Prosper Funding 10-Q 17 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 07, 2016
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	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		69,783,206
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Prosper Funding LLC
Document And Entity Information [Line Items]
Entity Registrant Name	Prosper Funding LLC
Entity Central Index Key	1,542,574
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, 2016	Dec. 31, 2015
Assets
Cash and Cash Equivalents	$ 31,853	$ 66,295
Restricted Cash	120,648	151,223
Available for Sale Investments, at Fair Value	42,783	73,187
Accounts Receivable	918	2,434
Loans Held for Sale, at Fair Value	136	32
Borrower Loans, at Fair Value	314,671	297,273
Property and Equipment, Net	26,678	24,965
Prepaid and Other Assets	7,420	6,433
Servicing Assets	12,664	14,363
Goodwill	36,368	36,368
Intangibles Assets, Net	10,069	13,051
Total Assets	604,208	685,624
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities	11,639	22,409
Payable to Investors	101,162	136,507
Notes at Fair Value	313,920	297,405
Other Liabilities	20,954	20,735
Total Liabilities	447,675	477,056
Commitments and Contingencies (see Note 16)
Convertible Preferred Stock – $0.01 par value; 177,388,425 shares authorized, issued and outstanding as of September 30, 2016 and December 31, 2015. Aggregate liquidation preference of $325,952 as of September 30, 2016 and December 31, 2015.	275,938	275,938
Stockholders' Deficit
Common Stock ($0.01 par value; 298,222,103 shares authorized, 70,708,055 issued and 69,772,120 outstanding as of September 30, 2016; and 270,326,075 shares authorized, 70,367,425 shares issued and 69,431,490 outstanding as of December 31, 2015)	194	127
Additional Paid-In Capital	121,206	102,971
Less: Treasury Stock (5,177,235 common shares at cost, September 30, 2016 and December 31, 2015)	(23,417)	(23,417)
Retained Earnings (Accumulated Deficit)	(217,413)	(146,907)
Accumulated Other Comprehensive Income/(Loss)	25	(144)
Total Stockholders' Equity (Deficit)	(119,405)	(67,370)
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit	604,208	685,624
Prosper Funding LLC
Assets
Cash and Cash Equivalents	14,276	15,026
Restricted Cash	104,544	139,937
Short Term Investments	1,279	1,277
Loans Held for Sale, at Fair Value	136	32
Borrower Loans, at Fair Value	314,671	297,273
Property and Equipment, Net	9,632	8,419
Servicing Assets	12,274	13,605
Other Assets	139	122
Total Assets	456,951	475,691
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities	1,024	2,122
Payable to Related Party	1,703	2,989
Payable to Investors	99,992	135,661
Notes at Fair Value	313,920	297,405
Other Liabilities	1,412	1,209
Total Liabilities	418,051	439,386
Stockholders' Deficit
Retained Earnings (Accumulated Deficit)	38,900	36,305
Total Stockholders' Equity (Deficit)	38,900	36,305
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit	$ 456,951	$ 475,691

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares
Statement of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Convertible preferred stock, shares authorized (in shares)	177,388,425	177,388,425
Convertible preferred stock, shares issued (in shares)	177,388,425	177,388,425
Convertible preferred stock, shares outstanding (in shares)	177,388,425	177,388,425
Convertible preferred stock, aggregate liquidation preference | $	$ 325,952	$ 325,952
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	298,222,103	270,326,075
Common stock, shares issued (in shares)	70,708,055	70,367,425
Common stock, shares outstanding (in shares)	69,772,120	69,431,490
Common shares at cost (in shares)	5,177,235	5,177,235
Stock split conversion ratio	5

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating Revenues
Transaction Fees, Net	$ 14,086,000	$ 46,842,000	$ 75,186,000	$ 111,984,000
Servicing Fees, Net	7,079,000	4,652,000	21,898,000	10,796,000
Gain on Sale of Borrower Loans	761,000	4,263,000	3,865,000	9,881,000
Other Revenue	973,000	2,229,000	4,562,000	4,935,000
Total Operating Revenues	22,899,000	57,986,000	105,511,000	137,596,000
Interest Income
Interest Income on Borrower Loans	11,735,000	10,280,000	33,710,000	30,892,000
Interest Expense on Notes	(10,636,000)	(9,550,000)	(30,456,000)	(28,561,000)
Net Interest Income	1,099,000	730,000	3,254,000	2,331,000
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	(47,000)	(87,000)	(126,000)	(66,000)
Total Net Revenue	23,951,000	58,629,000	108,639,000	139,861,000
Expenses
Origination and Servicing	7,633,000	8,357,000	26,850,000	22,335,000
Sales and Marketing	9,391,000	31,844,000	54,303,000	76,996,000
General and Administrative	24,740,000	22,236,000	83,498,000	57,570,000
Restructuring Charges, Net	(470,000)	0	14,153,000	0
Total Expenses	41,294,000	62,437,000	178,804,000	156,901,000
Net Loss Before Taxes	(17,343,000)	(3,808,000)	(70,165,000)	(17,040,000)
Income Tax Expense	74,000	35,000	344,000	284,000
