Block (XYZ) 10-Q 1 Aug 19 2019 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-37622
Entity Registrant Name	Square, Inc.
Entity Central Index Key	0001512673
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	80-0429876
Entity Address, Address Line One	1455 Market Street
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94103
City Area Code	415
Local Phone Number	375-3176
Title of 12(b) Security	Class A common stock, $0.0000001 par value per share
Trading Symbol	SQ
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Class A
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		342,633,007
Class B
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		84,497,676

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 617,282	$ 583,173
Short-term investments	572,206	540,991
Restricted cash	31,148	33,838
Settlements receivable	1,506,194	364,946
Customer funds	484,945	334,017
Loans held for sale	136,511	89,974
Other current assets	180,360	164,966
Total current assets	3,528,646	2,111,905
Property and equipment, net	130,747	142,402
Goodwill	270,161	261,705
Acquired intangible assets, net	84,216	77,102
Long-term investments	460,827	464,680
Restricted cash	14,433	15,836
Built-to-suit lease asset	0	149,000
Operating lease right-of-use assets	107,809
Other non-current assets	57,167	58,393
Total assets	4,654,006	3,281,023
Current liabilities:
Customers payable	1,802,128	749,215
Settlements payable	290,652	54,137
Accrued transaction losses	39,630	33,682
Accrued expenses	106,351	82,354
Operating lease liabilities, current	24,955	0
Other current liabilities	111,878	99,153
Total current liabilities	2,375,594	1,018,541
Long-term debt, net of current portion (Note 12)	919,026	899,695
Built-to-suit lease liability	0	149,000
Operating lease liabilities, non-current	107,265
Other non-current liabilities	67,649	93,286
Total liabilities	3,469,534	2,160,522
Commitments and contingencies (Note 17)
Stockholders’ equity:
Preferred stock, $0.0000001 par value: 100,000,000 shares authorized at June 30, 2019 and December 31, 2018. None issued and outstanding at June 30, 2019 and December 31, 2018.	0	0
Additional paid-in capital	2,116,063	2,012,328
Accumulated other comprehensive loss	(926)	(6,053)
Accumulated deficit	(930,665)	(885,774)
Total stockholders’ equity	1,184,472	1,120,501
Total liabilities and stockholders’ equity	4,654,006	3,281,023
Class A
Stockholders’ equity:
Common stock	0	0
Class B
Stockholders’ equity:
Common stock	$ 0	$ 0

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Preferred stock, par value (in USD per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A
Class of Stock [Line Items]
Common stock, par value (in USD per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	341,709,651	323,546,864
Common stock, shares outstanding (in shares)	341,709,651	323,546,864
Class B
Class of Stock [Line Items]
Common stock, par value (in USD per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	84,508,342	93,501,142
Common stock, shares outstanding (in shares)	84,508,342	93,501,142

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Revenue	$ 1,174,238	$ 814,938	$ 2,133,597	$ 1,483,541
Cost of revenue:
Total cost of revenue	708,393	499,122	1,270,998	912,555
Gross profit	465,845	315,816	862,599	570,986
Operating expenses:
Product development	174,201	114,800	328,551	219,895
Sales and marketing	156,421	98,243	290,134	175,509
General and administrative	100,508	82,772	202,106	158,273
Transaction, loan and advance losses	34,264	21,976	62,105	40,007
Amortization of acquired customer assets	1,294	672	2,588	941
Total operating expenses	466,688	318,463	885,484	594,625
Operating loss	(843)	(2,647)	(22,885)	(23,639)
Interest expense, net	5,143	3,470	9,824	5,582
Other expense (income), net	1,230	(815)	12,529	(108)
Loss before income tax	(7,216)	(5,302)	(45,238)	(29,113)
Provision (benefit) for income taxes	(476)	604	(347)	779
Net loss	$ (6,740)	$ (5,906)	$ (44,891)	$ (29,892)
Net loss per share:
Basic (in USD per share)	$ (0.02)	$ (0.01)	$ (0.11)	$ (0.07)
Diluted (in USD per share)	$ (0.02)	$ (0.01)	$ (0.11)	$ (0.07)
Weighted-average shares used to compute net loss per share
Basic (in shares)	423,305	403,301	421,297	399,624
Diluted (in shares)	423,305	403,301	421,297	399,624
Technology assets
Cost of revenue:
Amortization of acquired technology	$ 1,719	$ 1,857	$ 3,095	$ 3,437
Transaction-based revenue
Revenue:
Revenue	775,510	625,228	1,432,272	1,148,265
Cost of revenue:
Cost of revenue	490,349	395,349	899,418	723,260
Subscription and services-based revenue
Revenue:
Revenue	216,491	111,670	405,693	188,885
Revenue	251,383	134,332	470,240	231,386
Cost of revenue:
Cost of revenue	60,119	39,784	120,642	70,152
Hardware revenue
Revenue:
Revenue	22,260	18,362	40,472	32,779
Cost of revenue:
Cost of revenue	33,268	25,536	60,209	45,238
Bitcoin revenue
Revenue:
Revenue	125,085	37,016	190,613	71,111
Cost of revenue:
Cost of revenue	$ 122,938	$ 36,596	$ 187,634	$ 70,468

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (6,740)	$ (5,906)	$ (44,891)	$ (29,892)
Net foreign currency translation adjustments	261	(2,944)	527	(2,395)
Net unrealized gain (loss) on revaluation of intercompany loans	0	(458)	75	207
Net unrealized gain (loss) on marketable debt securities, net of tax	2,237	240	4,525	(950)
Total comprehensive loss	$ (4,242)	$ (9,068)	$ (39,764)	$ (33,030)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss	$ (44,891)	$ (29,892)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	37,754	22,488
Non-cash interest and other expense	16,802	11,855
Share-based compensation	140,554	98,943
Replacement stock awards issued in connection with acquisition	0	757
Loss on revaluation of equity investment	18,929	0
Amortization of operating lease right-of-use assets and accretion of operating lease liabilities	14,354
Recovery of common stock in connection with indemnification settlement agreement	(789)	(2,745)
Transaction, loan and advance losses	62,105	40,007
Change in deferred income taxes	(2,229)	(688)
Changes in operating assets and liabilities:
Settlements receivable	(1,148,376)	(191,987)
Customer funds	(125,042)	(105,813)
Purchase of loans held for sale	(1,035,500)	(734,251)
Sales and principal payments of loans held for sale	975,823	716,950
Customers payable	1,052,867	267,746
Settlements payable	236,515	25,828
Charge-offs to accrued transaction losses	(36,050)	(26,030)
Other assets and liabilities	3,010	(22,136)
Net cash provided by operating activities	165,836	71,032
Cash flows from investing activities:
Purchase of marketable debt securities	(354,908)	(165,024)
Proceeds from maturities of marketable debt securities	220,229	79,273
Proceeds from sale of marketable debt securities	116,522	56,259
Purchase of marketable debt securities from customer funds	(88,064)	0
Proceeds from maturities of marketable debt securities from customer funds	63,000	0
Purchase of property and equipment	(30,162)	(23,143)
Payments for other investments	(2,000)	0
Purchase of intangible assets	0	(1,584)
Business combinations, net of cash acquired	(20,372)	(111,828)
Net cash used in investing activities	(95,755)	(166,047)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net	0	855,663
Purchase of convertible senior note hedges	0	(172,586)
Proceeds from issuance of warrants	0	112,125
Payment of deferred purchase consideration	(95)	(640)
Principal payments on finance lease obligation	(2,568)	(1,375)
Proceeds from the exercise of stock options, net	66,921	67,199
Payments for tax withholding related to vesting of restricted stock units	(106,663)	(68,575)
Net cash provided by (used in) financing activities	(42,405)	791,811
Effect of foreign exchange rate on cash and cash equivalents	2,340	(3,505)
Net increase in cash, cash equivalents and restricted cash	30,016	693,291
Cash, cash equivalents and restricted cash, beginning of period	632,847	735,081
Cash, cash equivalents and restricted cash, end of period	$ 662,863	$ 1,428,372

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Class A and B common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2017		395,194,075
Beginning balance at Dec. 31, 2017	$ 786,333	$ 0	$ 1,630,386	$ (1,318)	$ (842,735)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(23,986)				(23,986)
Shares issued in connection with:
Exercise of stock options (in shares)		4,213,775
Exercise of stock options	31,354		31,354
Vesting of early exercised stock options and other	136		136
Vesting of restricted stock units (in shares)		1,625,534
Change in other comprehensive loss	24			24
Share-based compensation	48,356		48,356
Tax withholding related to vesting of restricted stock units (in shares)		(649,305)
Tax withholding related to vesting of restricted stock units	(27,651)		(27,651)
Ending balance (in shares) at Mar. 31, 2018		400,384,079
Ending balance at Mar. 31, 2018	809,980	$ 0	1,682,581	(1,294)	(871,307)
Beginning balance (in shares) at Dec. 31, 2017		395,194,075
Beginning balance at Dec. 31, 2017	786,333	$ 0	1,630,386	(1,318)	(842,735)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(29,892)
Ending balance (in shares) at Jun. 30, 2018		407,881,823
Ending balance at Jun. 30, 2018	1,081,629	$ 0	1,963,298	(4,456)	(877,213)
Beginning balance (in shares) at Mar. 31, 2018		400,384,079
Beginning balance at Mar. 31, 2018	809,980	$ 0	1,682,581	(1,294)	(871,307)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(5,906)				(5,906)
Shares issued in connection with:
Exercise of stock options (in shares)		3,246,683
Exercise of stock options	23,267		23,267
Vesting of early exercised stock options and other	19		19
Purchases under employee stock purchase plan (in shares)		450,236
Purchases under employee stock purchase plan	12,578		12,578
Vesting of restricted stock units (in shares)		2,385,704
Issuance of common stock in connection with business combination (in shares)		2,658,139
Issuance of common stock in connection with business combination	140,154		140,154
Change in other comprehensive loss	(3,162)			(3,162)
Share-based compensation	54,810		54,810
Tax withholding related to vesting of restricted stock units (in shares)		(773,120)
Tax withholding related to vesting of restricted stock units	(40,924)		(40,924)
Conversion feature of convertible senior notes, due 2023, net of allocated costs	154,019		154,019
Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2023	(172,586)		(172,586)
Sale of warrants in conjunction with issuance of convertible senior notes, due 2023	112,125		112,125
Recovery of common stock in connection with indemnification settlement agreement (in shares)		(469,898)
Recovery of common stock in connection with indemnification settlement agreement	(2,745)		(2,745)
Ending balance (in shares) at Jun. 30, 2018		407,881,823
Ending balance at Jun. 30, 2018	1,081,629	$ 0	1,963,298	(4,456)	(877,213)
Beginning balance (in shares) at Dec. 31, 2018		417,048,006
Beginning balance at Dec. 31, 2018	1,120,501	$ 0	2,012,328	(6,053)	(885,774)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(38,151)				(38,151)
Shares issued in connection with:
Exercise of stock options (in shares)		3,588,052
Exercise of stock options	$ 25,328		25,328
Vesting of early exercised stock options and other (in shares)	425
Vesting of early exercised stock options and other	$ 36		36
Vesting of restricted stock units (in shares)		1,994,156
Change in other comprehensive loss	2,629			2,629
Share-based compensation	62,835		62,835
Tax withholding related to vesting of restricted stock units (in shares)		(741,324)
Tax withholding related to vesting of restricted stock units	(50,801)		(50,801)
Issuance of common stock in conjunction with the conversion of senior notes, due 2022 (in shares)		43
Issuance of common stock in conjunction with the conversion of senior notes, due 2022	1		1
Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022 (in shares)		(250,614)
Recovery of common stock in connection with indemnification settlement agreement (in shares)		(14,798)
Recovery of common stock in connection with indemnification settlement agreement	(789)		(789)
Ending balance (in shares) at Mar. 31, 2019		421,623,946
Ending balance at Mar. 31, 2019	1,121,589	$ 0	2,048,938	(3,424)	(923,925)
Beginning balance (in shares) at Dec. 31, 2018		417,048,006
Beginning balance at Dec. 31, 2018	1,120,501	$ 0	2,012,328	(6,053)	(885,774)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (44,891)
Shares issued in connection with:
Exercise of stock options (in shares)	6,259,582
Ending balance (in shares) at Jun. 30, 2019		426,217,993
Ending balance at Jun. 30, 2019	$ 1,184,472	$ 0	2,116,063	(926)	(930,665)
Beginning balance (in shares) at Mar. 31, 2019		421,623,946
Beginning balance at Mar. 31, 2019	1,121,589	$ 0	2,048,938	(3,424)	(923,925)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(6,740)				(6,740)
Shares issued in connection with:
Exercise of stock options (in shares)		2,671,530
Exercise of stock options	22,651		22,651
Purchases under employee stock purchase plan (in shares)		360,328
Purchases under employee stock purchase plan	18,942		18,942
Vesting of restricted stock units (in shares)		2,339,193
Change in other comprehensive loss	2,498			2,498
Share-based compensation	81,392		81,392
Tax withholding related to vesting of restricted stock units (in shares)		(777,006)
Tax withholding related to vesting of restricted stock units	(55,862)		(55,862)
Issuance of common stock in conjunction with the conversion of senior notes, due 2022 (in shares)		86
Issuance of common stock in conjunction with the conversion of senior notes, due 2022	2		2
Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022 (in shares)		(84)
Ending balance (in shares) at Jun. 30, 2019		426,217,993
Ending balance at Jun. 30, 2019	$ 1,184,472	$ 0	$ 2,116,063	$ (926)	$ (930,665)

