares of capital stock (in shares)		11,100,000					19,200,000
Exercise price of warrants (in USD per share) | $ / shares		$ 109.26					$ 31.18
Common Stock Warrant, 2022 Notes
Class of Stock [Line Items]
Outstanding warrants to purchase aggregate shares of capital stock (in shares)							19,200,000
Exercise price of warrants (in USD per share) | $ / shares					$ 31.18
Common Stock Warrant, 2023 Notes
Class of Stock [Line Items]
Outstanding warrants to purchase aggregate shares of capital stock (in shares)					11,100,000
Exercise price of warrants (in USD per share) | $ / shares					$ 109.26
Class A Common Stock
Class of Stock [Line Items]
Number of votes per share | vote		1
Common stock, shares authorized (in shares)		1,000,000,000	1,000,000,000
Common stock, par value (in USD per share) | $ / shares		$ 0.00	$ 0.00
Common stock, shares outstanding (in shares)		323,546,864	280,400,813
Class B Common Stock
Class of Stock [Line Items]
Number of votes per share | vote		10
Common stock, shares authorized (in shares)		500,000,000	500,000,000
Common stock, par value (in USD per share) | $ / shares		$ 0.00	$ 0.00
Common stock, shares outstanding (in shares)		93,501,142	114,793,262
Caviar, Inc.
Class of Stock [Line Items]
Shares withheld for indemnification (in shares)								1,291,979
Shares held back released to former owners (in shares)						822,085
Shares forfeited back to the Company (in shares)						469,894
Cash withheld as security for indemnification obligations | $								$ 2,700
Convertible Debt | 2022 Notes
Class of Stock [Line Items]
Shares received upon exercise of convertible notes (in shares)		6,900,000
Class A and B common stock
Class of Stock [Line Items]
Shares issued in connection with conversion (in shares)		7,288,907

STOCKHOLDER'S EQUITY Stockhol_2

STOCKHOLDER'S EQUITY Stockholder's Equity - Share-Based Compensation Narrative (Details) $ / shares in Units, $ in Thousands	12 Months Ended			37 Months Ended
	Dec. 31, 2018USD ($)planpayment_plan$ / sharesshares	Dec. 31, 2017USD ($)$ / shares	Dec. 31, 2016USD ($)$ / shares	Dec. 31, 2018USD ($)shares	Nov. 17, 2015shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based compensation plans | plan	2
Aggregate intrinsic value for options exercised | $	$ 720,100	$ 464,100	$ 202,600
Weighted average grant-date fair value of options granted (in USD per share) | $ / shares	$ 16.25	$ 5.97	$ 5.80
Share-based compensation expense | $	$ 216,881	$ 155,836	$ 138,786
Share-based compensation expense related to capitalized software | $	9,300	3,700	$ 2,800
Unrecognized compensation cost related to outstanding stock options and restricted stock awards | $	$ 564,500			$ 564,500
Unrecognized compensation cost related to outstanding stock options and restricted stock awards, recognition period	2 years 9 months 4 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting term	4 years
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $	$ 9,000	$ 6,000
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved (in shares)					30,000,000
Shares reserved for issuance, percent	5.00%
Number of shares available for future issuance (in shares)	64,851,998			64,851,998
2015 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of number of shares reserved (in shares)	40,000,000			40,000,000
2015 Equity Incentive Plan | Options and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options and RSU outstanding (in shares)	22,666,464			22,666,464
2009 Stock Option Plan | Options and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options and RSU outstanding (in shares)	28,421,145			28,421,145
2009 Stock Option Plan | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting term	4 years
Expiration period	10 years
2009 Stock Option Plan | Options | Vesting Year One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting rate	25.00%
2015 Employee Stock Purchase Plan | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance, percent	1.00%
Number of shares available for future issuance (in shares)	10,797,606			10,797,606
Discount through payroll deductions as a percentage of eligible compensation	15.00%
Offering period	12 months
Number of purchase periods | payment_plan	2
Purchase price of common stock as a percentage of fair market value	85.00%
Shares purchased under the plan (in shares)				4,349,301
2015 Employee Stock Purchase Plan | Employee Stock Purchase Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of number of shares reserved (in shares)	8,400,000			8,400,000

STOCKHOLDER'S EQUITY Stockhol_3

STOCKHOLDER'S EQUITY Stockholder's Equity - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Number of options outstanding
Beginning balance (in shares)	47,270,091
Granted (in shares)	783,625
Exercised (in shares)	(13,402,680)
Forfeited and canceled (in shares)	(1,498,155)
Ending balance (in shares)	33,152,881	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)	7.98
Forfeited and canceled (in USD per share)	14.75
Ending balance (in USD per share)	$ 9.52	$ 8.67
Options Vested and Expected to Vest
Number of stock options outstanding (in shares)	33,152,881
Weighted average exercise price (in USD per share)	$ 9.52
Weighted Average Remaining Contractual Term (in years)	5 years 5 months 13 days
Aggregate Intrinsic Value	$ 1,543,793
Additional Disclosures
Weighted Average Remaining Contractual Term (in years)	5 years 5 months 13 days	6 years 6 months 6 days
Aggregate Intrinsic Value	$ 1,543,793	$ 1,229,103
Options exercisable, number of stock options outstanding (in shares)	31,066,578
Options exercisable, weighted average exercise price (in USD per share)	$ 8.63
Options exercisable, weighted average remaining contractual term (in years)	5 years 3 months 9 days
Options exercisable, aggregate intrinsic value	$ 1,474,339