Net Income (Loss)	$ (17,417,000)	$ (3,843,000)	$ (70,509,000)	$ (17,324,000)
Net Loss Per Share – Basic and Diluted (in dollars per share)	$ (0.27)	$ (0.07)	$ (1.12)	$ (0.32)
Weighted-Average Shares - Basic and Diluted (in shares)	65,393,175	55,907,765	63,015,616	54,746,980
Prosper Funding LLC
Operating Revenues
Administration Fee Revenue - Related Party	$ 5,530,000	$ 16,544,000	$ 27,878,000	$ 40,430,000
Servicing Fees, Net	7,026,000	4,408,000	21,650,000	9,945,000
Gain on Sale of Borrower Loans	761,000	4,263,000	3,865,000	9,881,000
Other Revenue	30,000	561,000	448,000	557,000
Total Operating Revenues	13,347,000	25,776,000	53,841,000	60,813,000
Interest Income
Interest Income on Borrower Loans	11,566,000	10,258,000	33,062,000	30,960,000
Interest Expense on Notes	(10,636,000)	(9,550,000)	(30,456,000)	(28,561,000)
Net Interest Income	930,000	708,000	2,606,000	2,399,000
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	(47,000)	(87,000)	(126,000)	(66,000)
Total Net Revenue	14,230,000	26,397,000	56,321,000	63,146,000
Expenses
Servicing	1,374,000	675,000	4,139,000	2,946,000
Administration Fee - Related Party	12,243,000	18,236,000	48,500,000	41,615,000
General and Administrative	342,000	358,000	1,082,000	903,000
Total Expenses	13,959,000	19,269,000	53,721,000	45,464,000
Income Tax Expense			0	0
Net Income (Loss)	$ 271,000	$ 7,128,000	$ 2,600,000	$ 17,682,000

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical)	Feb. 16, 2016	Sep. 30, 2016
Income Statement [Abstract]
Stock split conversion ratio	5	5

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Other Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net Loss	$ (17,417)	$ (3,843)	$ (70,509)	$ (17,324)
Other Comprehensive Income (Loss), Before Tax
Change in Net Unrealized Gain (Loss) on Available for Sale Investments, at Fair Value	(54)	4	161	4
Realized Gain (Loss) on Sale of Available for Sale Investments, at Fair Value	1	0	7	0
Other Comprehensive Income (Loss), Before Tax	(53)	4	168	4
Income tax effect	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	(53)	4	168	4
Comprehensive Income (Loss)	$ (17,470)	$ (3,839)	$ (70,341)	$ (17,320)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from Operating Activities:
Net Loss	$ (70,509)	$ (17,324)
Adjustments to Reconcile Net Loss to Net Cash Provided by (Used in) Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	126	66
Depreciation and Amortization	9,892	4,967
Gain on Sales of Borrower Loans	(7,030)	(9,958)
Change in Fair Value of Servicing Rights	8,550	3,322
Stock-Based Compensation Expense	17,181	7,439
Restructuring Liability	5,107	0
Other, Net	968	94
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value	(1,619,866)	(2,426,963)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	1,619,757	2,435,253
Restricted Cash Except for those Related to Investing Activities	37,044	(69,651)
Accounts Receivable	1,516	1,800
Prepaid and Other Assets	(989)	(4,168)
Accounts Payable and Accrued Liabilities	(6,677)	7,483
Payable to Investors	(35,345)	72,263
Other Liabilities	(7,247)	(2,000)
Net Cash (Used in) Provided by Operating Activities	(47,522)	2,623
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	(164,436)	(142,103)
Principal Payments of Borrower Loans Held at Fair Value	127,308	111,864
Purchases of Property and Equipment	(10,049)	(9,518)
Maturities of Short Term Investments	1,279	1,274
Purchases of Short Term Investments	(1,277)	(1,275)
Purchases of Available for Sale Investments, at Fair Value	(11,725)	(47,100)
Proceeds from Sale of Available for Sale Investments	10,444	0
Maturities of Available for Sale Investments	31,645	0
Acquisition of Businesses, Net of Cash Acquired	0	(19,000)
Changes in Restricted Cash Related to Investing Activities	(6,469)	(1,446)
Net Cash Used in Investing Activities	(23,280)	(107,304)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	165,727	142,246
Payments of Notes Held at Fair Value	(129,603)	(111,711)
Proceeds from Issuance of Convertible Preferred Stock, Net	0	164,793
Proceeds from Exercise of Warrants and Stock Options including Early Exercise, and Issuance of Restricted Stock	526	4,950
Repurchase of Common Stock and Restricted Stock	(71)	(23,245)
Taxes Paid for Awards Vested Under Equity Incentive Plans	(219)	(2,387)
Net Cash Provided by Financing Activities	36,360	174,646
Net (Decrease) Increase in Cash and Cash Equivalents	(34,442)	69,965
Cash and Cash Equivalents at Beginning of the Period	66,295	50,557
Cash and Cash Equivalents at End of the Period	31,853	120,522
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	30,228	28,698
Non-Cash Investing Activity- Accrual for Property and Equipment, Net	241	5
Non-Cash Investing Activity- Amount Payable for the Acquisition of Business	0	840
Prosper Funding LLC
Cash flows from Operating Activities:
Net Loss	2,600	17,682
Adjustments to Reconcile Net Loss to Net Cash Provided by (Used in) Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	126	66