DESCRIPTION OF BUSINESS AND SUM

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2019
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 empower businesses, sellers and individuals to participate in the economy. Square enables sellers to accept card payments and also provides reporting and analytics, and next-day settlement. 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. Cash App is an easy way to send, spend, and store money, and Caviar is a food-ordering service. In July 2019, the Company entered into a definitive agreement to sell the Caviar business. Square was founded in 2009 and is headquartered in San Francisco, with offices in the United States, Canada, Japan, Australia, Ireland, and the UK. Basis of Presentation The accompanying interim condensed consolidated financial statements of the Company are unaudited. These interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and the applicable rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The December 31, 2018 condensed consolidated balance sheet was derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The accompanying unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments of a normal recurring nature considered necessary to state fairly the Company's consolidated financial position, results of operations, comprehensive income (loss), and cash flows for the interim periods. All intercompany transactions and balances have been eliminated in consolidation. The interim results for the three and six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 , or for any other future annual or interim period. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Quantitative and Qualitative Disclosures About Market Risk,” and the Consolidated Financial Statements and notes thereto included in Items 7, 7A, and 8, respectively, in the Company's Annual Report on Form 10-K for the year ended December 31, 2018 . 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, operating and financing lease right-of-use assets and related liabilities, and share-based compensation. Concentration of Credit Risk For the three and six months ended June 30, 2019 and 2018 , the Company had no customer that accounted for greater than 10% of total net revenue. The Company had three third-party payment processors that represented approximately 55% , 35% , and 7% of settlements receivable as of June 30, 2019 . The same three parties represented approximately 45% , 33% , and 9% of settlements receivable as of December 31, 2018 . 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. New Accounting Policies The Company adopted Accounting Standards Codification (ASC) 842, Leases on January 1, 2019, and elected the optional transition method to apply the transition provisions from the effective date of adoption, which requires the Company to report the cumulative effect of the adoption of the standard on the date of adoption with no changes to the prior period balances. Pursuant to the practical expedients, the Company has elected not to reassess: (i) whether expired or existing contracts are or contain leases, (ii) the lease classification for any expired or existing leases, or, (iii) initial direct costs for any existing leases. Additionally, the Company has lease agreements with lease and non-lease components, which are accounted for separately. The Company recognized $112.0 million of operating right-of-use lease assets and $135.6 million of operating lease liabilities on its consolidated balance sheet upon adoption of this standard. Additionally, the Company derecognized $149 million related to the build-to-suit asset and liability upon adoption of this standard because the Company is no longer deemed to be the owner of the related asset under construction under the new standard. Refer to Note 17 for further detail. Except for the adoption of ASC 842, there have been no material changes to the Company’s accounting policies during the six months ended June 30, 2019 , as compared to the accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 . Recent Accounting Pronouncements Recently issued accounting pronouncements not yet adopted In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments - Credit Losses , 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’s preliminary conclusion is that the new guidance will not have a material impact on its consolidated financial statements and related disclosures. The Company will continue to monitor this initial evaluation through the adoption date and therefore this preliminary conclusion may change. 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 which it performs as of December 31. 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 does not expect the adoption of this guidance to have a material impact on the consolidated financial statements and related disclosures.

REVENUE

REVENUE	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
REVENUE	REVENUE The following table presents the Company's revenue disaggregated by revenue source (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenue from Contracts with Customers: Transaction-based revenue $ 775,510 $ 625,228 $ 1,432,272 $ 1,148,265 Subscription and services-based revenue 216,491 111,670 405,693 188,885 Hardware revenue 22,260 18,362 40,472 32,779 Bitcoin revenue $ 125,085 $ 37,016 $ 190,613 $ 71,111 Revenue from other sources: Subscription and services-based revenue $ 34,892 $ 22,662 $ 64,547 $ 42,501 The deferred revenue balances were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Deferred revenue, beginning of the period $ 42,160 $ 3,353 $ 36,451 $ 5,893 Less: cumulative impact of the adoption of ASC 606 — — — (4,303 ) Deferred revenue, beginning of the period, as adjusted 42,160 3,353 36,451 1,590 Deferred revenue, end of the period 44,812 27,155 44,812 27,155 Deferred revenue arising from business combination — 22,800 — 22,800 Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period $ 14,889 $ 1,975 $ 21,786 $ 1,095

INVESTMENTS

INVESTMENTS	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS The Company's short-term and long-term investments as of June 30, 2019 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 125,614 $ 230 $ (5 ) $ 125,839 Corporate bonds 95,901 220 (72 ) 96,049 Commercial paper 3,973 — — 3,973 Municipal securities 15,947 78 (4 ) 16,021 U.S. government securities 314,603 617 (47 ) 315,173 Non-U.S. government securities 15,175 21 (45 ) 15,151 Total $ 571,213 $ 1,166 $ (173 ) $ 572,206 Long-term debt securities: U.S. agency securities $ 81,861 $ 400 $ (84 ) $ 82,177 Corporate bonds 196,687 805 (97 ) 197,395 Municipal securities 14,591 137 (16 ) 14,712 U.S. government securities 156,706 861 (149 ) 157,418 Non-U.S. government securities 9,081 54 (10 ) 9,125 Total $ 458,926 $ 2,257 $ (356 ) $ 460,827 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 debt 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 debt 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 For the periods presented, gains or losses realized on the sale of investments were not material. Investments are reviewed periodically to identify possible other-than-temporary impairments. As the Company has the ability and intent to hold these investments with unrealized losses for a reasonable period of time sufficient for the recovery of fair value, which may be maturity, the Company does not consider these investments to be other-than-temporarily impaired for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's short-term and long-term investments as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 571,213 $ 572,206 Due in one to five years 458,926 460,827 Total $ 1,030,139 $ 1,033,033 The following table presents the assets underlying customer funds (in thousands): June 30, December 31, Cash $ 307,848 $ 158,697 Cash Equivalents: Money market funds 163 18 U.S. agency securities 23,112 39,991 U.S. government securities 27,974 35,349 Short-term debt securities: U.S. agency securities 10,867 27,291 U.S. government securities 114,981 72,671 Total $ 484,945 $ 334,017 The Company's investments within customer funds as of June 30, 2019 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 10,868 $ 1 $ (2 ) $ 10,867 U.S. government securities 114,910 81 (10 ) 114,981 Total $ 125,778 $ 82 $ (12 ) $ 125,848 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 For the periods presented, gains or losses realized on the sale of investments were not material. Investments are reviewed periodically to identify possible other-than-temporary impairments. As the Company has the ability and intent to hold these investments with unrealized losses for a reasonable period of time sufficient for the recovery of fair value, which may be maturity, the Company does not consider these investments to be other-than-temporarily impaired for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's investments within customer funds as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 125,778 $ 125,848 Total $ 125,778 $ 125,848

CUSTOMER FUNDS

CUSTOMER FUNDS	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
CUSTOMER FUNDS	INVESTMENTS The Company's short-term and long-term investments as of June 30, 2019 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 125,614 $ 230 $ (5 ) $ 125,839 Corporate bonds 95,901 220 (72 ) 96,049 Commercial paper 3,973 — — 3,973 Municipal securities 15,947 78 (4 ) 16,021 U.S. government securities 314,603 617 (47 ) 315,173 Non-U.S. government securities 15,175 21 (45 ) 15,151 Total $ 571,213 $ 1,166 $ (173 ) $ 572,206 Long-term debt securities: U.S. agency securities $ 81,861 $ 400 $ (84 ) $ 82,177 Corporate bonds 196,687 805 (97 ) 197,395 Municipal securities 14,591 137 (16 ) 14,712 U.S. government securities 156,706 861 (149 ) 157,418 Non-U.S. government securities 9,081 54 (10 ) 9,125 Total $ 458,926 $ 2,257 $ (356 ) $ 460,827 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 debt 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 debt 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 For the periods presented, gains or losses realized on the sale of investments were not material. Investments are reviewed periodically to identify possible other-than-temporary impairments. As the Company has the ability and intent to hold these investments with unrealized losses for a reasonable period of time sufficient for the recovery of fair value, which may be maturity, the Company does not consider these investments to be other-than-temporarily impaired for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's short-term and long-term investments as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 571,213 $ 572,206 Due in one to five years 458,926 460,827 Total $ 1,030,139 $ 1,033,033 The following table presents the assets underlying customer funds (in thousands): June 30, December 31, Cash $ 307,848 $ 158,697 Cash Equivalents: Money market funds 163 18 U.S. agency securities 23,112 39,991 U.S. government securities 27,974 35,349 Short-term debt securities: U.S. agency securities 10,867 27,291 U.S. government securities 114,981 72,671 Total $ 484,945 $ 334,017 The Company's investments within customer funds as of June 30, 2019 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 10,868 $ 1 $ (2 ) $ 10,867 U.S. government securities 114,910 81 (10 ) 114,981 Total $ 125,778 $ 82 $ (12 ) $ 125,848 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 For the periods presented, gains or losses realized on the sale of investments were not material. Investments are reviewed periodically to identify possible other-than-temporary impairments. As the Company has the ability and intent to hold these investments with unrealized losses for a reasonable period of time sufficient for the recovery of fair value, which may be maturity, the Company does not consider these investments to be other-than-temporarily impaired for any of the periods presented. The amortized cost of investments classified as cash equivalents approximated the fair value due to the short term nature of the investments. The contractual maturities of the Company's investments within customer funds as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 125,778 $ 125,848 Total $ 125,778 $ 125,848

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	6 Months Ended
	Jun. 30, 2019
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 marketable 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): June 30, 2019 December 31, 2018 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash Equivalents: Money market funds $ 272,313 $ — $ — $ 218,109 $ — $ — U.S. agency securities — 102,904 — — 46,423 — Commercial paper — — — — — — Time deposits 10,081 — — — — — U.S. government securities 39,663 — — — — — Municipal securities — — — 86,239 — — Non-U.S. government securities — — — — 23,981 — Customer funds: Money market funds 163 — — 18 — — U.S. agency securities — 33,978 — — 67,282 — U.S. government securities 142,956 — — 108,020 — — Short-term debt securities: U.S. agency securities — 125,839 — — 80,122 — Corporate bonds — 96,049 — — 109,519 — Commercial paper — 3,973 — — — — Municipal securities — 16,021 — — 27,832 — U.S. government securities 315,173 — — 292,267 — — Non-U.S. government securities — 15,151 — — 31,251 — Long-term debt securities: U.S. agency securities — 82,177 — — 114,560 — Corporate bonds — 197,395 — — 159,252 — Municipal securities — 14,712 — — 28,594 — U.S. government securities 157,418 — — 154,124 — — Non-U.S. government securities — 9,125 — — 8,150 — Other: Marketable equity investment 26,413 — — 45,342 — — Total $ 964,180 $ 697,324 $ — $ 904,119 $ 696,966 $ — The carrying amounts of certain financial instruments, including settlements receivable, accounts payable, customers payable, accrued expenses 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): June 30, 2019 December 31, 2018 Carrying Value Fair Value (Level 2) Carrying Value Fair Value (Level 2) 2023 Notes $ 733,366 $ 1,032,318 $ 718,522 $ 901,468 2022 Notes 185,660 672,074 181,173 515,693 Total $ 919,026 $ 1,704,392 $ 899,695 $ 1,417,161 The estimated fair value and carrying value of loans held for sale is as follows (in thousands): June 30, 2019 December 31, 2018 Carrying Value Fair Value (Level 3) Carrying Value Fair Value (Level 3) Loans held for sale $ 136,511 $ 143,023 $ 89,974 $ 93,064 Total $ 136,511 $ 143,023 $ 89,974 $ 93,064 For the three and six months ended June 30, 2019 , the Company recorded a charge for the excess of amortized cost over fair value of the loans of $6.4 million and $13.1 million , respectively. For the three and six months ended June 30, 2018 , the Company recorded a charge for the excess of amortized cost over fair value of the loans of $3.2 million and $5.7 million , respectively. If applicable, the Company will recognize transfers into and out of levels within the fair value hierarchy at the end of the reporting period in which the actual event or change in circumstance occurs. During the three and six months ended June 30, 2019 and 2018 , 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	6 Months Ended
	Jun. 30, 2019
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): June 30, December 31, Leasehold improvements $ 105,411 $ 107,611 Computer equipment 85,930 80,093 Capitalized software 70,667 58,908 Office furniture and equipment 21,531 20,699 283,539 267,311 Less: Accumulated depreciation and amortization (152,792 ) (124,909 ) Property and equipment, net $ 130,747 $ 142,402 Depreciation and amortization expense on property and equipment was $14.8 million and $30.3 million for the three and six months ended June 30, 2019 , respectively. Depreciation and amortization expense on property and equipment was $9.3 million and $17.5 million for the three and six months ended June 30, 2018 , respectively.

ACQUISITIONS

ACQUISITIONS	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Weebly, Inc. On May 31, 2018 , the Company acquired 100% of the outstanding shares of Weebly, Inc., a technology company that offers customers website hosting and domain name registration solutions. The acquisition of Weebly enabled 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) $ 46,978 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) (37,509 ) Total identifiable net assets acquired 79,330 Goodwill 193,209 Total $ 272,539 The Company had 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 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 $3.7 million and $4.7 million , respectively. There was no impact to the consolidated statements of operations as result of these adjustments. As of June 30, 2019 , $19.4 million of cash and 363,266 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 spent an aggregate of $20.4 million , net of cash acquired, in connection with other immaterial acquisitions during the six months ended June 30, 2019, which resulted in the recognition of additional intangible assets and goodwill. Pro forma financial information has not been presented for any of our acquisitions as the impact to our consolidated financial statements was not material.

