Prosper Funding 10-Q 9 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Nov. 03, 2015
Document And Entity Information [Line Items]
Entity Registrant Name	PROSPER MARKETPLACE, INC
Entity Central Index Key	1,416,265
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		13,881,056
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Prosper Funding LLC [Member]
Document And Entity Information [Line Items]
Entity Registrant Name	Prosper Funding LLC
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		0

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets
Cash and Cash Equivalents	$ 120,522	$ 50,557
Restricted Cash	152,397	81,300
Available for Sale Investments, at Fair Value	47,104
Accounts Receivable	1,499	3,152
Loans Held for Sale, at Fair Value	34	8,463
Borrower Loans, at Fair Value	286,462	273,243
Property and Equipment, Net	20,067	14,424
Prepaid and Other Assets	9,024	4,856
Servicing Assets	11,300	4,163
Goodwill	16,825
Intangibles Assets, Net	2,979
Total Assets	668,213	440,158
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities	26,188	17,239
Payable to Investors	136,757	64,494
Class Action Settlement Liability	5,926	7,861
Notes at Fair Value	287,254	273,783
Repurchase Liability for Unvested Restricted Stock Awards	568	1,010
Total Liabilities	$ 456,693	$ 364,387
Commitments and Contingencies (see Note 13)
Convertible Preferred Stock – $0.01 par value; 35,477,685 shares authorized; 35,477,685 issued and outstanding as of September 30, 2015; 32,155,022 shares authorized; 30,699,957 issued and outstanding as of December 31, 2014. Aggregate liquidation preference of $325,952 as of September 30, 2015 and $160,952 as of December 31, 2014.	$ 275,938	$ 111,145
Stockholders' Deficit
Common Stock ($0.01 par value; 54,065,215 shares authorized; 14,058,509 issued and 13,871,322 outstanding as of September 30, 2015; and 47,928,883 shares authorized; 14,448,700 issued and 14,448,700 outstanding as of December 31, 2014)	123	102
Additional Paid-In Capital	97,131	86,340
Less: Treasury Stock	(23,417)	(303)
Accumulated Deficit	(138,259)	(121,513)
Accumulated Other Comprehensive Income	4
Total Stockholders' Deficit	(64,418)	(35,374)
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit	668,213	440,158
Prosper Funding LLC [Member]
Assets
Cash and Cash Equivalents	10,068	23,777
Restricted Cash	140,874	73,103
Short Term Investments	1,276	1,274
Loans Held for Sale, at Fair Value	34	8,463
Borrower Loans, at Fair Value	286,462	273,243
Property and Equipment, Net	5,492	1,125
Related Party Receivable		1,135
Servicing Assets	10,421	3,116
Other assets	22	4
Total Assets	454,649	385,240
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities	2,698	1,357
Payable to Related Party	468
Payable to Investors	135,582	63,809
Notes at Fair Value	287,254	273,783
Total Liabilities	426,002	338,949
Stockholders' Deficit
Member's Equity		29,619
Accumulated Deficit	28,647	16,672
Total Stockholders' Deficit	28,647	46,291
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit	$ 454,649	$ 385,240

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Apr. 30, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Convertible preferred stock, shares authorized (in shares)	35,477,685	35,477,685	32,155,022
Convertible preferred stock, shares issued (in shares)	35,477,685		30,699,957
Convertible preferred stock, shares outstanding (in shares)	35,477,685		30,699,957
Convertible preferred stock, aggregate liquidation preference	$ 325,952		$ 160,952
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	54,065,215	54,065,215	47,928,883
Common stock, shares issued (in shares)	14,058,509		14,448,700
Common stock, shares outstanding (in shares)	13,871,322		14,448,700

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Operating Revenue
Transaction Fees, Net	$ 46,842,000	$ 21,061,000	$ 111,984,000	$ 45,404,000
Servicing Fees, Net	4,652,000	1,401,000	10,796,000	2,512,000
Gain on Sale of Borrower Loans	4,263,000	1,268,000	9,881,000	2,246,000
Other Revenue	2,229,000	479,000	4,935,000	662,000
Total Operating Revenue	57,986,000	24,209,000	137,596,000	50,824,000
Interest Income
Interest Income on Borrower Loans	10,280,000	10,781,000	30,892,000	31,153,000
Interest Expense on Notes	(9,550,000)	(9,886,000)	(28,561,000)	(28,872,000)
Net Interest Income	730,000	895,000	2,331,000	2,281,000
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	(87,000)	21,000	(66,000)	291,000
Total Net Revenue	58,629,000	25,125,000	139,861,000	53,396,000
Expenses
Origination and Servicing	8,357,000	3,376,000	22,335,000	8,220,000
Sales and Marketing	31,844,000	11,201,000	76,996,000	27,028,000
General and Administrative	22,236,000	7,204,000	57,570,000	16,808,000
Total Expenses	62,437,000	21,781,000	156,901,000	52,056,000
Net Income (Loss) Before Taxes	(3,808,000)	3,344,000	(17,040,000)	1,340,000
Income Tax Expense	35,000		284,000
Net Income (Loss)	(3,843,000)	3,344,000	(17,324,000)	1,340,000
Less: Excess Return to Preferred Shareholders on Repurchase		(14,892,000)		(14,892,000)
Net Loss Attributable to Common Stockholders	$ (3,843,000)	$ (11,548,000)	$ (17,324,000)	$ (13,552,000)
Net Loss Per Share – Basic and Diluted	$ (0.34)	$ (1.26)	$ (1.58)	$ (1.57)
Weighted-Average Shares - Basic and Diluted	11,181,553	9,179,426	10,949,396	8,620,434
Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party	$ 16,544,000	$ 8,574,000	$ 40,430,000	$ 19,525,000
Servicing Fees, Net	4,408,000	1,253,000	9,945,000	2,379,000
Gain on Sale of Borrower Loans	4,263,000	1,240,000	9,881,000	2,218,000
Other Revenue	561,000		557,000
Total Operating Revenue	25,776,000	11,067,000	60,813,000	24,122,000
Interest Income
Interest Income on Borrower Loans	10,258,000	10,860,000	30,960,000	31,443,000
Interest Expense on Notes	(9,550,000)	(9,886,000)	(28,561,000)	(28,873,000)
Net Interest Income	708,000	974,000	2,399,000	2,570,000
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	(87,000)	21,000	(66,000)	302,000
Total Net Revenue	26,397,000	12,062,000	63,146,000	26,994,000
Expenses
Administration Fee - Related Party	18,236,000	7,371,000	41,615,000	16,401,000
Servicing	675,000	308,000	2,946,000	1,064,000
General and Administrative	358,000	129,000	903,000	315,000
Total Expenses	19,269,000	7,808,000	45,464,000	17,780,000
Income Tax Expense	0	0	0	0
Net Income (Loss)	$ 7,128,000	$ 4,254,000	$ 17,682,000	$ 9,214,000

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Other Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net Income (Loss)	$ (3,843)	$ 3,344	$ (17,324)	$ 1,340
Other Comprehensive Income, Before Tax
Change in Net Unrealized Gain on Available for Sale Investments, at Fair Value	4		4
Other Comprehensive Income, Before Tax	4		4
Other Comprehensive Income, Net of Tax	4		4
Comprehensive Income (Loss)	$ (3,839)	$ 3,344	$ (17,320)	$ 1,340

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from Operating Activities:
Net Income (Loss)	$ (17,324)	$ 1,340
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	66	(291)
Depreciation and Amortization	4,967	1,228
Gain on sales of Borrower Loans	(9,958)	(2,480)
Amortization and Change in Fair Value of Servicing Rights	3,322	372
Stock-Based Compensation Expense	7,439	763
Other, Net	94	278
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value	(2,426,963)	(919,770)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	2,435,253	909,897
Restricted Cash Except for those Related to Investing Activities	(69,651)	(26,976)
Accounts Receivable	1,800	(595)
Prepaid and Other Assets	(4,168)	(2,515)
Accounts Payable and Accrued Liabilities	7,483	5,030
Class Action Settlement Liability	(2,000)	(2,000)
Payable to Investors	72,263	22,596
Net Cash Provided by (Used in) Operating Activities	2,623	(13,123)
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	(142,103)	(130,857)
Principal Payments of Borrower Loans Held at Fair Value	111,864	88,974
Purchases of Property and Equipment	(9,518)	(4,806)
Maturities of Short Term Investments	1,274
Purchases of Short Term Investments	(1,275)
Purchases of Available for Sale Investments, at Fair Value	(47,100)
Acquisition of Business, Net of Cash Acquired	(19,000)
Changes in Restricted Cash Related to Investing Activities	(1,446)	869
Net Cash Used in Investing Activities	(107,304)	(45,820)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	142,246	130,756
Payment of Notes Held at Fair Value	(111,711)	(88,909)
Proceeds from Issuance of Convertible Preferred Stock, Net	164,793	69,958
Proceeds from Early Exercise of Stock Options and Issuance of Restricted Stock	1,714	454
Proceeds from Exercise of Vested Stock Options and Common Stock Warrants	849	161
Repurchase of Preferred Stock		(18,525)
Repurchase of Common Stock and Restricted Stock	(23,245)	(24)
Net Cash Provided by Financing Activities	174,646	93,871
Net Increase (Decrease) in Cash and Cash Equivalents	69,965	34,928
Cash and Cash Equivalents at Beginning of the Period	50,557	18,339
Cash and Cash Equivalents at End of the Period	120,522	53,267
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	28,698	28,961
Non-Cash Investing Activity-Accrual for Property and Equipment, Net	5	423
Non-Cash Investing Activity-Amount Payable for the Acquisition of Business	840
Prosper Funding LLC [Member]
Cash flows from Operating Activities:
Net Income (Loss)	17,682	9,214
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	66	(302)
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes	29	(28)
Depreciation and Amortization	2,483	788
Gain on sales of Borrower Loans	(9,958)	(2,480)
Amortization and Change in Fair Value of Servicing Rights	2,758	294
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value	(2,426,963)	(919,770)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	2,435,253	909,897
Restricted Cash Except for those Related to Investing Activities	(69,242)	(26,976)
Other Assets	(18)	(4)
Accounts Payable and Accrued Liabilities	1,415	328
Payable to Investors	71,773	21,906
Net Related Party Receivable/Payable	1,603	(879)
Net Cash Provided by (Used in) Operating Activities	26,881	(8,012)
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	(142,103)	(130,857)
Principal Payments of Borrower Loans Held at Fair Value	111,864	88,984
Purchases of Property and Equipment	(6,850)	(811)
Maturities of Short Term Investments	1,274	1,271
Purchases of Short Term Investments	(1,276)	(1,274)
Changes in Restricted Cash Related to Investing Activities	1,471	5,925
Net Cash Used in Investing Activities	(35,620)	(36,762)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	142,246	130,756
Payment of Notes Held at Fair Value	(111,711)	(88,909)
Net Cash Provided by Financing Activities	(4,970)	41,847
Net Cash Included in Transfer of Assets to Parent	(35,505)
Net Increase (Decrease) in Cash and Cash Equivalents	(13,709)	(2,927)
Cash and Cash Equivalents at Beginning of the Period	23,777	5,789
Cash and Cash Equivalents at End of the Period	10,068	2,862
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	28,698	28,961
Non-Cash Operating Activity - Servicing Rights Fair Value Adjustment	428
Non-Cash Financing Activity - Distribution to Parent	$ 249	$ 733

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2015
Basis of Presentation	1. Basis of Presentation The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. The preparation of Prosper’s condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in Prosper’s financial statements and accompanying notes. Prosper bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material. The accompanying interim condensed consolidated financial statements include the accounts of PMI and its wholly-owned subsidiaries, PFL and PHL. All intercompany balances have been eliminated in consolidation. On January 23, 2015, Prosper acquired all of the outstanding limited liability company units of American HealthCare Lending, LLC (“AHL”), a company that operated a cloud-based patient financing platform, and merged AHL with and into PHL, a newly, with PHL a newly established entity surviving the merger. Prosper’s condensed consolidated financial statements include PHL's results of operations and financial position from this date forward (see Note 8 – American HealthCare Lending Acquisition Reclassifications During the period ended September 30, 2015, Prosper changed the presentation of its revenue in the consolidated statements of operations. A new line called “Gain on Sales of Borrower Loans” was created with the amounts included in this line previously classified as “Other Revenue”. Prior period amounts have been reclassified to conform to the current presentation. Prosper also changed the definitions used to classify expenses. Expenses were previously classified as cost of services, compensation and benefits, marketing and advertising, depreciation and amortization, professional services, facilities and maintenance, class action settlement, loss on impairment of fixed assets and other. The revised classification approach replaces the previous classifications with origination and servicing, sales and marketing, and general and administration. The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Lastly, the subtotals were realigned to reflect the new presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper’s competitors. Prosper also changed the presentation of the servicing assets on its balance sheet by reclassifying them from “Prepaids and Other Assets” to “Servicing Assets”. Prior period amounts have been reclassified to conform to the current presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper’s competitors.
Prosper Funding LLC [Member]
Basis of Presentation	1. Basis of Presentation The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. Prosper Funding did not have any items of other comprehensive income (loss) during any of the periods presented in the condensed consolidated financial statements as of and for the three and nine months ended September 30, 2015 and 2014. The preparation of Prosper Funding's condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in its condensed consolidated financial statements and accompanying notes. Prosper Funding bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material. Reclassifications During the period ended September 30, 2015, Prosper Funding changed the presentation of its revenue in the consolidated statements of operations. A new line called “Gain on Sales of Borrower Loans” was created with the amounts included in this line previously classified as “Other Revenue”. The gain on sale related to the sale of Borrower Loans was reclassified from “Other Revenues” to a new line call “Gain on Sales of Borrower Loans.” Prosper Funding also changed the definitions used to classify expenses. Expenses were previously classified as cost of services, administration fee, depreciation and amortization, professional services and other operating expenses. The revised classification approach replaces the previous classifications with servicing, administration fee –related party, and general and administration. The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Prosper Funding believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper Funding’s competitors. Prosper Funding also changed the presentation of the servicing assets on its balance sheet by reclassifying them from “Prepaids and Other Assets” to “Servicing Assets”. Prior period amounts have been reclassified to conform to the current presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper Funding’s competitors.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Significant Accounting Policies [Line Items]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Prosper’s significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Investments at Fair Value, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature. Borrower Loans, Loans Held for Sale and Notes Borrower Loans, Loans Held for Sale and Notes are recorded at fair value. Prosper has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”). Loan Servicing Assets and Liabilities On January 1, 2015, Prosper elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities subsequent to initial recognition. ASC Subtopic 860-50, Servicing Assets and Liabilities, Recent Accounting Pronouncements In May 2014, as part of its ongoing efforts to assist in the convergence of US GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “ Revenue from Contracts with Customers In November 2014, the FASB issued ASU 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity to eliminate the use of different methods in practice and thereby reduce existing diversity in the accounting for hybrid financial instruments issued in the form of a share. For hybrid financial instruments issued in the form of a share, an entity should determine the nature of the contract by considering the economic characteristics and risks of the entire hybrid financial instrument. The existence or omission of any single term or feature does not necessarily determine the economic characteristics and risks of the host contract. This standard will be effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance. In February 2015, the FASB issued ASU 2015-02, " Consolidation (Topic 810): Amendments to the Consolidation Analysis. In April 2015, the FASB issued ASU 2015-05 “ Customers’ Accounting for Fees Paid in Cloud Computing Arrangement ”, which will be effective for the annual reporting period ending after December 15, 2015 . The guidance changes what a customer must consider in determining whether a cloud computing arrangement contains a software license. If the arrangement contains a software license, the customer would account for the fees related to the software license element in accordance with guidance related to internal use software; if the arrangement does not contain a software license, the customer would account for the arrangement as a service contract. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance. In September 2015, the FASB issued ASU No. 2015-16, Simplifying the Accounting for Measurement-Period Adjustments. The new guidance simplifies the accounting for measurement period adjustments in connection with business combinations by requiring that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
Prosper Funding LLC [Member]
Significant Accounting Policies [Line Items]
Summary of Significant Accounting Policies	2. Significant Accounting Policies Prosper Funding's significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Short Term Investments, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature. Borrower Loans, Loans Held for Sale and Notes Borrower Loans, Loans Held for Sale and Notes are recorded at fair value. Prosper Funding has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”). Loan Servicing Assets and Liabilities On January 1, 2015, Prosper Funding elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities, subsequent to initial recognition. ASC 860, Servicing Assets and Liabilities Recent Accounting Pronouncements In May 2014, as part of its ongoing efforts to assist in the convergence of U.S. GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “ Revenue from Contracts with Customers In February 2015, the FASB issued ASU 2015-02, " Consolidation (Topic 810): Amendments to the Consolidation Analysis.

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2015
Property and Equipment, Net	3. Property and Equipment, Net Property and equipment consist of the following (in thousands): September 30, December 31, 2015 2014 Property and equipment: Computer equipment $ 6,789 $ 3,824 Internal-use software and website development costs 11,186 4,486 Office equipment and furniture 2,327 1,904 Leasehold improvements 5,646 5,274 Assets not yet placed in service 3,717 4,361 Property and equipment 29,665 19,849 Less accumulated depreciation and amortization (9,598 ) (5,425 ) Total property and equipment, net $ 20,067 $ 14,424 Depreciation expense for the three months ended September 30, 2015 and 2014 was $1,309 thousand and $438 thousand respectively. Prosper capitalized internal-use software and website development costs in the amount of $1,950 thousand and $316 thousand for the three months ended September 30, 2015 and 2014, respectively. Depreciation expense for the nine months ended September 30, 2015 and 2014 was $4,426 thousand and $1,228 thousand respectively. Prosper capitalized internal-use software and website development costs in the amount of $5,883 thousand and $1,124 thousand for the nine months ended September 30, 2015 and 2014, respectively. Prosper recorded internal-use software and website development impairment charges of $0 and $233 thousand for the nine months ended September 30, 2015 and 2014 respectively, as a result of its decision to discontinue several software and website development projects. These charges are included in general and administration expenses on the condensed consolidated statement of operations.
Prosper Funding LLC [Member]
Property and Equipment, Net	3. Property and Equipment Property and equipment consist of the following (in thousands): September 30, December 31, 2015 2014 Property and equipment: Internal-use software and web site development costs $ 7,220 $ 4,042 Less accumulated depreciation and amortization (1,728 ) (2,917 ) Total property and equipment, net $ 5,492 $ 1,125 Depreciation expense for the three months ended September 30, 2015 and 2014 was $587 thousand and $249 thousand, respectively. Depreciation expense for the nine months ended September 30, 2015 and 2014 was $2,483 thousand and $788 thousand, respectively

Borrower Loans, Loans Held for

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	9 Months Ended
	Sep. 30, 2015
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	4. Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value The aggregate principal balances outstanding and fair values of Borrower Loans, Loans Held for Sale and Notes as of September 30, 2015 and December 31, 2014, are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Aggregate principal balance outstanding $ 285,837 $ 268,598 $ (284,562 ) $ (272,269 ) $ 44 $ 8,295 Fair value adjustments 625 4,645 (2,692 ) (1,514 ) (10 ) 168 Fair value $ 286,462 $ 273,243 $ (287,254 ) $ (273,783 ) $ 34 $ 8,463 At September 30, 2015, Borrower Loans, Loans Held for Sale and Notes had original terms to maturity of either 36 or 60 months; had monthly payments with fixed interest rates ranging from 5.32% to 33.04% and had various maturity dates through September 2020. At December 31, 2014, Borrower Loans, loans held for sale, and Notes had original maturities of either 36 or 60 months; had monthly payments with fixed interest rates ranging from 5.77% to 33.04% and had various maturity dates through December 2019. Approximately $1.3 million and $3.4 million represents the loss that is attributable to changes in the instrument specific credit risks related to Borrower Loans that were recorded in the change in fair value during the three and nine months ending September 30, 2015, respectively. As of September 30, 2015, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $1.7 million and a fair value of $0.7 million. As of December 31, 2014, Borrower Loans that were 90 days or more delinquent, had an aggregate principal amount of $1.7 million and a fair value of $0.6 million. Prosper places loans on non-accrual status when they are over 120 days past due. As of September 30, 2015 and December 31, 2014, Borrower Loans in non-accrual status had a fair value of $0.1 million and $0, respectively.
Prosper Funding LLC [Member]
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	4. Borrower Loans, Loans Held For Sale and Notes Held at Fair Value The fair value of the Borrower Loans, Loans Held for Sale and Notes are estimated using discounted cash flow methodologies based upon a set of valuation assumptions. The primary cash flow assumptions used to value such Borrower Loans, Loans Held for Sale and Notes include default rates derived from historical performance and discount rates applied to each credit grade based on the perceived credit risk of each credit grade. The obligation to pay principal and interest on any series of Notes is equal to the loan payments, if any, received on the corresponding Borrower Loan, net of the servicing fee. As such, the fair value of the Notes is approximately equal to the fair value of the Borrower Loans funded through the Note Channel, adjusted for the servicing fee and the timing of borrower payments subsequently disbursed to the Note holders. The effective interest rate associated with a series of Notes will be less than the interest rate earned on the corresponding Borrower Loan due to the servicing fee. The aggregate principal balances outstanding and fair values of Borrower Loans, Loans Held for Sale and Notes as of September 30, 2015 and December 31, 2014, are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Aggregate principal balance outstanding $ 285,837 $ 268,598 $ (284,562 ) $ (272,269 ) $ 44 $ 8,295 Fair value adjustments 625 4,645 (2,692 ) (1,514 ) (10 ) 168 Fair value $ 286,462 $ 273,243 $ (287,254 ) $ (273,783 ) $ 34 $ 8,463 At September 30, 2015, Borrower Loans, Loans Held for Sale and Notes had original terms to maturity of either 36 or 60 months; had monthly payments with fixed interest rates ranging from 5.32% to 33.04% and had various maturity dates through September 2020. At December 31, 2014, Borrower Loans, Notes and Loans Held for Sale had original maturities of either 36 or 60 months; had monthly payments with fixed interest rates ranging from 5.77% to 33.04% and had various maturity dates through December 2019. Significant Unobservable Inputs The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding’s Borrower Loans, Loans Held for Sale and Notes fair value measurements at September 30, 2015 and December 31, 2014: Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 2.9%-10.5% 3.2%-10.6% Default rate 2.7%-22.8% 2.6%-19.7% Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at September 30, 2015 for Borrower Loans, Loans Held for Sale and Notes funded are presented in the following table (in thousands): Borrower Loans and Loans Held for Sale Notes Discount rate assumption: 4.57 %* 4.57 %* Resulting fair value from: 100 basis point increase $ 283,684 $ 284,453 200 basis point increase 280,688 281,443 Resulting fair value from: 100 basis point decrease $ 289,923 $ 290,720 200 basis point decrease 293,172 293,985 Default rate assumption: 12.73 %* 12.73 %* Resulting fair value from: 200 basis point decrease $ 283,157 $ 283,915 100 basis point decrease 279,610 280,343 Resulting fair value from: 100 basis point increase $ 290,392 $ 291,201 200 basis point increase 294,042 294,877 * Represents weighted average assumptions considering all credit grades. These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a fixed basis points variation in assumptions generally cannot be determined because the relationship of the change in assumptions to the fair value may not be linear. Additionally, the impact of a variation in a particular assumption on the fair value is calculated while holding other assumptions constant. In reality, changes in one factor may lead to changes in other factors, which could impact the above hypothetical effects. The changes in the Borrower Loans, loans held for sale and Notes, which are Level 3 assets and liabilities measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at January 1, 2014 $ 233,105 $ (234,218 ) $ 3,206 $ 2,093 Originations 130,857 (130,756 ) 919,770 919,871 Principal repayments (88,984 ) 88,909 (533 ) (608 ) Borrower Loans sold to third parties - - (909,364 ) (909,364 ) Other changes (55 ) 67 16 28 Change in fair value (14,830 ) 15,132 - 302 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at January 1, 2015 $ 273,243 $ (273,783 ) $ 8,463 $ 7,923 Originations 142,103 (142,246 ) 2,426,963 2,426,820 Principal repayments (111,864 ) 111,711 (546 ) (699 ) Borrower Loans sold to third parties (447 ) 425 (2,434,707 ) (2,434,729 ) Other changes (108 ) 119 (18 ) (7 ) Change in fair value (16,465 ) 16,520 (121 ) (66 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at July 1, 2014 $ 252,971 $ (253,943 ) $ 7,998 $ 7,026 Originations 44,141 (44,077 ) 443,835 443,899 Principal repayments (31,244 ) 31,334 (403 ) (313 ) Borrower Loans sold to third parties - - (438,342 ) (438,342 ) Other changes 46 (22 ) 7 31 Change in fair value (5,821 ) 5,842 - 21 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at July 1, 2015 $ 284,200 $ (284,627 ) $ 1,431 $ 1,004 Originations 47,591 (47,670 ) 1,024,464 1,024,385 Principal repayments (38,407 ) 38,202 (4 ) (209 ) Borrower Loans sold to third parties (447 ) 425 (1,025,824 ) (1,025,846 ) Other changes 21 (18 ) (8 ) (5 ) Change in fair value (6,496 ) 6,434 (25 ) (87 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Approximately $1.3 million and $3.4 million, represents the loss that is attributable to changes in the instrument specific credit risks related to Borrower Loans that were recorded in the change in fair value during the three and nine months ending September 30, 2015 and September 30, 2014 respectively. As September 30, 2015, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $1.7 million and a fair value of $0.7 million. As December 31, 2014, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $1.5 million and a fair value of $0.14 million. Prosper Funding places Borrower Loans on non-accrual status when they are over 120 days past due. As of September 30, 2015 and December 31, 2014, Borrower Loans in non-accrual status had a fair value of $0.1 million and $0, respectively.