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes	0	29
Depreciation and Amortization	2,940	2,483
Gain on Sales of Borrower Loans	(7,030)	(9,958)
Change in Fair Value of Servicing Rights	8,182	2,758
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value	(1,619,866)	(2,426,963)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	1,619,757	2,435,253
Restricted Cash Except for those Related to Investing Activities	37,545	(69,242)
Other Assets	(17)	(18)
Accounts Payable and Accrued Liabilities	(1,103)	1,415
Payable to Investors	(35,669)	71,773
Net Related Party Receivable/Payable	(2)	1,603
Other Liabilities	382	0
Net Cash (Used in) Provided by Operating Activities	7,845	26,881
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	(164,436)	(142,103)
Principal Payments of Borrower Loans Held at Fair Value	127,308	111,864
Purchases of Property and Equipment	(5,437)	(6,850)
Maturities of Short Term Investments	1,277	1,274
Purchases of Short Term Investments	(1,279)	(1,276)
Changes in Restricted Cash Related to Investing Activities	(2,152)	1,471
Net Cash Used in Investing Activities	(44,719)	(35,620)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	165,727	142,246
Payments of Notes Held at Fair Value	(129,603)	(111,711)
Cash Distributions to Parent	0	(35,505)
Net Cash Provided by Financing Activities	36,124	(4,970)
Net (Decrease) Increase in Cash and Cash Equivalents	(750)	(13,709)
Cash and Cash Equivalents at Beginning of the Period	15,026	23,777
Cash and Cash Equivalents at End of the Period	14,276	10,068
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	30,228	28,698
Non-Cash Investing Activity- Accrual for Property and Equipment, Net	152	0
Non-Cash Financing Activity, Distribution to Parent	$ 0	$ 249

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Marketplace, Inc. (“PMI”) was incorporated in the state of Delaware on March 22, 2005. Except as the context requires otherwise, as used in these notes to the condensed consolidated financial statements of Prosper Marketplace, Inc., “Prosper,” “we,” “us,” and “our” refer to PMI and its wholly-owned subsidiaries, on a consolidated basis. 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 Article 10 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, 2015 . The balance sheet at December 31, 2015 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. Management 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. The accompanying interim condensed consolidated financial statements include the accounts of PMI and its wholly-owned subsidiaries. All intercompany balances have been eliminated in consolidation. On January 23, 2015, PMI acquired all of the outstanding limited liability company units of American HealthCare Lending, LLC (“American HealthCare Lending”), a company that operated a patient financing platform, and merged American HealthCare Lending with and into Prosper Healthcare Lending LLC (“PHL”), a newly established entity surviving the merger. Prosper’s condensed consolidated financial statements include PHL’s results of operations and financial position from the date of acquisition forward. On October 9, 2015, PMI acquired all of the outstanding stock of BillGuard, Inc. (“BillGuard”), a company incorporated in Delaware in 2010 that developed applications that help consumers manage their identity, finances and credit. PMI merged BillGuard with and into Beach Merger Sub, Inc., a newly established entity wholly owned by PMI, with BillGuard surviving the merger. Prosper’s condensed consolidated financial statements include BillGuard’s results of operations and financial position from the date of acquisition forward. Reclassifications Due to the early adoption of ASU 2016-09 on January 1, 2016, reclassifications were made to the financing section of the condensed consolidated statements of cash flows to reflect taxes paid for awards vested under equity incentive plans. Prior period amounts have been reclassified to conform to the current presentation.
Prosper Funding LLC
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Funding LLC (“PFL”) was formed in the state of Delaware on February 17, 2012 as a limited liability company with the sole equity member being Prosper Marketplace, Inc. (“PMI”, "Parent"). Except as the context otherwise requires, as used in these Notes to the condensed consolidated financial statements of Prosper Funding LLC, “Prosper Funding,” “we,” “us,” and “our” refers to PFL and its wholly owned subsidiary, Prosper Asset Holdings LLC (“PAH”), a Delaware limited liability company, on a consolidated basis. 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 Article 10 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, 2015 . The balance sheet at December 31, 2015 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 no t 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 nine months ended September 30, 2016 and 2015 . 