GOODWILL

GOODWILL	6 Months Ended
	Jun. 30, 2019
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, 2018 $ 261,705 Acquisitions 10,832 Other adjustments (2,376 ) Balance at June 30, 2019 $ 270,161 The Company performs a goodwill impairment test annually on December 31 and more frequently if events and circumstances indicate that the asset might be impaired. For the periods presented, the Company had recorded no

ACQUIRED INTANGIBLE ASSETS

ACQUIRED INTANGIBLE ASSETS	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
ACQUIRED INTANGIBLE ASSETS	ACQUIRED INTANGIBLE ASSETS During the three and six months ended June 30, 2019 , 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 June 30, 2019 Cost Accumulated Amortization Net Technology assets 57,484 (31,515 ) 25,969 Customer assets 57,109 (10,656 ) 46,453 Trade name 11,300 (3,060 ) 8,240 Other 5,299 (1,745 ) 3,554 Total $ 131,192 $ (46,976 ) $ 84,216 Balance at December 31, 2018 Cost Accumulated Amortization Net 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 2,246 (1,395 ) 851 Total $ 116,633 $ (39,531 ) $ 77,102 All intangible assets are amortized over their estimated useful lives. The weighted average amortization periods for acquired technology, customer intangible assets, and acquired trade name are approximately 5 years , 11 years and 4 years , respectively. The changes to the carrying value of intangible assets were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Acquired intangible assets, net, beginning of the period $ 79,697 $ 14,138 $ 77,102 $ 14,334 Acquisitions 8,477 74,192 14,559 75,871 Amortization expense 3,958 2,816 7,445 4,691 Acquired intangible assets, net, end of the period $ 84,216 $ 85,514 $ 84,216 $ 85,514 The total estimated future amortization expense of these intangible assets as of June 30, 2019 is as follows (in thousands): 2019 (remaining 6 months) $ 8,216 2020 14,306 2021 13,109 2022 11,179 2023 9,649 Thereafter 27,757 Total $ 84,216

OTHER CONSOLIDATED BALANCE SHEE

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT)	6 Months Ended
	Jun. 30, 2019
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): June 30, December 31, Inventory, net $ 29,354 $ 28,627 Processing costs receivable 61,116 46,102 Prepaid expenses 18,697 21,782 Accounts receivable, net 32,157 22,393 Other 39,036 46,062 Total $ 180,360 $ 164,966 Accrued Expenses The following table presents the detail of accrued expenses (in thousands): June 30, December 31, Accrued facilities expenses $ 16,868 $ 13,040 Accrued payroll 12,125 9,612 Accrued advertising and other marketing 21,892 12,201 Processing costs payable 16,730 12,683 Accrued non income tax liabilities 9,131 9,503 Other accrued liabilities 29,605 25,315 Total $ 106,351 $ 82,354 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): June 30, December 31, Accounts payable $ 29,021 $ 36,416 Deferred revenue, current 38,639 31,474 Square Capital payable (i) 16,668 6,092 Square Payroll payable (ii) 12,394 7,534 Other 15,156 17,637 Total $ 111,878 $ 99,153 (i) Square Capital payable represents unpaid amounts arising from the purchase of loans or loan repayments collected on behalf of third parties. (ii) 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 Non-Current Assets The following table presents the detail of other non-current assets (in thousands): June 30, December 31, Marketable equity investment (i) $ 26,413 $ 45,342 Other 30,754 13,051 Total $ 57,167 $ 58,393 (i) This balance represents the Company's investment in Class B common shares of Eventbrite, Inc. (Eventbrite). The investment is carried at fair value with changes in fair value being recorded on the consolidated statement of operations. During the three and six months ended June 30, 2019 , the Company recorded a loss of $4.8 million and $18.9 million , respectively, to other expense (income), net on the consolidated statements of operations arising from revaluation of this investment. Other Non-Current Liabilities The following table presents the detail of other non-current liabilities (in thousands): June 30, December 31, Statutory liabilities (i) $ 48,516 $ 54,748 Deferred rent, non-current (ii) — 23,003 Deferred revenue, non-current 6,173 4,977 Other 12,960 10,558 Total $ 67,649 $ 93,286 (i) 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. (ii) The adoption of ASC 842 on January 1, 2019 resulted in the reclassification of deferred rent as an offset to right-of-use lease assets.

OTHER CONSOLIDATED BALANCE SH_2

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT)	6 Months Ended
	Jun. 30, 2019
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): June 30, December 31, Inventory, net $ 29,354 $ 28,627 Processing costs receivable 61,116 46,102 Prepaid expenses 18,697 21,782 Accounts receivable, net 32,157 22,393 Other 39,036 46,062 Total $ 180,360 $ 164,966 Accrued Expenses The following table presents the detail of accrued expenses (in thousands): June 30, December 31, Accrued facilities expenses $ 16,868 $ 13,040 Accrued payroll 12,125 9,612 Accrued advertising and other marketing 21,892 12,201 Processing costs payable 16,730 12,683 Accrued non income tax liabilities 9,131 9,503 Other accrued liabilities 29,605 25,315 Total $ 106,351 $ 82,354 Other Current Liabilities The following table presents the detail of other current liabilities (in thousands): June 30, December 31, Accounts payable $ 29,021 $ 36,416 Deferred revenue, current 38,639 31,474 Square Capital payable (i) 16,668 6,092 Square Payroll payable (ii) 12,394 7,534 Other 15,156 17,637 Total $ 111,878 $ 99,153 (i) Square Capital payable represents unpaid amounts arising from the purchase of loans or loan repayments collected on behalf of third parties. (ii) 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 Non-Current Assets The following table presents the detail of other non-current assets (in thousands): June 30, December 31, Marketable equity investment (i) $ 26,413 $ 45,342 Other 30,754 13,051 Total $ 57,167 $ 58,393 (i) This balance represents the Company's investment in Class B common shares of Eventbrite, Inc. (Eventbrite). The investment is carried at fair value with changes in fair value being recorded on the consolidated statement of operations. During the three and six months ended June 30, 2019 , the Company recorded a loss of $4.8 million and $18.9 million , respectively, to other expense (income), net on the consolidated statements of operations arising from revaluation of this investment. Other Non-Current Liabilities The following table presents the detail of other non-current liabilities (in thousands): June 30, December 31, Statutory liabilities (i) $ 48,516 $ 54,748 Deferred rent, non-current (ii) — 23,003 Deferred revenue, non-current 6,173 4,977 Other 12,960 10,558 Total $ 67,649 $ 93,286 (i) 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. (ii) The adoption of ASC 842 on January 1, 2019 resulted in the reclassification of deferred rent as an offset to right-of-use lease assets.

INDEBTEDNESS

INDEBTEDNESS	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
INDEBTEDNESS	INDEBTEDNESS Revolving Credit Facility In November 2015 , the Company entered into a revolving credit agreement with certain lenders, which extinguished the prior revolving credit agreement and provided for a $375.0 million revolving secured credit facility maturing in November 2020 . This revolving credit agreement is secured by certain tangible and intangible assets. Loans under the credit facility bear interest at the Company’s option of (i) a base rate based on the highest of the prime rate, the federal funds rate plus 0.50% , and an adjusted LIBOR rate for a one-month interest period, in each case plus a margin ranging from 0.00% to 1.00% , or (ii) an adjusted LIBOR rate plus a margin ranging from 1.00% to 2.00% . This margin is determined based on the Company’s total leverage ratio for the preceding four fiscal quarters. The Company is obligated to pay other customary fees for a credit facility of this size and type including an annual administrative agent fee of $0.1 million and an unused commitment fee of 0.15% . To date no funds have been drawn under the credit facility, with $375.0 million remaining available. The Company paid $0.1 million and $0.3 million in unused commitment fees during both the three and six months ended June 30, 2019 and 2018 , respectively. As of June 30, 2019 , 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. The Company's current policy is to settle 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. The circumstances required to allow the holders to convert their 2023 Notes were not met during the six months ended June 30, 2019. 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 June 30, 2019 . In 2018, certain holders of the 2022 Notes converted an aggregate principal amount of $228.3 million of their Notes. The Company settled the conversions through a combination of $219.4 million in cash and issuance of 7.3 million shares of the Company's Class A common stock. Conversions in the six months ended June 30, 2019 were not material. The Company 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 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 as of December 31, 2018, 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 June 30, 2019 2023 Notes $ 862,500 $ (124,525 ) $ (4,609 ) $ 733,366 2022 Notes 211,728 (23,531 ) (2,537 ) 185,660 Total $ 1,074,228 $ (148,056 ) $ (7,146 ) $ 919,026 December 31, 2018 2023 Notes $ 862,500 $ (138,924 ) $ (5,054 ) $ 718,522 2022 Notes 211,728 (27,569 ) (2,986 ) 181,173 $ 1,074,228 $ (166,493 ) $ (8,040 ) $ 899,695 The net carrying amount of the equity component of the 2023 Notes and 2022 Notes were as follows (in thousands): Amount allocated to conversion option Less: allocated issuance costs Equity component, net June 30, 2019 and 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 The Company recognized interest expense on the Notes as follows (in thousands, except for percentages): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Contractual interest expense $ 1,277 $ 850 $ 2,554 $ 1,263 Amortization of debt discount and issuance costs 9,725 6,830 19,333 11,223 Total $ 11,002 $ 7,680 $ 21,887 $ 12,486 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 condensed consolidated balance sheets. In 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 in 2018. During the six months ended June 30, 2019, the Company received an additional 0.3 million shares of the Company's Class A common stock.

ACCRUED TRANSACTION LOSSES

ACCRUED TRANSACTION LOSSES	6 Months Ended
	Jun. 30, 2019
Product Warranties Disclosures [Abstract]
ACCRUED TRANSACTION LOSSES	ACCRUED TRANSACTION LOSSES The Company is exposed to transaction losses due to chargebacks as a result of fraud or uncollectibility. The following table summarizes the activities of the Company’s reserve for transaction losses (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Accrued transaction losses, beginning of the period $ 36,047 $ 28,309 $ 33,682 $ 26,893 Provision for transaction losses 22,190 14,087 41,998 28,345 Charge-offs to accrued transaction losses (18,607 ) (13,189 ) (36,050 ) (26,031 ) Accrued transaction losses, end of the period $ 39,630 $ 29,207 $ 39,630 $ 29,207