Loan Servicing Assets and Liabi

Loan Servicing Assets and Liabilities	9 Months Ended
	Sep. 30, 2015
Loan Servicing Assets and Liabilities	5. Loan Servicing Assets and Liabilities Prosper accounts for servicing assets and liabilities at their estimated fair values with changes in fair values recorded in servicing fees. The initial asset or liability is recognized when Prosper sells Borrower Loans to unrelated third-party buyers and the servicing rights are retained. Prior to January 1, 2015, the initial fair value of such servicing assets or liabilities was amortized in proportion to and over the servicing period. Subsequent to January 1, 2015, the servicing assets and liabilities are measured at fair value throughout the servicing period. The total gain recognized on the sale of such Borrower Loans was $4.3 million and $1.3 million for the three months ended September 30, 2015 and 2014, respectively. The total gain recognized on the sale of such Borrower Loans was $9.9 million and $2.2 million for the nine months ended September 30, 2015 and 2014, respectively. As of September 30, 2015, Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $3,116 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 5.32% to 31.90% and various maturity dates through September 2020. At December 31, 2014, Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $1,358 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and various maturity dates through December 2019. The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes assumptions of the market servicing rate, the default rate and discount rate as important inputs (see note 6).
Prosper Funding LLC [Member]
Loan Servicing Assets and Liabilities	5. Loan Servicing Assets and Liabilities Prosper Funding accounts for servicing assets and liabilities at their estimated fair values with changes in fair values recorded in servicing fees. The initial asset or liability is recognized when Prosper Funding sells Borrower Loans to unrelated third-party buyers and the servicing rights are retained. Prior to January 1, 2015, the initial fair value of such servicing assets or liabilities was amortized in proportion to and over the servicing period. Subsequent to January 1, 2015, the servicing assets and liabilities are measured at fair value throughout the servicing period. The total gain recognized on the sale of such Borrower Loans was $1.2 million and $2.2 million for the three and nine months ended September 30, 2014, respectively. Effective January 1, 2015, Prosper Funding elected to adopt the fair value method to measure the servicing assets and liabilities for all classes subsequent to initial recognition. The total gain recognized on the sale of the Borrower Loans sold to unrelated third-party buyers was $4.3 million and $9.9 million for the three and nine months ended September 30, 2015, respectively. At September 30, 2015, Borrower Loans that were sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $2,078 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 5.32% to 31.90% and various maturity dates through September 2020. At December 31, 2014, Borrower Loans that were sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $1,045 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and various maturity dates through December 2019. The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes assumptions of the market servicing rate, the default rate and discount rate as important inputs. Significant Unobservable Inputs The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding's servicing asset/liability fair value measurements at September 30, 2015 and December 31, 2014: Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 15% - 25% 15% - 25% Default rate 2.1% - 21.8% 2.6% - 26.3% Market servicing rate 0.625% 0.625% - 0.70% Loan Servicing Assets and Liabilities Activity: The following table presents additional information about Level 3 servicing assets and liabilities recorded at fair value for the three months ended March 31, 2015 (in thousands). Servicing Servicing Assets Liabilities Amortized cost at January 1, 2015 $ 3,116 $ 624 Adjustment to adopt fair value measurement 399 (29 ) Fair value at January 1, 2015 3,515 595 Additions 10,204 246 Less: Transfers to PMI (249 ) - Less: changes in fair value (3,049 ) (291 ) Fair value at September 30, 2015 $ 10,421 $ 550 Servicing Servicing Assets Liabilities Fair value at July 1, 2015 $ 7,634 $ 606 Additions 4,367 53 Less: Transfers to PMI - - Less: changes in fair value (1,580 ) (109 ) Fair value at September 30, 2015 $ 10,421 $ 550 Servicing Asset and Liability Fair Value Input Sensitivity: The following table presents the estimated impact on Prosper Funding’s estimated fair value of servicing assets and liabilities, calculated using different market servicing rates and different default rates as of September 30, 2015 (in thousands, except percentages). Servicing Assets Servicing Liabilities Weighted average market servicing rate assumptions 0.625 % 0.625 % Resulting fair value from: Servicing rate increase to 0.65% $ 9,952 $ (605 ) Servicing rate decrease to 0.60% $ 11,547 $ (496 ) Weighted average default assumptions 14 % 14 % Resulting fair value from: 100 basis point increase $ 10,230 $ (550 ) 100 basis point decrease $ 10,617 $ (551 ) These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a 10% variation in assumptions generally cannot be determined because the relationship of the change in assumptions to the fair value may not be linear. Additionally, the impact of a variation in a particular assumption on the fair value is calculated while holding other assumptions constant. In reality, changes in one factor may lead to changes in other factors, which could impact the above hypothetical effects.

Available for Sale Investments,

Available for Sale Investments, at Fair Value	9 Months Ended
	Sep. 30, 2015
Investments Debt And Equity Securities [Abstract]
Available for Sale Investments, at Fair Value	6. Available for Sale Investments, at Fair Value Prosper purchased available for sale investments during the third quarter of 2015. Available for sale investments are recorded at fair value and unrealized gains and losses are reported, net of taxes, in accumulated other comprehensive income (loss) included in stockholders' equity unless management determines that an investment is other-than-temporarily impaired (OTTI). The amortized cost, gross unrealized gains and losses, and fair value of available for sale investments as of September 30, 2015, are as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate debt securities $ 33,618 $ 18 $ (15 ) $ 33,621 Commercial paper 11,481 - - 11,481 US Treasury securities 2,001 1 - 2,002 Total Available for Sale Investments $ 47,100 $ 19 $ (15 ) $ 47,104 A summary of available for sale investments with unrealized losses as of September 30, 2015, aggregated by category and period of continuous unrealized loss, is as follows: Less than 12 months 12 months or longer Total Fair Value Unrealized losses Fair Value Unrealized losses Fair Value Unrealized losses Corporate Debt Securities $ 12,602 $ (15 ) $ - $ - $ 12,602 $ (15 ) Total investments with unrealized losses $ 12,602 $ (15 ) $ - $ - $ 12,602 $ (15 ) Management evaluates whether available for sale investment are OTTI on a quarterly basis. Debt securities with unrealized losses are considered OTTI if Prosper intends to sell the investment or if it is more likely than not that it will be required to sell such investment before any anticipated recovery. If management determines that an investment is OTTI under these circumstances, the impairment recognized in earnings is measured as the entire difference between the amortized cost and then-current fair value. An investment is also OTTI if management does not expect to recover all of the amortized cost of the investment. In this circumstance, the impairment recognized in earnings represents estimated credit losses, and is measured by the difference between the present value of expected cash flows and the amortized cost of the investment. Management utilizes cash flow models to estimate the expected future cash flow from the securities to estimate the credit loss. Expected cash flows are discounted using the investment's effective interest rate. The evaluation of whether Prosper expects to recover the amortized cost of a investment is inherently judgmental. The evaluation includes the assessment of several bond performance indicators, including the current price and magnitude of the unrealized loss and whether Prosper has received all scheduled principal and interest payments. There were no impairment charges recognized during the three and nine months ending September 30, 2015. The maturities of available for sale investments at September 30, 2015, are as follows: Within 1 year After 1 year through 5 years After 5 years to 10years After 10 years Total Corporate debt securities $ 20,496 $ 13,125 $ - $ - $ 33,621 Commercial paper 11,481 - - - 11,481 US Treasury securities - 2,002 - - 2,002 Total Fair Value $ 31,977 $ 15,127 $ - $ - $ 47,104 Total Amortized Cost $ 31,987 $ 15,113 $ - $ - $ 47,100 Prosper did not sell any available for sale investments during the three and nine months ended September 30, 2015 and as a result did not realize any gains or losses on sale.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	7. Fair Value of Assets and Liabilities For a description of the fair value hierarchy and Prosper’s fair value methodologies, see "Part IV - Item 15 - Financial Statements and Supplementary Data - Note 2 - Summary of Significant Accounting Policies" in Prosper’s Annual Report on Form 10-K for the year ended December 31, 2014, except for Investments at Fair value which is discussed below. Prosper did not transfer any assets or liabilities in or out of level 3 during the three months or nine months ended September 30, 2015 or the year ended December 31, 2014. Financial Instruments Recorded at Fair Value The fair value of the Borrower Loans, Loans Held for Sale and Notes are estimated using discounted cash flow methodologies based upon a set of valuation assumptions. The primary cash flow assumptions used to value such Borrower Loans, Loans Held for Sale and Notes include default rates derived from historical performance and discount rates applied to each credit grade based on the perceived credit risk of each credit grade. The obligation to pay principal and interest on any series of Notes is equal to the loan payments, if any, received on the corresponding Borrower Loan, net of the servicing fee. As such, the fair value of the Notes is approximately equal to the fair value of the Borrower Loans funded through the Note Channel, adjusted for the servicing fee and the timing of borrower payments subsequently disbursed to the Note holders. The effective interest rate associated with a series of Notes will be less than the interest rate earned on the corresponding Borrower Loan due to the servicing fee. Investments held at fair value consists of available for sale investments. The available for sale investments consist of corporate and government bonds. When available, Prosper uses quoted prices in active markets to measure the fair value of securities available for sale. When utilizing market data and bid-ask spreads, Prosper uses the price within the bid-ask spread that best represents fair value. When quoted prices do not exist, Prosper uses prices obtained from independent third-party pricing services to measure the fair value of investment assets. Prosper generally obtains prices from at least two independent pricing sources for assets recorded at fair value. Prosper's primary independent pricing service provides prices based on observable trades and discounted cash flows that incorporate observable information, such as yields for similar types of securities (a benchmark interest rate plus observable spreads) and weighted-average maturity for the same or similar securities. Prosper compares the prices obtained from its primary independent pricing service to the prices obtained from the additional independent pricing services to determine if the price obtained from the primary independent pricing service is reasonable. Prosper does not adjust the prices received from independent third-party pricing services unless such prices are inconsistent with the definition of fair value and result in a material difference in the recorded amounts. The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands): September 30, 2015 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ - $ - $ 286,462 $ 286,462 Loans Held for Sale - 34 34 Available for Sale Investments, at Fair Value - 47,104 - 47,104 Servicing Assets - 11,300 11,300 Total Assets - 47,104 297,796 344,900 Liabilities: Notes $ - $ - $ 287,254 $ 287,254 Servicing Liabilities - - 550 550 Total Liabilities $ - $ - $ 287,804 $ 287,804 December 31, 2014 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ - $ - $ 273,243 $ 273,243 Loans Held for Sale - - 8,463 8,463 Servicing Assets - 4,709 4,709 Total Assets - - 286,415 286,415 Liabilities: Notes $ - $ - $ 273,783 $ 273,783 Servicing Liabilities - - 595 595 Total Liabilities $ - $ - $ 274,378 $ 274,378 As Prosper’s Borrower Loans, Loans Held for Sale, Notes and loan servicing rights do not trade in an active market with readily observable prices, Prosper uses significant unobservable inputs to measure the fair value of these assets and liabilities. Financial instruments are categorized in the level 3 valuation hierarchy based on the significance of unobservable factors in the overall fair value measurement. These fair value estimates may also include observable, actively quoted components derived from external sources. As a result, the realized and unrealized gains and losses for assets and liabilities within the level 3 category may include changes in fair value that were attributable to both observable and unobservable inputs. Significant Unobservable Inputs The following tables present quantitative information about the significant unobservable inputs used for Prosper’s level 3 fair value measurements at September 30, 2015 and December 31, 2014: Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 2.9%-10.5% 3.3%-10.6% Default rate 2.7%-22.8% 2.6%-19.7% Servicing Rights Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 15% - 25% 15% - 25% Default rate 2.0% - 21.8% 2.6% - 26.3% Market servicing rate 0.625% 0.625% - 0.70% At September 30, 2015, the discounted cash flow methodology used to estimate the Note fair values used the same projected cash flows as the related Borrower Loans. As demonstrated in the following table, the fair value adjustments for Borrower Loans were largely offset by the fair value adjustments of the Notes due to the member payment dependent design of the Notes and because the principal balances of the Borrower Loans approximated the principal balances of the Notes. The following tables present additional information about level 3 Borrower Loans, Loans Held for Sale and Notes measured at fair value on a recurring basis: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2015 $ 284,200 $ (284,627 ) $ 1,431 $ 1,004 Purchase of Borrower Loans/Issuance of Notes 47,591 (47,670 ) 1,024,464 1,024,385 Principal repayments (38,407 ) 38,202 (4 ) (209 ) Borrower Loans sold to third parties (447 ) 425 (1,025,824 ) (1,025,846 ) Other changes 21 (18 ) (8 ) (5 ) Change in fair value (6,496 ) 6,434 (25 ) (87 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2014 $ 252,971 $ (253,943 ) $ 7,998 $ 7,026 Purchase of Borrower Loans/Issuance of Notes 44,141 (44,077 ) 443,835 443,899 Principal repayments (31,244 ) 31,334 (403 ) (313 ) Borrower Loans sold to third parties - - (438,342 ) (438,342 ) Other changes 46 (22 ) 7 31 Change in fair value (5,821 ) 5,842 - 21 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2015 $ 273,243 $ (273,783 ) $ 8,463 $ 7,923 Purchase of Borrower Loans/Issuance of Notes 142,103 (142,246 ) 2,426,963 2,426,820 Principal repayments (111,864 ) 111,711 (546 ) (699 ) Borrower Loans sold to third parties (447 ) 425 (2,434,707 ) (2,434,729 ) Other changes (108 ) 119 (18 ) (7 ) Change in fair value (16,465 ) 16,520 (121 ) (66 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2014 $ 233,105 $ (234,218 ) $ 3,206 $ 2,093 Purchase of Borrower Loans/Issuance of Notes 130,857 (130,756 ) 919,770 919,871 Principal repayments (88,974 ) 88,909 (533 ) (598 ) Borrower Loans sold to third parties - - (909,364 ) (909,364 ) Other changes (54 ) 67 16 29 Change in fair value (14,841 ) 15,132 - 291 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 The following table presents additional information about level 3 servicing assets and liabilities measured at fair value on a recurring basis: Servicing Assets Servicing Liabilities Fair Value at July 1, 2015 $ 8,682 $ 606 Additions 4,370 53 Less: Changes in fair value (1,752 ) (109 ) Fair value at September 30, 2015 $ 11,300 $ 550 Servicing Assets Servicing Liabilities Amortized cost at January 1, 2015 $ 4,163 $ 624 Adjustment to adopt fair value measurement 546 (29 ) Fair value at January 1, 2015 4,709 595 Additions 10,204 246 Less: Changes in fair value (3,613 ) (291 ) Fair value at September 30, 2015 $ 11,300 $ 550 Significant Recurring Level 3 Fair Value Asset and Liability Input Sensitivity Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at September 30, 2015 for Borrower Loans, Loans Held for Sale and Notes funded through the Note Channel are presented in the following table (in thousands, except percentages): Borrower Loans and Loans Held for Sale Notes Discount rate assumption: 4.57 %* 4.57 %* Resulting fair value from: 100 basis point increase $ 283,684 $ 284,453 200 basis point increase 280,688 281,443 Resulting fair value from: 100 basis point decrease $ 289,923 $ 290,720 200 basis point decrease 293,172 293,985 Default rate assumption: 12.73 %* 12.73 %* Resulting fair value from: 100 basis point increase $ 283,157 $ 283,915 200 basis point increase 279,610 280,343 Resulting fair value from: 100 basis point decrease $ 290,392 $ 291,201 200 basis point decrease 294,042 294,877 * Represents weighted average assumptions considering all credit grades. These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a fixed basis points variation in assumptions generally cannot be determined because the relationship of the change in assumptions to the fair value may not be linear. Additionally, the impact of a variation in a particular assumption on the fair value is calculated while holding other assumptions constant. In reality, changes in one factor may lead to changes in other factors, which could impact the above hypothetical effects. The following table presents the estimated impact on Prosper’s estimated fair value of servicing assets and liabilities, calculated using different market servicing rates and different default rates as of September 30, 2015 (in thousands, except percentages). Servicing Assets Servicing Liabilities Market servicing rate assumptions 0.625 % 0.625 % Resulting fair value from: Market servicing rate increase to 0.65% $ 10,462 $ (605 ) Market servicing rate decrease to 0.60% $ 12,138 $ (496 ) Weighted average default assumptions 14 % 14 % Resulting fair value from: 100 basis point increase $ 11,091 $ (550 ) 100 basis point decrease $ 11,510 $ (551 ) These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a 10% variation in assumptions generally cannot be determined because the relationship of the change in assumptions to the fair value may not be linear. Additionally, the impact of a variation in a particular assumption on the fair value is calculated while holding other assumptions constant. In reality, changes in one factor may lead to changes in other factors, which could impact the above hypothetical effects.

American HealthCare Lending Acq

American HealthCare Lending Acquisition	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
American HealthCare Lending Acquisition	8. American HealthCare Lending Acquisition On January 23, 2015, Prosper acquired all of the outstanding limited liability company interests of AHL, and merged AHL with and into PHL, with PHL surviving the merger (the “Merger”). Under the terms of the purchase agreement, the sellers of AHL received an aggregate of $20.2 million in cash on the closing date and will receive $0.8 million in cash one year after the closing date subject to general representations and warranties. PHL operates a cloud-based patient financing company for healthcare providers in the cosmetic, dentistry, bariatric surgery, fertility, plastic surgery and other markets. PHL has relationships with a nationwide network of healthcare providers. These healthcare providers refer individuals who would like to finance medical procedures to the Prosper platform. The preliminary purchase price allocation as of the merger date is as follows (in thousands): Fair Value Assets: Cash $ 1,219 Accounts Receivable 147 Property, equipment and software 6 Other assets 63 Identified intangible assets 3,520 Goodwill 16,825 Liabilities: Accrued expenses and other liabilities 708 Total purchase consideration $ 21,072 The allocation of the purchase price is preliminary and subject to further adjustment as information relative to closing date balances and related tax balances are finalized. The goodwill balance is primarily attributed to expected operational synergies and the assembled workforce. Goodwill is expected to be deductible for U.S. income tax purposes. Intangible assets as of September 30, 2015 are as follows (in thousands): September 30, 2015 Gross Carrying Value Accumulated Amortization Net Carrying Value Remaining Useful Life (In Years) Customer relationships $ 2,650 $ (321 ) $ 2,329 9.3 Technology 810 (180 ) 630 2.3 Brand name 60 (40 ) 20 0.3 Total intangible assets subject to amortization $ 3,520 $ (541 ) $ 2,979 The customer relationship intangible assets are being amortized on an accelerated basis over a 10 year period. The technology and brand name intangible assets are being amortized on a straight line basis over three and one years, respectively. Amortization expense associated with intangible assets for the three and nine months ended September 30, 2015 was $203 thousand and $541 thousand respectively. Prosper valued the customer relationships, technology and brand name assets using the income approach. Significant assumptions include forecasts of revenues, costs of revenues, operating expenses and customer attrition rates. The impact was not material on Prosper’s revenue and net earnings on a pro forma basis for all periods presented.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Net Income Per Share	9. Net Loss Per Share The weighted average shares used in calculating basic and diluted net loss per share excludes certain shares that are disclosed as outstanding shares in the condensed consolidated balance sheets because such shares are restricted as they were associated with options that were early exercised and continue to remain unvested. Basic and diluted net loss per share was calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Numerator: Net Income (loss) (in thousands) $ (3,843 ) $ 3,344 $ (17,324 ) $ 1,340 Less: Excess return to preferred shareholders on repurchase - (14,892 ) - (14,892 ) Net loss available to common stockholders for basic and diluted loss per share (in thousands) $ (3,843 ) $ (11,548 ) $ (17,324 ) $ (13,552 ) Denominator: Weighted average shares used in computing basic and diluted net loss per share 11,181,553 9,179,426 10,949,396 8,620,434 Basic and Diluted net loss per share $ (0.34 ) $ (1.26 ) $ (1.58 ) $ (1.57 ) The following common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (shares) (shares) (shares) (shares) Excluded securities: Convertible preferred stock issued and outstanding 35,477,685 30,699,957 35,477,685 30,699,957 Stock options issued and outstanding 7,012,630 4,540,101 6,518,522 4,540,101 Unvested stock options exercised 2,381,385 4,768,109 2,381,385 4,768,109 Warrants issued and outstanding 120,471 197,870 120,471 197,870 Total common stock equivalents excluded from diluted net loss per common share computation 44,992,171 40,206,037 44,498,063 40,206,037

Convertible Preferred Stock and

Convertible Preferred Stock and Stockholders' Deficit	9 Months Ended
	Sep. 30, 2015
Stockholders Equity Note [Abstract]
Convertible Preferred Stock and Stockholders' Deficit	10. Convertible Preferred Stock and Stockholders’ Deficit Convertible Preferred Stock Under Prosper’s amended and restated certificate of incorporation, preferred stock is issuable in series, and the board of directors is authorized to determine the rights, preferences, and terms of each series. In April 2015, Prosper issued and sold 4,777,728 shares of new Series D (“New Series D”) convertible preferred stock in a private placement at a purchase price of $34.54 per share for proceeds of approximately $164.8 million, net of issuance costs. The New Series D convertible preferred stock was sold in reliance on the exemption from the registration requirements of the Securities Act set forth in Section 4(2) of the Securities Act and Regulation D promulgated thereunder regarding sales by an issuer not involving a public offering. The purpose of the New Series D private placement was to raise funds for general corporate needs and for the share repurchase discussed below. Dividends Dividends on shares of the New Series D convertible preferred stock are payable only when, as, and if declared by the Board of Directors. No dividends will be paid with respect to the common stock until any declared dividends on the New Series A, New Series B, New Series C and New Series D convertible preferred stock have been paid or set aside for payment to the New Series A, New Series B, New Series C and New Series D convertible preferred stockholders. After payment of any such dividends, any additional dividends or distributions will be distributed among all holders of common stock and preferred stock in proportion to the number of shares of common stock that would be held by each such holder if all shares of preferred stock were converted to common stock at the then effective conversion rate. To date, no dividends have been declared on any of Prosper’s preferred stock or common stock, and there are no dividends in arrears at September 30, 2015. Liquidation Rights Prosper’s convertible preferred stock has been classified as temporary equity on the accompanying balance sheets. The preferred stock is not redeemable; however, in the event of a voluntary or involuntary liquidation, dissolution, change in control or winding up of Prosper, holders of convertible preferred stock may have the right to receive such convertible preferred stock’s liquidation preference under the terms of Prosper’s certificate of incorporation. The New Series D convertible preferred stock is entitled to receive, on a pari passu Voting Each holder of shares of convertible preferred stock is entitled to the number of votes equal to the number of shares of common stock into which such shares of convertible preferred stock could be converted and has voting rights and powers equal to the voting rights and powers of the common stock. The holders of convertible preferred stock and the holders of common stock vote together as a single class (except with respect to certain matters that require separate votes or as required by law), and are entitled to notice of any stockholders’ meeting in accordance with Prosper’s bylaws. The number of authorized, issued and outstanding shares, their par value and liquidation preference for each series of convertible preferred stock as of September 30, 2015 are disclosed in the table below (amounts in thousands except share and per share amounts): Convertible Preferred Stock Par Value Authorized shares Outstanding and Issued shares Liquidation Preference New Series A $ 0.01 13,711,644 13,711,644 $ 19,774 Series A-1 0.01 4,952,183 4,952,183 49,522 New Series B 0.01 7,155,176 7,155,176 21,581 New Series C 0.01 4,880,954 4,880,954 70,075 New Series D 0.01 4,777,728 4,777,728 165,000 35,477,685 35,477,685 $ 325,952 Common Stock Prosper, through its amended and restated certificate of incorporation, is the sole issuer of common stock and related options and warrants. In April 2015, Prosper amended and restated its certificate of incorporation to effect an increase in the number of authorized shares of stock. The total number of shares of stock which Prosper has the authority to issue is 89,542,900, consisting of 54,065,215 shares of common stock, $0.01 par value per share, and 35,477,685 shares of preferred stock, $0.01 par value per share. As of September 30, 2015, 14,058,509 shares of common stock were issued and 13,871,322 shares of common stock were outstanding. As of December 31, 2014, 14,448,700 shares of common stock were issued and 14,448,700 shares of common stock were outstanding. Each holder of common stock is entitled to one vote for each share of common stock held. On June 12, 2015, Prosper repurchased 777,025 shares of common stock from certain employees at a price equal to $34.54 per share for an aggregate purchase price of $26.8 million. As the purchase price exceeded the fair value of common stock at the time of the repurchase, Prosper recognized compensation costs of $5.7 million of which $0.13 million is recorded in Origination and Servicing, $0.04 million in Sales and Marketing and $5.50 million in General and Administrative on the Condensed Consolidated Statement of Operations. As part of this transaction Prosper repurchased 721,419 shares for a total of $24.9 million from Prosper’s executive officers. On September 11, 2015, Prosper repurchased 68,073 shares of common stock from certain employees at a price equal to $34.54 per share for an aggregate purchase price of $2.4 million. As the purchase price exceeded the fair value of common stock at the time of the repurchase, Prosper recognized compensation costs of $0.5 million of which $0.2 million is recorded in Origination and Servicing, $0.03 million in Sales and Marketing and $0.2 million in General and Administrative on the Condensed Consolidated Statement of Operations. None of these repurchases were from Prosper’s executive officers. Common Stock Issued upon Exercise of Stock Options During the nine months ended September 30, 2015 Prosper issued 628,150 shares of common stock, upon the exercise of options for cash proceeds of $0.77 million, of which 15,209 shares were unvested. With the approval of Prosper’s board of directors, Prosper allows certain employees and directors to exercise stock options granted under the 2005 Plan prior to vesting. The unvested shares are subject to Prosper’s repurchase right at the original exercise price. Early exercises of options are not deemed to be substantive exercises for accounting purposes and therefore, amounts received for early exercises are initially recorded in Repurchase Liability for Unvested Restricted Stock Awards. Such amounts are reclassified to common stock and additional paid-in capital as the underlying shares vest. At September 30, 2015 and December 31, 2014, there were 2,381,385 and 4,112,269 shares respectively of restricted stock outstanding that remain unvested and subject to Prosper’s right of repurchase. For the nine months ended September 30, 2015, Prosper repurchased 291,536 shares of restricted stock for $130 thousand upon termination of employment of various employees. Common Stock Issued upon Exercise of Warrants For the nine months ended September 30, 2015, Prosper issued 38,674 shares of common stock upon the exercise of warrants for aggregate proceeds of $120 thousand.