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. Management 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Prosper’s significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies in Prosper’s Annual Report on Form 10-K for the year ended December 31, 2015 . There have been no changes to these accounting policies during the first nine months of 2016 . Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Available for Sale 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. Restructuring Charges Restructuring charges consist of severance and contract termination related costs. A liability for severance costs is typically recognized when the plan of termination has been communicated to the affected employees and is measured at its fair value at the communication date. Contract termination costs consist primarily of costs that will continue to be incurred under operating leases for their remaining terms without economic benefit to the Company. A liability for contract termination costs is recognized at the date the Company ceases using the rights conveyed by the lease contract and is measured at its fair value, which is determined based on the remaining contractual lease rentals reduced by estimated sublease rentals. Borrower Loans, Loans Held for Sale and Notes Through the Note Channel, Prosper purchases Borrower Loans from WebBank then issues Notes, and holds the Borrower Loans until maturity. The obligation to repay a series of Notes issued through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans funded and Notes issued through the Note Channel are carried on Prosper’s condensed consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes. Loan Trailing Fee On July 1, 2016, Prosper signed a series of agreements with WebBank to include an additional program fee (Loan Trailing Fee). These agreements are effective August 1, 2016. The Loan Trailing Fee is dependent on the amount and timing of principal and interest payments made by borrowers of the underlying loans, irrespective of whether the loans are sold by Prosper, and gives the issuing bank an ongoing financial interest in the performance of the loans it originates. This fee is paid by Prosper to the issuing bank partner over the term of the respective loans and is a function of the principal and interest payments. In the event that principal and interest payments are not made, Prosper is not required to make this Loan Trailing Fee payment. The obligation to pay the Loan Trailing Fee is recorded at fair value at the time of the origination of the loan with Other Liabilities and recorded as a reduction of Transaction Fees, net. Any changes in the fair value of this liability are recorded in changes in fair value of Borrower Loans, Loans Held for Sale and Notes, Net on the statements of operations. The fair value of the Loan Trailing Fee represents the present value of the expected monthly Loan Trailing Fee payments, which considers assumptions of expected prepayment rates and defaults rates. 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 .” The new guidance sets forth a new five-step revenue recognition model which replaces the prior revenue recognition guidance in its entirety and is intended to eliminate numerous industry-specific pieces of revenue recognition guidance that have historically existed in U.S. GAAP. The underlying principle of the new standard is that a business or other organization will recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects what it expects in exchange for the goods or services. The standard also requires more detailed disclosures and provides additional guidance for transactions that were not addressed completely in the prior accounting guidance. The standard will be effective for Prosper in the first quarter of fiscal 2018. In August 2015, the FASB issued ASU No. 2015-14, which amended the standard to provide a one-year deferral of the effective date, as well as providing the option to early adopt the standard on the original effective date. Accordingly, Prosper may adopt the standard in either Prosper’s fiscal year ending December 31, 2017 or 2018. The guidance can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. In March 2016, April 2016 and May 2016, the FASB further amended the guidance to clarify the implementation on principal versus agent considerations, the identification of performance obligation and the licensing implementation guidance, and to provide narrow-scope improvements and practical expedients. Prosper has not yet selected a transition method and is evaluating the impact of adopting this new accounting standard update on the consolidated financial statements and related disclosures. 