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company recorded an income tax benefit of $0.5 million and $0.3 million for the three and six months ended June 30, 2019 , respectively, compared to income tax expense of $0.6 million and $0.8 million for the three and six months ended June 30, 2018 , respectively. The income tax benefit recorded for the three and six months ended June 30, 2019 was primarily due to state and foreign income tax expense offset by a change in the valuation allowance on the Company's deferred tax assets. The Company’s effective tax rate was 6.6% and 0.8% for the three and six months ended June 30, 2019 , respectively, compared to an effective tax rate of (11.4)% and (2.7)% for the three and six months ended June 30, 2018 , respectively. The difference between the effective tax rate and the federal statutory tax rate for the three and six months ended June 30, 2019 and June 30, 2018 primarily relates to losses in the U.S. and certain foreign jurisdictions for which no benefit can be taken. The Company’s effective tax rate may be subject to fluctuation during the year as new information is obtained, which may affect the assumptions used to estimate the annual effective tax rate, including factors such as the mix of forecasted pre-tax earnings in the various jurisdictions in which the Company operates, valuation allowances against deferred tax assets, the recognition and de-recognition of tax benefits related to uncertain tax positions, and changes in or the interpretation of tax laws in jurisdictions where the Company conducts business. As of June 30, 2019 , the Company retains a full valuation allowance on its deferred tax assets in the U.S. and certain foreign jurisdictions. The realization of the Company’s deferred tax assets depends primarily on its ability to generate taxable income in future periods. The amount of deferred tax assets considered realizable in future periods may change as management continues to reassess the underlying factors it uses in estimating future taxable income. The tax provision for the three and six months ended June 30, 2019 and June 30, 2018 , was calculated on a jurisdictional basis. The Company estimated the foreign income tax provision using the effective income tax rate expected to be applicable for the full year.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS’ EQUITY Common Stock The Company has authorized the issuance of Class A common stock and Class B common stock. Class A common stock and Class B common stock are referred to as "common stock" throughout these Notes to the Condensed Consolidated Financial Statements, unless otherwise noted. As of June 30, 2019 , 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 June 30, 2019 , there were 341,709,651 shares of Class A common stock and 84,508,342 shares of Class B common stock outstanding. Options and awards granted following the Company's initial public offering are related to underlying Class A common stock. Additionally, holders of Class B common stock are able to convert such shares into Class A common stock. Warrants In conjunction with the 2023 Notes offering, the Company sold the 2023 warrants whereby the 2018 Counterparties have the option to purchase a total of approximately 11.1 million shares of the Company’s Class A common stock at a price of $109.26 per share. The Company received $112.1 million in cash proceeds from the sale of the 2023 warrants. See Note 12 , Indebtedness , for more details on this transaction. In conjunction with the 2022 Notes offering, the Company sold warrants whereby the 2017 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 associated with the 2022 and 2023 Notes offering were exercised as of June 30, 2019. Stock Plans The Company maintains two share-based employee compensation plans: the 2009 Stock Plan (2009 Plan) and the 2015 Equity Incentive Plan (2015 Plan). The 2015 Plan serves as the successor to the 2009 Plan. The 2015 Plan became effective as of November 17, 2015. Outstanding awards under the 2009 Plan continue to be subject to the terms and conditions of the 2009 Plan. Since November 17, 2015, no additional awards have been nor will be in the future granted under the 2009 Plan. Under the 2015 Plan, shares of the Company's Class A common stock are reserved for the issuance of incentive and nonstatutory stock options, restricted stock awards (RSAs), restricted stock units (RSUs), performance shares, and stock bonuses to qualified employees, directors, and consultants. The awards must be granted at a price per share not less than the fair market value at the date of grant. Initially, 30,000,000 shares were reserved under the 2015 Plan, and any shares subject to options or other similar awards granted under the 2009 Plan that expire, are forfeited, are repurchased by the Company, or otherwise terminate unexercised, will become available under the 2015 Plan. The number of shares available for issuance under the 2015 Plan will be increased on the first day of each fiscal year, in an amount equal to the least of (i) 40,000,000 shares, (ii) 5% of the outstanding shares on the last day of the immediately preceding fiscal year, or (iii) such number of shares determined by the Company’s board of directors or a committee thereof. As of June 30, 2019 , the total number of shares subject to stock options, RSAs and RSUs outstanding under the 2015 Plan was 23,518,561 , and 82,520,758 shares were available for future issuance. As of June 30, 2019 , the total number of shares subject to stock options, RSAs and RSUs outstanding under the 2009 Plan was 22,067,602 . A summary of stock option activity for the six months ended June 30, 2019 is as follows (in thousands, except share and per share data): Number of Stock Options Outstanding Weighted Weighted Aggregate Balance at December 31, 2018 33,152,881 $ 9.52 5.45 $ 1,543,793 Granted 1,184,657 72.15 Exercised (6,259,582 ) 7.66 Forfeited (130,671 ) 11.54 Balance at June 30, 2019 27,947,285 $ 12.59 5.42 $ 1,675,414 Options exercisable as of June 30, 2019 25,358,359 $ 9.12 5.12 $ 1,607,944 Restricted Stock Activity Activity related to RSAs and RSUs during the six months ended June 30, 2019 is set forth below: Number of Weighted Unvested as of December 31, 2018 17,934,728 $ 31.34 Granted 4,625,215 71.99 Vested (3,943,408 ) 27.21 Forfeited (977,657 ) 30.30 Unvested as of June 30, 2019 17,638,878 $ 42.98 Share-Based Compensation The fair value of stock options and employee stock purchase plan rights are estimated on the date of grant using the Black-Scholes-Merton option valuation model. The fair value of RSAs and RSUs is determined by the closing price of the Company’s common stock on each grant date. The fair value of stock options granted was estimated using the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Dividend yield — % — % — % — % Risk-free interest rate 2.37 % 2.92 % 2.48 % 2.92 % Expected volatility 40.48 % 30.87 % 39.52 % 30.87 % Expected term (years) 6.02 6.19 6.05 6.19 The following table summarizes the effects of share-based compensation on the Company's condensed consolidated statements of operations (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Cost of revenue $ 29 $ 30 $ 50 $ 61 Product development 56,144 33,806 98,793 64,288 Sales and marketing 7,833 5,634 14,035 10,595 General and administrative 15,460 12,649 27,676 23,999 Total $ 79,466 $ 52,119 $ 140,554 $ 98,943 The Company recorded $4.7 million and $9.0 million of share-based compensation expense related to the Company's 2015 Employee Stock Purchase Plan during the three and six months ended June 30, 2019 , respectively, compared to $2.0 million and $4.2 million for the three and six months ended June 30, 2018 , which are included in the table above. The Company capitalized $1.9 million and $3.7 million of share-based compensation expense related to capitalized software costs during the three and six months ended June 30, 2019 , respectively, compared to $2.7 million and $4.3 million for the three and six months ended June 30, 2018 , respectively. As of June 30, 2019 , there was $772.0 million of total unrecognized compensation cost related to outstanding awards that are expected to be recognized over a weighted-average period of 2.9 years .

NET LOSS PER SHARE

NET LOSS PER SHARE	6 Months Ended
	Jun. 30, 2019
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 net loss per share is the same as basic net loss per share because the effects of potentially dilutive items were anti-dilutive given the Company’s net loss. The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Net loss $ (6,740 ) $ (5,906 ) $ (44,891 ) $ (29,892 ) Basic shares: Weighted-average common shares outstanding 424,105 403,390 421,983 400,318 Weighted-average unvested shares (800 ) (89 ) (686 ) (694 ) Weighted-average shares used to compute basic net loss per share 423,305 403,301 421,297 399,624 Diluted shares: Weighted-average shares used to compute diluted net loss per share 423,305 403,301 421,297 399,624 Net loss per share: Basic $ (0.02 ) $ (0.01 ) $ (0.11 ) $ (0.07 ) Diluted $ (0.02 ) $ (0.01 ) $ (0.11 ) $ (0.07 ) Additionally, 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): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Stock options and restricted stock units 46,686 62,908 47,256 64,635 Common stock warrants 30,252 23,605 30,252 21,377 Convertible senior notes 20,305 — 20,305 — Unvested shares 800 89 686 694 Employee stock purchase plan 169 170 195 189 Total anti-dilutive securities 98,212 86,772 98,694 86,895

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Operating and Finance Leases The Company’s operating leases are primarily comprised of office facilities, with the most significant leases relating to corporate headquarters in San Francisco and an office in New York. The Company's leases have remaining lease terms of 1 year to 12 years , some of which include options to extend for 5 year terms, or include options to terminate the leases within 1 year . None of the options to extend the leases have been included in the measurement of the right of use asset or the associated lease liability. The Company elects to apply the short-term lease measurement and recognition exemption to its leases where applicable. 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 extend the lease term for two 5 year terms. The lease commencement date is expected to be in November 2019 with total lease payments over the term of approximately $276 million . Under the terms of this lease, the Company is required to make certain payments during the construction stage of the office space, which the Company will record as a prepaid lease asset. Additionally, the Company has finance leases for data center equipment, with remaining lease terms of approximately 2 years . The components of lease expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2019 Operating lease costs $ 7,487 $ 14,177 Sublease income — — Finance lease costs Amortization of right-of-use assets 1,284 2,577 Interest on lease liabilities — — Total lease costs $ 8,771 $ 16,754 For the periods presented, costs associated with short-term leases were not material. Other information related to leases was as follows: June 30, 2019 Weighted Average Remaining Lease Term: Operating leases 4.5 years Finance leases 1.1 years Weighted Average Discount Rate: Operating leases 4 % Finance leases — % Cash flows related to leases were as follows (in thousands): Six Months Ended June 30, 2019 Cash flows from operating activities: Payments for operating lease liabilities $ 16,067 Cash flows from financing activities: Principal payments on finance lease obligation $ 2,568 Supplemental Cash Flow Data: Right-of-use assets obtained in exchange for operating lease obligations $ 21,905 Future minimum lease payments under non-cancelable operating leases (with initial lease terms in excess of one year) and future minimum finance lease payments as of June 30, 2019 are as follows (in thousands): Finance Operating Year: 2019 (remaining 6 months) $ 2,461 $ 13,305 2020 2,446 40,578 2021 — 57,178 2022 — 57,054 2023 — 50,866 Thereafter — 233,739 Total $ 4,907 $ 452,720 Less amount representing interest — 13,072 Less leases executed but not yet commenced — 307,428 Total $ 4,907 $ 132,220 The current portion of the finance lease liability is included within other current liabilities while the non-current portion is included within other non-current liabilities on the condensed consolidated balance sheets. The associated finance lease assets are included in property and equipment, net on the condensed 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, but disagrees with the Tax Collector’s assessment of the Company’s primary business activity. The Company believes its position has merit and intends to vigorously defend its position, including possibly through litigation. 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 in aggregate could be material. The Company is currently unable to estimate the range of possible loss given the uncertainties associated with this matter, including uncertainties about the Tax Collector’s rationale for its position and about the amounts that may ultimately be subject to such taxes. On May 14, 2018, Joshua Woodle, on behalf of a class of couriers who have delivered with Caviar in California, filed a lawsuit in San Francisco County Superior Court against the Company doing business as Caviar, which alleges that Caviar misclassified Mr. Woodle and other similarly situated couriers as independent contractors and, in doing so, violated various provisions of the California Labor Code and California Business and Professions Code. Plaintiffs seek damages and injunctive relief. The Court compelled arbitration of Mr. Woodle’s arbitrable claims on November 5, 2018. On August 24, 2018, Mervyn Cole, on behalf of the State of California and similarly situated couriers who have delivered with Caviar in California filed a lawsuit in Los Angeles County Superior Court against the Company doing business as Caviar. The complaint alleges that Caviar misclassified Mr. Cole and other similarly situated couriers as independent contractors and, in doing so, violated certain provisions of the California Labor Code. The action is being brought as a representative action under the Private Attorneys General Act (“PAGA”). Plaintiffs seek civil penalties and injunctive relief. Given the early stage of these proceedings, it is not yet possible to reliably determine any potential liability that could result from these matters. In addition, from time to time, the Company is involved in various other litigation matters and disputes arising in the ordinary course of business, including similar claims as those referenced above, alleging misclassification of couriers as independent contractors. 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	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
SEGMENT AND GEOGRAPHIC INFORMATION	SEGMENT AND GEOGRAPHICAL INFORMATION Operating segments are defined as components of an enterprise for which discrete financial information is available that is evaluated regularly by the chief operating decision maker (CODM) for purposes of allocating resources and evaluating financial performance. The Company’s CODM is the chief executive officer who reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. As such, the Company’s operations constitute a single operating segment and one reportable segment. Revenue Revenue by geography is based on the billing addresses of the sellers or customers. The following table sets forth revenue by geographic area (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenue United States $ 1,119,039 $ 777,335 $ 2,033,695 $ 1,417,508 International 55,199 37,603 99,902 66,033 Total net revenue $ 1,174,238 $ 814,938 $ 2,133,597 $ 1,483,541 No individual country from the international markets contributed in excess of 10% of total revenue for the three and six months ended June 30, 2019 and 2018 . Long-Lived Assets The following table sets forth long-lived assets by geographic area (in thousands): June 30, December 31, Long-lived assets United States $ 580,939 $ 471,970 International 11,994 9,239 Total long-lived assets $ 592,933 $ 481,209

SUPPLEMENTAL CASH FLOW INFORMAT

SUPPLEMENTAL CASH FLOW INFORMATION	6 Months Ended
	Jun. 30, 2019
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): Six Months Ended June 30, 2019 2018 Supplemental Cash Flow Data: Cash paid for interest $ 2,836 $ 1,108 Cash paid for income taxes 1,717 854 Right-of-use assets obtained in exchange for operating lease obligations 21,905 — Supplemental disclosures of non-cash investing and financing activities: Change in purchases of property and equipment in accounts payable and accrued expenses 14,047 9,708 Unpaid business combination purchase price 8,411 3,995 Fair value of common stock issued related to business combination — (139,396 ) Recovery of common stock in connection with indemnification settlement agreement 789 2,745

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On July 25, 2019, the Company entered into a lease for certain office space located in St Louis, Missouri, from an affiliate of one of the Company’s co-founders and current member of its board of directors, Mr. Jim McKelvey, under an operating lease agreement. The lease commencement date is expected to be in July 2020. The term of the agreement is 15.5 years and the future minimum lease payments for the term of the lease total $42.7 million . On July 31, 2019 , the Company entered into a definitive agreement with DoorDash, Inc. for the sale of the Company’s Caviar business, which offers food ordering and delivery services to customers. The Company is expected to receive $410 million in gross proceeds comprised of a combination of cash and DoorDash, Inc.'s preferred stock, subject to adjustments based on contractual provisions. The transaction is expected to close in 2019 .

DESCRIPTION OF BUSINESS AND S_2

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying interim condensed consolidated financial statements of the Company are unaudited. These interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and the applicable rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The December 31, 2018 condensed consolidated balance sheet was derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The accompanying unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments of a normal recurring nature considered necessary to state fairly the Company's consolidated financial position, results of operations, comprehensive income (loss), and cash flows for the interim periods. All intercompany transactions and balances have been eliminated in consolidation. The interim results for the three and six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 , or for any other future annual or interim period. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Quantitative and Qualitative Disclosures About Market Risk,” and the Consolidated Financial Statements and notes thereto included in Items 7, 7A, and 8, respectively, in the Company's Annual Report on Form 10-K for the year ended December 31, 2018 .
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, operating and financing lease right-of-use assets and related liabilities, and share-based compensation.
Concentration of Credit Risk	Concentration of Credit Risk For the three and six months ended June 30, 2019 and 2018 , the Company had no customer that accounted for greater than 10% of total net revenue. The Company had three third-party payment processors that represented approximately 55% , 35% , and 7% of settlements receivable as of June 30, 2019 . The same three parties represented approximately 45% , 33% , and 9% of settlements receivable as of December 31, 2018 . 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.
New Accounting Policies and Recent Accounting Pronouncements	New Accounting Policies The Company adopted Accounting Standards Codification (ASC) 842, Leases on January 1, 2019, and elected the optional transition method to apply the transition provisions from the effective date of adoption, which requires the Company to report the cumulative effect of the adoption of the standard on the date of adoption with no changes to the prior period balances. Pursuant to the practical expedients, the Company has elected not to reassess: (i) whether expired or existing contracts are or contain leases, (ii) the lease classification for any expired or existing leases, or, (iii) initial direct costs for any existing leases. Additionally, the Company has lease agreements with lease and non-lease components, which are accounted for separately. The Company recognized $112.0 million of operating right-of-use lease assets and $135.6 million of operating lease liabilities on its consolidated balance sheet upon adoption of this standard. Additionally, the Company derecognized $149 million related to the build-to-suit asset and liability upon adoption of this standard because the Company is no longer deemed to be the owner of the related asset under construction under the new standard. Refer to Note 17 for further detail. Except for the adoption of ASC 842, there have been no material changes to the Company’s accounting policies during the six months ended June 30, 2019 , as compared to the accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 . Recent Accounting Pronouncements Recently issued accounting pronouncements not yet adopted In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments - Credit Losses , 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’s preliminary conclusion is that the new guidance will not have a material impact on its consolidated financial statements and related disclosures. The Company will continue to monitor this initial evaluation through the adoption date and therefore this preliminary conclusion may change. 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 which it performs as of December 31. 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 does not expect the adoption of this guidance to have a material impact on the consolidated financial statements and related disclosures.