Shared Based Incentive Plan and

Shared Based Incentive Plan and Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shared Based Incentive Plan and Compensation	11. Share Based Incentive Plan and Compensation In 2005, Prosper’s stockholders approved the adoption of the 2005 Stock Plan. In December 2010, Prosper’s stockholders approved the adoption of the Amended and Restated 2005 Stock Plan (the “2005 Plan”). The 2005 Plan expired during the three months ending September 30, 2015 and Prosper’s stockholders approved the adoption of the 2015 Equity Incentive Plan (the “2015 Plan”). As of September 30, 2015 under the 2005 Plan, up to 14,273,773 shares of common stock are reserved and may be issued to employees, directors, and consultants by Prosper’s board of directors and stockholders to promote the success of its business. As of September 30, 2015 under the 2015 Plan, up to 2,349,901 shares of common stock are reserved and may be granted to employees, directors, and consultants by Prosper’s board of directors and stockholders to promote the success of its business. Options generally vest 25% one year from the vesting commencement date and 1/48 th At September 30, 2015, there were 1,537,101 shares available for grant under the 2015 Plan and zero shares available for grant under the 2005 Plan. Early Exercised Stock Options The activity of options that were early exercised under the 2005 Plan for the nine months ended September 30, 2015 is below: Early exercised options, unvested Weighted average exercise price Balance as of January 1, 2015 4,112,269 $ 0.25 Exercise of non-vested stock options 15,209 5.54 Repurchase of restricted stock (291,536 ) 0.45 Restricted stock vested (1,454,557 ) 0.27 Balance as of September 30, 2015 2,381,385 $ 0.24 Additional information regarding the unvested early exercised stock options outstanding as of September 30, 2015 is as follows: Options Outstanding Range of Exercise Number Weighted –Avg. Weighted –Avg. Prices Outstanding Remaining Life Exercise Price $ 0.10 2,220,565 1.39 $ 0.10 0.57 116,814 2.35 0.57 5.65 41,506 2.84 5.65 18.11 2,500 3.42 18.11 $0.10 - $18.11 2,381,385 1.46 $ 0.24 Stock Option Activity Stock option activity under the 2005 Plan and 2015 Plan is summarized for the nine months ended September 30, 2015 below: Options Issued and Outstanding Weighted- Average Exercise Price Balance as of January 1, 2015 4,994,998 $ 1.85 Options granted 3,358,114 20.55 Options exercised – vested (612,941 ) 1.12 Options exercised – nonvested (15,209 ) 5.54 Options forfeited (689,484 ) 4.83 Balance as of September 30, 2015 7,035,478 10.53 Options vested and/or exercisable at September 30, 2015 5,554,074 8.43 For the nine months ended September 30, 2015, Prosper granted stock options to purchase 3,358,114 shares of common stock with a weighted average grant date fair value of $14.52 per share and an estimated aggregate fair value of approximately $48.8 million. Other Information Regarding Stock Options Additional information regarding common stock options outstanding as of September 30, 2015 is as follows: Options Outstanding Options Vested and Exercisable Weighted – Weighted – Weighted - Range of Avg. Avg. Avg. Exercise Number Remaining Exercise Number Exercise Prices Outstanding Life Price Vested Price $0.10 - $0.99 2,553,872 8.33 $ 0.55 2,553,872 $ 0.55 1.00 - 4.99 180,372 5.56 1.67 176,271 1.67 5.00 - 9.99 1,075,995 8.82 5.64 456,492 5.64 10.00 - 19.99 2,367,439 9.38 18.11 2,367,439 18.11 20.00 - 27.45 857,800 9.74 27.34 - - $0.10 - $27.45 7,035,478 8.86 $ 10.53 5,554,074 $ 8.49 The fair value of options granted to employees is estimated on the grant date using the Black-Scholes option valuation model. This valuation model for stock-based compensation expense requires Prosper to make assumptions and judgments about the variables used in the calculation, including the fair value of its common stock, the expected term (the period of time that the options granted are expected to be outstanding), the volatility of its common stock value, a risk-free interest rate, and expected dividends. Given the absence of a publicly traded market, Prosper considered numerous objective and subjective factors to determine the fair value of its common stock at each grant date. These factors included, but were not limited to, (i) contemporaneous valuations of common stock performed by unrelated third-party specialists; (ii) the prices for its preferred stock sold to outside investors; (iii) the rights, preferences and privileges of its preferred stock relative to its common stock; (iv) the lack of marketability of its common stock; (v) developments in its business; (vi) secondary transactions of its common and preferred shares and (vii) the likelihood of achieving a liquidity event, such as an initial public offering or a merger or acquisition of Prosper, given prevailing market conditions. Prosper also estimates forfeitures of unvested stock options. To the extent actual forfeitures differ from the estimates, the difference will be recorded as a cumulative adjustment in the period estimates are revised. No compensation cost is recorded for options that do not vest. As Prosper’s stock is not publicly traded, the expected volatility of its stock price is based on an average of the historical volatilities of the common stock of several entities with characteristics similar to those of Prosper. The expected term assumptions is based on the expected life of the stock options giving consideration to the contractual terms and vesting schedules. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. Prosper uses an expected dividend yield of zero as it does not anticipate paying any dividends in the foreseeable future. Expected forfeitures are based on Prosper’s historical experience. The fair value of Prosper’s stock option awards for the three months and nine months ended September 30, 2015 and 2014 was estimated at the date of grant using the Black-Scholes model with the following average assumptions: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Volatility of common stock 50.71 % 57.63 % 56.14 % 67.95 % Risk-free interest rate 1.70 % 1.72 % 1.71 % 1.76 % Expected life 6.0 years 5.9 years 6.0 years 5.6 years Dividend yield 0 % 0 % 0 % 0 % During the nine months ended September 30, 2015, Prosper issued 90,000 shares of restricted stock to employees at a purchase price of $18.11 per share. One third of these shares vest on the annual anniversary date of the grant over the three year term of the agreement. The following table presents the amount of stock-based compensation related to stock-based awards granted to employees recognized in Prosper’s condensed consolidated statements of operations during the three and nine months ended September 30, 2015 and 2014 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Origination and servicing $ 369 $ 14 $ 805 $ 139 Sales and marketing 669 22 1,734 53 General and administrative 2,209 237 4,900 571 Total stock based compensation $ 3,247 $ 273 $ 7,439 $ 763 During the three months ended September 30, 2015 and 2014, Prosper capitalized $202 thousand and $8 thousand respectively, of stock-based compensation as internal use software and website development costs. During the nine months ended September 30, 2015 and 2014, Prosper capitalized $499 thousand and $18 thousand respectively, of stock-based compensation as internal use software and website development costs. As of September 30, 2015, the unamortized stock-based compensation expense adjusted for forfeiture estimates related to Prosper’s employees’ unvested stock-based awards was approximately $36.4 million, which will be recognized over the remaining weighted-average vesting period of approximately 3.2 years.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Taxes [Line Items]
Income Taxes	12. Income Taxes For the three and nine months ended September 30, 2015, Prosper recognized $35 thousand and $284 thousand respectively of income tax expense. The income tax expense relates to state income tax expense and the amortization of tax deductible goodwill which gives rise to an indefinite-lived deferred tax liability. No other income tax expense or benefit was recorded for the three and nine months ended September 30, 2015 and 2014 due to a full valuation allowance recorded against our deferred tax assets. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to utilize our existing deferred tax assets. On the basis of this evaluation, it is not more likely than not that our deferred tax assets will be realized and therefore a full valuation allowance has been. Prosper files U.S. Federal and multiple state tax returns. Prosper is currently not subject to any income tax examinations in any jurisdiction. Due to Prosper’s losses, generally income tax returns related to all years remain open to examination. The net amount of unrecognized tax benefits as of September 30, 2015 is $4.9 million related to the uncertainty of whether Prosper will be allowed to utilize certain California NOL carryforwards and R&D credits to offset future taxable income due to Section 382 limitations. Prosper does not expect any material changes in the next 12 months to its unrecognized tax benefits. Subsequent to the issuance of the consolidated financial statements for the year ended December 31, 2014, Prosper identified an error that affected the disclosure of Unrecognized Tax Benefits as of December 31, 2014. The error was the result of presenting a portion of the unrecognized tax benefit gross of the application of the applicable tax rate, which resulted in an overstatement of the amount. The amount of unrecognized tax benefits as of January 1, 2015 has been revised to reflect the correction of the error. All unrecognized tax benefits are netted against deferred tax assets with a full valuation allowance. If these amounts are recognized there will be no effect on Prosper's effective tax rate due to the full valuation allowance. The following table summarizes Prosper’s activity related to its unrecognized tax benefits (in thousands): Beginning balance as of January 1, 2015 $ 4,927 Decrease related to prior year positions - Increase related to current year positions - Ending balance as of September 30, 2015 $ 4,927 The unrecognized tax benefits would not affect income tax expense if recognized, after consideration of the valuation allowance. Prosper recognizes interest and/or penalties related to uncertain tax positions. To the extent accrued interest and penalties do not ultimately become payable, amounts accrued will be reduced and reflected in the period that such determination is made. The interest and penalties are recognized as other expense in the income statement. Prosper currently has no interest and penalties related to uncertain tax positions.
Prosper Funding LLC [Member]
Income Taxes [Line Items]
Income Taxes	6. Income Taxes Prosper Funding incurred no income tax provision for the three and nine months ended September 30, 2015 and 2014. Prosper Funding is a US disregarded entity and its income and loss is included in the return of its parent, PMI. Since PMI is in a loss position, not currently subject to income taxes, and has fully reserved its deferred tax asset, the net effective tax rate for Prosper Funding is 0%.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies	13. Commitments and Contingencies Future Minimum Lease Payments During 2014, Prosper entered into leases for its new corporate headquarters at 221 Main Street in San Francisco, California and for its co-location facility. The 221 Main Street lease is a non-cancelable operating lease that expires in February 2023. The co-location facility lease expired in August 2015. In 2014, Prosper entered into a lease for office space in Phoenix, Arizona under an operating lease that expires in July 2021. In 2015, Prosper entered into a lease for office space in Lehi, Utah and San Francisco, California under operating leases that expire in February 2027 and February 2023, respectively. Future minimum rental payments under these leases as of September 30, 2015 are as follows (in thousands): Remaining three months of 2015 994 2016 5,976 2017 7,700 2018 8,133 2019 8,364 2020 8,601 Thereafter 26,820 Total future operating lease obligations $ 66,588 Rental expense under operating lease arrangements was $1.0 million and $0.7 million for the three months ended September 30, 2015 and 2014, respectively. Rental expense under operating lease arrangements was $2.7 million and $1.1 million for the nine months ended September 30, 2015 and 2014, respectively. Operating Commitments Prosper has an agreement with WebBank, under which all Borrower Loans originated through Prosper’s marketplace are made by WebBank under its bank charter. The arrangement allows for Borrower Loans to be offered to borrowers nationwide on uniform terms. Prosper is required to pay the greater of a monthly minimum fee or a fee calculated based on a certain percentage of monthly Borrower Loan origination volume. The minimum annual fee for the year ended December 31, 2015 is $1.4 million. Loan Purchase Commitments Prosper has entered into an agreement with WebBank to purchase $38.8 million of Borrower Loans that WebBank is originating within the first two business days of the three months ended December 31, 2015. Repurchase and Indemnification Contingency Under the terms of the loan purchase agreements between Prosper and investor members that participate in the Whole Loan Channel, Prosper may, in certain circumstances, become obligated to repurchase a Borrower Loan from an investor member. Generally, these circumstances include the occurrence of verifiable identity theft, the failure to properly follow loan listing or bidding protocols, or a violation of the applicable federal, state, or local lending laws. The fair value of the indemnification and repurchase obligation is estimated based on historical experience and the initial fair value is insignificant. Prosper recognizes a liability for the repurchase and indemnification obligation when the Borrower Loans are issued. Indemnified or repurchased Borrower Loans associated with violations of federal, state, or local lending laws or verifiable identity theft are written off at the time of repurchase or at the time an indemnification payment is made. The maximum potential amount of future payments associated under this obligation is the outstanding balances of the Borrower Loans issued through the Whole Loan Channel, which at September 30, 2015 is $3,116 million. Prosper has accrued $298 thousand and $171 thousand as of September 30, 2015 and December 31, 2014, respectively in regard to this obligation. Securities Law Compliance From inception through October 16, 2008, Prosper sold approximately $178.0 million of Borrower Loans to investor members through its old platform structure, whereby Prosper assigned promissory notes directly to investor members. Prosper did not register the offer and sale of the promissory notes corresponding to these Borrower Loans under the Securities Act or under the registration or qualification provisions of any state securities laws. Prosper believes that the question of whether or not the operation of the platform during this period constituted an offer or sale of “securities” involved a complicated factual and legal analysis and was uncertain. If the sales of promissory notes offered through the platform during this period were viewed as a securities offering, Prosper would have failed to comply with the registration and qualification requirements of federal and state laws. Prosper’s decision to restructure the platform and cease sales of promissory notes offered through the platform effective October 16, 2008 limited this contingent liability to the period covering its activities prior to October 16, 2008. On April 21, 2009, Prosper and the North American Securities Administrators Association (“NASAA”) reached agreement on the terms of a model consent order between Prosper and the states in which it, under its initial platform structure, offered promissory notes for sale directly to investor members prior to November 2008. The consent order involves payment by Prosper of up to an aggregate of $1 million in penalties, which have been allocated among the states based on Prosper’s promissory note sale transaction volume in each state prior to November 2008. A state that enters into a consent order receives its portion of the $1 million in exchange for its agreement to terminate, or refrain from initiating, any investigation of our promissory note sale activities prior to November 2008. Penalties are paid promptly after a state enters into a consent order. NASAA has recommended that each state enter into a consent order; however, no state is obliged to do so, and there is no deadline by which a state must make its decision. Prosper is not required to pay any portion of the penalty to those states that do not elect to enter into a consent order. If a state does not enter into a consent order, it is free to pursue its own remedies against Prosper, subject to any applicable statute of limitations. As of September 30, 2015, Prosper has entered into consent orders with 35 states and has paid an aggregate of $0.48 million in penalties to those states. As of September 30, 2015 and December 31, 2014, Prosper has accrued approximately $0.23 million and $0.25 million, respectively, in connection with the contingent liability associated with the states that have not entered into consent orders, in accordance with ASC Topic 450, Contingencies. The methodology applied to estimate the accrual was to divide the $1 million maximum fee pro-rata by state, using Prosper’s promissory note sales from inception through November 2008. A weighting was then applied by state to each state that has not entered into a consent order, assigning a likelihood that the penalty will be claimed. In estimating the probability of a claim being made by a state, Prosper considered factors such as the standard terms of the consent orders; whether the state ever gave any indication of concern regarding the sale of promissory notes through the platform; the probability of a state electing not to enter into a consent order in order to pursue its own litigation against Prosper; whether the penalty is sufficient to compensate a state for the cost of processing the settlement consent order; and finally the impact that current economic conditions have had on state governments. Prosper will continue to evaluate this accrual and related assumptions as new information becomes known. In 2008, plaintiffs filed a class action lawsuit against Prosper and certain of its executive officers and directors in the Superior Court of California, County of San Francisco, California. The suit was brought on behalf of all promissory note purchasers on the platform from January 1, 2006 through October 14, 2008. The lawsuit alleged that Prosper offered and sold unqualified and unregistered securities in violation of the California and federal securities laws. On July 19, 2013 solely to avoid the costs, risks and uncertainties inherent in litigation, and without admitting any liability or wrongdoing, the parties to the class action litigation agreed to enter into a settlement to resolve all claims related thereto (the “Settlement”). In connection with the Settlement, Prosper agreed to pay an aggregate amount of $10 million into a settlement fund, split into four annual installments of $2 million in 2014, $2 million in 2015, $3 million in 2016 and $3 million in 2017. The Settlement received final approval in a final order and judgment entered by the Superior Court on April 16, 2014. Pursuant to the final order and judgment, the claims in the class action were dismissed, and the defendants were released by the plaintiffs from all claims that were or could have been asserted concerning the issues alleged in the class action lawsuit. The reserve for the class action settlement liability is $5.9 million in the condensed consolidated balance sheet as of September 30, 2015.
Prosper Funding LLC [Member]
Commitments and Contingencies	7. Commitments and Contingencies Operating Commitments Prosper Funding has an agreement with WebBank, under which Prosper Funding is required to pay WebBank the greater of a monthly minimum fee or a fee calculated based on a certain percentage of Borrower Loans purchased by Prosper Funding. The minimum annual fee for the year ended December 31, 2015 is $1.4 million. Loan Purchase Commitments Under the terms of Prosper Funding’s agreement with WebBank, Prosper Funding is committed to purchase $38.8 million of Borrower Loans that WebBank will originate within the first two business days of July 2015. Repurchase and Indemnification Contingency Under the terms of the loan purchase agreements between Prosper Funding and investor members that participate in the Whole Loan Channel, Prosper Funding may, in certain circumstances, become obligated to repurchase a Borrower Loan from an investor member. Generally, these circumstances include the occurrence of verifiable identity theft, the failure to properly follow loan listing or bidding protocols, or a violation of the applicable federal, state, or local lending laws. The fair value of the indemnification and repurchase obligation is estimated based on historical experience. Prosper Funding recognizes a liability for the repurchase and indemnification obligation when the Borrower Loans are issued. Indemnified or repurchased Borrower Loans associated with violations of federal, state, or local lending laws or verifiable identity theft are written off at the time of repurchase or at the time an indemnification payment is made. The maximum potential amount of future payments associated under this obligation is the outstanding balances of the Borrower Loans issued through the Whole Loan Channel, which at September 30, 2015 is $2.8 billion. Prosper Funding had accrued $248 thousand and $171 thousand as of September 30, 2015 and December 31, 2014 in regard to this obligation, respectively.

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2015
Related Parties	14. Related Parties Since Prosper’s inception, it has engaged in various transactions with its directors, executive officers and holders of more than 10% of its voting securities, and immediate family members and other affiliates of its directors, executive officers and 10% stockholders. Prosper believes that all of the transactions described below were made on terms no less favorable to Prosper than could have been obtained from unaffiliated third parties. Prosper’s executive officers, directors who are not executive officers and certain affiliates participate in its marketplace by placing bids and purchasing Notes. The aggregate amount of the Notes purchased and the income earned by parties deemed to be affiliates and related parties of Prosper for the three and nine months ended September 30, 2015 and 2014, as well as the Notes outstanding as of September 30, 2015 and December 31, 2014 are summarized below (in thousands): Aggregate Amount of Notes Purchased Interest Earned on Notes Nine Months Ended September 30, Nine Months Ended September 30, Related Party 2015 2014 2015 2014 Executive officers and management $ 1,232 $ 591 $ 152 $ 110 Directors 31 22 6 7 Total $ 1,263 $ 613 $ 158 $ 117 Aggregate Amount of Notes Purchased Interest Earned on Notes Three Months Ended September 30, Three Months Ended September 30, Related Party 2015 2014 2015 2014 Executive officers and management $ 386 $ 188 $ 53 $ 41 Directors 10 19 2 2 Total $ 396 $ 207 $ 55 $ 43 Notes Balance as of Related Party September 30, 2015 December 31, 2014 Executive officers and management $ 2,173 $ 1,614 Directors 99 76 $ 2,272 $ 1,690
Prosper Funding LLC [Member]
Related Parties	8. Related Parties Since inception, Prosper Funding has engaged in various transactions with its directors, executive officers and sole member, and immediate family members and other affiliates of its directors, executive officers and sole member. Prosper Funding believes that all of the transactions described below were made on terms no less favorable to Prosper Funding than could have been obtained from unaffiliated third parties. Prosper Funding’s executive officers, directors who are not executive officers participate in its marketplace by placing bids and purchasing Notes. The aggregate amount of the Notes purchased and the income earned by parties deemed to be related parties of Prosper as of September 30, 2015 and December 31, 2014 are summarized below (in thousands): Aggregate Amount of Notes Purchased Interest Earned on Notes Nine Months Ended September 30, Nine Months Ended September 30, Related Party 2015 2014 2015 2014 Executive officers and management $ 1,232 $ 591 $ 152 $ 110 Directors - - - - Total $ 1,232 $ 591 $ 152 $ 110 Note Balance as of Related Party September 30, 2015 December 31, 2014 Executive officers and management $ 2,173 $ 1,614 Directors - - $ 2,173 $ 1,614 During the nine months ended September 30, 2015 Prosper Funding distributed $35.5 million to its parent.

Postretirement Benefit Plans

Postretirement Benefit Plans	9 Months Ended
	Sep. 30, 2015
Compensation And Retirement Disclosure [Abstract]
Postretirement Benefit Plans	15. Postretirement Benefit Plans Prosper has a 401(k) plan that covers all employees meeting certain eligibility requirements. The 401(k) plan is designed to provide tax-deferred retirement benefits in accordance with the provisions of Section 401(k) of the Internal Revenue Code. Eligible employees may defer eligible compensation up to the annual maximum as determined by the Internal Revenue Service. Prosper’s contributions to the 401(k) plan are discretionary. During the three months ended September 30, 2015 and 2014, Prosper has contributed $0.5 million and $0.2 million to the 401 (k) plan. During the nine months ended September 30, 2015 and 2014, Prosper has contributed $1.3 million and $0.4 million to the 401 (k) plan.

Segments

Segments	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segments	16. Segments Prosper’s chief operating decision maker, which is its executive group, reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. The chief operating decision maker does not review any financial information that is at a lower level than the overall Prosper results. As such, Prosper has a single reporting segment and operating unit structure.