STOCKHOLDER'S EQUITY Stockhol_4

STOCKHOLDER'S EQUITY Stockholder's Equity - RSU Activity (Details) - RSUs	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Number of shares
Beginning balance (in shares) | shares	21,317,525
Granted (in shares) | shares	7,147,541
Vested (in shares) | shares	(7,786,561)
Forfeited (in shares) | shares	(2,743,777)
Ending balance (in shares) | shares	17,934,728
Weighted Average Grant Date Fair Value
Beginning balance (in USD per share) | $ / shares	$ 17.84
Granted (in USD per share) | $ / shares	54.43
Vested (in USD per share) | $ / shares	19.62
Forfeited (in USD per share) | $ / shares	19.88
Ending balance (in USD per share) | $ / shares	$ 31.34

STOCKHOLDER'S EQUITY Stockhol_5

STOCKHOLDER'S EQUITY Stockholder's Equity - Stock Options Fair Value Assumptions (Details) - Options	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Risk-free interest rate	2.92%	1.88%	1.54%
Expected volatility	30.87%	32.22%	42.74%
Expected term (years)	6 years 2 months 9 days	6 years 7 days	6 years 29 days

STOCKHOLDER'S EQUITY Stockhol_6

STOCKHOLDER'S EQUITY Stockholder's Equity - Effects of Share-Based Compensation on Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 216,881	$ 155,836	$ 138,786
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	97	77	0
Product development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	144,601	98,310	91,404
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	22,797	17,568	14,122
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 49,386	$ 39,881	$ 33,260

NET LOSS PER SHARE - Calculati

NET LOSS PER SHARE - Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net loss	$ (38,453)	$ (62,813)	$ (171,590)
Basic shares:
Weighted-average common shares outstanding (in shares)	406,313	380,921	344,393
Weighted-average unvested shares (in shares)	(582)	(1,577)	(2,838)
Weighted-average shares used to compute basic net loss per share (in shares)	405,731	379,344	341,555
Diluted shares:
Weighted-average shares used to compute diluted net loss per share (in shares)	405,731	379,344	341,555
Loss per share:
Basic (in USD per share)	$ (0.09)	$ (0.17)	$ (0.50)
Diluted (in USD per share)	$ (0.09)	$ (0.17)	$ (0.50)

NET LOSS PER SHARE - Antidiluti

NET LOSS PER SHARE - Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	110,929	89,218	100,270
Stock options and restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	60,589	68,588	88,705
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	23,820	0	0
Unvested shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	582	1,300	1,892
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	140	157	216
Common stock warrants | Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	25,798	19,173	9,457

COMMITMENTS AND CONTINGENCIES C

COMMITMENTS AND CONTINGENCIES Commitments and Contingencies - Narrative (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2018USD ($)ft²	Dec. 31, 2018USD ($)extension	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Rental expenses under operating leases		$ 23,300	$ 12,900	$ 11,300
Operating Leased Assets [Line Items]
Total lease payments over term	$ 429,466	429,466
Build-to-suit lease asset	$ 149,000	$ 149,000	$ 0
Build-to-suit Lease
Operating Leased Assets [Line Items]
Leased area of office space | ft²	355,762
Lease term	12 years	12 years
Total lease payments over term	$ 272,000	$ 272,000
Number of extensions | extension		2
Extension terms		5 years

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Operating and Capital Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
Capital
2,019	$ 5,029
2,020	2,446
2,021	0
2,022	0
2,023	0
Thereafter	0
Total	7,475
Less amount representing interest	0
Present value of capital lease obligations	7,475
Less current portion of capital lease obligation	(5,029)
Non-current portion of capital lease obligation	2,446
Operating
2,019	28,405
2,020	38,131
2,021	52,319
2,022	53,430
2,023	47,222
Thereafter	209,959
Total	$ 429,466

SEGMENT AND GEOGRAPHICAL INFO_3

SEGMENT AND GEOGRAPHICAL INFORMATION Segment and Geographical Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2018segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

SEGMENT AND GEOGRAPHICAL INFO_4

SEGMENT AND GEOGRAPHICAL INFORMATION Segment and Geographical Information - Revenue by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 3,298,177	$ 2,214,253	$ 1,708,721
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	3,138,859	2,120,088	1,643,852
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 159,318	$ 94,165	$ 64,869

SEGMENT AND GEOGRAPHICAL INFO_5

SEGMENT AND GEOGRAPHICAL INFORMATION Segment and Geographical Information - Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 481,209	$ 164,157
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	471,970	158,820
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 9,239	$ 5,337

SUPPLEMENTAL CASH FLOW INFORM_3

SUPPLEMENTAL CASH FLOW INFORMATION Supplemental Cash Flow Information - Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Data:
Cash paid for interest	$ 4,125	$ 1,374	$ 570
Cash paid for income taxes	1,622	1,254	395
Supplemental disclosures of non-cash investing and financing activities:
Change in purchases of property and equipment in accounts payable and accrued expenses	15,067	143	2,554
Unpaid business acquisition purchase price	3,995	2,115	240
Fair value of shares issued related to business combination	140,107	0	0
Recovery of common stock in connection with indemnification settlement agreement	2,745	0	0
Fair value of common stock issued to settle the conversion of senior notes, due 2022	(571,408)	0	0
Fair value of shares received to settle senior note hedges, due 2022	$ 544,276	$ 0	$ 0

Uncategorized Items - sq-201812

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 0
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(4,586,000)
Additional Paid-in Capital [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	683,000
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(683,000)
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (4,586,000)