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. Prosper adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In April 2015, the FASB issued ASU 2015-05 “ Customers’ Accounting for Fees Paid in Cloud Computing Arrangement ”, which became effective for the annual reporting period beginning 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 adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In September 2015, the FASB issued ASU 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, and interim periods within those fiscal years, beginning after December 15, 2015. Prosper adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , which requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases, along with additional qualitative and quantitative disclosures. This guidance will be effective for us in the first quarter of our fiscal year 2019, and early adoption is permitted. Prosper will be required to recognize and measure leases at the beginning off the earliest period presented using a modified retrospective approach. Prosper anticipates that this standard will have a material impact on our consolidated financial statements. While Prosper is continuing to assess all potential impacts of the standard, Prosper currently believes the most significant impact relates to our accounting for office operating leases. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting (Topic 718). This guidance makes several modifications to Topic 718 related to the accounting for forfeitures, employer tax withholding on share-based compensation and the financial statement presentation of excess tax benefits or deficiencies. ASU 2016-09 also clarifies the statement of cash flows presentation for certain components of share-based awards. This guidance will be effective for us in the first quarter of our fiscal year 2017, and early adoption is permitted. Prosper has decided to early adopt this guidance effective January 1, 2016, the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” The standard provides guidance for eight targeted changes with respect to how cash receipts and cash payments are classified in the statements of cash flows, with the objective of reducing diversity in practice. This guidance will be effective for Prosper in the first quarter of our fiscal year 2018, and early adoption is permitted. Prosper is currently evaluating the impacts the adoption of this accounting standard will have on Prosper's cash flows.
Prosper Funding LLC
Entity Information [Line Items]
Summary of Significant Accounting Policies	Significant Accounting Policies Prosper Funding's significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies in Prosper Funding’s Annual Report on Form 10-K for the year ended December 31, 2015 . There have been no changes to these accounting policies during the first nine months of 2016 . 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 Through the Note Channel, Prosper Funding purchases Borrower Loans from WebBank then issues Notes, and holds the Borrower Loans until maturity. The obligation to repay a series of Notes funded through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans and Notes funded through the Note Channel are carried on Prosper Funding’s consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper Funding estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper Funding maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes. Loan Trailing Fee On July 1, 2016, Prosper Funding signed a series of agreements with WebBank to include an additional program fee (Loan Trailing Fee). These agreements are effective August 1, 2016. The Loan Trailing Fee is dependent on the amount and timing of principal and interest payments made by borrowers of the underlying loans, irrespective of whether the loans are sold by Propser and gives the issuing bank an ongoing financial interest in the performance of the loans it originates. This fee is paid by Prosper Funding to the issuing bank partner over the term of the respective loans and is a function of the principal and interest payments. In the event that principal and interest payments are not made, Prosper Funding is not required to make this Loan Trailing Fee payment. The obligation to pay the Loan Trailing Fee is recorded at fair value at the time of the origination of the loan within Other Liabilities and is recorded as a reduction in related party expenses on the statement of operations. Any changes in the fair value of this liability are recorded in changes in fair value of Borrower Loans, Loans Held for Sale and Notes, Net on the statements of operations. The fair value of the Loan Trailing Fee represents the present value of the expected monthly Loan Trailing Fee payments, which considers assumptions of expected prepayment rates and defaults rates. 