Restatement of Condensed Consol

Restatement of Condensed Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2015
Condensed Financial Statements Captions [Line Items]
Restatement of Condensed Consolidated Financial Statements	17. Restatement of Condensed Consolidated Financial Statements Subsequent to the issuance of the condensed consolidated financial statements for the three and nine months ended September 30, 2014, Prosper identified errors that affected the interim condensed financial statements as of and for the three and nine months ended September 30, 2014. Financial statements presented herein have been restated to correct for these errors that are described below and summarized in the tables that follow. Prosper discovered that certain fees that Prosper pays to WebBank were incorrectly classified as expenses. Since WebBank is a customer of Prosper and Prosper earns transaction fees from WebBank any cash consideration paid to WebBank should be recorded as a reduction of the Transaction Fees earned by Prosper. This resulted in an overstatement of Transaction Fee revenues and Origination and Servicing expenses of $923 thousand and $2,012 thousand for the three and nine months ended September 30, 2014, respectively. Prosper also discovered that certain rebates offered on the sale of Borrower Loans and Notes were incorrectly classified as Transaction Fee revenue and should have been classified as Gain on Sale Borrower Loans or Change in Fair value of Borrower Loans, Loans Held for Sale and Notes. This resulted in an understatement of Transaction Fee revenues of $5 thousand and an overstatement of Gain on Sale Borrower Loans of $5 thousand for the three months ended September 30, 2014. This resulted in an understatement of Transaction Fee revenues of $665 thousand, an overstatement of Gain on Sale Borrower Loans of $585 thousand and an overstatement of Change in Fair Values of Borrower Loans, Loans Held for Sale and Notes of $80 thousand for the nine months ended September 30, 2014. Additionally, Prosper discovered certain errors in its valuation of servicing assets and liabilities which resulted in an overstatement of net loan servicing rights and an understatement of the Gain on Sale Borrower Loans of $718 thousand and $1,666 thousand for the three and nine months ended September 30, 2015, respectively. Also, Prosper discovered errors in its amortization of the servicing assets and liabilities which overstated Servicing Fees by $202 thousand and understated by $749 thousand for the three and nine months ending September 30, 2014, respectively. Prosper also discovered errors related to internal use software and web site development costs including an impairment that was not recorded when the project was abandoned in the prior year and assets were being amortized incorrectly which overstated amortization included in Origination and Servicing expense for $25 thousand and understated for $26 thousand for the three and nine months ended September 30, 2014, respectively. In addition to the restatements described above, Prosper has made other corrections, some of which were previously identified, but were not corrected because management had determined they were not material, individually or in the aggregate, to our consolidated financial statements. These corrections related to the fair value of Loans Held for Sale, reclassification of certain loans from Loans Held for Sale to Borrower Loans, amortization of prepaid assets, estimation of various accruals and a correction for vesting of options that were early exercised. Prosper also discovered the following classification errors within its Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2014: ● Changes in Restricted Cash and Payable to Investors balances related to operating activities were inappropriately presented due to certain bank accounts being inappropriately excluded from the balance sheet. The use of the cash in these bank accounts is restricted and may only be used by Prosper to fund Borrower Loans, at Fair Value on which investors have bid . ● Cash flows from the principal payments and proceeds from sale related to Borrower Loans Held for Sale were inappropriately classified within cash flows from investing activities rather than cash flows from operating activities. ● A portion of the change in fair value of Borrower Loans and Notes was inappropriately reflected as a cash flow from investing and financing activities, respectively, rather than an adjustment to reconcile net income to net cash used in operating activities. ● The proceeds from sale of Borrower Loans Held at Fair Value were netted against purchase of Borrower Loans at Fair Value. ● Other changes related to the correction of errors in the balance sheet and statement of operations as described above. Lastly, Prosper corrected its calculation of basic and diluted earnings (loss) per share for the changes to net income (loss) and errors in the calculation of the weighted average basic and diluted shares which was overstated by 120,351 shares for the nine months ended September 30, 2014. Further the weighted average shares for basic and diluted earnings per share were overstated by 100,908 shares for the three months ended September 30, 2014. The following tables present the impact of these corrections on three and nine months ended September 30, 2014 ($ in thousands): Condensed Consolidated Statement of Operations – Three months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Transaction Fees, Net $ 22,233 $ - $ 22,233 $ (1,172 ) $ 21,061 Servicing Fees, Net 1,749 - 1,749 (348 ) 1,401 Gain on Sale of Borrower Loans - 635 635 633 1,268 Other Revenue 1,147 (635 ) 512 (33 ) 479 Total Operating Revenue 25,129 - 25,129 (920 ) 24,209 Interest Income Interest Income on Borrower Loans 10,705 - 10,705 76 10,781 Interest Expense on Notes (9,850 ) - (9,850 ) (36 ) (9,886 ) Net Interest Income 855 - 855 40 895 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 59 - 59 (38 ) 21 Total Net Revenue 26,043 - 26,043 (918 ) 25,125 Expenses Cost of Services 1,408 (1,408 ) - - - Compensation and benefits 6,260 (6,260 ) - - - Marketing and advertising 10,717 (10,717 ) - - - Depreciation and amortization 462 (462 ) - - - Professional services 582 (582 ) - - - Facilities and maintenance 1,441 (1,441 ) - - Origination and Servicing - 4,298 4,298 (922 ) 3,376 Sales and Marketing - 11,201 11,201 - 11,201 General and Administrative - 7,820 7,820 (616 ) 7,204 Other 2,449 (2,449 ) - - - Total Expenses 23,319 - 23,319 (1,538 ) 21,781 Net Income 2,724 - 2,724 620 3,344 Excess return to preferred shareholders on repurchase (14,892 ) - (14,892 ) - (14,892 ) Net loss available to common shareholders (12,168 ) - (12,168 ) 620 (11,548 ) Net loss per share - basic and diluted (1.31 ) - (1.31 ) 0.05 (1.26 ) Weighted-average shares - basic and diluted 9,280,334 - 9,280,334 (100,908 ) 9,179,426 *See note 1 for a description of the reclassifications. Condensed Consolidated Statement of Operations – Nine months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Transaction Fees, Net $ 46,849 $ - $ 46,849 $ (1,445 ) $ 45,404 Servicing Fees, Net 3,044 - 3,044 (532 ) 2,512 Gain on Sale of Borrower Loans - 814 814 1,432 2,246 Other Revenue 2,090 (814 ) 1,276 (614 ) 662 Total Operating Revenue 51,983 - 51,983 (1,159 ) 50,824 Interest Income Interest Income on Borrower Loans 30,995 - 30,995 158 31,153 Interest Expense on Notes (28,613 ) (28,613 ) (259 ) (28,872 ) Net Interest Income 2,382 - 2,382 (101 ) 2,281 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 448 - 448 (157 ) 291 Total Net Revenue 54,813 - 54,813 (1,417 ) 53,396 Expenses Cost of Services 3,275 (3,275 ) - - - Compensation and benefits 16,327 (16,327 ) - - - Marketing and advertising 25,743 (25,743 ) - - - Depreciation and amortization 1,201 (1,201 ) - - - Professional services 1,169 (1,169 ) - - - Facilities and maintenance 2,604 (2,604 ) - - Loss on impairment of fixed assets 215 (215 ) - - - Origination and Servicing - 10,232 10,232 (2,012 ) 8,220 Sales and Marketing - 27,028 27,028 27,028 General and Administrative - 17,371 17,371 (563 ) 16,808 Other 4,097 (4,097 ) - - - Total Expenses 54,631 - 54,631 (2,575 ) 52,056 Net Income 182 - 182 1,158 1,340 Excess return to preferred shareholders on repurchase (14,892 ) - (14,892 ) - (14,892 ) Net loss available to common shareholders (14,710 ) - (14,710 ) 1,158 (13,552 ) Net loss per share - basic and diluted (1.68 ) - (1.68 ) 0.11 (1.57 ) Weighted-average shares - basic and diluted 8,740,785 - 8,740,785 (120,351 ) 8,620,434 *See note 1 for a description of the reclassifications. Condensed Consolidated Statements of Cash Flows – Nine months ended September 30, 2014 As previously reported Adjustments As corrected Cash flows from operating activities: Net Income $ 182 $ 1,158 $ 1,340 Adjustments to Reconcile Net Income to Net Cash Used in Operating Activities: Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes (448 ) 157 (291 ) Depreciation and Amortization 1,201 27 1,228 Gain on sales of Borrower Loans - (2,480 ) (2,480 ) Amortization of and Change in Fair Value of Servicing Rights (803 ) 1,175 372 Stock-Based Compensation 777 (14 ) 763 Other, Net 215 63 278 Changes in Operating Assets and Liabilities: - Purchase of Loans Held for Sale at Fair Value (12,444 ) (907,326 ) (919,770 ) Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value - 909,897 909,897 Restricted Cash Except for those Related to Investing Activities - (26,976 ) (26,976 ) Accounts Receivable (703 ) 108 (595 ) Prepaid and Other Assets (2,543 ) 28 (2,515 ) Class Action Settlement Liability (1,909 ) (91 ) (2,000 ) Accounts Payable and Accrued Liabilities 4,406 624 5,030 Payable to Investors - 22,596 22,596 Net Cash Used in Operating Activities (12,069 ) (1,054 ) (13,123 ) Cash Flows From Investing Activities: Purchase of Borrower Loans Held at Fair Value (823,841 ) 692,984 (130,857 ) Principal Payments of Borrower Loans Held at Fair Value 88,944 30 88,974 Proceeds from Sale of Borrower Loans Held at Fair Value 693,007 (693,007 ) - Purchases of Property and Equipment (3,151 ) (1,655 ) (4,806 ) Changes in Restricted Cash Related to Investing Activities (1,478 ) 2,347 869 Net Cash Used in Investing Activities (46,519 ) 699 (45,820 ) Cash Flows from Financing Activities: Proceeds from Issuance of Notes Held at Fair Value 130,828 (72 ) 130,756 Payment of Notes Held at Fair Value (89,336 ) 427 (88,909 ) Proceeds from Issuance of Convertible Preferred Stock, net 69,958 - 69,958 Proceeds from Early Exercise of Stock Options and Issuance of Restricted Stock 454 - 454 Proceeds from Exercise of Vested Stock Options and Common Stock Warrants 161 - 161 Repurchase of Preferred Stock (18,525 ) - (18,525 ) Repurchase of Restricted Stock (24 ) - (24 ) Net Cash Provided by Financing Activities 93,516 355 93,871 Net Increase in Cash and Cash Equivalents 34,928 - 34,928 Cash and Cash Equivalents at Beginning of the Period 18,339 - 18,339 Cash and Cash Equivalents at End of the Period $ 53,267 $ - $ 53,267
Prosper Funding LLC [Member]
Condensed Financial Statements Captions [Line Items]
Restatement of Condensed Consolidated Financial Statements	9. Restatement of Condensed Consolidated Financial Statements Subsequent to the issuance of the condensed consolidated financial statements for the three and nine months ended September 30, 2014, Prosper Funding identified errors that affected the interim condensed financial statements as of and for the three and nine months ended September 30, 2014. The financial statements presented herein have been restated to correct for these errors that are described below. Prosper Funding discovered certain errors in its valuation of servicing assets and liabilities which resulted in an overstatement of the servicing assets, an understatement of the servicing liabilities and an understatement of the Gain on Sale of Borrower Loans of $718 thousand and $1,666 thousand for the three and nine months ended September 30, 2014, respectively. Also, Prosper Funding discovered errors in its amortization of the servicing assets and liabilities which overstated Servicing Income by $151 thousand and understated by$471 thousand for the three and nine months ending September 30, 2014, respectively. Prosper Funding also discovered that the Administration Fee Related Party Expense was understated by $524 thousand and Servicing expenses were overstated by $906 thousand for the three months ended September 30, 2014 due to a misclassification of an expense between the two statement of operations line items and an error in the calculation of the Administration Fee Related Party Expense. Prosper Funding also discovered that the Administration Fee Related Party Expense was understated by $1,373 thousand and Servicing expenses were overstated by $1,974 thousand for the nine months ended September 30, 2014 due to a misclassification of an expense between the two statement of operations classifications and an error in the calculation of the Administration Fee Related Party Expense. The offset to the above errors was to Related Party Receivable which was understated as a result. Prosper Funding also discovered errors related to internal use software including an overstatement of assets transferred from PMI and assets that were being amortized over their original estimated useful life after Prosper Funding decided to replace the assets before the originally estimated useful life which overstated amortization by $25 thousand and understated by$ 26 thousand for the three and nine months ended September 30, 2014, respectively, which is included in Servicing expenses. In addition to the restatements described above, Prosper Funding has made other corrections, some of which were previously identified, but were not corrected because management had determined they were not material, individually or in the aggregate, to its consolidated financial statements. These corrections related to the fair value of Loans Held for Sale, and reclassification of certain Borrower Loans from Loans Held for Sale to Borrower Loans. Lastly, Prosper Funding discovered the following classification errors within its Condensed Consolidated Statement of Cash Flows: ● Changes in Restricted Cash and Payable to Investors balances related to operating activities were inappropriately presented due to certain bank accounts being inappropriately excluded from the balance sheet. The use of the cash in these bank accounts is restricted and may only be used by Prosper Funding to fund Borrower Loans, at Fair Value on which investors have bid. ● Cash flows from the principal payments and proceeds from sale related to Borrower Loans Held for Sale were inappropriately classified within cash flows from investing activities rather than cash flows from operating activities. ● A portion of the change in fair value of Borrower Loans and Notes was inappropriately reflected as a cash flow from investing and financing activities, respectively, rather than an adjustment to reconcile net income to net cash used in operating activities. ● Other changes related to the correction of errors in the balance sheet and statement of operations as described above The following tables present the impact of these corrections and corrections of other immaterial errors on the interim periods (in thousands): Condensed Consolidated Statement of Operations – Three months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Administration Fee Revenue - Related Party $ 8,574 $ — $ 8,574 $ — $ 8,574 Servicing Income, Net 1,574 — 1,574 (321 ) 1,253 Gain on Sale of Borrower Loans — 635 635 605 1,240 Other Revenue 635 (635 ) — — — Total Operating Revenue 10,783 — 10,783 284 11,067 Interest Income on Borrower Loans 10,724 — 10,724 136 10,860 Interest Expense on Notes (9,850 ) — (9,850 ) (36 ) (9,886 ) Net Interest Income 874 — 874 100 974 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 59 — 59 (38 ) 21 Total Net Revenue 11,716 — 11,716 346 12,062 Expenses Cost of Services 958 (958 ) — — — Administration Fee - Related Party 6836 — 6836 535 7,371 Depreciation and Amortization 273 (273 ) — — — Professional Services 1 (1 ) — — — Servicing — 1,231 1,231 (923 ) 308 General and Administration — 129 129 — 129 Other Operating Expenses 128 (128 ) — — — Total Expenses 8,196 — 8,196 (388 ) 7,808 Total Net Income $ 3,520 $ — $ 3,520 $ 734 $ 4,254 *See note 1 for further details on the reclassifications. Condensed Consolidated Statement of Operations – Nine months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Administration Fee Revenue - Related Party $ 19,525 $ — $ 19,525 $ — $ 19,525 Servicing Income, Net 2,965 — 2,965 (586 ) 2,379 Gain on Sale of Borrower Loans — 814 814 1,404 2,218 Other Revenue 814 (814 ) — — — Total Operating Revenue 23,304 — 23,304 818 24,122 Interest Income on Borrower Loans 31,014 — 31,014 429 31,443 Interest Expense on Notes (28,613 ) — (28,613 ) (260 ) (28,873 ) Net Interest Income 2,401 — 2,401 169 2,570 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 448 — 448 (146 ) 302 Total Net Revenue 26,153 — 26,153 841 26,994 Expenses Cost of Services 2297 (2,297 ) — — — Administration Fee - Related Party 15018 — 15,018 1,383 16,401 Depreciation and Amortization 761 (761 ) — — — Professional Services 16 (16 ) — — — Servicing — 3,058 3,058 (1,994 ) 1,064 General and Administration — 329 329 (14 ) 315 Other Operating Expenses 313 (313 ) — — — Total Expenses 18,405 — 18,405 (625 ) 17,780 Total Net Income $ 7,748 $ — $ 7,748 $ 1,466 $ 9,214 *See note 1 for further details on the reclassifications. Condensed Consolidated Statements of Cash Flows – Nine months ended September 30, 2014 As previously reported Adjustments As corrected Cash flows from operating activities: Net Income $ 7,748 $ 1,466 $ 9,214 Adjustments to Reconcile Net Income to Net Cash Used in Operating Activities: Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes (448 ) 146 (302 ) Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes - (28 ) (28 ) Depreciation and Amortization 761 27 788 Change in Servicing Rights (808 ) 808 - Gain on Sale of Borrower Loans - (2,480 ) (2,480 ) Amortization and Change in Fair Value of Servicing Rights - 294 294 Changes in Operating Assets and Liabilities: Purchase of Borrower Loans Held for Sale at Fair Value (12,444 ) (907,326 ) (919,770 ) Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value - 909,897 909,897 Restricted Cash Except for those Related to Investing Activities - (26,976 ) (26,976 ) Other Assets (21 ) 17 (4 ) Accounts Payable and Accrued Liabilities 212 116 328 Payable to Investors - 21,906 21,906 Net Related Party Payable (278 ) (601 ) (879 ) Net Cash Used in Operating Activities (5,278 ) (2,734 ) (8,012 ) Cash Flows From Investing Activities: Purchase of Borrower Loans Held at Fair Value (823,841 ) 692,984 (130,857 ) Principal Payments of Borrower Loans Held at Fair Value 88,944 40 88,984 Proceeds from Sale of Borrower Loans Receivable Held at Fair Value 693,007 (693,007 ) - Maturities of Short Term Investments - 1,271 1,271 Purchase of Short Term Investments - (1,274 ) (1,274 ) Purchases of Property and Equipment (829 ) 18 (811 ) Changes in Restricted Cash Related to Investing Activities 3,578 2,347 5,925 Net Cash Used in Investing Activities (39,141 ) 2,379 (36,762 ) Cash Flows from Financing Activities: Proceeds from Issuance of Notes Held at Fair Value 130,828 (72 ) 130,756 Payment of Notes Held at Fair Value (89,336 ) 427 (88,909 ) Net Cash Provided by Financing Activities 41,492 355 41,847 Net Decrease in Cash and Cash Equivalents (2,927 ) - (2,927 ) Cash and Cash Equivalents at Beginning of the Period 5,789 - 5,789 Cash and Cash Equivalents at End of the Period $ 2,862 $ - $ 2,862

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	18. Subsequent Events On October 9, 2015, PMI acquired all of the outstanding shares of BillGuard, Inc. (“BillGuard”), and merged BillGuard with and into Beach Merger Sub, Inc., a wholly owned subsidiary of PMI, with BillGuard surviving the merger. Under the terms of the Agreement and Plan of Merger, dated as of September 23, 2015 the BillGuard stockholders received an aggregate of $25 million in cash at the closing of the merger, subject to certain deductions for debt and expenses. If certain conditions of an earn-out are met within a 12-month period of the closing of the merger, the BillGuard stockholders will receive an additional $5 million, subject to certain indemnification obligations of the BillGuard stockholders. Billguard is a personal finance analytics company that develops popular consumer apps to manage, protect and do more with money and credit. The acquisition will enable PMI to offer borrowers and investors a full suite of powerful tools to help them make smarter financial decisions, and will give PMI access to Israel's extraordinary engineering and product talent pool. The initial accounting for this acquisition was not complete as of November 6, 2015. The acquisition of Billguard will be accounted for as business combinations, accordingly, the total purchase price will be allocated to the tangible and intangible assets acquired and the liabilities assumed based on their respective fair values on the acquisition dates. Prosper is currently working on the preliminary purchase price allocations and expects them to be completed by the end of the fourth quarter of 2015.

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Significant Accounting Policies [Line Items]
Basis of Presentation	The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. The preparation of Prosper’s condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in Prosper’s financial statements and accompanying notes. Prosper bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material. The accompanying interim condensed consolidated financial statements include the accounts of PMI and its wholly-owned subsidiaries, PFL and PHL. All intercompany balances have been eliminated in consolidation. On January 23, 2015, Prosper acquired all of the outstanding limited liability company units of American HealthCare Lending, LLC (“AHL”), a company that operated a cloud-based patient financing platform, and merged AHL with and into PHL, a newly, with PHL a newly established entity surviving the merger. Prosper’s condensed consolidated financial statements include PHL's results of operations and financial position from this date forward (see Note 8 – American HealthCare Lending Acquisition
Reclassifications	Reclassifications During the period ended September 30, 2015, Prosper changed the presentation of its revenue in the consolidated statements of operations. A new line called “Gain on Sales of Borrower Loans” was created with the amounts included in this line previously classified as “Other Revenue”. Prior period amounts have been reclassified to conform to the current presentation. Prosper also changed the definitions used to classify expenses. Expenses were previously classified as cost of services, compensation and benefits, marketing and advertising, depreciation and amortization, professional services, facilities and maintenance, class action settlement, loss on impairment of fixed assets and other. The revised classification approach replaces the previous classifications with origination and servicing, sales and marketing, and general and administration. The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Lastly, the subtotals were realigned to reflect the new presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper’s competitors. Prosper also changed the presentation of the servicing assets on its balance sheet by reclassifying them from “Prepaids and Other Assets” to “Servicing Assets”. Prior period amounts have been reclassified to conform to the current presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper’s competitors.
Fair Value Measurement	Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Investments at Fair Value, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature.
Borrower Loans, Loans Held for Sale and Notes	Borrower Loans, Loans Held for Sale and Notes Borrower Loans, Loans Held for Sale and Notes are recorded at fair value. Prosper has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”).
Loan Servicing Assets and Liabilities	Loan Servicing Assets and Liabilities On January 1, 2015, Prosper elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities subsequent to initial recognition. ASC Subtopic 860-50, Servicing Assets and Liabilities,
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, as part of its ongoing efforts to assist in the convergence of US GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “ Revenue from Contracts with Customers In November 2014, the FASB issued ASU 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity to eliminate the use of different methods in practice and thereby reduce existing diversity in the accounting for hybrid financial instruments issued in the form of a share. For hybrid financial instruments issued in the form of a share, an entity should determine the nature of the contract by considering the economic characteristics and risks of the entire hybrid financial instrument. The existence or omission of any single term or feature does not necessarily determine the economic characteristics and risks of the host contract. This standard will be effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance. In February 2015, the FASB issued ASU 2015-02, " Consolidation (Topic 810): Amendments to the Consolidation Analysis. In April 2015, the FASB issued ASU 2015-05 “ Customers’ Accounting for Fees Paid in Cloud Computing Arrangement ”, which will be effective for the annual reporting period ending after December 15, 2015 . The guidance changes what a customer must consider in determining whether a cloud computing arrangement contains a software license. If the arrangement contains a software license, the customer would account for the fees related to the software license element in accordance with guidance related to internal use software; if the arrangement does not contain a software license, the customer would account for the arrangement as a service contract. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance. In September 2015, the FASB issued ASU No. 2015-16, Simplifying the Accounting for Measurement-Period Adjustments. The new guidance simplifies the accounting for measurement period adjustments in connection with business combinations by requiring that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
Prosper Funding LLC [Member]
Significant Accounting Policies [Line Items]
Basis of Presentation	The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. Prosper Funding did not have any items of other comprehensive income (loss) during any of the periods presented in the condensed consolidated financial statements as of and for the three and nine months ended September 30, 2015 and 2014. The preparation of Prosper Funding's condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in its condensed consolidated financial statements and accompanying notes. Prosper Funding bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material.
Reclassifications	Reclassifications During the period ended September 30, 2015, Prosper Funding changed the presentation of its revenue in the consolidated statements of operations. A new line called “Gain on Sales of Borrower Loans” was created with the amounts included in this line previously classified as “Other Revenue”. The gain on sale related to the sale of Borrower Loans was reclassified from “Other Revenues” to a new line call “Gain on Sales of Borrower Loans.” Prosper Funding also changed the definitions used to classify expenses. Expenses were previously classified as cost of services, administration fee, depreciation and amortization, professional services and other operating expenses. The revised classification approach replaces the previous classifications with servicing, administration fee –related party, and general and administration. The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Prosper Funding believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper Funding’s competitors. Prosper Funding also changed the presentation of the servicing assets on its balance sheet by reclassifying them from “Prepaids and Other Assets” to “Servicing Assets”. Prior period amounts have been reclassified to conform to the current presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper Funding’s competitors.
Fair Value Measurement	Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Short Term Investments, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature.
Borrower Loans, Loans Held for Sale and Notes	Borrower Loans, Loans Held for Sale and Notes Borrower Loans, Loans Held for Sale and Notes are recorded at fair value. Prosper Funding has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”).
Loan Servicing Assets and Liabilities	Loan Servicing Assets and Liabilities On January 1, 2015, Prosper Funding elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities, subsequent to initial recognition. ASC 860, Servicing Assets and Liabilities
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, as part of its ongoing efforts to assist in the convergence of U.S. GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “ Revenue from Contracts with Customers In February 2015, the FASB issued ASU 2015-02, " Consolidation (Topic 810): Amendments to the Consolidation Analysis.