REVENUE (Tables)

REVENUE (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table presents the Company's revenue disaggregated by revenue source (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenue from Contracts with Customers: Transaction-based revenue $ 775,510 $ 625,228 $ 1,432,272 $ 1,148,265 Subscription and services-based revenue 216,491 111,670 405,693 188,885 Hardware revenue 22,260 18,362 40,472 32,779 Bitcoin revenue $ 125,085 $ 37,016 $ 190,613 $ 71,111 Revenue from other sources: Subscription and services-based revenue $ 34,892 $ 22,662 $ 64,547 $ 42,501
Schedule of Deferred Revenue	The deferred revenue balances were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Deferred revenue, beginning of the period $ 42,160 $ 3,353 $ 36,451 $ 5,893 Less: cumulative impact of the adoption of ASC 606 — — — (4,303 ) Deferred revenue, beginning of the period, as adjusted 42,160 3,353 36,451 1,590 Deferred revenue, end of the period 44,812 27,155 44,812 27,155 Deferred revenue arising from business combination — 22,800 — 22,800 Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period $ 14,889 $ 1,975 $ 21,786 $ 1,095

INVESTMENTS (Tables)

INVESTMENTS (Tables)	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Short-term and Long-term Investments	The Company's short-term and long-term investments as of June 30, 2019 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 125,614 $ 230 $ (5 ) $ 125,839 Corporate bonds 95,901 220 (72 ) 96,049 Commercial paper 3,973 — — 3,973 Municipal securities 15,947 78 (4 ) 16,021 U.S. government securities 314,603 617 (47 ) 315,173 Non-U.S. government securities 15,175 21 (45 ) 15,151 Total $ 571,213 $ 1,166 $ (173 ) $ 572,206 Long-term debt securities: U.S. agency securities $ 81,861 $ 400 $ (84 ) $ 82,177 Corporate bonds 196,687 805 (97 ) 197,395 Municipal securities 14,591 137 (16 ) 14,712 U.S. government securities 156,706 861 (149 ) 157,418 Non-U.S. government securities 9,081 54 (10 ) 9,125 Total $ 458,926 $ 2,257 $ (356 ) $ 460,827 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 debt 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 debt 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
Contractual Maturities of Short-Term and Long-Term Investments	The contractual maturities of the Company's short-term and long-term investments as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 571,213 $ 572,206 Due in one to five years 458,926 460,827 Total $ 1,030,139 $ 1,033,033 The contractual maturities of the Company's investments within customer funds as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 125,778 $ 125,848 Total $ 125,778 $ 125,848

CUSTOMER FUNDS (Tables)

CUSTOMER FUNDS (Tables)	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Assets Underlying Customer Funds	The following table presents the assets underlying customer funds (in thousands): June 30, December 31, Cash $ 307,848 $ 158,697 Cash Equivalents: Money market funds 163 18 U.S. agency securities 23,112 39,991 U.S. government securities 27,974 35,349 Short-term debt securities: U.S. agency securities 10,867 27,291 U.S. government securities 114,981 72,671 Total $ 484,945 $ 334,017
Investments within Customer Funds	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 The Company's investments within customer funds as of June 30, 2019 are as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term debt securities: U.S. agency securities $ 10,868 $ 1 $ (2 ) $ 10,867 U.S. government securities 114,910 81 (10 ) 114,981 Total $ 125,778 $ 82 $ (12 ) $ 125,848
Contractual Maturities of Short-Term and Long-Term Investments within Customer Funds	The contractual maturities of the Company's short-term and long-term investments as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 571,213 $ 572,206 Due in one to five years 458,926 460,827 Total $ 1,030,139 $ 1,033,033 The contractual maturities of the Company's investments within customer funds as of June 30, 2019 are as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 125,778 $ 125,848 Total $ 125,778 $ 125,848

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The Company’s financial assets and liabilities that are measured at fair value on a recurring basis are classified as follows (in thousands): June 30, 2019 December 31, 2018 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash Equivalents: Money market funds $ 272,313 $ — $ — $ 218,109 $ — $ — U.S. agency securities — 102,904 — — 46,423 — Commercial paper — — — — — — Time deposits 10,081 — — — — — U.S. government securities 39,663 — — — — — Municipal securities — — — 86,239 — — Non-U.S. government securities — — — — 23,981 — Customer funds: Money market funds 163 — — 18 — — U.S. agency securities — 33,978 — — 67,282 — U.S. government securities 142,956 — — 108,020 — — Short-term debt securities: U.S. agency securities — 125,839 — — 80,122 — Corporate bonds — 96,049 — — 109,519 — Commercial paper — 3,973 — — — — Municipal securities — 16,021 — — 27,832 — U.S. government securities 315,173 — — 292,267 — — Non-U.S. government securities — 15,151 — — 31,251 — Long-term debt securities: U.S. agency securities — 82,177 — — 114,560 — Corporate bonds — 197,395 — — 159,252 — Municipal securities — 14,712 — — 28,594 — U.S. government securities 157,418 — — 154,124 — — Non-U.S. government securities — 9,125 — — 8,150 — Other: Marketable equity investment 26,413 — — 45,342 — — Total $ 964,180 $ 697,324 $ — $ 904,119 $ 696,966 $ — The estimated fair value and carrying value of loans held for sale is as follows (in thousands): June 30, 2019 December 31, 2018 Carrying Value Fair Value (Level 3) Carrying Value Fair Value (Level 3) Loans held for sale $ 136,511 $ 143,023 $ 89,974 $ 93,064 Total $ 136,511 $ 143,023 $ 89,974 $ 93,064 June 30, 2019 December 31, 2018 Carrying Value Fair Value (Level 2) Carrying Value Fair Value (Level 2) 2023 Notes $ 733,366 $ 1,032,318 $ 718,522 $ 901,468 2022 Notes 185,660 672,074 181,173 515,693 Total $ 919,026 $ 1,704,392 $ 899,695 $ 1,417,161

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	The following is a summary of property and equipment, less accumulated depreciation and amortization (in thousands): June 30, December 31, Leasehold improvements $ 105,411 $ 107,611 Computer equipment 85,930 80,093 Capitalized software 70,667 58,908 Office furniture and equipment 21,531 20,699 283,539 267,311 Less: Accumulated depreciation and amortization (152,792 ) (124,909 ) Property and equipment, net $ 130,747 $ 142,402

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Schedule of Assets Acquired and Liabilities Assumed	The table below summarizes the consideration paid for Weebly and the preliminary assessment of the fair value of the assets acquired and liabilities assumed at the closing date (in thousands, except share data). Consideration: Cash $ 132,432 Stock (2,418,271 shares of Class A common stock) 140,107 $ 272,539 Recognized amounts of identifiable assets acquired and liabilities assumed: Current assets (inclusive of cash acquired of $25,758) $ 46,978 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) (37,509 ) Total identifiable net assets acquired 79,330 Goodwill 193,209 Total $ 272,539

GOODWILL (Tables)

GOODWILL (Tables)	6 Months Ended
	Jun. 30, 2019
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, 2018 $ 261,705 Acquisitions 10,832 Other adjustments (2,376 ) Balance at June 30, 2019 $ 270,161

ACQUIRED INTANGIBLE ASSETS (Tab

ACQUIRED INTANGIBLE ASSETS (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite Lived Intangible Assets	The changes to the carrying value of intangible assets were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Acquired intangible assets, net, beginning of the period $ 79,697 $ 14,138 $ 77,102 $ 14,334 Acquisitions 8,477 74,192 14,559 75,871 Amortization expense 3,958 2,816 7,445 4,691 Acquired intangible assets, net, end of the period $ 84,216 $ 85,514 $ 84,216 $ 85,514 The following table presents the detail of acquired intangible assets as of the periods presented (in thousands): Balance at June 30, 2019 Cost Accumulated Amortization Net Technology assets 57,484 (31,515 ) 25,969 Customer assets 57,109 (10,656 ) 46,453 Trade name 11,300 (3,060 ) 8,240 Other 5,299 (1,745 ) 3,554 Total $ 131,192 $ (46,976 ) $ 84,216 Balance at December 31, 2018 Cost Accumulated Amortization Net 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 2,246 (1,395 ) 851 Total $ 116,633 $ (39,531 ) $ 77,102
Schedule of Future Amortization Expense of Intangible Assets	The total estimated future amortization expense of these intangible assets as of June 30, 2019 is as follows (in thousands): 2019 (remaining 6 months) $ 8,216 2020 14,306 2021 13,109 2022 11,179 2023 9,649 Thereafter 27,757 Total $ 84,216

OTHER CONSOLIDATED BALANCE SH_3

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) (Tables)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Other Current Assets	The following table presents the detail of other current assets (in thousands): June 30, December 31, Inventory, net $ 29,354 $ 28,627 Processing costs receivable 61,116 46,102 Prepaid expenses 18,697 21,782 Accounts receivable, net 32,157 22,393 Other 39,036 46,062 Total $ 180,360 $ 164,966
Schedule of Accrued Expenses	The following table presents the detail of accrued expenses (in thousands): June 30, December 31, Accrued facilities expenses $ 16,868 $ 13,040 Accrued payroll 12,125 9,612 Accrued advertising and other marketing 21,892 12,201 Processing costs payable 16,730 12,683 Accrued non income tax liabilities 9,131 9,503 Other accrued liabilities 29,605 25,315 Total $ 106,351 $ 82,354
Schedule of Other Current Liabilities	The following table presents the detail of other current liabilities (in thousands): June 30, December 31, Accounts payable $ 29,021 $ 36,416 Deferred revenue, current 38,639 31,474 Square Capital payable (i) 16,668 6,092 Square Payroll payable (ii) 12,394 7,534 Other 15,156 17,637 Total $ 111,878 $ 99,153 (i) Square Capital payable represents unpaid amounts arising from the purchase of loans or loan repayments collected on behalf of third parties. (ii) 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)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Other Non-Current Assets	The following table presents the detail of other non-current assets (in thousands): June 30, December 31, Marketable equity investment (i) $ 26,413 $ 45,342 Other 30,754 13,051 Total $ 57,167 $ 58,393 (i) This balance represents the Company's investment in Class B common shares of Eventbrite, Inc. (Eventbrite). The investment is carried at fair value with changes in fair value being recorded on the consolidated statement of operations. During the three and six months ended June 30, 2019 , the Company recorded a loss of $4.8 million and $18.9 million , respectively, to other expense (income), net on the consolidated statements of operations arising from revaluation of this investment.
Schedule of Other Non-Current Liabilities	The following table presents the detail of other non-current liabilities (in thousands): June 30, December 31, Statutory liabilities (i) $ 48,516 $ 54,748 Deferred rent, non-current (ii) — 23,003 Deferred revenue, non-current 6,173 4,977 Other 12,960 10,558 Total $ 67,649 $ 93,286 (i) 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. (ii) The adoption of ASC 842 on January 1, 2019 resulted in the reclassification of deferred rent as an offset to right-of-use lease assets.

