DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
Mar. 31, 2020
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, 2019 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 loss, and cash flows for the interim periods. All intercompany transactions and balances have been eliminated in consolidation. The interim results for the three months ended March 31, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020, 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 the Consolidated Financial Statements and related notes in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.
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. Generally, the Company's estimates and assumptions consider current and past experience, to the extent that historical experience is predictive of future performance. Estimates, judgments, and assumptions in these consolidated financial statements include, but are not limited to, those related to revenue recognition, accrued transaction losses, credit loss allowances from marketable debt securities, contingencies, valuation of the debt component of convertible senior notes, valuation of loans held for sale, goodwill, acquired intangible assets, income and other taxes, operating and financing lease right-of-use assets and related liabilities, assessing the likelihood of adverse outcomes from claims and disputes, and share-based compensation.
Concentration of Credit Risk	Concentration of Credit Risk For the three months ended March 31, 2020 and March 31, 2019, the Company had no customer that accounted for greater than 10% of total net revenue. The Company had two third-party payment processors that represented approximately 45% and 28% of settlements receivable as of March 31, 2020. As of December 31, 2019, the Company had three parties that represented approximately 48%, 29%, and 9% of settlements receivable. 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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements  Recently adopted accounting pronouncements In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments - Credit Losses, which requires the measurement and recognition of expected credit losses for financial assets held. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available for sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2020 and has applied the guidance prospectively. The Company has concluded that the adoption of the guidance did not have a material impact on the balances reported in its consolidated financial statements and has included disclosures under the guidance. 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 for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The amendments should be applied on a prospective basis. The Company adopted this guidance effective January 1, 2020 and will apply the guidance during its annual goodwill impairment test for the year ending December 31, 2020. The adoption of this guidance did not 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 adopted this guidance effective January 1, 2020 and has applied the guidance prospectively, and included additional disclosures required by the new guidance relating to significant unobservable inputs used to develop Level 3 fair value measurements. 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 adopted this guidance effective January 1, 2020 and has applied the guidance prospectively. The adoption of this guidance did not have a material impact on the consolidated financial statements and related disclosures. In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments — Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments. The amendments clarify the scope of the credit losses standard and hedge accounting among other things. The Company adopted ASC 326 on January 1, 2020 for credit losses. With respect to hedge accounting, the amendments address partial-term fair value hedges and fair value hedge basis adjustments, among other things. 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 as long an entity has also adopted the amendments in ASU 2016-13. The adoption of this guidance did not have a material impact on the consolidated financial statements and related disclosures. For entities which have already adopted ASU 2017-12, they are permitted to elect either retrospectively or prospectively adopt the amendments. The Company had previously adopted ASU 2017-12 on January 1, 2019 and therefore is eligible to and has prospectively adopted the amendments. In December 2019, the FASB issued ASU 2019-12, Income Taxes: Simplifying the Accounting for Income Taxes, as part of its overall simplification initiative to reduce costs and complexity of applying accounting standards while maintaining or improving the usefulness of the information provided to users of financial statements. Among other things, the new guidance simplifies intraperiod tax allocation and reduces the complexity in accounting for income taxes with year-to-date losses in interim periods. The guidance is effective for financial statements issued for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years, with early adoption permitted. The Company early adopted this guidance effective January 1, 2020 and has applied the guidance prospectively. The adoption did not have a material impact on the consolidated financial statements and related disclosures.

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

3 Months Ended

Mar. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

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, 2019 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 loss, and cash flows for the interim periods. All intercompany transactions and balances have been eliminated in consolidation. The interim results for the three months ended March 31, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020, 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 the Consolidated Financial Statements and related notes in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.

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. Generally, the Company's estimates and assumptions consider current and past experience, to the extent that historical experience is predictive of future performance.

Estimates, judgments, and assumptions in these consolidated financial statements include, but are not limited to, those related to revenue recognition, accrued transaction losses, credit loss allowances from marketable debt securities, contingencies, valuation of the debt component of convertible senior notes, valuation of loans held for sale, goodwill, acquired intangible assets, income and other taxes, operating and financing lease right-of-use assets and related liabilities, assessing the likelihood of adverse outcomes from claims and disputes, and share-based compensation.

Concentration of Credit Risk

For the three months ended March 31, 2020 and March 31, 2019, the Company had no customer that accounted for greater than 10% of total net revenue.

The Company had two third-party payment processors that represented approximately 45% and 28% of settlements receivable as of March 31, 2020. As of December 31, 2019, the Company had three parties that represented approximately 48%, 29%, and 9% of settlements receivable. 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.

Recent Accounting Pronouncements

Recent Accounting Pronouncements  Recently adopted accounting pronouncements

In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments - Credit Losses, which requires the measurement and recognition of expected credit losses for financial assets held. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available for sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2020 and has applied the guidance prospectively. The Company has concluded that the adoption of the guidance did not have a material impact on the balances reported in its consolidated financial statements and has included disclosures under the guidance.

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 for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The amendments should be applied on a

prospective basis. The Company adopted this guidance effective January 1, 2020 and will apply the guidance during its annual goodwill impairment test for the year ending December 31, 2020. The adoption of this guidance did not 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 adopted this guidance effective January 1, 2020 and has applied the guidance prospectively, and included additional disclosures required by the new guidance relating to significant unobservable inputs used to develop Level 3 fair value measurements.

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 adopted this guidance effective January 1, 2020 and has applied the guidance prospectively. The adoption of this guidance did not have a material impact on the consolidated financial statements and related disclosures.

In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments — Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments. The amendments clarify the scope of the credit losses standard and hedge accounting among other things. The Company adopted ASC 326 on January 1, 2020 for credit losses. With respect to hedge accounting, the amendments address partial-term fair value hedges and fair value hedge basis adjustments, among other things. 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 as long an entity has also adopted the amendments in ASU 2016-13. The adoption of this guidance did not have a material impact on the consolidated financial statements and related disclosures. For entities which have already adopted ASU 2017-12, they are permitted to elect either retrospectively or prospectively adopt the amendments. The Company had previously adopted ASU 2017-12 on January 1, 2019 and therefore is eligible to and has prospectively adopted the amendments.

In December 2019, the FASB issued ASU 2019-12, Income Taxes: Simplifying the Accounting for Income Taxes, as part of its overall simplification initiative to reduce costs and complexity of applying accounting standards while maintaining or improving the usefulness of the information provided to users of financial statements. Among other things, the new guidance simplifies intraperiod tax allocation and reduces the complexity in accounting for income taxes with year-to-date losses in interim periods. The guidance is effective for financial statements issued for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years, with early adoption permitted. The Company early adopted this guidance effective January 1, 2020 and has applied the guidance prospectively. The adoption did not have a material impact on the consolidated financial statements and related disclosures.