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2015
Property and Equipment, Net	Property and equipment consist of the following (in thousands): September 30, December 31, 2015 2014 Property and equipment: Computer equipment $ 6,789 $ 3,824 Internal-use software and website development costs 11,186 4,486 Office equipment and furniture 2,327 1,904 Leasehold improvements 5,646 5,274 Assets not yet placed in service 3,717 4,361 Property and equipment 29,665 19,849 Less accumulated depreciation and amortization (9,598 ) (5,425 ) Total property and equipment, net $ 20,067 $ 14,424
Prosper Funding LLC [Member]
Property and Equipment, Net	Property and equipment consist of the following (in thousands): September 30, December 31, 2015 2014 Property and equipment: Internal-use software and web site development costs $ 7,220 $ 4,042 Less accumulated depreciation and amortization (1,728 ) (2,917 ) Total property and equipment, net $ 5,492 $ 1,125

Borrower Loans, Loans Held fo27

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value (Tables)	9 Months Ended
	Sep. 30, 2015
Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale	The aggregate principal balances outstanding and fair values of Borrower Loans, Loans Held for Sale and Notes as of September 30, 2015 and December 31, 2014, are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Aggregate principal balance outstanding $ 285,837 $ 268,598 $ (284,562 ) $ (272,269 ) $ 44 $ 8,295 Fair value adjustments 625 4,645 (2,692 ) (1,514 ) (10 ) 168 Fair value $ 286,462 $ 273,243 $ (287,254 ) $ (273,783 ) $ 34 $ 8,463
Quantitative Information About Significant Unobservable Inputs	Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 2.9%-10.5% 3.3%-10.6% Default rate 2.7%-22.8% 2.6%-19.7%
Fair Value Assumptions for Loans Held for Sale, Borrower Loans and Notes	Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at September 30, 2015 for Borrower Loans, Loans Held for Sale and Notes funded through the Note Channel are presented in the following table (in thousands, except percentages): Borrower Loans and Loans Held for Sale Notes Discount rate assumption: 4.57 %* 4.57 %* Resulting fair value from: 100 basis point increase $ 283,684 $ 284,453 200 basis point increase 280,688 281,443 Resulting fair value from: 100 basis point decrease $ 289,923 $ 290,720 200 basis point decrease 293,172 293,985 Default rate assumption: 12.73 %* 12.73 %* Resulting fair value from: 100 basis point increase $ 283,157 $ 283,915 200 basis point increase 279,610 280,343 Resulting fair value from: 100 basis point decrease $ 290,392 $ 291,201 200 basis point decrease 294,042 294,877 * Represents weighted average assumptions considering all credit grades.
Changes in Borrower Loans, Loans Held for Sale and Notes, and Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present additional information about level 3 Borrower Loans, Loans Held for Sale and Notes measured at fair value on a recurring basis Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2015 $ 284,200 $ (284,627 ) $ 1,431 $ 1,004 Purchase of Borrower Loans/Issuance of Notes 47,591 (47,670 ) 1,024,464 1,024,385 Principal repayments (38,407 ) 38,202 (4 ) (209 ) Borrower Loans sold to third parties (447 ) 425 (1,025,824 ) (1,025,846 ) Other changes 21 (18 ) (8 ) (5 ) Change in fair value (6,496 ) 6,434 (25 ) (87 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2014 $ 252,971 $ (253,943 ) $ 7,998 $ 7,026 Purchase of Borrower Loans/Issuance of Notes 44,141 (44,077 ) 443,835 443,899 Principal repayments (31,244 ) 31,334 (403 ) (313 ) Borrower Loans sold to third parties - - (438,342 ) (438,342 ) Other changes 46 (22 ) 7 31 Change in fair value (5,821 ) 5,842 - 21 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2015 $ 273,243 $ (273,783 ) $ 8,463 $ 7,923 Purchase of Borrower Loans/Issuance of Notes 142,103 (142,246 ) 2,426,963 2,426,820 Principal repayments (111,864 ) 111,711 (546 ) (699 ) Borrower Loans sold to third parties (447 ) 425 (2,434,707 ) (2,434,729 ) Other changes (108 ) 119 (18 ) (7 ) Change in fair value (16,465 ) 16,520 (121 ) (66 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2014 $ 233,105 $ (234,218 ) $ 3,206 $ 2,093 Purchase of Borrower Loans/Issuance of Notes 130,857 (130,756 ) 919,770 919,871 Principal repayments (88,974 ) 88,909 (533 ) (598 ) Borrower Loans sold to third parties - - (909,364 ) (909,364 ) Other changes (54 ) 67 16 29 Change in fair value (14,841 ) 15,132 - 291 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322
Prosper Funding LLC [Member]
Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale	The aggregate principal balances outstanding and fair values of Borrower Loans, Loans Held for Sale and Notes as of September 30, 2015 and December 31, 2014, are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Aggregate principal balance outstanding $ 285,837 $ 268,598 $ (284,562 ) $ (272,269 ) $ 44 $ 8,295 Fair value adjustments 625 4,645 (2,692 ) (1,514 ) (10 ) 168 Fair value $ 286,462 $ 273,243 $ (287,254 ) $ (273,783 ) $ 34 $ 8,463
Quantitative Information About Significant Unobservable Inputs	The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding’s Borrower Loans, Loans Held for Sale and Notes fair value measurements at September 30, 2015 and December 31, 2014: Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 2.9%-10.5% 3.2%-10.6% Default rate 2.7%-22.8% 2.6%-19.7%
Fair Value Assumptions for Loans Held for Sale, Borrower Loans and Notes	Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at September 30, 2015 for Borrower Loans, Loans Held for Sale and Notes funded are presented in the following table (in thousands): Borrower Loans and Loans Held for Sale Notes Discount rate assumption: 4.57 %* 4.57 %* Resulting fair value from: 100 basis point increase $ 283,684 $ 284,453 200 basis point increase 280,688 281,443 Resulting fair value from: 100 basis point decrease $ 289,923 $ 290,720 200 basis point decrease 293,172 293,985 Default rate assumption: 12.73 %* 12.73 %* Resulting fair value from: 200 basis point decrease $ 283,157 $ 283,915 100 basis point decrease 279,610 280,343 Resulting fair value from: 100 basis point increase $ 290,392 $ 291,201 200 basis point increase 294,042 294,877 * Represents weighted average assumptions considering all credit grades.
Changes in Borrower Loans, Loans Held for Sale and Notes, and Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The changes in the Borrower Loans, loans held for sale and Notes, which are Level 3 assets and liabilities measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at January 1, 2014 $ 233,105 $ (234,218 ) $ 3,206 $ 2,093 Originations 130,857 (130,756 ) 919,770 919,871 Principal repayments (88,984 ) 88,909 (533 ) (608 ) Borrower Loans sold to third parties - - (909,364 ) (909,364 ) Other changes (55 ) 67 16 28 Change in fair value (14,830 ) 15,132 - 302 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at January 1, 2015 $ 273,243 $ (273,783 ) $ 8,463 $ 7,923 Originations 142,103 (142,246 ) 2,426,963 2,426,820 Principal repayments (111,864 ) 111,711 (546 ) (699 ) Borrower Loans sold to third parties (447 ) 425 (2,434,707 ) (2,434,729 ) Other changes (108 ) 119 (18 ) (7 ) Change in fair value (16,465 ) 16,520 (121 ) (66 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at July 1, 2014 $ 252,971 $ (253,943 ) $ 7,998 $ 7,026 Originations 44,141 (44,077 ) 443,835 443,899 Principal repayments (31,244 ) 31,334 (403 ) (313 ) Borrower Loans sold to third parties - - (438,342 ) (438,342 ) Other changes 46 (22 ) 7 31 Change in fair value (5,821 ) 5,842 - 21 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Loans Held for Borrower Notes Sale Total Balance at July 1, 2015 $ 284,200 $ (284,627 ) $ 1,431 $ 1,004 Originations 47,591 (47,670 ) 1,024,464 1,024,385 Principal repayments (38,407 ) 38,202 (4 ) (209 ) Borrower Loans sold to third parties (447 ) 425 (1,025,824 ) (1,025,846 ) Other changes 21 (18 ) (8 ) (5 ) Change in fair value (6,496 ) 6,434 (25 ) (87 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 )

Available for Sale Investment28

Available for Sale Investments, at Fair Value (Tables)	9 Months Ended
	Sep. 30, 2015
Investments Debt And Equity Securities [Abstract]
Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Securities Available for Sale	The amortized cost, gross unrealized gains and losses, and fair value of available for sale investments as of September 30, 2015, are as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate debt securities $ 33,618 $ 18 $ (15 ) $ 33,621 Commercial paper 11,481 - - 11,481 US Treasury securities 2,001 1 - 2,002 Total Available for Sale Investments $ 47,100 $ 19 $ (15 ) $ 47,104
Summary of Securities Available for Sale of Continuous Unrealized Loss	A summary of available for sale investments with unrealized losses as of September 30, 2015, aggregated by category and period of continuous unrealized loss, is as follows: Less than 12 months 12 months or longer Total Fair Value Unrealized losses Fair Value Unrealized losses Fair Value Unrealized losses Corporate Debt Securities $ 12,602 $ (15 ) $ - $ - $ 12,602 $ (15 ) Total investments with unrealized losses $ 12,602 $ (15 ) $ - $ - $ 12,602 $ (15 )
Schedule of Maturities of Securities Available for Sale	The maturities of available for sale investments at September 30, 2015, are as follows: Within 1 year After 1 year through 5 years After 5 years to 10years After 10 years Total Corporate debt securities $ 20,496 $ 13,125 $ - $ - $ 33,621 Commercial paper 11,481 - - - 11,481 US Treasury securities - 2,002 - - 2,002 Total Fair Value $ 31,977 $ 15,127 $ - $ - $ 47,104 Total Amortized Cost $ 31,987 $ 15,113 $ - $ - $ 47,100

Fair Value of Assets and Liab29

Fair Value of Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value	The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands) September 30, 2015 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ - $ - $ 286,462 $ 286,462 Loans Held for Sale - 34 34 Available for Sale Investments, at Fair Value - 47,104 - 47,104 Servicing Assets - 11,300 11,300 Total Assets - 47,104 297,796 344,900 Liabilities: Notes $ - $ - $ 287,254 $ 287,254 Servicing Liabilities - - 550 550 Total Liabilities $ - $ - $ 287,804 $ 287,804 December 31, 2014 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ - $ - $ 273,243 $ 273,243 Loans Held for Sale - - 8,463 8,463 Servicing Assets - 4,709 4,709 Total Assets - - 286,415 286,415 Liabilities: Notes $ - $ - $ 273,783 $ 273,783 Servicing Liabilities - - 595 595 Total Liabilities $ - $ - $ 274,378 $ 274,378
Quantitative Information About Significant Unobservable Inputs	Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 2.9%-10.5% 3.3%-10.6% Default rate 2.7%-22.8% 2.6%-19.7%
Significant Unobservable Inputs Fair Value	Servicing Rights Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 15% - 25% 15% - 25% Default rate 2.0% - 21.8% 2.6% - 26.3% Market servicing rate 0.625% 0.625% - 0.70%
Changes in Borrower Loans, Loans Held for Sale and Notes, and Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present additional information about level 3 Borrower Loans, Loans Held for Sale and Notes measured at fair value on a recurring basis Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2015 $ 284,200 $ (284,627 ) $ 1,431 $ 1,004 Purchase of Borrower Loans/Issuance of Notes 47,591 (47,670 ) 1,024,464 1,024,385 Principal repayments (38,407 ) 38,202 (4 ) (209 ) Borrower Loans sold to third parties (447 ) 425 (1,025,824 ) (1,025,846 ) Other changes 21 (18 ) (8 ) (5 ) Change in fair value (6,496 ) 6,434 (25 ) (87 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2014 $ 252,971 $ (253,943 ) $ 7,998 $ 7,026 Purchase of Borrower Loans/Issuance of Notes 44,141 (44,077 ) 443,835 443,899 Principal repayments (31,244 ) 31,334 (403 ) (313 ) Borrower Loans sold to third parties - - (438,342 ) (438,342 ) Other changes 46 (22 ) 7 31 Change in fair value (5,821 ) 5,842 - 21 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2015 $ 273,243 $ (273,783 ) $ 8,463 $ 7,923 Purchase of Borrower Loans/Issuance of Notes 142,103 (142,246 ) 2,426,963 2,426,820 Principal repayments (111,864 ) 111,711 (546 ) (699 ) Borrower Loans sold to third parties (447 ) 425 (2,434,707 ) (2,434,729 ) Other changes (108 ) 119 (18 ) (7 ) Change in fair value (16,465 ) 16,520 (121 ) (66 ) Balance at September 30, 2015 $ 286,462 $ (287,254 ) $ 34 $ (758 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2014 $ 233,105 $ (234,218 ) $ 3,206 $ 2,093 Purchase of Borrower Loans/Issuance of Notes 130,857 (130,756 ) 919,770 919,871 Principal repayments (88,974 ) 88,909 (533 ) (598 ) Borrower Loans sold to third parties - - (909,364 ) (909,364 ) Other changes (54 ) 67 16 29 Change in fair value (14,841 ) 15,132 - 291 Balance at September 30, 2014 $ 260,093 $ (260,866 ) $ 13,095 $ 12,322
Schedule of Servicing Assets and Liabilities Measured at Fair Value	The following table presents additional information about level 3 servicing assets and liabilities measured at fair value on a recurring basis: Servicing Assets Servicing Liabilities Fair Value at July 1, 2015 $ 8,682 $ 606 Additions 4,370 53 Less: Changes in fair value (1,752 ) (109 ) Fair value at September 30, 2015 $ 11,300 $ 550 Servicing Assets Servicing Liabilities Amortized cost at January 1, 2015 $ 4,163 $ 624 Adjustment to adopt fair value measurement 546 (29 ) Fair value at January 1, 2015 4,709 595 Additions 10,204 246 Less: Changes in fair value (3,613 ) (291 ) Fair value at September 30, 2015 $ 11,300 $ 550
Fair Value Assumptions for Loans Held for Sale, Borrower Loans and Notes	Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at September 30, 2015 for Borrower Loans, Loans Held for Sale and Notes funded through the Note Channel are presented in the following table (in thousands, except percentages): Borrower Loans and Loans Held for Sale Notes Discount rate assumption: 4.57 %* 4.57 %* Resulting fair value from: 100 basis point increase $ 283,684 $ 284,453 200 basis point increase 280,688 281,443 Resulting fair value from: 100 basis point decrease $ 289,923 $ 290,720 200 basis point decrease 293,172 293,985 Default rate assumption: 12.73 %* 12.73 %* Resulting fair value from: 100 basis point increase $ 283,157 $ 283,915 200 basis point increase 279,610 280,343 Resulting fair value from: 100 basis point decrease $ 290,392 $ 291,201 200 basis point decrease 294,042 294,877 * Represents weighted average assumptions considering all credit grades.
Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities	The following table presents the estimated impact on Prosper’s estimated fair value of servicing assets and liabilities, calculated using different market servicing rates and different default rates as of September 30, 2015 (in thousands, except percentages). Servicing Assets Servicing Liabilities Market servicing rate assumptions 0.625 % 0.625 % Resulting fair value from: Market servicing rate increase to 0.65% $ 10,462 $ (605 ) Market servicing rate decrease to 0.60% $ 12,138 $ (496 ) Weighted average default assumptions 14 % 14 % Resulting fair value from: 100 basis point increase $ 11,091 $ (550 ) 100 basis point decrease $ 11,510 $ (551 )

American HealthCare Lending A30

American HealthCare Lending Acquisition - (Tables)	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Preliminary Purchase Price Allocation	The preliminary purchase price allocation as of the merger date is as follows (in thousands): Fair Value Assets: Cash $ 1,219 Accounts Receivable 147 Property, equipment and software 6 Other assets 63 Identified intangible assets 3,520 Goodwill 16,825 Liabilities: Accrued expenses and other liabilities 708 Total purchase consideration $ 21,072
Schedule of Intangible Assets	Intangible assets as of September 30, 2015 are as follows (in thousands): September 30, 2015 Gross Carrying Value Accumulated Amortization Net Carrying Value Remaining Useful Life (In Years) Customer relationships $ 2,650 $ (321 ) $ 2,329 9.3 Technology 810 (180 ) 630 2.3 Brand name 60 (40 ) 20 0.3 Total intangible assets subject to amortization $ 3,520 $ (541 ) $ 2,979

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Basic and Diluted Net Loss Per Share	Basic and diluted net loss per share was calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Numerator: Net Income (loss) (in thousands) $ (3,843 ) $ 3,344 $ (17,324 ) $ 1,340 Less: Excess return to preferred shareholders on repurchase - (14,892 ) - (14,892 ) Net loss available to common stockholders for basic and diluted loss per share (in thousands) $ (3,843 ) $ (11,548 ) $ (17,324 ) $ (13,552 ) Denominator: Weighted average shares used in computing basic and diluted net loss per share 11,181,553 9,179,426 10,949,396 8,620,434 Basic and Diluted net loss per share $ (0.34 ) $ (1.26 ) $ (1.58 ) $ (1.57 )
Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share	The following common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (shares) (shares) (shares) (shares) Excluded securities: Convertible preferred stock issued and outstanding 35,477,685 30,699,957 35,477,685 30,699,957 Stock options issued and outstanding 7,012,630 4,540,101 6,518,522 4,540,101 Unvested stock options exercised 2,381,385 4,768,109 2,381,385 4,768,109 Warrants issued and outstanding 120,471 197,870 120,471 197,870 Total common stock equivalents excluded from diluted net loss per common share computation 44,992,171 40,206,037 44,498,063 40,206,037

Convertible Preferred Stock a32

Convertible Preferred Stock and Stockholders' Deficit (Tables)	9 Months Ended
	Sep. 30, 2015
Stockholders Equity Note [Abstract]
Summary of Shares Authorized, Issued, Outstanding, Par Value and Liquidation Preference of Convertible Preferred Stock	The number of authorized, issued and outstanding shares, their par value and liquidation preference for each series of convertible preferred stock as of September 30, 2015 are disclosed in the table below (amounts in thousands except share and per share amounts): Convertible Preferred Stock Par Value Authorized shares Outstanding and Issued shares Liquidation Preference New Series A $ 0.01 13,711,644 13,711,644 $ 19,774 Series A-1 0.01 4,952,183 4,952,183 49,522 New Series B 0.01 7,155,176 7,155,176 21,581 New Series C 0.01 4,880,954 4,880,954 70,075 New Series D 0.01 4,777,728 4,777,728 165,000 35,477,685 35,477,685 $ 325,952

Shared Based Incentive Plan a33

Shared Based Incentive Plan and Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Activity of Options that were Early Exercised under the Plan	The activity of options that were early exercised under the 2005 Plan for the nine months ended September 30, 2015 is below: Early exercised options, unvested Weighted average exercise price Balance as of January 1, 2015 4,112,269 $ 0.25 Exercise of non-vested stock options 15,209 5.54 Repurchase of restricted stock (291,536 ) 0.45 Restricted stock vested (1,454,557 ) 0.27 Balance as of September 30, 2015 2,381,385 $ 0.24
Additional Information Regarding the Unvested Early Exercised Stock Options Outstanding	Additional information regarding the unvested early exercised stock options outstanding as of September 30, 2015 is as follows: Options Outstanding Range of Exercise Number Weighted –Avg. Weighted –Avg. Prices Outstanding Remaining Life Exercise Price $ 0.10 2,220,565 1.39 $ 0.10 0.57 116,814 2.35 0.57 5.65 41,506 2.84 5.65 18.11 2,500 3.42 18.11 $0.10 - $18.11 2,381,385 1.46 $ 0.24
Summarized Option Activity under Option Plan	Stock option activity under the 2005 Plan and 2015 Plan is summarized for the nine months ended September 30, 2015 below: Options Issued and Outstanding Weighted- Average Exercise Price Balance as of January 1, 2015 4,994,998 $ 1.85 Options granted 3,358,114 20.55 Options exercised – vested (612,941 ) 1.12 Options exercised – nonvested (15,209 ) 5.54 Options forfeited (689,484 ) 4.83 Balance as of September 30, 2015 7,035,478 10.53 Options vested and/or exercisable at September 30, 2015 5,554,074 8.43
Additional Information Regarding Common Stock Options Outstanding	Additional information regarding common stock options outstanding as of September 30, 2015 is as follows: Options Outstanding Options Vested and Exercisable Weighted – Weighted – Weighted - Range of Avg. Avg. Avg. Exercise Number Remaining Exercise Number Exercise Prices Outstanding Life Price Vested Price $0.10 - $0.99 2,553,872 8.33 $ 0.55 2,553,872 $ 0.55 1.00 - 4.99 180,372 5.56 1.67 176,271 1.67 5.00 - 9.99 1,075,995 8.82 5.64 456,492 5.64 10.00 - 19.99 2,367,439 9.38 18.11 2,367,439 18.11 20.00 - 27.45 857,800 9.74 27.34 - - $0.10 - $27.45 7,035,478 8.86 $ 10.53 5,554,074 $ 8.49
Fair Value of Stock Option Awards	The fair value of Prosper’s stock option awards for the three months and nine months ended September 30, 2015 and 2014 was estimated at the date of grant using the Black-Scholes model with the following average assumptions: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Volatility of common stock 50.71 % 57.63 % 56.14 % 67.95 % Risk-free interest rate 1.70 % 1.72 % 1.71 % 1.76 % Expected life 6.0 years 5.9 years 6.0 years 5.6 years Dividend yield 0 % 0 % 0 % 0 %
Stock Based Compensation Included in Consolidated Statements of Operations	The following table presents the amount of stock-based compensation related to stock-based awards granted to employees recognized in Prosper’s condensed consolidated statements of operations during the three and nine months ended September 30, 2015 and 2014 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Origination and servicing $ 369 $ 14 $ 805 $ 139 Sales and marketing 669 22 1,734 53 General and administrative 2,209 237 4,900 571 Total stock based compensation $ 3,247 $ 273 $ 7,439 $ 763

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	The following table summarizes Prosper’s activity related to its unrecognized tax benefits (in thousands): Beginning balance as of January 1, 2015 $ 4,927 Decrease related to prior year positions - Increase related to current year positions - Ending balance as of September 30, 2015 $ 4,927

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2015
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	During 2014, Prosper entered into leases for its new corporate headquarters at 221 Main Street in San Francisco, California and for its co-location facility. The 221 Main Street lease is a non-cancelable operating lease that expires in February 2023. The co-location facility lease expired in August 2015. In 2014, Prosper entered into a lease for office space in Phoenix, Arizona under an operating lease that expires in July 2021. In 2015, Prosper entered into a lease for office space in Lehi, Utah and San Francisco, California under operating leases that expire in February 2027 and February 2023, respectively. Future minimum rental payments under these leases as of September 30, 2015 are as follows (in thousands): Remaining three months of 2015 994 2016 5,976 2017 7,700 2018 8,133 2019 8,364 2020 8,601 Thereafter 26,820 Total future operating lease obligations $ 66,588

Related Parties (Tables)

Related Parties (Tables)	9 Months Ended
	Sep. 30, 2015
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes purchased and the income earned by parties deemed to be affiliates and related parties of Prosper for the three and nine months ended September 30, 2015 and 2014, as well as the Notes outstanding as of September 30, 2015 and December 31, 2014 are summarized below (in thousands): Aggregate Amount of Notes Purchased Interest Earned on Notes Nine Months Ended September 30, Nine Months Ended September 30, Related Party 2015 2014 2015 2014 Executive officers and management $ 1,232 $ 591 $ 152 $ 110 Directors 31 22 6 7 Total $ 1,263 $ 613 $ 158 $ 117 Aggregate Amount of Notes Purchased Interest Earned on Notes Three Months Ended September 30, Three Months Ended September 30, Related Party 2015 2014 2015 2014 Executive officers and management $ 386 $ 188 $ 53 $ 41 Directors 10 19 2 2 Total $ 396 $ 207 $ 55 $ 43 Notes Balance as of Related Party September 30, 2015 December 31, 2014 Executive officers and management $ 2,173 $ 1,614 Directors 99 76 $ 2,272 $ 1,690
Prosper Funding LLC [Member]
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes purchased and the income earned by parties deemed to be related parties of Prosper as of September 30, 2015 and December 31, 2014 are summarized below (in thousands): Aggregate Amount of Notes Purchased Interest Earned on Notes Nine Months Ended September 30, Nine Months Ended September 30, Related Party 2015 2014 2015 2014 Executive officers and management $ 1,232 $ 591 $ 152 $ 110 Directors - - - - Total $ 1,232 $ 591 $ 152 $ 110 Note Balance as of Related Party September 30, 2015 December 31, 2014 Executive officers and management $ 2,173 $ 1,614 Directors - - $ 2,173 $ 1,614