INDEBTEDNESS (Tables)

INDEBTEDNESS (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019 2023 Notes $ 862,500 $ (124,525 ) $ (4,609 ) $ 733,366 2022 Notes 211,728 (23,531 ) (2,537 ) 185,660 Total $ 1,074,228 $ (148,056 ) $ (7,146 ) $ 919,026 December 31, 2018 2023 Notes $ 862,500 $ (138,924 ) $ (5,054 ) $ 718,522 2022 Notes 211,728 (27,569 ) (2,986 ) 181,173 $ 1,074,228 $ (166,493 ) $ (8,040 ) $ 899,695 The net carrying amount of the equity component of the 2023 Notes and 2022 Notes were as follows (in thousands): Amount allocated to conversion option Less: allocated issuance costs Equity component, net June 30, 2019 and 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
Interest Expense on Convertible Notes	The Company recognized interest expense on the Notes as follows (in thousands, except for percentages): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Contractual interest expense $ 1,277 $ 850 $ 2,554 $ 1,263 Amortization of debt discount and issuance costs 9,725 6,830 19,333 11,223 Total $ 11,002 $ 7,680 $ 21,887 $ 12,486

ACCRUED TRANSACTION LOSSES (Tab

ACCRUED TRANSACTION LOSSES (Tables)	6 Months Ended
	Jun. 30, 2019
Product Warranties Disclosures [Abstract]
Schedule of Reserve for Transaction Losses	The following table summarizes the activities of the Company’s reserve for transaction losses (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Accrued transaction losses, beginning of the period $ 36,047 $ 28,309 $ 33,682 $ 26,893 Provision for transaction losses 22,190 14,087 41,998 28,345 Charge-offs to accrued transaction losses (18,607 ) (13,189 ) (36,050 ) (26,031 ) Accrued transaction losses, end of the period $ 39,630 $ 29,207 $ 39,630 $ 29,207

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Summary of Stock Option Activity	A summary of stock option activity for the six months ended June 30, 2019 is as follows (in thousands, except share and per share data): Number of Stock Options Outstanding Weighted Weighted Aggregate Balance at December 31, 2018 33,152,881 $ 9.52 5.45 $ 1,543,793 Granted 1,184,657 72.15 Exercised (6,259,582 ) 7.66 Forfeited (130,671 ) 11.54 Balance at June 30, 2019 27,947,285 $ 12.59 5.42 $ 1,675,414 Options exercisable as of June 30, 2019 25,358,359 $ 9.12 5.12 $ 1,607,944
Schedule of Restricted Stock Awards and Restricted Stock Units Activity	Activity related to RSAs and RSUs during the six months ended June 30, 2019 is set forth below: Number of Weighted Unvested as of December 31, 2018 17,934,728 $ 31.34 Granted 4,625,215 71.99 Vested (3,943,408 ) 27.21 Forfeited (977,657 ) 30.30 Unvested as of June 30, 2019 17,638,878 $ 42.98
Schedule of Fair Value Assumptions for Options	The fair value of stock options granted was estimated using the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Dividend yield — % — % — % — % Risk-free interest rate 2.37 % 2.92 % 2.48 % 2.92 % Expected volatility 40.48 % 30.87 % 39.52 % 30.87 % Expected term (years) 6.02 6.19 6.05 6.19
Summary of the Effect of Share-Based Compensation on the Condensed Consolidated Statements of Operations	The following table summarizes the effects of share-based compensation on the Company's condensed consolidated statements of operations (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Cost of revenue $ 29 $ 30 $ 50 $ 61 Product development 56,144 33,806 98,793 64,288 Sales and marketing 7,833 5,634 14,035 10,595 General and administrative 15,460 12,649 27,676 23,999 Total $ 79,466 $ 52,119 $ 140,554 $ 98,943

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2019
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): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Net loss $ (6,740 ) $ (5,906 ) $ (44,891 ) $ (29,892 ) Basic shares: Weighted-average common shares outstanding 424,105 403,390 421,983 400,318 Weighted-average unvested shares (800 ) (89 ) (686 ) (694 ) Weighted-average shares used to compute basic net loss per share 423,305 403,301 421,297 399,624 Diluted shares: Weighted-average shares used to compute diluted net loss per share 423,305 403,301 421,297 399,624 Net loss per share: Basic $ (0.02 ) $ (0.01 ) $ (0.11 ) $ (0.07 ) Diluted $ (0.02 ) $ (0.01 ) $ (0.11 ) $ (0.07 )
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): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Stock options and restricted stock units 46,686 62,908 47,256 64,635 Common stock warrants 30,252 23,605 30,252 21,377 Convertible senior notes 20,305 — 20,305 — Unvested shares 800 89 686 694 Employee stock purchase plan 169 170 195 189 Total anti-dilutive securities 98,212 86,772 98,694 86,895

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Lease Expense Components and Other Information Related to Leases	The components of lease expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2019 Operating lease costs $ 7,487 $ 14,177 Sublease income — — Finance lease costs Amortization of right-of-use assets 1,284 2,577 Interest on lease liabilities — — Total lease costs $ 8,771 $ 16,754 For the periods presented, costs associated with short-term leases were not material. Other information related to leases was as follows: June 30, 2019 Weighted Average Remaining Lease Term: Operating leases 4.5 years Finance leases 1.1 years Weighted Average Discount Rate: Operating leases 4 % Finance leases — % Cash flows related to leases were as follows (in thousands): Six Months Ended June 30, 2019 Cash flows from operating activities: Payments for operating lease liabilities $ 16,067 Cash flows from financing activities: Principal payments on finance lease obligation $ 2,568 Supplemental Cash Flow Data: Right-of-use assets obtained in exchange for operating lease obligations $ 21,905
Future Minimum Lease Payments under Non-Cancelable Operating Leases	Future minimum lease payments under non-cancelable operating leases (with initial lease terms in excess of one year) and future minimum finance lease payments as of June 30, 2019 are as follows (in thousands): Finance Operating Year: 2019 (remaining 6 months) $ 2,461 $ 13,305 2020 2,446 40,578 2021 — 57,178 2022 — 57,054 2023 — 50,866 Thereafter — 233,739 Total $ 4,907 $ 452,720 Less amount representing interest — 13,072 Less leases executed but not yet commenced — 307,428 Total $ 4,907 $ 132,220
Future Minimum Finance Lease Payments	Future minimum lease payments under non-cancelable operating leases (with initial lease terms in excess of one year) and future minimum finance lease payments as of June 30, 2019 are as follows (in thousands): Finance Operating Year: 2019 (remaining 6 months) $ 2,461 $ 13,305 2020 2,446 40,578 2021 — 57,178 2022 — 57,054 2023 — 50,866 Thereafter — 233,739 Total $ 4,907 $ 452,720 Less amount representing interest — 13,072 Less leases executed but not yet commenced — 307,428 Total $ 4,907 $ 132,220

SEGMENT AND GEOGRAPHICAL INFO_2

SEGMENT AND GEOGRAPHICAL INFORMATION (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Revenue by Geographic Area	Revenue by geography is based on the billing addresses of the sellers or customers. The following table sets forth revenue by geographic area (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenue United States $ 1,119,039 $ 777,335 $ 2,033,695 $ 1,417,508 International 55,199 37,603 99,902 66,033 Total net revenue $ 1,174,238 $ 814,938 $ 2,133,597 $ 1,483,541
Long-lived Assets by Geographic Area	The following table sets forth long-lived assets by geographic area (in thousands): June 30, December 31, Long-lived assets United States $ 580,939 $ 471,970 International 11,994 9,239 Total long-lived assets $ 592,933 $ 481,209

SUPPLEMENTAL CASH FLOW INFORM_2

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)	6 Months Ended
	Jun. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	The supplemental disclosures of cash flow information consist of the following (in thousands): Six Months Ended June 30, 2019 2018 Supplemental Cash Flow Data: Cash paid for interest $ 2,836 $ 1,108 Cash paid for income taxes 1,717 854 Right-of-use assets obtained in exchange for operating lease obligations 21,905 — Supplemental disclosures of non-cash investing and financing activities: Change in purchases of property and equipment in accounts payable and accrued expenses 14,047 9,708 Unpaid business combination purchase price 8,411 3,995 Fair value of common stock issued related to business combination — (139,396 ) Recovery of common stock in connection with indemnification settlement agreement 789 2,745

DESCRIPTION OF BUSINESS AND S_3

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)customer	Jun. 30, 2018customer	Jun. 30, 2019USD ($)customerthird_party_processor	Jun. 30, 2018customer	Dec. 31, 2018USD ($)third_party_processor	Mar. 31, 2019USD ($)
Concentration Risk [Line Items]
Operating lease right-of-use assets	$ 107,809		$ 107,809
Operating lease liability	132,220		132,220
Derecognition of build-to-suit lease asset	0		0		$ (149,000)
Derecognition of build-to-suit lease liability	$ 0		$ 0		$ (149,000)
Total Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Number of customers accounting for greater than 10% of total net revenue | customer	0	0	0	0
Settlements Receivable | Credit Concentration Risk
Concentration Risk [Line Items]
Number of third party processors | third_party_processor			3		3
Settlements Receivable | Credit Concentration Risk | Third Party Processor One
Concentration Risk [Line Items]
Concentration risk, settlements receivable			55.00%		45.00%
Settlements Receivable | Credit Concentration Risk | Third Party Processor Two
Concentration Risk [Line Items]
Concentration risk, settlements receivable			35.00%		33.00%
Settlements Receivable | Credit Concentration Risk | Third Party Processor Three
Concentration Risk [Line Items]
Concentration risk, settlements receivable			7.00%		9.00%
Minimum
Concentration Risk [Line Items]
Settlements receivable period			1 day
Maximum
Concentration Risk [Line Items]
Settlements receivable period			2 days
Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Operating lease right-of-use assets						$ 112,000
Operating lease liability						135,600
Derecognition of build-to-suit lease asset						$ 149,000
Derecognition of build-to-suit lease liability	$ 149,000		$ 149,000

REVENUE - Disaggregation of Rev

REVENUE - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Transaction-based revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 775,510	$ 625,228	$ 1,432,272	$ 1,148,265
Subscription and services-based revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	216,491	111,670	405,693	188,885
Revenues from other sources	34,892	22,662	64,547	42,501
Hardware revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22,260	18,362	40,472	32,779
Bitcoin revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 125,085	$ 37,016	$ 190,613	$ 71,111

REVENUE - Deferred Revenue (Det

REVENUE - Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue	$ 44,812	$ 27,155	$ 44,812	$ 27,155	$ 36,451	$ 42,160	$ 1,590	$ 3,353
Deferred revenue arising from business combination	0	22,800	0	22,800
Revenue recognized in the period from amounts included in deferred revenue at the beginning of the period	$ 14,889	$ 1,975	$ 21,786	$ 1,095
Balances without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue					36,451	42,160	5,893	3,353
Accounting Standards Update 2014-09 | Effect of change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue					$ 0	$ 0	$ (4,303)	$ 0

INVESTMENTS - Short-Term and L

INVESTMENTS - Short-Term and Long-Term Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,030,139
Fair Value	1,033,033
Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	571,213	$ 541,684
Gross Unrealized Gains	1,166	329
Gross Unrealized Losses	(173)	(1,022)
Fair Value	572,206	540,991
Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	458,926	464,545
Gross Unrealized Gains	2,257	1,361
Gross Unrealized Losses	(356)	(1,226)
Fair Value	460,827	464,680
U.S. agency securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	125,614	80,160
Gross Unrealized Gains	230	32
Gross Unrealized Losses	(5)	(70)
Fair Value	125,839	80,122
U.S. agency securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	81,861	114,444
Gross Unrealized Gains	400	194
Gross Unrealized Losses	(84)	(78)
Fair Value	82,177	114,560
Corporate bonds | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	95,901	109,807
Gross Unrealized Gains	220	80
Gross Unrealized Losses	(72)	(368)
Fair Value	96,049	109,519
Corporate bonds | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	196,687	159,783
Gross Unrealized Gains	805	419
Gross Unrealized Losses	(97)	(950)
Fair Value	197,395	159,252
Commercial paper | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,973
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	3,973
Municipal securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15,947	27,839
Gross Unrealized Gains	78	52
Gross Unrealized Losses	(4)	(59)
Fair Value	16,021	27,832
Municipal securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	14,591	28,453
Gross Unrealized Gains	137	167
Gross Unrealized Losses	(16)	(26)
Fair Value	14,712	28,594
U.S. government securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	314,603	292,615
Gross Unrealized Gains	617	161
Gross Unrealized Losses	(47)	(509)
Fair Value	315,173	292,267
U.S. government securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	156,706	153,743
Gross Unrealized Gains	861	553
Gross Unrealized Losses	(149)	(172)
Fair Value	157,418	154,124
Non-U.S. government securities | Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15,175	31,263
Gross Unrealized Gains	21	4
Gross Unrealized Losses	(45)	(16)
Fair Value	15,151	31,251
Non-U.S. government securities | Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,081	8,122
Gross Unrealized Gains	54	28
Gross Unrealized Losses	(10)	0
Fair Value	$ 9,125	$ 8,150

INVESTMENTS - Contractual Matu

INVESTMENTS - Contractual Maturities of Short-Term and Long-Term Investments (Details) $ in Thousands	Jun. 30, 2019USD ($)
Amortized Cost
Due in one year or less	$ 571,213
Due in one to five years	458,926
Amortized Cost	1,030,139
Fair Value
Due in one year or less	572,206
Due in one to five years	460,827
Fair Value	$ 1,033,033

CUSTOMER FUNDS - Assets Underly

CUSTOMER FUNDS - Assets Underlying Customer Funds (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Customer funds	$ 484,945	$ 334,017
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	10,867	27,291
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	114,981	72,671
Cash
Debt Securities, Available-for-sale [Line Items]
Customer funds	307,848	158,697
Cash Equivalents | Money market funds
Debt Securities, Available-for-sale [Line Items]
Customer funds	163	18
Cash Equivalents | U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	23,112	39,991
Cash Equivalents | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Customer funds	$ 27,974	$ 35,349

CUSTOMER FUNDS - Investments wi

CUSTOMER FUNDS - Investments within Customer Funds (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,030,139
Fair Value	1,033,033
Customer funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	125,778	$ 99,955
Gross Unrealized Gains	82	14
Gross Unrealized Losses	(12)	(7)
Fair Value	125,848	99,962
Customer funds | U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,868	27,293
Gross Unrealized Gains	1	2
Gross Unrealized Losses	(2)	(4)
Fair Value	10,867	27,291
Customer funds | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	114,910	72,662
Gross Unrealized Gains	81	12
Gross Unrealized Losses	(10)	(3)
Fair Value	$ 114,981	$ 72,671