Restatement of Condensed Cons37

Restatement of Condensed Consolidated Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2015
Condensed Financial Statements Captions [Line Items]
Restatement of Consolidated Balance Sheets, Consolidated Statements of Operations and Consolidated Statements of Cash Flows	The following tables present the impact of these corrections on three and nine months ended September 30, 2014 ($ in thousands): Condensed Consolidated Statement of Operations – Three months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Transaction Fees, Net $ 22,233 $ - $ 22,233 $ (1,172 ) $ 21,061 Servicing Fees, Net 1,749 - 1,749 (348 ) 1,401 Gain on Sale of Borrower Loans - 635 635 633 1,268 Other Revenue 1,147 (635 ) 512 (33 ) 479 Total Operating Revenue 25,129 - 25,129 (920 ) 24,209 Interest Income Interest Income on Borrower Loans 10,705 - 10,705 76 10,781 Interest Expense on Notes (9,850 ) - (9,850 ) (36 ) (9,886 ) Net Interest Income 855 - 855 40 895 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 59 - 59 (38 ) 21 Total Net Revenue 26,043 - 26,043 (918 ) 25,125 Expenses Cost of Services 1,408 (1,408 ) - - - Compensation and benefits 6,260 (6,260 ) - - - Marketing and advertising 10,717 (10,717 ) - - - Depreciation and amortization 462 (462 ) - - - Professional services 582 (582 ) - - - Facilities and maintenance 1,441 (1,441 ) - - Origination and Servicing - 4,298 4,298 (922 ) 3,376 Sales and Marketing - 11,201 11,201 - 11,201 General and Administrative - 7,820 7,820 (616 ) 7,204 Other 2,449 (2,449 ) - - - Total Expenses 23,319 - 23,319 (1,538 ) 21,781 Net Income 2,724 - 2,724 620 3,344 Excess return to preferred shareholders on repurchase (14,892 ) - (14,892 ) - (14,892 ) Net loss available to common shareholders (12,168 ) - (12,168 ) 620 (11,548 ) Net loss per share - basic and diluted (1.31 ) - (1.31 ) 0.05 (1.26 ) Weighted-average shares - basic and diluted 9,280,334 - 9,280,334 (100,908 ) 9,179,426 *See note 1 for a description of the reclassifications. Condensed Consolidated Statement of Operations – Nine months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Transaction Fees, Net $ 46,849 $ - $ 46,849 $ (1,445 ) $ 45,404 Servicing Fees, Net 3,044 - 3,044 (532 ) 2,512 Gain on Sale of Borrower Loans - 814 814 1,432 2,246 Other Revenue 2,090 (814 ) 1,276 (614 ) 662 Total Operating Revenue 51,983 - 51,983 (1,159 ) 50,824 Interest Income Interest Income on Borrower Loans 30,995 - 30,995 158 31,153 Interest Expense on Notes (28,613 ) (28,613 ) (259 ) (28,872 ) Net Interest Income 2,382 - 2,382 (101 ) 2,281 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 448 - 448 (157 ) 291 Total Net Revenue 54,813 - 54,813 (1,417 ) 53,396 Expenses Cost of Services 3,275 (3,275 ) - - - Compensation and benefits 16,327 (16,327 ) - - - Marketing and advertising 25,743 (25,743 ) - - - Depreciation and amortization 1,201 (1,201 ) - - - Professional services 1,169 (1,169 ) - - - Facilities and maintenance 2,604 (2,604 ) - - Loss on impairment of fixed assets 215 (215 ) - - - Origination and Servicing - 10,232 10,232 (2,012 ) 8,220 Sales and Marketing - 27,028 27,028 27,028 General and Administrative - 17,371 17,371 (563 ) 16,808 Other 4,097 (4,097 ) - - - Total Expenses 54,631 - 54,631 (2,575 ) 52,056 Net Income 182 - 182 1,158 1,340 Excess return to preferred shareholders on repurchase (14,892 ) - (14,892 ) - (14,892 ) Net loss available to common shareholders (14,710 ) - (14,710 ) 1,158 (13,552 ) Net loss per share - basic and diluted (1.68 ) - (1.68 ) 0.11 (1.57 ) Weighted-average shares - basic and diluted 8,740,785 - 8,740,785 (120,351 ) 8,620,434 *See note 1 for a description of the reclassifications. Condensed Consolidated Statements of Cash Flows – Nine months ended September 30, 2014 As previously reported Adjustments As corrected Cash flows from operating activities: Net Income $ 182 $ 1,158 $ 1,340 Adjustments to Reconcile Net Income to Net Cash Used in Operating Activities: Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes (448 ) 157 (291 ) Depreciation and Amortization 1,201 27 1,228 Gain on sales of Borrower Loans - (2,480 ) (2,480 ) Amortization of and Change in Fair Value of Servicing Rights (803 ) 1,175 372 Stock-Based Compensation 777 (14 ) 763 Other, Net 215 63 278 Changes in Operating Assets and Liabilities: - Purchase of Loans Held for Sale at Fair Value (12,444 ) (907,326 ) (919,770 ) Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value - 909,897 909,897 Restricted Cash Except for those Related to Investing Activities - (26,976 ) (26,976 ) Accounts Receivable (703 ) 108 (595 ) Prepaid and Other Assets (2,543 ) 28 (2,515 ) Class Action Settlement Liability (1,909 ) (91 ) (2,000 ) Accounts Payable and Accrued Liabilities 4,406 624 5,030 Payable to Investors - 22,596 22,596 Net Cash Used in Operating Activities (12,069 ) (1,054 ) (13,123 ) Cash Flows From Investing Activities: Purchase of Borrower Loans Held at Fair Value (823,841 ) 692,984 (130,857 ) Principal Payments of Borrower Loans Held at Fair Value 88,944 30 88,974 Proceeds from Sale of Borrower Loans Held at Fair Value 693,007 (693,007 ) - Purchases of Property and Equipment (3,151 ) (1,655 ) (4,806 ) Changes in Restricted Cash Related to Investing Activities (1,478 ) 2,347 869 Net Cash Used in Investing Activities (46,519 ) 699 (45,820 ) Cash Flows from Financing Activities: Proceeds from Issuance of Notes Held at Fair Value 130,828 (72 ) 130,756 Payment of Notes Held at Fair Value (89,336 ) 427 (88,909 ) Proceeds from Issuance of Convertible Preferred Stock, net 69,958 - 69,958 Proceeds from Early Exercise of Stock Options and Issuance of Restricted Stock 454 - 454 Proceeds from Exercise of Vested Stock Options and Common Stock Warrants 161 - 161 Repurchase of Preferred Stock (18,525 ) - (18,525 ) Repurchase of Restricted Stock (24 ) - (24 ) Net Cash Provided by Financing Activities 93,516 355 93,871 Net Increase in Cash and Cash Equivalents 34,928 - 34,928 Cash and Cash Equivalents at Beginning of the Period 18,339 - 18,339 Cash and Cash Equivalents at End of the Period $ 53,267 $ - $ 53,267
Prosper Funding LLC [Member]
Condensed Financial Statements Captions [Line Items]
Restatement of Consolidated Balance Sheets, Consolidated Statements of Operations and Consolidated Statements of Cash Flows	The following tables present the impact of these corrections and corrections of other immaterial errors on the interim periods (in thousands): Condensed Consolidated Statement of Operations – Three months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Administration Fee Revenue - Related Party $ 8,574 $ — $ 8,574 $ — $ 8,574 Servicing Income, Net 1,574 — 1,574 (321 ) 1,253 Gain on Sale of Borrower Loans — 635 635 605 1,240 Other Revenue 635 (635 ) — — — Total Operating Revenue 10,783 — 10,783 284 11,067 Interest Income on Borrower Loans 10,724 — 10,724 136 10,860 Interest Expense on Notes (9,850 ) — (9,850 ) (36 ) (9,886 ) Net Interest Income 874 — 874 100 974 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 59 — 59 (38 ) 21 Total Net Revenue 11,716 — 11,716 346 12,062 Expenses Cost of Services 958 (958 ) — — — Administration Fee - Related Party 6836 — 6836 535 7,371 Depreciation and Amortization 273 (273 ) — — — Professional Services 1 (1 ) — — — Servicing — 1,231 1,231 (923 ) 308 General and Administration — 129 129 — 129 Other Operating Expenses 128 (128 ) — — — Total Expenses 8,196 — 8,196 (388 ) 7,808 Total Net Income $ 3,520 $ — $ 3,520 $ 734 $ 4,254 *See note 1 for further details on the reclassifications. Condensed Consolidated Statement of Operations – Nine months ended September 30, 2014 As previously reported Reclassifications* As reclassified Adjustments As corrected Revenue Operating Revenue Administration Fee Revenue - Related Party $ 19,525 $ — $ 19,525 $ — $ 19,525 Servicing Income, Net 2,965 — 2,965 (586 ) 2,379 Gain on Sale of Borrower Loans — 814 814 1,404 2,218 Other Revenue 814 (814 ) — — — Total Operating Revenue 23,304 — 23,304 818 24,122 Interest Income on Borrower Loans 31,014 — 31,014 429 31,443 Interest Expense on Notes (28,613 ) — (28,613 ) (260 ) (28,873 ) Net Interest Income 2,401 — 2,401 169 2,570 Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net 448 — 448 (146 ) 302 Total Net Revenue 26,153 — 26,153 841 26,994 Expenses Cost of Services 2297 (2,297 ) — — — Administration Fee - Related Party 15018 — 15,018 1,383 16,401 Depreciation and Amortization 761 (761 ) — — — Professional Services 16 (16 ) — — — Servicing — 3,058 3,058 (1,994 ) 1,064 General and Administration — 329 329 (14 ) 315 Other Operating Expenses 313 (313 ) — — — Total Expenses 18,405 — 18,405 (625 ) 17,780 Total Net Income $ 7,748 $ — $ 7,748 $ 1,466 $ 9,214 *See note 1 for further details on the reclassifications. Condensed Consolidated Statements of Cash Flows – Nine months ended September 30, 2014 As previously reported Adjustments As corrected Cash flows from operating activities: Net Income $ 7,748 $ 1,466 $ 9,214 Adjustments to Reconcile Net Income to Net Cash Used in Operating Activities: Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes (448 ) 146 (302 ) Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes - (28 ) (28 ) Depreciation and Amortization 761 27 788 Change in Servicing Rights (808 ) 808 - Gain on Sale of Borrower Loans - (2,480 ) (2,480 ) Amortization and Change in Fair Value of Servicing Rights - 294 294 Changes in Operating Assets and Liabilities: Purchase of Borrower Loans Held for Sale at Fair Value (12,444 ) (907,326 ) (919,770 ) Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value - 909,897 909,897 Restricted Cash Except for those Related to Investing Activities - (26,976 ) (26,976 ) Other Assets (21 ) 17 (4 ) Accounts Payable and Accrued Liabilities 212 116 328 Payable to Investors - 21,906 21,906 Net Related Party Payable (278 ) (601 ) (879 ) Net Cash Used in Operating Activities (5,278 ) (2,734 ) (8,012 ) Cash Flows From Investing Activities: Purchase of Borrower Loans Held at Fair Value (823,841 ) 692,984 (130,857 ) Principal Payments of Borrower Loans Held at Fair Value 88,944 40 88,984 Proceeds from Sale of Borrower Loans Receivable Held at Fair Value 693,007 (693,007 ) - Maturities of Short Term Investments - 1,271 1,271 Purchase of Short Term Investments - (1,274 ) (1,274 ) Purchases of Property and Equipment (829 ) 18 (811 ) Changes in Restricted Cash Related to Investing Activities 3,578 2,347 5,925 Net Cash Used in Investing Activities (39,141 ) 2,379 (36,762 ) Cash Flows from Financing Activities: Proceeds from Issuance of Notes Held at Fair Value 130,828 (72 ) 130,756 Payment of Notes Held at Fair Value (89,336 ) 427 (88,909 ) Net Cash Provided by Financing Activities 41,492 355 41,847 Net Decrease in Cash and Cash Equivalents (2,927 ) - (2,927 ) Cash and Cash Equivalents at Beginning of the Period 5,789 - 5,789 Cash and Cash Equivalents at End of the Period $ 2,862 $ - $ 2,862

Loan Servicing Assets and Lia38

Loan Servicing Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2015
Significant Unobservable Inputs Fair Value	Servicing Rights Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 15% - 25% 15% - 25% Default rate 2.0% - 21.8% 2.6% - 26.3% Market servicing rate 0.625% 0.625% - 0.70%
Schedule of Servicing Assets and Liabilities Measured at Fair Value	The following table presents additional information about level 3 servicing assets and liabilities measured at fair value on a recurring basis: Servicing Assets Servicing Liabilities Fair Value at July 1, 2015 $ 8,682 $ 606 Additions 4,370 53 Less: Changes in fair value (1,752 ) (109 ) Fair value at September 30, 2015 $ 11,300 $ 550 Servicing Assets Servicing Liabilities Amortized cost at January 1, 2015 $ 4,163 $ 624 Adjustment to adopt fair value measurement 546 (29 ) Fair value at January 1, 2015 4,709 595 Additions 10,204 246 Less: Changes in fair value (3,613 ) (291 ) Fair value at September 30, 2015 $ 11,300 $ 550
Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities	The following table presents the estimated impact on Prosper’s estimated fair value of servicing assets and liabilities, calculated using different market servicing rates and different default rates as of September 30, 2015 (in thousands, except percentages). Servicing Assets Servicing Liabilities Market servicing rate assumptions 0.625 % 0.625 % Resulting fair value from: Market servicing rate increase to 0.65% $ 10,462 $ (605 ) Market servicing rate decrease to 0.60% $ 12,138 $ (496 ) Weighted average default assumptions 14 % 14 % Resulting fair value from: 100 basis point increase $ 11,091 $ (550 ) 100 basis point decrease $ 11,510 $ (551 )
Prosper Funding LLC [Member]
Significant Unobservable Inputs Fair Value	The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding's servicing asset/liability fair value measurements at September 30, 2015 and December 31, 2014: Range Unobservable Input September 30, 2015 December 31, 2014 Discount rate 15% - 25% 15% - 25% Default rate 2.1% - 21.8% 2.6% - 26.3% Market servicing rate 0.625% 0.625% - 0.70%
Schedule of Servicing Assets and Liabilities Measured at Fair Value	The following table presents additional information about Level 3 servicing assets and liabilities recorded at fair value for the three months ended March 31, 2015 (in thousands). Servicing Servicing Assets Liabilities Amortized cost at January 1, 2015 $ 3,116 $ 624 Adjustment to adopt fair value measurement 399 (29 ) Fair value at January 1, 2015 3,515 595 Additions 10,204 246 Less: Transfers to PMI (249 ) - Less: changes in fair value (3,049 ) (291 ) Fair value at September 30, 2015 $ 10,421 $ 550 Servicing Servicing Assets Liabilities Fair value at July 1, 2015 $ 7,634 $ 606 Additions 4,367 53 Less: Transfers to PMI - - Less: changes in fair value (1,580 ) (109 ) Fair value at September 30, 2015 $ 10,421 $ 550
Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities	The following table presents the estimated impact on Prosper Funding’s estimated fair value of servicing assets and liabilities, calculated using different market servicing rates and different default rates as of September 30, 2015 (in thousands, except percentages). Servicing Assets Servicing Liabilities Weighted average market servicing rate assumptions 0.625 % 0.625 % Resulting fair value from: Servicing rate increase to 0.65% $ 9,952 $ (605 ) Servicing rate decrease to 0.60% $ 11,547 $ (496 ) Weighted average default assumptions 14 % 14 % Resulting fair value from: 100 basis point increase $ 10,230 $ (550 ) 100 basis point decrease $ 10,617 $ (551 )

Summary of Significant Accoun39

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Significant Accounting Policies [Line Items]
Increase in net servicing asset	$ 546
Decrease in net servicing liabilities	(29)
Prosper Funding LLC [Member]
Significant Accounting Policies [Line Items]
Increase in net servicing asset	399
Decrease in net servicing liabilities	(29)
Change in Accounting Principle [Member]
Significant Accounting Policies [Line Items]
Increase/ (Decrease) to retained earnings	(575)
Change in Accounting Principle [Member] | Prosper Funding LLC [Member]
Significant Accounting Policies [Line Items]
Increase/ (Decrease) to retained earnings	$ 428

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 29,665	$ 19,849
Less accumulated depreciation and amortization	(9,598)	(5,425)
Total property and equipment, net	20,067	14,424
Prosper Funding LLC [Member]
Property, Plant and Equipment [Line Items]
Less accumulated depreciation and amortization	(1,728)	(2,917)
Total property and equipment, net	5,492	1,125
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	6,789	3,824
Internal-use Software and Website Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	11,186	4,486
Internal-use Software and Website Development Costs [Member] | Prosper Funding LLC [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	7,220	4,042
Office Equipment and Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	2,327	1,904
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	5,646	5,274
Assets Not Yet Placed in Service [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 3,717	$ 4,361

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 1,309	$ 438	$ 4,426	$ 1,228
Prosper Funding LLC [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	587	249	2,483	788
Internal-use Software and Website Development Costs [Member]
Property, Plant and Equipment [Line Items]
Capitalized internal-use software and website development costs	$ 1,950	$ 316	5,883	1,124
Recorded internal-use software and website development impairment charges			$ 0	$ 233

Borrower Loans, Loans Held fo42

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower Loans, at Fair Value	$ 286,462	$ 273,243
Notes at Fair Value	(287,254)	(273,783)
Loans Held for Sale, at Fair Value	34	8,463
Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower Loans, at Fair Value	286,462	273,243
Notes at Fair Value	(287,254)	(273,783)
Loans Held for Sale, at Fair Value	34	8,463
Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Notes	(284,562)	(272,269)
Fair value adjustments	(2,692)	(1,514)
Notes at Fair Value	(287,254)	(273,783)
Notes [Member] | Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Notes	(284,562)	(272,269)
Fair value adjustments	(2,692)	(1,514)
Notes at Fair Value	(287,254)	(273,783)
Borrower Loans [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Borrower Loans	285,837	268,598
Fair value adjustments	625	4,645
Borrower Loans, at Fair Value	286,462	273,243
Borrower Loans [Member] | Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Borrower Loans	285,837	268,598
Fair value adjustments	625	4,645
Borrower Loans, at Fair Value	286,462	273,243
Loans Held for Sale [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value adjustments	(10)	168
Aggregate principal balance outstanding, Loans Held for Sale	44	8,295
Loans Held for Sale, at Fair Value	34	8,463
Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value adjustments	(10)	168
Aggregate principal balance outstanding, Loans Held for Sale	44	8,295
Loans Held for Sale, at Fair Value	$ 34	$ 8,463

Borrower Loans, Loans Held fo43

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower loans original maturity term, description		Original terms to maturity of either 36 or 60 months
Fixed interest rate, Minimum		5.32%	5.77%
Fixed interest rate, Maximum		33.04%	33.04%
Loans maturity date		Sep. 30, 2020	Dec. 31, 2019
Loss related to credit risks on borrower loans	$ 1,300,000	$ 3,400,000
Minimum number of days for which loans originated were delinquent		90 days	90 days
Aggregate principal amount of loans originated	1,700,000	$ 1,700,000	$ 1,700,000
Non accrual status past due date		120 days
Fair value of loans originated	700,000	$ 700,000	600,000
Borrower Loans receivable	100,000	$ 100,000	$ 0
Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower loans original maturity term, description		Original terms to maturity of either 36 or 60 months
Fixed interest rate, Minimum		5.32%	5.77%
Fixed interest rate, Maximum		33.04%	33.04%
Loans maturity date		Sep. 30, 2020	Dec. 31, 2019
Loss related to credit risks on borrower loans	1,300,000	$ 3,400,000
Minimum number of days for which loans originated were delinquent		90 days	90 days
Aggregate principal amount of loans originated	1,700,000	$ 1,700,000	$ 1,500,000
Non accrual status past due date		120 days
Fair value of loans originated	700,000	$ 700,000	140,000
Borrower Loans receivable	$ 100,000	$ 100,000	$ 0

Loan Servicing Assets and Lia44

Loan Servicing Assets and Liabilities - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Servicing Assets And Liabilities Fair Value [Line Items]
Gain on sale of Borrower Loans	$ 4,263	$ 1,268	$ 9,881	$ 2,246
Borrower loans original maturity term, description			Original terms to maturity of either 36 or 60 months
Fixed interest rate, Minimum			5.32%		5.77%
Fixed interest rate, Maximum			33.04%		33.04%
Loans maturity date			Sep. 30, 2020		Dec. 31, 2019
Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Gain on sale of Borrower Loans	4,263	$ 1,240	$ 9,881	$ 2,218
Borrower loans original maturity term, description			Original terms to maturity of either 36 or 60 months
Fixed interest rate, Minimum			5.32%		5.77%
Fixed interest rate, Maximum			33.04%		33.04%
Loans maturity date			Sep. 30, 2020		Dec. 31, 2019
Borrower Loans [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	3,116,000		$ 3,116,000		$ 1,358,000
Borrower loans original maturity term, description			Original terms of either 36 or 60 months
Fixed interest rate, Minimum			5.32%		6.05%
Fixed interest rate, Maximum			31.90%		31.34%
Loans maturity date			Sep. 30, 2020		Dec. 31, 2019
Debt instrument, Description			As of September 30, 2015, Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $3,116 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 5.32% to 31.90% and various maturity dates through September 2020. At December 31, 2014, Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $1,358 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and various maturity dates through December 2019. The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes assumptions of the market servicing rate, the default rate and discount rate as important inputs (see note 6).
Borrower Loans [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	$ 2,078,000		$ 2,078,000		$ 1,045,000
Borrower loans original maturity term, description			Original terms of either 36 or 60 months
Fixed interest rate, Minimum			5.32%		6.05%
Fixed interest rate, Maximum			31.90%		31.34%
Loans maturity date			Sep. 30, 2020		Dec. 31, 2019
Debt instrument, Description			At September 30, 2015, Borrower Loans that were sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $2,078 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 5.32% to 31.90% and various maturity dates through September 2020. At December 31, 2014, Borrower Loans that were sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $1,045 million, original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and various maturity dates through December 2019. The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes assumptions of the market servicing rate, the default rate and discount rate as important inputs.

Available for Sale Investments

Available for Sale Investments at Fair Value - Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Available for Sale Investments (Details) $ in Thousands	Sep. 30, 2015USD ($)
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 47,100
Gross Unrealized Gains	19
Gross Unrealized Losses	(15)
Available for Sale Investments, at Fair Value	47,104
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	33,618
Gross Unrealized Gains	18
Gross Unrealized Losses	(15)
Available for Sale Investments, at Fair Value	33,621
Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	11,481
Available for Sale Investments, at Fair Value	11,481
U S Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,001
Gross Unrealized Gains	1
Available for Sale Investments, at Fair Value	$ 2,002

Available for Sale Investment46

Available for Sale Investments at Fair Value - Summary of Available for Sale Investments of Continuous Unrealized Loss (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	$ 12,602
Unrealized losses, less than 12 months	(15)
Fair Value	12,602
Unrealized losses	(15)
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	12,602
Unrealized losses, less than 12 months	(15)
Fair Value	12,602
Unrealized losses	$ (15)

Available for Sale Investment47

Available for Sale Investments at Fair Value - Schedule of Maturities of Available for Sale Investments (Details) $ in Thousands	Sep. 30, 2015USD ($)
Schedule Of Available For Sale Securities [Line Items]
Fair value within 1 year	$ 31,977
Fair value after 1 year through 5 years	15,127
Fair value	47,104
Amortized cost within 1 year	31,987
Amortized cost after 1 year through 5 years	15,113
Amortized cost	47,100
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Fair value within 1 year	20,496
Fair value after 1 year through 5 years	13,125
Fair value	33,621
Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair value within 1 year	11,481
Fair value	11,481
U S Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Fair value after 1 year through 5 years	2,002
Fair value	$ 2,002

Available for Sale Investment48

Available for Sale Investments at Fair Value - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Segment Reporting [Abstract]
Impairment charges recognized during period	$ 0	$ 0
Available-for-sale investments, realized gains	$ 0	$ 0

Fair Value of Assets and Liab49

Fair Value of Assets and Liabilities - Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets:
Borrower Loans	$ 286,462	$ 273,243
Loans Held for Sale	34	8,463
Available for Sale Investments, at Fair Value	47,104
Servicing Assets	11,300	4,709
Total Assets	344,900	286,415
Liabilities:
Notes	287,254	273,783
Servicing Liabilities	550	595
Total Liabilities	287,804	274,378
Level 2 Inputs [Member]
Assets:
Available for Sale Investments, at Fair Value	47,104
Total Assets	47,104
Level 3 Inputs [Member]
Assets:
Borrower Loans	286,462	273,243
Loans Held for Sale	34	8,463
Servicing Assets	11,300	4,709
Total Assets	297,796	286,415
Liabilities:
Notes	287,254	273,783
Servicing Liabilities	550	595
Total Liabilities	$ 287,804	$ 274,378

Fair Value of Assets and Liab50

Fair Value of Assets and Liabilities - Borrower Loans, Loans Held For Sale and Notes - Quantitative Information about the Significant Unobservable Inputs (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Minimum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	2.90%	3.30%
Default rate	2.70%	2.60%
Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	10.50%	10.60%
Default rate	22.80%	19.70%

Fair Value of Assets and Liab51

Fair Value of Assets and Liabilities - Servicing Rights - Quantitative Information about the Significant Unobservable Inputs (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate	0.625%
Minimum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	2.00%	2.60%
Market servicing rate		0.625%
Maximum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	21.80%	26.30%
Market servicing rate		0.70%

Fair Value of Assets and Liab52

Fair Value of Assets and Liabilities - Summary of Level 3 Borrower Loans, Loans Held for Sale and Notes, Measured at Fair Value on a Recurring Basis (Details) - Recurring [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Total	$ 1,004	$ 7,026	$ 7,923	$ 2,093
Purchase of Borrower Loans/Issuance of Notes, Total	1,024,385	443,899	2,426,820	919,871
Principal repayments, Total	(209)	(313)	(699)	(598)
Borrower Loans sold to third parties, Total	(1,025,846)	(438,342)	(2,434,729)	(909,364)
Other changes, Total	(5)	31	(7)	29
Change in fair value, Total	(87)	21	(66)	291
Ending balance, Total	(758)	12,322	(758)	12,322
Notes [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Liabilities	(284,627)	(253,943)	(273,783)	(234,218)
Purchase of Borrower Loans/Issuance of Notes, Liabilities	(47,670)	(44,077)	(142,246)	(130,756)
Principal repayments, Liabilities	38,202	31,334	111,711	88,909
Borrower Loans sold to third parties, Liabilities	425		425
Other changes, Liabilities	(18)	(22)	119	67
Change in fair value, Liabilities	6,434	5,842	16,520	15,132
Ending balance, Liabilities	(287,254)	(260,866)	(287,254)	(260,866)
Borrower Loans [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	284,200	252,971	273,243	233,105
Purchase of Borrower Loans/Issuance of Notes, Assets	47,591	44,141	142,103	130,857
Principal repayments, Assets	(38,407)	(31,244)	(111,864)	(88,974)
Borrower Loans sold to third parties, Assets	(447)		(447)
Other changes, Assets	21	46	(108)	(54)
Change in fair value, Assets	(6,496)	(5,821)	(16,465)	(14,841)
Ending balance, Assets	286,462	260,093	286,462	260,093
Loans Held for Sale [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	1,431	7,998	8,463	3,206
Purchase of Borrower Loans/Issuance of Notes, Assets	1,024,464	443,835	2,426,963	919,770
Principal repayments, Assets	(4)	(403)	(546)	(533)
Borrower Loans sold to third parties, Assets	(1,025,824)	(438,342)	(2,434,707)	(909,364)
Other changes, Assets	(8)	7	(18)	16
Change in fair value, Assets	(25)		(121)
Ending balance, Assets	$ 34	$ 13,095	$ 34	$ 13,095

Fair Value of Assets and Liab53

Fair Value of Assets and Liabilities - Schedule of Servicing Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Adjustment to adopt fair value measurement, servicing assets		$ 546
Servicing Liability at Amortized Cost [Roll Forward]
Adjustment to adopt fair value measurement		(29)
Servicing assets [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Amortized cost at beginning of period		4,163
Adjustment to adopt fair value measurement, servicing assets		546
Fair value at beginning of period	$ 8,682	4,709
Additions	4,370	10,204
Less: Changes in fair value	(1,752)	(3,613)
Fair Value at end of period	11,300	11,300
Servicing liabilities [Member]
Servicing Liability at Amortized Cost [Roll Forward]
Amortized cost at beginning of the period		624
Adjustment to adopt fair value measurement		(29)
Fair value at beginning of the period	606	595
Additions	53	246
Less: Changes in fair value	(109)	(291)
Fair value at end of the period	$ 550	$ 550

Fair Value of Assets and Liab54

Fair Value of Assets and Liabilities - Fair Value Assumptions for Borrower Loans, Loans Held for Sale and Notes (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Discount rate assumption [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.57%	[1]
Discount rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.57%	[1]
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 283,684
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	284,453
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	280,688
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	281,443
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	289,923
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	290,720
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	293,172
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 293,985
Default rate assumption [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate	12.73%	[1]
Default rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate	12.73%	[1]
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 283,157
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	283,915
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	279,610
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	280,343
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	290,392
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	291,201
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	294,042
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 294,877
[1]	Represents weighted average assumptions considering all credit grades.