CUSTOMER FUNDS - Contractual Ma

CUSTOMER FUNDS - Contractual Maturities of Short-Term and Long-Term Investments within Customer Funds (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Amortized Cost
Due in one year or less	$ 571,213
Amortized Cost	1,030,139
Fair Value
Due in one year or less	572,206
Fair Value	1,033,033
Customer funds
Amortized Cost
Due in one year or less	125,778
Amortized Cost	125,778	$ 99,955
Fair Value
Due in one year or less	125,848
Fair Value	$ 125,848	$ 99,962

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	$ 484,945	$ 334,017
Short-term debt securities	572,206	540,991
Long-term debt securities	460,827	464,680
Marketable equity investment	26,413	45,342
U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	10,867	27,291
U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer funds	114,981	72,671
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity investment	26,413	45,342
Total	964,180	904,119
Fair Value, Measurements, Recurring | Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	272,313	218,109
Customer funds	163	18
Fair Value, Measurements, Recurring | Level 1 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 1 | Time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	10,081	0
Fair Value, Measurements, Recurring | Level 1 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	39,663	0
Customer funds	142,956	108,020
Short-term debt securities	315,173	292,267
Long-term debt securities	157,418	154,124
Fair Value, Measurements, Recurring | Level 1 | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	86,239
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity investment	0	0
Total	697,324	696,966
Fair Value, Measurements, Recurring | Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Customer funds	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	102,904	46,423
Customer funds	33,978	67,282
Short-term debt securities	125,839	80,122
Long-term debt securities	82,177	114,560
Fair Value, Measurements, Recurring | Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 | Time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	96,049	109,519
Long-term debt securities	197,395	159,252
Fair Value, Measurements, Recurring | Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	3,973	0
Fair Value, Measurements, Recurring | Level 2 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 2 | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term debt securities	16,021	27,832
Long-term debt securities	14,712	28,594
Fair Value, Measurements, Recurring | Level 2 | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	23,981
Short-term debt securities	15,151	31,251
Long-term debt securities	9,125	8,150
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity investment	0	0
Total	0	0
Fair Value, Measurements, Recurring | Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Customer funds	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | Time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Customer funds	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term debt securities	0	0
Long-term debt securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term debt securities	0	0
Long-term debt securities	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Convertible Senior Notes (Details) - Level 2 - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	$ 919,026	$ 899,695
Fair Value (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	1,704,392	1,417,161
2023 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	733,366	718,522
2023 Notes | Fair Value (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	1,032,318	901,468
2022 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	185,660	181,173
2022 Notes | Fair Value (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	$ 672,074	$ 515,693

FAIR VALUE OF FINANCIAL INSTR_5

FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Loans Held for Sale (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Carrying Value | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 136,511		$ 136,511		$ 89,974
Fair Value (Level 3) | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	143,023		143,023		$ 93,064
Loans Receivable Held-For-Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Excess amortized cost over fair value of loans	$ 6,400	$ 3,200	$ 13,100	$ 5,700

PROPERTY AND EQUIPMENT, NET (De

PROPERTY AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 283,539		$ 283,539		$ 267,311
Less: Accumulated depreciation and amortization	(152,792)		(152,792)		(124,909)
Property and equipment, net	130,747		130,747		142,402
Depreciation and amortization expense	14,800	$ 9,300	30,300	$ 17,500
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	105,411		105,411		107,611
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	85,930		85,930		80,093
Capitalized software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	70,667		70,667		58,908
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 21,531		$ 21,531		$ 20,699

ACQUISITIONS - Narrative (Detai

ACQUISITIONS - Narrative (Details) - USD ($) $ in Thousands	May 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired		$ 20,372	$ 111,828
Weebly, Inc.
Business Acquisition [Line Items]
Percent of outstanding shares acquired	100.00%
Cash consideration	$ 132,432
Equity consideration (in shares)	2,418,271
Equity consideration fair value	$ 140,107
Payment to settle outstanding vested and unvested employee options	17,700
Post-combination compensation expense	$ 2,600
Goodwill adjustment to purchase price allocation		3,700
Tax liabilities adjustment to purchase price allocation		4,700
Cash withheld for indemnification		$ 19,400
Shares withheld for indemnification (in shares)		363,266
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired		$ 20,400

ACQUISITIONS - Schedule of Asse

ACQUISITIONS - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	May 31, 2018	Jun. 30, 2019	Dec. 31, 2018
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill		$ 270,161	$ 261,705
Weebly, Inc.
Consideration:
Cash	$ 132,432
Stock (2,418,271 shares of Class A common stock)	$ 140,107
Stock (in shares)	2,418,271
Total consideration	$ 272,539
Recognized amounts of identifiable assets acquired and liabilities assumed:
Current assets (inclusive of cash acquired of $25,758)	46,978
Cash acquired	25,758
Total liabilities assumed (including deferred revenue of $22,800)	(37,509)
Deferred revenue	22,800
Total identifiable net assets acquired	79,330
Goodwill	193,209
Total	272,539
Weebly, Inc. | Intangible customer assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	42,700
Weebly, Inc. | Intangible technology assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	14,900
Weebly, Inc. | Intangible trade name
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	11,300
Weebly, Inc. | Intangible other assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangible assets	$ 961

GOODWILL (Details)

GOODWILL (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Goodwill [Roll Forward]
Goodwill, beginning balance			$ 261,705,000
Acquisitions			10,832,000
Other adjustments			(2,376,000)
Goodwill, ending balance	$ 270,161,000		270,161,000
Goodwill, impairment charges	$ 0	$ 0	$ 0	$ 0

ACQUIRED INTANGIBLE ASSETS - S

ACQUIRED INTANGIBLE ASSETS - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 131,192		$ 116,633
Accumulated Amortization	(46,976)		(39,531)
Net	84,216	$ 79,697	77,102	$ 85,514	$ 14,138	$ 14,334
Technology assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	57,484		45,978
Accumulated Amortization	(31,515)		(28,420)
Net	25,969		17,558
Customer assets
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	57,109		57,109
Accumulated Amortization	(10,656)		(8,068)
Net	46,453		49,041
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	11,300		11,300
Accumulated Amortization	(3,060)		(1,648)
Net	8,240		9,652
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	5,299		2,246
Accumulated Amortization	(1,745)		(1,395)
Net	$ 3,554		$ 851

ACQUIRED INTANGIBLE ASSETS - N

ACQUIRED INTANGIBLE ASSETS - Narrative (Details)	6 Months Ended
	Jun. 30, 2019
Technology assets
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period	5 years
Customer assets
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period	11 years
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period	4 years

ACQUIRED INTANGIBLE ASSETS - Ch

ACQUIRED INTANGIBLE ASSETS - Change in Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Finite-lived Intangible Assets [Roll Forward]
Acquired intangible assets, net, beginning of the period	$ 79,697	$ 14,138	$ 77,102	$ 14,334
Acquisitions	8,477	74,192	14,559	75,871
Amortization expense	3,958	2,816	7,445	4,691
Acquired intangible assets, net, end of the period	$ 84,216	$ 85,514	$ 84,216	$ 85,514

ACQUIRED INTANGIBLE ASSETS - F

ACQUIRED INTANGIBLE ASSETS - Future Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
2019 (remaining 6 months)	$ 8,216
2020	14,306
2021	13,109
2022	11,179
2023	9,649
Thereafter	27,757
Net	$ 84,216	$ 79,697	$ 77,102	$ 85,514	$ 14,138	$ 14,334

OTHER CONSOLIDATED BALANCE SH_5

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventory, net	$ 29,354	$ 28,627
Processing costs receivable	61,116	46,102
Prepaid expenses	18,697	21,782
Accounts receivable, net	32,157	22,393
Other	39,036	46,062
Total	$ 180,360	$ 164,966

OTHER CONSOLIDATED BALANCE SH_6

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued facilities expenses	$ 16,868	$ 13,040
Accrued payroll	12,125	9,612
Accrued advertising and other marketing	21,892	12,201
Processing costs payable	16,730	12,683
Accrued non income tax liabilities	9,131	9,503
Other accrued liabilities	29,605	25,315
Total	$ 106,351	$ 82,354

OTHER CONSOLIDATED BALANCE SH_7

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts payable	$ 29,021	$ 36,416
Deferred revenue, current	38,639	31,474
Square Capital payable	16,668	6,092
Square Payroll payable	12,394	7,534
Other	15,156	17,637
Total	$ 111,878	$ 99,153

OTHER CONSOLIDATED BALANCE SH_8

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) - Other Non-Current Assets (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Marketable equity investment	$ 26,413	$ 26,413		$ 45,342
Other	30,754	30,754		13,051
Total	57,167	57,167		$ 58,393
Loss on equity investment	$ 4,800	$ 18,929	$ 0

OTHER CONSOLIDATED BALANCE SH_9

OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) - Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Statutory liabilities	$ 48,516	$ 54,748
Deferred rent, non-current	0	23,003
Deferred revenue, non-current	6,173	4,977
Other	12,960	10,558
Total	$ 67,649	$ 93,286

INDEBTEDNESS - Revolving Credi

INDEBTEDNESS - Revolving Credit Facility Narrative (Details) - Revolving Credit Facility - Line of Credit - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Nov. 30, 2015	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 375,000,000
Administrative agent fee	$ 100,000
Unused commitment fee percentage	0.15%
Amounts drawn to date		$ 0		$ 0
Remaining borrowing capacity		375,000,000		375,000,000
Unused commitment fees		$ 100,000	$ 300,000	$ 100,000	$ 300,000
Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
One Month LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.00%
One Month LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%

INDEBTEDNESS - Convertible Seni

INDEBTEDNESS - Convertible Senior Notes Narrative (Details) $ / shares in Units, shares in Millions	Dec. 31, 2018USD ($)	May 25, 2018USD ($)day$ / shares	Mar. 06, 2017USD ($)day$ / shares	Dec. 31, 2018USD ($)shares	Jun. 30, 2019USD ($)
Debt Instrument [Line Items]
Principal payment on conversion of senior notes				$ 219,400,000
Convertible Debt
Debt Instrument [Line Items]
Conversion price (in USD per share) | $ / shares		$ 77.85	$ 22.95
Carrying amount of equity component	$ 194,392,000			194,392,000	$ 194,392,000
Issuance costs attributable to the liability component	8,040,000			8,040,000	7,146,000
Convertible Debt | 2023 Notes
Debt Instrument [Line Items]
Aggregate principal amount		$ 862,500,000
Interest rate		0.50%
Conversion rate		0.0128456
Conversion price (in USD per share) | $ / shares		$ 77.85
Carrying amount of equity component	154,019,000	$ 155,300,000		154,019,000	$ 154,019,000
Effective interest rate of the liability component		4.69%			4.69%
Discounts and commissions payable		$ 6,000,000
Third party offering costs		800,000
Issuance costs attributable to the liability component	5,054,000	$ 5,600,000		5,054,000	$ 4,609,000
Convertible Debt | 2023 Notes | Debt Instrument, Conversion Term One
Debt Instrument [Line Items]
Threshold trading days | day		20
Threshold consecutive trading days | day		30
Threshold percentage of stock price trigger		130.00%
Convertible Debt | 2023 Notes | Debt Instrument Conversion Term Two
Debt Instrument [Line Items]
Threshold trading days | day		5
Threshold consecutive trading days | day		5
Threshold percentage of stock price trigger		98.00%
Convertible Debt | 2022 Notes
Debt Instrument [Line Items]
Aggregate principal amount			$ 440,000,000
Interest rate			0.375%
Conversion rate			0.0435749
Conversion price (in USD per share) | $ / shares			$ 22.95
Carrying amount of equity component	40,373,000		$ 86,200,000	40,373,000	$ 40,373,000
Effective interest rate of the liability component			5.34%		5.34%
Discounts and commissions payable			$ 11,000,000
Third party offering costs			800,000
Issuance costs attributable to the liability component	2,986,000		$ 9,400,000	2,986,000	$ 2,537,000
Notes converted				$ 228,300,000
Shares issued upon conversion (in shares) | shares				7.3
Loss on extinguishment of long-term debt	5,000,000
Reduction to additional paid in capital	$ 21,000,000
Convertible Debt | 2022 Notes | Debt Instrument, Conversion Term One
Debt Instrument [Line Items]
Threshold trading days | day			20
Threshold consecutive trading days | day			30
Threshold percentage of stock price trigger			130.00%
Convertible Debt | 2022 Notes | Debt Instrument Conversion Term Two
Debt Instrument [Line Items]
Threshold trading days | day			5
Threshold consecutive trading days | day			5
Threshold percentage of stock price trigger			98.00%

INDEBTEDNESS - Components of Co

INDEBTEDNESS - Components of Convertible Notes (Details) - Convertible Debt - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	May 25, 2018	Mar. 06, 2017
Debt Instrument [Line Items]
Principal outstanding	$ 1,074,228	$ 1,074,228
Unamortized debt discount	(148,056)	(166,493)
Unamortized debt issuance costs	(7,146)	(8,040)
Net carrying value	919,026	899,695
2023 Notes
Debt Instrument [Line Items]
Principal outstanding	862,500	862,500
Unamortized debt discount	(124,525)	(138,924)
Unamortized debt issuance costs	(4,609)	(5,054)	$ (5,600)
Net carrying value	733,366	718,522
2022 Notes
Debt Instrument [Line Items]
Principal outstanding	211,728	211,728
Unamortized debt discount	(23,531)	(27,569)
Unamortized debt issuance costs	(2,537)	(2,986)		$ (9,400)
Net carrying value	$ 185,660	$ 181,173