Fair Value of Assets and Liab55

Fair Value of Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%
Servicing assets [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%
Resulting fair value from:
Market servicing rate increase to 0.65%	$ 10,462
Market servicing rate decrease to 0.60%	$ 12,138
Weighted average default assumptions	14.00%
100 basis point increase	$ 11,091
100 basis point decrease	$ 11,510
Servicing liabilities [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%
Resulting fair value from:
Market servicing rate increase to 0.65%	$ (605)
Market servicing rate decrease to 0.60%	$ (496)
Weighted average default assumptions	14.00%
100 basis point increase	$ (550)
100 basis point decrease	$ (551)

Fair Value of Assets and Liab56

Fair Value of Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Parenthetical) (Details)	9 Months Ended
	Sep. 30, 2015
Transfers And Servicing [Abstract]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Default rate increase	1.00%
Default rate decrease	1.00%

American HealthCare Lending A57

American HealthCare Lending Acquisition - Additional Information (Details) - American HealthCare Lending, LLC [Member] - USD ($) $ in Thousands	Jan. 23, 2015	Sep. 30, 2015	Sep. 30, 2015
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 20,200
Future payments to acquire businesses			$ 800
Business Acquisition, Effective Date of Acquisition			Jan. 23, 2015
Business Acquisition, Name of Acquired Entity			American HealthCare Lending LLC
Revenue of acquiree included in consolidated statement since merger date			$ 2,100
Loss of acquiree included in consolidated statement since merger date			3,300
Acquisition expenses			200
Amortization of intangible assets		$ 203	$ 541
Customer Relationships [member]
Business Acquisition [Line Items]
Intangible assets amortized period			10 years
Technology [Member]
Business Acquisition [Line Items]
Intangible assets amortized period			3 years
Brand Name [Member]
Business Acquisition [Line Items]
Intangible assets amortized period			1 year

American HealthCare Lending A58

American HealthCare Lending Acquisition - Preliminary Purchase Price Allocation (Details) $ in Thousands	Sep. 30, 2015USD ($)
Assets:
Goodwill	$ 16,825
American HealthCare Lending, LLC [Member]
Assets:
Cash	1,219
Accounts Receivable	147
Property, equipment and software	6
Other assets	63
Identified intangible assets	3,520
Goodwill	16,825
Liabilities:
Accrued expenses and other liabilities	708
Total purchase consideration	$ 21,072

American HealthCare Lending A59

American HealthCare Lending Acquisition - Schedule of Intangible Assets (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Acquired Finite Lived Intangible Assets [Line Items]
Net Carrying Value	$ 2,979
American HealthCare Lending, LLC [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	3,520
Accumulated Amortization	(541)
Net Carrying Value	2,979
American HealthCare Lending, LLC [Member] | Customer Relationships [member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	2,650
Accumulated Amortization	(321)
Net Carrying Value	$ 2,329
Remaining Useful Life (In Years)	9 years 3 months 18 days
American HealthCare Lending, LLC [Member] | Technology [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 810
Accumulated Amortization	(180)
Net Carrying Value	$ 630
Remaining Useful Life (In Years)	2 years 3 months 18 days
American HealthCare Lending, LLC [Member] | Brand Name [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 60
Accumulated Amortization	(40)
Net Carrying Value	$ 20
Remaining Useful Life (In Years)	3 months 18 days

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator [Abstract]
Net Income (Loss)	$ (3,843)	$ 3,344	$ (17,324)	$ 1,340
Less: Excess Return to Preferred Shareholders on Repurchase		(14,892)		(14,892)
Net Loss Attributable to Common Stockholders	$ (3,843)	$ (11,548)	$ (17,324)	$ (13,552)
Denominator [Abstract]
Weighted average shares used in computing basic and diluted net loss per share	11,181,553	9,179,426	10,949,396	8,620,434
Basic and Diluted net loss per share	$ (0.34)	$ (1.26)	$ (1.58)	$ (1.57)

Net Loss Per Share - Common Sto

Net Loss Per Share - Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	44,992,171	40,206,037	44,498,063	40,206,037
Convertible Preferred Stock Issued and Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	35,477,685	30,699,957	35,477,685	30,699,957
Stock Options Issued and Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	7,012,630	4,540,101	6,518,522	4,540,101
Unvested Stock Options Exercised [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	2,381,385	4,768,109	2,381,385	4,768,109
Warrants Issued and Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	120,471	197,870	120,471	197,870

Convertible Preferred Stock a62

Convertible Preferred Stock and Stockholders' Deficit - Additional Information (Details)	Sep. 11, 2015USD ($)$ / sharesshares	Jun. 12, 2015USD ($)$ / sharesshares	Apr. 30, 2015USD ($)$ / sharesshares	Sep. 30, 2015USD ($)Times$ / sharesshares	Sep. 30, 2014USD ($)	Dec. 31, 2014$ / sharesshares
Class of Stock [Line Items]
Proceeds from Issuance of Convertible Preferred Stock, Net | $				$ 164,793,000	$ 69,958,000
Dividends | $				$ 0
Common and preferred stock, shares authorized (in shares)			89,542,900
Common stock, shares authorized (in shares)			54,065,215	54,065,215		47,928,883
Preferred stock, shares authorized (in shares)			35,477,685	35,477,685		32,155,022
Common stock, par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01		$ 0.01
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01
Common stock, shares issued (in shares)				14,058,509		14,448,700
Common stock, shares outstanding (in shares)				13,871,322		14,448,700
Common stock voting rights				Each holder of common stock is entitled to one vote for each share of common stock held.
Recognized compensation cost relating to common stock | $	$ 500,000	$ 5,700,000
Common Stock [Member]
Class of Stock [Line Items]
Aggregate price for repurchase of common stock | $				$ 130,000
Exercise of stock options (in shares)				628,150
Proceeds from Exercise of Vested Stock Options | $				$ 770,000
Exercise of nonvested stock options (in shares)				15,209
Unvested restricted stock outstanding (in shares)				2,381,385		4,112,269
Stock repurchase upon termination of employment (in shares)				291,536
Warrant [Member]
Class of Stock [Line Items]
Shares issued (in shares)				38,674
Exercise of warrants aggregate proceeds | $				$ 120,000
Origination and Servicing [Member]
Class of Stock [Line Items]
Recognized compensation cost relating to common stock | $	200,000	130,000
Sales and Marketing [Member]
Class of Stock [Line Items]
Recognized compensation cost relating to common stock | $	30,000	40,000
General and Administrative [Member]
Class of Stock [Line Items]
Recognized compensation cost relating to common stock | $	$ 200,000	$ 5,500,000
Executives [Member]
Class of Stock [Line Items]
Stock repurchased during period, shares	0	721,419
Aggregate price for repurchase of common stock | $		$ 24,900,000
Employees [Member]
Class of Stock [Line Items]
Stock repurchased during period, shares	68,073	777,025
Stock repurchased during period, price per share | $ / shares	$ 34.54	$ 34.54
Aggregate price for repurchase of common stock | $	$ 2,400,000	$ 26,800,000
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Shares issued (in shares)			4,777,728
Convertible preferred stock, price per share (in dollars per share) | $ / shares			$ 34.54
Proceeds from Issuance of Convertible Preferred Stock, Net | $			$ 164,800,000
Liquidation preference per share (in dollars per share) | $ / shares				$ 34.54
Preferred stock, shares authorized (in shares)				4,777,728
Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Liquidation preference per share (in dollars per share) | $ / shares				$ 1.44
Number of times shareholders are entitled to receive original issue price | Times				3
Preferred stock, shares authorized (in shares)				13,711,644
Series A 1 [Member]
Class of Stock [Line Items]
Liquidation preference per share (in dollars per share) | $ / shares				$ 10
Preferred stock, shares authorized (in shares)				4,952,183
Series B Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Liquidation preference per share (in dollars per share) | $ / shares				$ 3.02
Preferred stock, shares authorized (in shares)				7,155,176
Series C Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Liquidation preference per share (in dollars per share) | $ / shares				$ 14.36
Preferred stock, shares authorized (in shares)				4,880,954

Convertible Preferred Stock a63

Convertible Preferred Stock and Stockholders' Deficit - Summary of Shares Authorized, Issued, Outstanding, Par Value and Liquidation Preference of Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2015	Apr. 30, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Convertible preferred stock, shares authorized (in shares)	35,477,685	35,477,685	32,155,022
Convertible preferred stock, shares outstanding (in shares)	35,477,685		30,699,957
Convertible preferred stock, shares issued (in shares)	35,477,685		30,699,957
Convertible preferred stock, liquidation preference	$ 325,952		$ 160,952
Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	13,711,644
Convertible preferred stock, shares outstanding (in shares)	13,711,644
Convertible preferred stock, shares issued (in shares)	13,711,644
Convertible preferred stock, liquidation preference	$ 19,774
Series A 1 [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	4,952,183
Convertible preferred stock, shares outstanding (in shares)	4,952,183
Convertible preferred stock, shares issued (in shares)	4,952,183
Convertible preferred stock, liquidation preference	$ 49,522
Series B Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	7,155,176
Convertible preferred stock, shares outstanding (in shares)	7,155,176
Convertible preferred stock, shares issued (in shares)	7,155,176
Convertible preferred stock, liquidation preference	$ 21,581
Series C Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	4,880,954
Convertible preferred stock, shares outstanding (in shares)	4,880,954
Convertible preferred stock, shares issued (in shares)	4,880,954
Convertible preferred stock, liquidation preference	$ 70,075
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	4,777,728
Convertible preferred stock, shares outstanding (in shares)	4,777,728
Convertible preferred stock, shares issued (in shares)	4,777,728
Convertible preferred stock, liquidation preference	$ 165,000

Shared Based Incentive Plan a64

Shared Based Incentive Plan and Compensation - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights			Options generally vest 25% one year from the vesting commencement date and 1/48th per month thereafter.
Options exercisable, maximum period			10 years
Unrecognized cost of unvested share-based compensation awards.	$ 0		$ 0
Dividend yield	0.00%	0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period			90,000
Unamortized expense related to unvested stock-based awards	$ 36,400,000		$ 36,400,000
Remaining weighted average vesting period			3 years 2 months 12 days
Internal-use Software and Website Development Costs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation, capitalized amount	$ 202,000	$ 8,000	$ 499,000	$ 18,000
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Issued, Price Per Share	$ 18.11		$ 18.11
Restricted Stock [Member] | Vesting 2016 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			33.33%
Restricted Stock [Member] | Vesting 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			33.33%
Restricted Stock [Member] | Vesting 2018 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			33.33%
2005 Stock Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options made available in pool (in shares)	14,273,773		14,273,773
Options Issued and Outstanding, Options granted			3,358,114
Weighted average grant fair value	$ 14.52		$ 14.52
Stock options estimated aggregate fair value			$ 48,800,000
2005 Stock Plan [Member] | Stock Options Issued and Outstanding [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant under the plan	0		0
2015 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options made available in pool (in shares)	2,349,901		2,349,901
Shares available for grant under the plan	1,537,101		1,537,101

Shared Based Incentive Plan a65

Shared Based Incentive Plan and Compensation - Schedule of Activity of Options that were Early Exercised under the Plan (Details) - Early Exercised Stock Options Under 2005 Stock Option Plan [Member]	9 Months Ended
	Sep. 30, 2015$ / sharesshares
Early exercised options, unvested [Roll Forward]
Beginning balance	4,112,269
Exercise of non-vested stock options	15,209
Repurchase of restricted stock	(291,536)
Restricted stock vested	(1,454,557)
Ending balance	2,381,385
Weighted average exercise price [Abstract]
Weighted-Average Exercise Price, Beginning balance | $ / shares	$ 0.25
Exercise of non-vested stock options | $ / shares	5.54
Repurchase of restricted stock | $ / shares	0.45
Restricted stock vested | $ / shares	0.27
Weighted-Average Exercise Price, Ending balance | $ / shares	$ 0.24

Shared Based Incentive Plan a66

Shared Based Incentive Plan and Compensation - Additional Information Regarding Unvested Early exercised stock options outstanding (Details)	9 Months Ended
	Sep. 30, 2015$ / sharesshares
$0.10 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 0.10
Number Outstanding | shares	2,220,565
Weighted Avg. Remaining Life	1 year 4 months 21 days
Weighted Avg. Exercise Price	$ 0.10
$0.57 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 0.57
Number Outstanding | shares	116,814
Weighted Avg. Remaining Life	2 years 4 months 6 days
Weighted Avg. Exercise Price	$ 0.57
$5.65 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 5.65
Number Outstanding | shares	41,506
Weighted Avg. Remaining Life	2 years 10 months 2 days
Weighted Avg. Exercise Price	$ 5.65
$18.11 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 18.11
Number Outstanding | shares	2,500
Weighted Avg. Remaining Life	3 years 5 months 1 day
Weighted Avg. Exercise Price	$ 18.11
$0.10-$18.11 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	0.10
Range of Exercise Prices, Maximum	$ 18.11
Number Outstanding | shares	2,381,385
Weighted Avg. Remaining Life	1 year 5 months 16 days
Weighted Avg. Exercise Price	$ 0.24

Shared Based Incentive Plan a67

Shared Based Incentive Plan and Compensation - Summarized Option Activity under Option Plan (Details) - 2005 Stock Plan and 2015 Stock Option Plan [Member]	9 Months Ended
	Sep. 30, 2015$ / sharesshares
Options Issued and Outstanding [Roll Forward]
Options Issued and Outstanding, Beginning Balance	4,994,998
Options Issued and Outstanding, Options granted	3,358,114
Options Issued and Outstanding, Options exercised - vested	(612,941)
Options Issued and Outstanding, Options exercised - nonvested	(15,209)
Options Issued and Outstanding, Options forfeited	(689,484)
Options Issued and Outstanding, Ending balance	7,035,478
Options Issued and Outstanding, Options vested and exercisable at September 30, 2015	5,554,074
Weighted-Average Exercise Price [Roll Forward]
Weighted-Average Exercise Price, Beginning balance | $ / shares	$ 1.85
Weighted-Average Exercise Price, Options granted | $ / shares	20.55
Weighted-Average Exercise Price, Options exercised - vested | $ / shares	1.12
Weighted-Average Exercise Price, Options exercised - nonvested | $ / shares	5.54
Weighted-Average Exercise Price, Options forfeited | $ / shares	4.83
Weighted-Average Exercise Price, Ending balance | $ / shares	10.53
Weighted-Average Exercise Price, Options vested and exercisable at September 30, 2015 | $ / shares	$ 8.43

Shared Based Incentive Plan a68

Shared Based Incentive Plan and Compensation - Additional Information Regarding Common Stock Options Outstanding (Details) - Stock Options Issued and Outstanding [Member]	9 Months Ended
	Sep. 30, 2015$ / sharesshares
$0.10 - $0.99 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 0.10
Range of Exercise Prices, Maximum	$ 0.99
Number Outstanding | shares	2,553,872
Weighted Avg. Remaining Life	8 years 3 months 29 days
Weighted Avg. Exercise Price	$ 0.55
Number Exercisable | shares	2,553,872
Weighted-Avg. Exercise Price	$ 0.55
$1.00 - $4.99 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	1
Range of Exercise Prices, Maximum	$ 4.99
Number Outstanding | shares	180,372
Weighted Avg. Remaining Life	5 years 6 months 22 days
Weighted Avg. Exercise Price	$ 1.67
Number Exercisable | shares	176,271
Weighted-Avg. Exercise Price	$ 1.67
$5.00 - $9.99 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	5
Range of Exercise Prices, Maximum	$ 9.99
Number Outstanding | shares	1,075,995
Weighted Avg. Remaining Life	8 years 9 months 26 days
Weighted Avg. Exercise Price	$ 5.64
Number Exercisable | shares	456,492
Weighted-Avg. Exercise Price	$ 5.64
$10.00 - $19.99 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	10
Range of Exercise Prices, Maximum	$ 19.99
Number Outstanding | shares	2,367,439
Weighted Avg. Remaining Life	9 years 4 months 17 days
Weighted Avg. Exercise Price	$ 18.11
Number Exercisable | shares	2,367,439
Weighted-Avg. Exercise Price	$ 18.11
$20.00 - $27.45 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	20
Range of Exercise Prices, Maximum	$ 27.45
Number Outstanding | shares	857,800
Weighted Avg. Remaining Life	9 years 8 months 27 days
Weighted Avg. Exercise Price	$ 27.34
$0.10 - $27.45 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	0.10
Range of Exercise Prices, Maximum	$ 27.45
Number Outstanding | shares	7,035,478
Weighted Avg. Remaining Life	8 years 10 months 10 days
Weighted Avg. Exercise Price	$ 10.53
Number Exercisable | shares	5,554,074
Weighted-Avg. Exercise Price	$ 8.49

Shared Based Incentive Plan a69

Shared Based Incentive Plan and Compensation - Fair Value of Stock Option Awards (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair value of stock option awards [Abstract]
Volatility of common stock	50.71%	57.63%	56.14%	67.95%
Risk-free interest rate	1.70%	1.72%	1.71%	1.76%
Expected life	6 years	5 years 10 months 24 days	6 years	5 years 7 months 6 days
Dividend yield	0.00%	0.00%	0.00%	0.00%

Shared Based Incentive Plan a70

Shared Based Incentive Plan and Compensation - Stock Based Compensation Included in Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	$ 3,247	$ 273	$ 7,439	$ 763
Origination and Servicing [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	369	14	805	139
Sales and Marketing [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	669	22	1,734	53
General and Administrative [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	$ 2,209	$ 237	$ 4,900	$ 571

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Taxes [Line Items]
Income Tax Expense	$ 35,000		$ 284,000
Unrecognized Tax Benefits	4,927,000		4,927,000		$ 4,927,000
Interest and penalties related to uncertain tax positions			0
Prosper Funding LLC [Member]
Income Taxes [Line Items]
Income Tax Expense	$ 0	$ 0	$ 0	$ 0
Net effective tax rate	0.00%	0.00%	0.00%	0.00%
Valuation ​Allowance of Deferred ​Tax ​Assets​
Income Taxes [Line Items]
Income Tax Expense	$ 0	$ 0	$ 0	$ 0

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) $ in Thousands	Sep. 30, 2015USD ($)
Unrecognized tax benefits [Roll Forward]
Beginning balance as of January 1, 2015	$ 4,927
Ending balance as of September 30, 2015	$ 4,927

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	3 Months Ended			9 Months Ended		12 Months Ended
	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)State	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)StateInstallment	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)	Nov. 30, 2008USD ($)	Oct. 16, 2008USD ($)
Commitments And Contingencies [Line Items]
Rental expense under operating lease arrangements		$ 1,000,000	$ 700,000	$ 2,700,000	$ 1,100,000
Maximum potential future payments		3,116,000,000		3,116,000,000
Accrued repurchase and indemnification obligation		$ 298,000		$ 298,000		$ 171,000
Amount of loans sold to lender members								$ 178,000,000
Aggregate amount of payment for penalties							$ 1,000,000
Number of states with which company entered into consent order | State		35		35
Aggregate amount paid by entity for penalties to states		$ 480,000		$ 480,000
Accrued contingent liability associated with states not entered into consent orders		230,000		230,000		250,000
Maximum fee liability taken to estimate accrued contingent liability		1,000,000		1,000,000
Agreed amount of settlement liability payable to plaintiffs				$ 10,000,000
Number of annual installments paid to plaintiffs | Installment				4
Other commitment paid				$ 2,000,000		2,000,000
Settlement installment due in 2016		3,000,000		3,000,000
Settlement installment due in 2017		3,000,000		3,000,000
Class action settlement liability		5,926,000		5,926,000		7,861,000
Prosper Funding LLC [Member]
Commitments And Contingencies [Line Items]
Purchase of borrower loans		38,800,000
Maximum potential future payments		2,800,000,000		2,800,000,000
Accrued repurchase and indemnification obligation		$ 248,000		$ 248,000		$ 171,000
Scenario, Forecast [Member]
Commitments And Contingencies [Line Items]
Minimum annual fee	$ 1,400,000
Purchase of borrower loans	38,800,000
Scenario, Forecast [Member] | Prosper Funding LLC [Member]
Commitments And Contingencies [Line Items]
Minimum annual fee	$ 1,400,000
Co Location Facility
Commitments And Contingencies [Line Items]
Non cancelable operating lease expiration				2015-08
San Francisco California
Commitments And Contingencies [Line Items]
Non cancelable operating lease expiration				2023-02
Office lease expiration				2023-02
Phoenix, Arizona
Commitments And Contingencies [Line Items]
Office lease expiration				2021-07
Lehi, Utah
Commitments And Contingencies [Line Items]
Office lease expiration				2027-02

Commitments and Contingencies74

Commitments and Contingencies - Future Minimum Lease Payments (Details) $ in Thousands	Sep. 30, 2015USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
Remaining three months of 2015	$ 994
2,016	5,976
2,017	7,700
2,018	8,133
2,019	8,364
2,020	8,601
Thereafter	26,820
Total future operating lease obligations	$ 66,588

Related Parties - Additional In

Related Parties - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Related Party Transaction [Line Items]
Minimum percentage of voting securities considered for related parties	10.00%
Minimum percentage of stock holders considered for related parties	10.00%
Prosper Funding LLC [Member]
Related Party Transaction [Line Items]
Payments of distributions to parent	$ 35,505

Related Parties - Aggregate Amo

Related Parties - Aggregate Amount of Notes Purchased and the Income Earned (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	$ 396	$ 207	$ 1,263	$ 613
Interest earned on Notes	55	43	158	117
Notes balance	2,272		2,272		$ 1,690
Prosper Funding LLC [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased			1,232	591
Interest earned on Notes			152	110
Notes balance	2,173		2,173		1,614
Executive Officers & Management [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	386	188	1,232	591
Interest earned on Notes	53	41	152	110
Notes balance	2,173		2,173		1,614
Executive Officers & Management [Member] | Prosper Funding LLC [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased			1,232	591
Interest earned on Notes			152	110
Notes balance	2,173		2,173		1,614
Directors [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	10	19	31	22
Interest earned on Notes	2	$ 2	6	$ 7
Notes balance	$ 99		$ 99		$ 76

Postretirement Benefit Plans -

Postretirement Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Compensation And Retirement Disclosure [Abstract]
Employer contribution during the period	$ 0.5	$ 0.2	$ 1.3	$ 0.4

Segments - Additional Informati

Segments - Additional Information (Details)	9 Months Ended
	Sep. 30, 2015Segment
Segment Reporting [Abstract]
Number of Reportable Segments	1

Restatement of Condensed Cons79

Restatement of Condensed Consolidated Financial Statements- Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Financial Statements Captions [Line Items]
Overstatement of transaction fee revenues and origination and servicing expenses		$ 923		$ 2,012
Understatement of transaction fee revenue		5		665
Overstatement of gain on sale borrower loans		5		585
Overstatement in fair value of borrower loan held for sale and notes				80
Understatement of gain on sale borrower loans	$ 718		$ 1,666
Adjustment for understated servicing fees		202		749
Understatement of Amortization Expenses		$ 25		$ 26
Overstatement of calculation of weighted average shares				120,351
Overstatement of calculation of weighted average shares, basic		100,908
Prosper Funding LLC [Member]
Condensed Financial Statements Captions [Line Items]
Understatement of gain on sale borrower loans		$ 718		$ 1,666
Adjustment for understated servicing fees		151		471
Understatement of Amortization Expenses		25		26
Understatement of administration fee related party expense due to misclassification		524		1,373
Overstatement of servicing expenses		$ 906		$ 1,974