INDEBTEDNESS - Carrying Amount

INDEBTEDNESS - Carrying Amount of Equity Component of Convertible Notes (Details) - Convertible Debt - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	May 25, 2018	Mar. 06, 2017
Debt Instrument [Line Items]
Amount allocated to conversion option	$ 196,731	$ 196,731
Less: allocated issuance costs	(2,339)	(2,339)
Equity component, net	194,392	194,392
2023 Notes
Debt Instrument [Line Items]
Amount allocated to conversion option	155,250	155,250
Less: allocated issuance costs	(1,231)	(1,231)
Equity component, net	154,019	154,019	$ 155,300
2022 Notes
Debt Instrument [Line Items]
Amount allocated to conversion option	41,481	41,481
Less: allocated issuance costs	(1,108)	(1,108)
Equity component, net	$ 40,373	$ 40,373		$ 86,200

INDEBTEDNESS - Interest Expense

INDEBTEDNESS - Interest Expense on Convertible Notes (Details) - Convertible Debt - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	May 25, 2018	Mar. 06, 2017
Debt Instrument [Line Items]
Contractual interest expense	$ 1,277	$ 850	$ 2,554	$ 1,263
Amortization of debt discount and issuance costs	9,725	6,830	19,333	11,223
Total	$ 11,002	$ 7,680	$ 21,887	$ 12,486
2023 Notes
Debt Instrument [Line Items]
Effective interest rate of the liability component	4.69%		4.69%		4.69%
2022 Notes
Debt Instrument [Line Items]
Effective interest rate of the liability component	5.34%		5.34%			5.34%

INDEBTEDNESS - Convertible Note

INDEBTEDNESS - Convertible Note Hedge and Warrant Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	May 25, 2018	Mar. 06, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Proceeds from issuance of warrants			$ 0	$ 112,125
Convertible Debt
Debt Instrument [Line Items]
Conversion price of convertible debt (in USD per share)	$ 77.85	$ 22.95
Conversion price of convertible debt after effect of warrants and note hedge (in USD per share)	$ 109.26	$ 31.18
Common Stock Warrant
Debt Instrument [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)	11.1	19.2
Warrants, weighted average exercise price (in USD per share)	$ 109.26	$ 31.18
Proceeds from issuance of warrants	$ 112,100	$ 57,200
Shares of common stock received due to exercise of note hedges (in shares)			0.3		6.9
Options
Debt Instrument [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)	11.1	19.2
Convertible note hedge, option to purchase common stock, price (in USD per share)	$ 77.85	$ 22.95
Cost of convertible note hedge	$ 172,600	$ 92,100

ACCRUED TRANSACTION LOSSES (Det

ACCRUED TRANSACTION LOSSES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Loss Contingency Accrual
Accrued transaction losses, beginning of the period			$ 33,682
Provision for transaction losses			62,105	$ 40,007
Accrued transaction losses, end of the period	$ 39,630		39,630
Transaction Losses
Loss Contingency Accrual
Accrued transaction losses, beginning of the period	36,047	$ 28,309	33,682	26,893
Provision for transaction losses	22,190	14,087	41,998	28,345
Charge-offs to accrued transaction losses	(18,607)	(13,189)	(36,050)	(26,031)
Accrued transaction losses, end of the period	$ 39,630	$ 29,207	$ 39,630	$ 29,207

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ (476)	$ 604	$ (347)	$ 779
Effective tax rate	6.60%	(11.40%)	0.80%	(2.70%)

STOCKHOLDERS' EQUITY - Common

STOCKHOLDERS' EQUITY - Common Stock and Warrants Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	May 25, 2018	Mar. 06, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Class of Stock [Line Items]
Proceeds from issuance of warrants			$ 0	$ 112,125
Common Stock Warrant
Class of Stock [Line Items]
Warrants to purchase aggregate shares of capital stock (in shares)	11,100,000	19,200,000
Warrants, weighted average exercise price (in USD per share)	$ 109.26	$ 31.18
Proceeds from issuance of warrants	$ 112,100	$ 57,200
Number of warrants exercised (in shares)			0
Class A
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			1,000,000,000		1,000,000,000
Common stock, par value (in USD per share)			$ 0		$ 0
Common stock, shares outstanding (in shares)			341,709,651		323,546,864
Class B
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			500,000,000		500,000,000
Common stock, par value (in USD per share)			$ 0		$ 0
Common stock, shares outstanding (in shares)			84,508,342		93,501,142

STOCKHOLDERS' EQUITY - Stock P

STOCKHOLDERS' EQUITY - Stock Plans and Share Based Compensation Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)shares	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)planshares	Jun. 30, 2018USD ($)	Nov. 17, 2015shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share based compensation plans | plan			2
Employee stock purchase plan, compensation expense | $	$ 79,466	$ 52,119	$ 140,554	$ 98,943
Capitalized share-based compensation expense | $	1,900	2,700	3,700	4,300
Unrecognized compensation cost, options | $	772,000		772,000
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan, compensation expense | $	$ 4,700	$ 2,000	$ 9,000	$ 4,200
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, period for recognition			2 years 10 months 24 days
2009 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	0		0
2009 Stock Option Plan | Stock options, RSAs, and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments outstanding (in shares)	22,067,602		22,067,602
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	82,520,758		82,520,758
Shares reserved for future issuance (in shares)					30,000,000
Shares reserved for future issuance, percentage of annual increase			5.00%
2015 Equity Incentive Plan | Stock options, RSAs, and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments outstanding (in shares)	23,518,561		23,518,561
2015 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance, amount of annual increase (in shares)	40,000,000		40,000,000

STOCKHOLDERS' EQUITY - Stock O

STOCKHOLDERS' EQUITY - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Number of Stock Options Outstanding
Beginning balance (in shares)		33,152,881
Granted (in shares)		1,184,657
Exercised (in shares)		(6,259,582)
Forfeited (in shares)		(130,671)
Ending balance (in shares)	27,947,285	27,947,285	33,152,881
Weighted Average Exercise Price
Beginning balance (in USD per share)		$ 9.52
Granted (in USD per share)		72.15
Exercised (in USD per share)		7.66
Forfeited (in USD per share)		11.54
Ending balance (in USD per share)	$ 12.59	$ 9.52	$ 9.52
Options Exercisable
Options exercisable (in shares)	25,358,359
Options exercisable (in USD per share)	$ 9.12
Additional Disclosures
Weighted average remaining contractual term, options outstanding		5 years 5 months 1 day	5 years 5 months 12 days
Weighted average remaining contractual term, options exercisable		5 years 1 month 13 days
Aggregate intrinsic value, options outstanding	$ 1,675,414		$ 1,543,793
Aggregate intrinsic value, options exercisable	$ 1,607,944

STOCKHOLDERS' EQUITY - Restric

STOCKHOLDERS' EQUITY - Restricted Stock Awards and Restricted Stock Units Activity (Details) - RSAs and RSUs	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Number of shares
Beginning balance (in shares) | shares	17,934,728
Granted (in shares) | shares	4,625,215
Vested (in shares) | shares	(3,943,408)
Forfeited (in shares) | shares	(977,657)
Ending balance (in shares) | shares	17,638,878
Weighted Average Grant Date Fair Value
Beginning balance (in USD per share) | $ / shares	$ 31.34
Granted (in USD per share) | $ / shares	71.99
Vested (in USD per share) | $ / shares	27.21
Forfeited (in USD per share) | $ / shares	30.30
Ending balance (in USD per share) | $ / shares	$ 42.98

STOCKHOLDERS' EQUITY - Stock_2

STOCKHOLDERS' EQUITY - Stock Option Fair Value Assumptions (Details) - Stock options	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate	2.37%	2.92%	2.48%	2.92%
Expected volatility	40.48%	30.87%	39.52%	30.87%
Expected term (years)	6 years 7 days	6 years 2 months 8 days	6 years 18 days	6 years 2 months 8 days

STOCKHOLDERS' EQUITY - Effects

STOCKHOLDERS' EQUITY - Effects of Share-Based Compensation on Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	$ 79,466	$ 52,119	$ 140,554	$ 98,943
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	29	30	50	61
Product development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	56,144	33,806	98,793	64,288
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	7,833	5,634	14,035	10,595
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	$ 15,460	$ 12,649	$ 27,676	$ 23,999

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	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net loss	$ (6,740)	$ (38,151)	$ (5,906)	$ (23,986)	$ (44,891)	$ (29,892)
Basic shares:
Weighted-average common shares outstanding (in shares)	424,105		403,390		421,983	400,318
Weighted-average unvested shares (in shares)	(800)		(89)		(686)	(694)
Weighted-average shares used to compute basic net loss per share (in shares)	423,305		403,301		421,297	399,624
Diluted shares:
Weighted-average shares used to compute diluted income (loss) per share (in shares)	423,305		403,301		421,297	399,624
Net loss per share:
Basic (in USD per share)	$ (0.02)		$ (0.01)		$ (0.11)	$ (0.07)
Diluted (in USD per share)	$ (0.02)		$ (0.01)		$ (0.11)	$ (0.07)

NET LOSS PER SHARE - Antidilut

NET LOSS PER SHARE - Antidilutive Securities Excluded from Computation of Diluted Net Income (Loss) Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	98,212	86,772	98,694	86,895
Stock options and restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	46,686	62,908	47,256	64,635
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	30,252	23,605	30,252	21,377
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	20,305	0	20,305	0
Unvested shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	800	89	686	694
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net income (loss) per share (in shares)	169	170	195	189

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES - Operating and Finance Leases Narrative (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Dec. 31, 2018USD ($)ft²renewal_option	Jun. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating lease renewal term		5 years
Operating lease option to terminate term		1 year
Total lease payments over term		$ 452,720
Minimum
Lessee, Lease, Description [Line Items]
Operating lease term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease term		12 years
Equipment
Lessee, Lease, Description [Line Items]
Finance lease, remaining lease term		2 years
Oakland, California | Building
Lessee, Lease, Description [Line Items]
Operating lease term	12 years
Operating lease renewal term	5 years
Leased area of office space (in sq ft) | ft²	355,762
Operating lease, number of renewal options | renewal_option	2
Total lease payments over term	$ 276,000

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Schedule of Lease Expense Components (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Operating lease costs	$ 7,487	$ 14,177
Sublease income	0	0
Finance lease costs
Amortization of right-of-use assets	1,284	2,577
Interest on lease liabilities	0	0
Total lease costs	$ 8,771	$ 16,754

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Other Information Related to Leases (Details)	Jun. 30, 2019
Weighted Average Remaining Lease Term:
Operating leases	4 years 6 months
Finance leases	1 year 1 month 6 days
Weighted Average Discount Rate:
Operating leases	4.00%
Finance leases	0.00%

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Cash Flows Related to Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Payments for operating lease liabilities	$ 16,067
Cash flows from financing activities:
Principal payments on finance lease obligation	2,568	$ 1,375
Supplemental Cash Flow Data:
Right-of-use assets obtained in exchange for operating lease obligations	$ 21,905

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases and Finance Leases (Details) $ in Thousands	Jun. 30, 2019USD ($)
Finance
2019 (remaining 6 months)	$ 2,461
2020	2,446
2021	0
2022	0
2023	0
Thereafter	0
Total	4,907
Less amount representing interest	0
Less leases executed but not yet commenced	0
Total	4,907
Operating
2019 (remaining 6 months)	13,305
2020	40,578
2021	57,178
2022	57,054
2023	50,866
Thereafter	233,739
Total	452,720
Less amount representing interest	13,072
Less leases executed but not yet commenced	307,428
Total	$ 132,220

SEGMENT AND GEOGRAPHICAL INFO_3

SEGMENT AND GEOGRAPHICAL INFORMATION - Narrative (Details)	6 Months Ended
	Jun. 30, 2019segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

SEGMENT AND GEOGRAPHICAL INFO_4

SEGMENT AND GEOGRAPHICAL INFORMATION - Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 1,174,238	$ 814,938	$ 2,133,597	$ 1,483,541
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,119,039	777,335	2,033,695	1,417,508
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 55,199	$ 37,603	$ 99,902	$ 66,033

SEGMENT AND GEOGRAPHICAL INFO_5

SEGMENT AND GEOGRAPHICAL INFORMATION - Long-lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 592,933	$ 481,209
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	580,939	471,970
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 11,994	$ 9,239

SUPPLEMENTAL CASH FLOW INFORM_3

SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Supplemental Cash Flow Data:
Cash paid for interest	$ 2,836	$ 1,108
Cash paid for income taxes	1,717	854
Right-of-use assets obtained in exchange for operating lease obligations	21,905
Supplemental disclosures of non-cash investing and financing activities:
Change in purchases of property and equipment in accounts payable and accrued expenses	14,047	9,708
Unpaid business combination purchase price	8,411	3,995
Fair value of common stock issued related to business combination	0	(139,396)
Recovery of common stock in connection with indemnification settlement agreement	$ 789	$ 2,745

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jul. 25, 2019	Jun. 30, 2019
Subsequent Event [Line Items]
Lease executed but not yet commenced			$ 307,428
Subsequent Event
Subsequent Event [Line Items]
Lease executed but not yet commenced		$ 42,700
Building | Subsequent Event
Subsequent Event [Line Items]
Lease executed but not yet commenced, term		15 years 6 months
Forecast | Caviar Business | Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Subsequent Event
Subsequent Event [Line Items]
Gross proceeds expected to be received for sale of business	$ 410,000

Uncategorized Items - q2fy19squ

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