Restatement of Condensed Cons80

Restatement of Condensed Consolidated Financial Statements - Condensed Consolidated Statements of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Operating Revenue
Transaction Fees, Net	$ 46,842	$ 21,061	$ 111,984	$ 45,404
Servicing Fees, Net	4,652	1,401	10,796	2,512
Gain on Sale of Borrower Loans	4,263	1,268	9,881	2,246
Other Revenue	2,229	479	4,935	662
Total Operating Revenue	57,986	24,209	137,596	50,824
Interest Income
Interest Income on Borrower Loans	10,280	10,781	30,892	31,153
Interest Expense on Notes	(9,550)	(9,886)	(28,561)	(28,872)
Net Interest Income	730	895	2,331	2,281
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	(87)	21	(66)	291
Total Net Revenue	58,629	25,125	139,861	53,396
Expenses
Origination and Servicing	8,357	3,376	22,335	8,220
Sales and Marketing	31,844	11,201	76,996	27,028
General and Administrative	22,236	7,204	57,570	16,808
Total Expenses	62,437	21,781	156,901	52,056
Net Income (Loss)	(3,843)	3,344	(17,324)	1,340
Less: Excess Return to Preferred Shareholders on Repurchase		(14,892)		(14,892)
Net Loss Attributable to Common Stockholders	$ (3,843)	$ (11,548)	$ (17,324)	$ (13,552)
Net Loss Per Share – Basic and Diluted	$ (0.34)	$ (1.26)	$ (1.58)	$ (1.57)
Weighted-Average Shares - Basic and Diluted	11,181,553	9,179,426	10,949,396	8,620,434
Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party	$ 16,544	$ 8,574	$ 40,430	$ 19,525
Servicing Fees, Net	4,408	1,253	9,945	2,379
Gain on Sale of Borrower Loans	4,263	1,240	9,881	2,218
Other Revenue	561		557
Total Operating Revenue	25,776	11,067	60,813	24,122
Interest Income
Interest Income on Borrower Loans	10,258	10,860	30,960	31,443
Interest Expense on Notes	(9,550)	(9,886)	(28,561)	(28,873)
Net Interest Income	708	974	2,399	2,570
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	(87)	21	(66)	302
Total Net Revenue	26,397	12,062	63,146	26,994
Expenses
Servicing	675	308	2,946	1,064
General and Administrative	358	129	903	315
Total Expenses	19,269	7,808	45,464	17,780
Administration Fee - Related Party	18,236	7,371	41,615	16,401
Servicing		308		1,064
Net Income (Loss)	$ 7,128	4,254	$ 17,682	9,214
Previously Stated [Member]
Operating Revenue
Transaction Fees, Net		22,233		46,849
Servicing Fees, Net		1,749		3,044
Other Revenue		1,147		2,090
Total Operating Revenue		25,129		51,983
Interest Income
Interest Income on Borrower Loans		10,705		30,995
Interest Expense on Notes		(9,850)		(28,613)
Net Interest Income		855		2,382
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		59		448
Total Net Revenue		26,043		54,813
Expenses
Servicing		1,408		3,275
Compensation and benefits		6,260		16,327
Marketing and advertising		10,717		25,743
Depreciation and amortization		462		1,201
Professional services		582		1,169
Facilities and maintenance		1,441		2,604
Loss on impairment of fixed assets				215
Other		2,449		4,097
Total Expenses		23,319		54,631
Net Income (Loss)		2,724		182
Less: Excess Return to Preferred Shareholders on Repurchase		(14,892)		(14,892)
Net Loss Attributable to Common Stockholders		$ (12,168)		$ (14,710)
Net Loss Per Share – Basic and Diluted		$ (1.31)		$ (1.68)
Weighted-Average Shares - Basic and Diluted		9,280,334		8,740,785
Previously Stated [Member] | Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party		$ 8,574		$ 19,525
Servicing Fees, Net		1,574		2,965
Other Revenue		635		814
Total Operating Revenue		10,783		23,304
Interest Income
Interest Income on Borrower Loans		10,724		31,014
Interest Expense on Notes		(9,850)		(28,613)
Net Interest Income		874		2,401
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		59		448
Total Net Revenue		11,716		26,153
Expenses
Servicing		958		2,297
Depreciation and amortization		273		761
Professional services		1		16
Total Expenses		8,196		18,405
Administration Fee - Related Party		6,836		15,018
Other Operating Expenses		128		313
Net Income (Loss)		3,520		7,748
Reclassification
Operating Revenue
Gain on Sale of Borrower Loans		635		814
Other Revenue		(635)		(814)
Expenses
Servicing		(1,408)		(3,275)
Compensation and benefits		(6,260)		(16,327)
Marketing and advertising		(10,717)		(25,743)
Depreciation and amortization		(462)		(1,201)
Professional services		(582)		(1,169)
Facilities and maintenance		(1,441)		(2,604)
Loss on impairment of fixed assets				(215)
Origination and Servicing		4,298		10,232
Sales and Marketing		11,201		27,028
General and Administrative		7,820		17,371
Other		(2,449)		(4,097)
Reclassification | Prosper Funding LLC [Member]
Operating Revenue
Gain on Sale of Borrower Loans		635		814
Other Revenue		(635)		(814)
Expenses
Servicing		(958)		(2,297)
Depreciation and amortization		(273)		(761)
Professional services		(1)		(16)
General and Administrative		129		329
Servicing		1,231		3,058
Other Operating Expenses		(128)		(313)
As Reclassified
Operating Revenue
Transaction Fees, Net		22,233		46,849
Servicing Fees, Net		1,749		3,044
Gain on Sale of Borrower Loans		635		814
Other Revenue		512		1,276
Total Operating Revenue		25,129		51,983
Interest Income
Interest Income on Borrower Loans		10,705		30,995
Interest Expense on Notes		(9,850)		(28,613)
Net Interest Income		855		2,382
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		59		448
Total Net Revenue		26,043		54,813
Expenses
Origination and Servicing		4,298		10,232
Sales and Marketing		11,201		27,028
General and Administrative		7,820		17,371
Total Expenses		23,319		54,631
Net Income (Loss)		2,724		182
Less: Excess Return to Preferred Shareholders on Repurchase		(14,892)		(14,892)
Net Loss Attributable to Common Stockholders		$ (12,168)		$ (14,710)
Net Loss Per Share – Basic and Diluted		$ (1.31)		$ (1.68)
Weighted-Average Shares - Basic and Diluted		9,280,334		8,740,785
As Reclassified | Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party		$ 8,574		$ 19,525
Servicing Fees, Net		1,574		2,965
Gain on Sale of Borrower Loans		635		814
Total Operating Revenue		10,783		23,304
Interest Income
Interest Income on Borrower Loans		10,724		31,014
Interest Expense on Notes		(9,850)		(28,613)
Net Interest Income		874		2,401
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		59		448
Total Net Revenue		11,716		26,153
Expenses
General and Administrative		129		329
Total Expenses		8,196		18,405
Administration Fee - Related Party		6,836		15,018
Servicing		1,231		3,058
Net Income (Loss)		3,520		7,748
Adjustment [Member]
Operating Revenue
Transaction Fees, Net		(1,172)		(1,445)
Servicing Fees, Net		(348)		(532)
Gain on Sale of Borrower Loans		633		1,432
Other Revenue		(33)		(614)
Total Operating Revenue		(920)		(1,159)
Interest Income
Interest Income on Borrower Loans		76		158
Interest Expense on Notes		(36)		(259)
Net Interest Income		40		(101)
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		(38)		(157)
Total Net Revenue		(918)		(1,417)
Expenses
Origination and Servicing		(922)		(2,012)
General and Administrative		(616)		(563)
Total Expenses		(1,538)		(2,575)
Net Income (Loss)		620		1,158
Net Loss Attributable to Common Stockholders		$ 620		$ 1,158
Net Loss Per Share – Basic and Diluted		$ 0.05		$ 0.11
Weighted-Average Shares - Basic and Diluted		(100,908)		(120,351)
Adjustment [Member] | Prosper Funding LLC [Member]
Operating Revenue
Servicing Fees, Net		$ (321)		$ (586)
Gain on Sale of Borrower Loans		605		1,404
Total Operating Revenue		284		818
Interest Income
Interest Income on Borrower Loans		136		429
Interest Expense on Notes		(36)		(260)
Net Interest Income		100		169
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		(38)		(146)
Total Net Revenue		346		841
Expenses
General and Administrative				(14)
Total Expenses		(388)		(625)
Administration Fee - Related Party		535		1,383
Servicing		(923)		(1,994)
Net Income (Loss)		$ 734		$ 1,466

Restatement of Condensed Cons81

Restatement of Condensed Consolidated Financial Statements - Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net Income (Loss)	$ (3,843)	$ 3,344	$ (17,324)	$ 1,340
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	87	(21)	66	(291)
Depreciation and Amortization			4,967	1,228
Gain on sales of Borrower Loans			(9,958)	(2,480)
Amortization and Change in Fair Value of Servicing Rights			3,322	372
Stock-Based Compensation			7,439	763
Other, Net			94	278
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value			(2,426,963)	(919,770)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value			2,435,253	909,897
Restricted Cash Except for those Related to Investing Activities			(69,651)	(26,976)
Accounts Receivable			1,800	(595)
Prepaid and Other Assets			(4,168)	(2,515)
Class Action Settlement Liability			(2,000)	(2,000)
Accounts Payable and Accrued Liabilities			7,483	5,030
Payable to Investors			72,263	22,596
Net Cash Provided by (Used in) Operating Activities			2,623	(13,123)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value			(142,103)	(130,857)
Principal Payments of Borrower Loans Held at Fair Value			111,864	88,974
Maturities of Short Term Investments			1,274
Purchases of Short Term Investments			(1,275)
Purchases of Property and Equipment			(9,518)	(4,806)
Changes in Restricted Cash Related to Investing Activities			(1,446)	869
Net Cash Used in Investing Activities			(107,304)	(45,820)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value			142,246	130,756
Payment of Notes Held at Fair Value			(111,711)	(88,909)
Proceeds from Issuance of Convertible Preferred Stock, Net			164,793	69,958
Proceeds from Early Exercise of Stock Options and Issuance of Restricted Stock			1,714	454
Proceeds from Exercise of Vested Stock Options and Common Stock Warrants			849	161
Repurchase of Preferred Stock				(18,525)
Repurchase of Restricted Stock				(24)
Net Cash Provided by Financing Activities			174,646	93,871
Net Increase (Decrease) in Cash and Cash Equivalents			69,965	34,928
Cash and Cash Equivalents at Beginning of the Period			50,557	18,339
Cash and Cash Equivalents at End of the Period	120,522	53,267	120,522	53,267
Prosper Funding LLC [Member]
Cash flows from operating activities:
Net Income (Loss)	7,128	4,254	17,682	9,214
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	87	(21)	66	(302)
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes			29	(28)
Depreciation and Amortization			2,483	788
Gain on sales of Borrower Loans			(9,958)	(2,480)
Amortization and Change in Fair Value of Servicing Rights			2,758	294
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value			(2,426,963)	(919,770)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value			2,435,253	909,897
Restricted Cash Except for those Related to Investing Activities			(69,242)	(26,976)
Other Assets			(18)	(4)
Accounts Payable and Accrued Liabilities			1,415	328
Payable to Investors			71,773	21,906
Net Related Party Payable				(879)
Net Cash Provided by (Used in) Operating Activities			26,881	(8,012)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value			(142,103)	(130,857)
Principal Payments of Borrower Loans Held at Fair Value			111,864	88,984
Maturities of Short Term Investments			1,274	1,271
Purchases of Short Term Investments			(1,276)	(1,274)
Purchases of Property and Equipment			(6,850)	(811)
Changes in Restricted Cash Related to Investing Activities			1,471	5,925
Net Cash Used in Investing Activities			(35,620)	(36,762)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value			142,246	130,756
Payment of Notes Held at Fair Value			(111,711)	(88,909)
Net Cash Provided by Financing Activities			(4,970)	41,847
Net Increase (Decrease) in Cash and Cash Equivalents			(13,709)	(2,927)
Cash and Cash Equivalents at Beginning of the Period			23,777	5,789
Cash and Cash Equivalents at End of the Period	$ 10,068	2,862	$ 10,068	2,862
Prosper Funding LLC [Member] | Property Plant and Equipment Two [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment				(811)
Previously Stated [Member]
Cash flows from operating activities:
Net Income (Loss)		2,724		182
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		(59)		(448)
Depreciation and Amortization				1,201
Amortization and Change in Fair Value of Servicing Rights				(803)
Stock-Based Compensation				777
Other, Net				215
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value				(12,444)
Accounts Receivable				(703)
Prepaid and Other Assets				(2,543)
Class Action Settlement Liability				(1,909)
Accounts Payable and Accrued Liabilities				4,406
Net Cash Provided by (Used in) Operating Activities				(12,069)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value				(823,841)
Principal Payments of Borrower Loans Held at Fair Value				88,944
Proceeds from Sale of Borrower Loans Held at Fair Value				693,007
Purchases of Property and Equipment				(3,151)
Changes in Restricted Cash Related to Investing Activities				(1,478)
Net Cash Used in Investing Activities				(46,519)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value				130,828
Payment of Notes Held at Fair Value				(89,336)
Proceeds from Issuance of Convertible Preferred Stock, Net				69,958
Proceeds from Early Exercise of Stock Options and Issuance of Restricted Stock				454
Proceeds from Exercise of Vested Stock Options and Common Stock Warrants				161
Repurchase of Preferred Stock				(18,525)
Repurchase of Restricted Stock				(24)
Net Cash Provided by Financing Activities				93,516
Net Increase (Decrease) in Cash and Cash Equivalents				34,928
Cash and Cash Equivalents at Beginning of the Period				18,339
Cash and Cash Equivalents at End of the Period		53,267		53,267
Previously Stated [Member] | Prosper Funding LLC [Member]
Cash flows from operating activities:
Net Income (Loss)		3,520		7,748
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		(59)		(448)
Depreciation and Amortization				761
Change in Servicing Rights				(808)
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value				(12,444)
Other Assets				(21)
Accounts Payable and Accrued Liabilities				212
Net Related Party Payable				(278)
Net Cash Provided by (Used in) Operating Activities				(5,278)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value				(823,841)
Principal Payments of Borrower Loans Held at Fair Value				88,944
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value				693,007
Changes in Restricted Cash Related to Investing Activities				3,578
Net Cash Used in Investing Activities				(39,141)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value				130,828
Payment of Notes Held at Fair Value				(89,336)
Net Cash Provided by Financing Activities				41,492
Net Increase (Decrease) in Cash and Cash Equivalents				(2,927)
Cash and Cash Equivalents at Beginning of the Period				5,789
Cash and Cash Equivalents at End of the Period		2,862		2,862
Previously Stated [Member] | Prosper Funding LLC [Member] | Property Plant and Equipment Two [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment				(829)
Adjustment [Member]
Cash flows from operating activities:
Net Income (Loss)		620		1,158
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		38		157
Depreciation and Amortization				27
Gain on sales of Borrower Loans				(2,480)
Amortization and Change in Fair Value of Servicing Rights				1,175
Stock-Based Compensation				(14)
Other, Net				63
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value				(907,326)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value				909,897
Restricted Cash Except for those Related to Investing Activities				(26,976)
Accounts Receivable				108
Prepaid and Other Assets				28
Class Action Settlement Liability				(91)
Accounts Payable and Accrued Liabilities				624
Payable to Investors				22,596
Net Cash Provided by (Used in) Operating Activities				(1,054)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value				692,984
Principal Payments of Borrower Loans Held at Fair Value				30
Proceeds from Sale of Borrower Loans Held at Fair Value				(693,007)
Purchases of Property and Equipment				(1,655)
Changes in Restricted Cash Related to Investing Activities				2,347
Net Cash Used in Investing Activities				699
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value				(72)
Payment of Notes Held at Fair Value				427
Net Cash Provided by Financing Activities				355
Adjustment [Member] | Prosper Funding LLC [Member]
Cash flows from operating activities:
Net Income (Loss)		734		1,466
Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		$ 38		146
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes				(28)
Depreciation and Amortization				27
Change in Servicing Rights				808
Gain on sales of Borrower Loans				(2,480)
Amortization and Change in Fair Value of Servicing Rights				294
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value				(907,326)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value				909,897
Restricted Cash Except for those Related to Investing Activities				(26,976)
Other Assets				17
Accounts Payable and Accrued Liabilities				116
Payable to Investors				21,906
Net Related Party Payable				(601)
Net Cash Provided by (Used in) Operating Activities				(2,734)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value				692,984
Principal Payments of Borrower Loans Held at Fair Value				40
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value				(693,007)
Maturities of Short Term Investments				1,271
Purchases of Short Term Investments				(1,274)
Changes in Restricted Cash Related to Investing Activities				2,347
Net Cash Used in Investing Activities				2,379
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value				(72)
Payment of Notes Held at Fair Value				427
Net Cash Provided by Financing Activities				355
Adjustment [Member] | Prosper Funding LLC [Member] | Property Plant and Equipment Two [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment				$ 18

Subsequent Events (Details)

Subsequent Events (Details) - BillGuard [Member] - USD ($) $ in Millions	Sep. 23, 2015	Sep. 30, 2015
Subsequent Event [Line Items]
Business Acquisition, Effective Date of Acquisition		Oct. 9, 2015
Payments to Acquire Businesses, Gross	$ 25
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Maximum earn out period		12 months
Indemnification Obligations [Member] | Scenario, Forecast [Member]
Subsequent Event [Line Items]
Business acquisition, contingent consideration		$ 5

Borrower Loans, Loans Held Fo83

Borrower Loans, Loans Held For Sale and Notes Held at Fair Value - Quantitative Information about the Significant Unobservable Inputs (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Minimum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	2.90%	3.30%
Default rate	2.70%	2.60%
Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	10.50%	10.60%
Default rate	22.80%	19.70%
Prosper Funding LLC [Member] | Minimum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	2.90%	3.20%
Default rate	2.70%	2.60%
Prosper Funding LLC [Member] | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	10.50%	10.60%
Default rate	22.80%	19.70%

Borrower Loans, Loans Held fo84

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Fair Value Assumptions for Borrower Loans, Loans Held for Sale and Notes (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Discount rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.57%	[1]
Discount rate assumption [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.57%	[1]
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 284,453
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	283,684
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	281,443
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	280,688
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	290,720
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	289,923
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	293,985
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 293,172
Default rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate assumption (in hundredths)	12.73%	[1]
Default rate assumption [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate assumption (in hundredths)	12.73%	[1]
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 283,915
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	283,157
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	280,343
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	279,610
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	291,201
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	290,392
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	294,877
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 294,042
Prosper Funding LLC [Member] | Discount rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.57%	[1]
Prosper Funding LLC [Member] | Discount rate assumption [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.57%	[1]
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 284,453
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	283,684
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	281,443
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	280,688
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	290,720
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	289,923
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	293,985
Prosper Funding LLC [Member] | Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 293,172
Prosper Funding LLC [Member] | Default rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate assumption (in hundredths)	12.73%	[1]
Prosper Funding LLC [Member] | Default rate assumption [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate assumption (in hundredths)	12.73%	[1]
Prosper Funding LLC [Member] | Default rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 291,201
Prosper Funding LLC [Member] | Default rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	290,392
Prosper Funding LLC [Member] | Default rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	294,877
Prosper Funding LLC [Member] | Default rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	294,042
Prosper Funding LLC [Member] | Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	280,343
Prosper Funding LLC [Member] | Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	279,610
Prosper Funding LLC [Member] | Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	283,915
Prosper Funding LLC [Member] | Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans and Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 283,157
[1]	Represents weighted average assumptions considering all credit grades.

Borrower Loans, Loans Held fo85

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Changes in Borrower Loans, Loans Held for Sale and Notes, which are Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Total	$ 1,004	$ 7,026	$ 7,923	$ 2,093
Principal repayments, Total	(209)	(313)	(699)	(598)
Borrower Loans sold to third parties, Total	(1,025,846)	(438,342)	(2,434,729)	(909,364)
Other changes, Total	(5)	31	(7)	29
Change in fair value, Total	(87)	21	(66)	291
Ending balance, Total	(758)	12,322	(758)	12,322
Notes [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Liabilities	(284,627)	(253,943)	(273,783)	(234,218)
Principal repayments, Liabilities	38,202	31,334	111,711	88,909
Borrower Loans sold to third parties, Liabilities	425		425
Other changes, Liabilities	(18)	(22)	119	67
Change in fair value, Liabilities	6,434	5,842	16,520	15,132
Ending balance, Liabilities	(287,254)	(260,866)	(287,254)	(260,866)
Borrower Loans [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	284,200	252,971	273,243	233,105
Principal repayments, Assets	(38,407)	(31,244)	(111,864)	(88,974)
Borrower Loans sold to third parties, Assets	(447)		(447)
Other changes, Assets	21	46	(108)	(54)
Change in fair value, Assets	6,496	5,821	16,465	14,841
Ending balance, Assets	286,462	260,093	286,462	260,093
Loans Held for Sale [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	1,431	7,998	8,463	3,206
Principal repayments, Assets	(4)	(403)	(546)	(533)
Borrower Loans sold to third parties, Assets	(1,025,824)	(438,342)	(2,434,707)	(909,364)
Other changes, Assets	(8)	7	(18)	16
Change in fair value, Assets	25		121
Ending balance, Assets	34	13,095	34	13,095
Prosper Funding LLC [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Total	1,004	7,026	7,923	2,093
Originations, Total	1,024,385	443,899	2,426,820	919,871
Principal repayments, Total	(209)	(313)	(699)	(608)
Borrower Loans sold to third parties, Total	(1,025,846)	(438,342)	(2,434,729)	(909,364)
Other changes, Total	(5)	31	(7)	28
Change in fair value, Total	(87)	21	(66)	302
Ending balance, Total	(758)	12,322	(758)	12,322
Prosper Funding LLC [Member] | Notes [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Liabilities	(284,627)	(253,943)	(273,783)	(234,218)
Originations, Liabilities	(47,670)	(44,077)	(142,246)	(130,756)
Principal repayments, Liabilities	38,202	31,334	111,711	88,909
Borrower Loans sold to third parties, Liabilities	425		425
Other changes, Liabilities	(18)	(22)	119	67
Change in fair value, Liabilities	6,434	5,842	16,520	15,132
Ending balance, Liabilities	(287,254)	(260,866)	(287,254)	(260,866)
Prosper Funding LLC [Member] | Borrower Loans [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	284,200	252,971	273,243	233,105
Originations, Assets	47,591	44,141	142,103	130,857
Principal repayments, Assets	(38,407)	(31,244)	(111,864)	(88,984)
Borrower Loans sold to third parties, Assets	(447)		(447)
Other changes, Assets	21	46	(108)	(55)
Change in fair value, Assets	(6,496)	(5,821)	(16,465)	(14,830)
Ending balance, Assets	286,462	260,093	286,462	260,093
Prosper Funding LLC [Member] | Loans Held for Sale [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	1,431	7,998	8,463	3,206
Originations, Assets	1,024,464	443,835	2,426,963	919,770
Principal repayments, Assets	(4)	(403)	(546)	(533)
Borrower Loans sold to third parties, Assets	(1,025,824)	(438,342)	(2,434,707)	(909,364)
Other changes, Assets	(8)	7	(18)	16
Change in fair value, Assets	(25)		(121)
Ending balance, Assets	$ 34	$ 13,095	$ 34	$ 13,095

Loan Servicing Assets and Lia86

Loan Servicing Assets and Liabilities - Significant Unobservable Inputs (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate	0.625%
Minimum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	2.00%	2.60%
Market servicing rate		0.625%
Maximum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	21.80%	26.30%
Market servicing rate		0.70%
Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate	0.625%
Prosper Funding LLC [Member] | Minimum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	2.10%	2.60%
Market servicing rate		0.625%
Prosper Funding LLC [Member] | Maximum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	21.80%	26.30%
Market servicing rate		0.70%

Loan Servicing Assets and Lia87

Loan Servicing Assets and Liabilities - Schedule of Servicing Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Adjustment to adopt fair value measurement, servicing assets		$ 546
Servicing Liability at Amortized Cost [Roll Forward]
Adjustment to adopt fair value measurement		(29)
Loan servicing assets [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Amortized cost at beginning of period		4,163
Adjustment to adopt fair value measurement, servicing assets		546
Fair value at beginning of period	$ 8,682	4,709
Additions	4,370	10,204
Less: Changes in fair value	(1,752)	(3,613)
Fair Value at end of period	11,300	11,300
Loan servicing liabilities [Member]
Servicing Liability at Amortized Cost [Roll Forward]
Amortized cost at beginning of the period		624
Adjustment to adopt fair value measurement		(29)
Fair value at beginning of the period	606	595
Additions	53	246
Less: Changes in fair value	(109)	(291)
Fair value at end of the period	550	550
Prosper Funding LLC [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Adjustment to adopt fair value measurement, servicing assets		399
Servicing Liability at Amortized Cost [Roll Forward]
Adjustment to adopt fair value measurement		(29)
Prosper Funding LLC [Member] | Loan servicing assets [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Amortized cost at beginning of period		3,116
Adjustment to adopt fair value measurement, servicing assets		399
Fair value at beginning of period	7,634	3,515
Additions	4,367	10,204
Less: Transfers to PMI		(249)
Less: Changes in fair value	(1,580)	(3,049)
Fair Value at end of period	10,421	10,421
Prosper Funding LLC [Member] | Loan servicing liabilities [Member]
Servicing Liability at Amortized Cost [Roll Forward]
Amortized cost at beginning of the period		624
Adjustment to adopt fair value measurement		(29)
Fair value at beginning of the period	606	595
Additions	53	246
Less: Changes in fair value	(109)	(291)
Fair value at end of the period	$ 550	$ 550

Loan Servicing Assets and Lia88

Loan Servicing Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Loan servicing assets [Member]
Resulting fair value from:
Market servicing rate increase to 0.65%	$ 10,462
Market servicing rate decrease to 0.60%	12,138
100 basis point increase	11,091
100 basis point decrease	$ 11,510
Weighted average default assumptions	14.00%
Loan servicing liabilities [Member]
Resulting fair value from:
Market servicing rate increase to 0.65%	$ (605)
Market servicing rate decrease to 0.60%	(496)
100 basis point increase	(550)
100 basis point decrease	$ (551)
Weighted average default assumptions	14.00%
Prosper Funding LLC [Member] | Loan servicing assets [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Weighted average market servicing rate assumptions	0.625%
Resulting fair value from:
Market servicing rate increase to 0.65%	$ 9,952
Market servicing rate decrease to 0.60%	11,547
100 basis point increase	10,230
100 basis point decrease	$ 10,617
Weighted average default assumptions	14.00%
Prosper Funding LLC [Member] | Loan servicing liabilities [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Weighted average market servicing rate assumptions	0.625%
Resulting fair value from:
Market servicing rate increase to 0.65%	$ (605)
Market servicing rate decrease to 0.60%	(496)
100 basis point increase	(550)
100 basis point decrease	$ (551)
Weighted average default assumptions	14.00%

Loan Servicing Assets and Lia89

Loan Servicing Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Parenthetical) (Details)	9 Months Ended
	Sep. 30, 2015
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Default rate increase	1.00%
Default rate decrease	1.00%
Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Default rate increase	1.00%
Default rate decrease	1.00%