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.” The new guidance sets forth a new five-step revenue recognition model which replaces the prior revenue recognition guidance in its entirety and is intended to eliminate numerous industry-specific pieces of revenue recognition guidance that have historically existed in U.S. GAAP. The underlying principle of the new standard is that a business or other organization will recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects what it expects in exchange for the goods or services. The standard also requires more detailed disclosures and provides additional guidance for transactions that were not addressed completely in the prior accounting guidance. The standard will be effective for Prosper Funding in the first quarter of fiscal 2018. In August 2015, the FASB issued ASU No. 2015-14, which amended the standard to provide a one-year deferral of the effective date, as well as providing the option to early adopt the standard on the original effective date. Accordingly, Prosper Funding may adopt the standard in either Prosper Funding’s fiscal year ending December 31, 2017 or 2018. The guidance can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. In March 2016, April 2016 and May 2016, the FASB further amended the guidance to clarify the implementation on principal versus agent considerations, the identification of performance obligation and the licensing implementation guidance, and to provide narrow-scope improvements and practical expedients. Prosper Funding has not yet selected a transition method and is evaluating the impact of adopting this new accounting standard update on the consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-05 “Customers’ Accounting for Fees Paid in Cloud Computing Arrangement”, which became effective for the annual reporting period beginning 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 Funding adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper Funding’s condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” The standard provides guidance for eight targeted changes with respect to how cash receipts and cash payments are classified in the statements of cash flows, with the objective of reducing diversity in practice. This guidance will be effective for Prosper Funding in the first quarter of our fiscal year 2018, and early adoption is permitted. Prosper Funding is currently evaluating the impacts the adoption of this accounting standard will have on the Prosper Funding's cash flows.

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Property and Equipment, Net	Property and Equipment, Net Property and equipment consist of the following (in thousands): September 30, December 31, Property and equipment: Computer equipment $ 14,241 $ 10,522 Internal-use software and website development costs 15,144 10,990 Office equipment and furniture 3,064 2,442 Leasehold improvements 7,071 5,719 Assets not yet placed in service 2,121 3,242 Property and equipment 41,641 32,915 Less accumulated depreciation and amortization (14,963 ) (7,950 ) Total property and equipment, net $ 26,678 $ 24,965 Depreciation and amortization expense for property and equipment for the three months ended September 30, 2016 and 2015 was $2.5 million and $1.3 million , respectively. Depreciation and amortization expense for property and equipment for the nine months ended September 30, 2016 and 2015 was $6.9 million and $4.4 million , respectively. Prosper capitalized internal-use software and website development costs in the amount of $1.3 million and $2.0 million for the three months ended September 30, 2016 and 2015 , respectively. Prosper capitalized internal-use software and website development costs in the amount of $5.2 million and $5.9 million for the nine months ended September 30, 2016 and 2015 , respectively. Prosper recorded internal-use software and website development impairment charges of $672 thousand and $0 for the nine months ended September 30, 2016 and 2015 , 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 statements of operations.
Prosper Funding LLC
Entity Information [Line Items]
Property and Equipment, Net	Property and Equipment Property and equipment consist of the following (in thousands): September 30, December 31, Property and equipment: Internal-use software and web site development costs $ 15,143 $ 10,990 Less accumulated depreciation and amortization (5,511 ) (2,571 ) Total property and equipment, net $ 9,632 $ 8,419 Depreciation expense for the three months ended September 30, 2016 and 2015 was $1,076 thousand and $587 thousand , respectively. Depreciation expense for the nine months ended September 30, 2016 and 2015 was $2,940 thousand and $2,483 thousand , respectively.

Borrower Loans, Loans Held for

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	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, 2016 and December 31, 2015 , are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, December 31, September 30, December 31, September 30, December 31, Aggregate principal balance outstanding $ 319,210 $ 296,945 $ (322,003 ) $ (294,331 ) $ 148 $ 42 Fair value adjustments (4,539 ) 328 8,083 (3,074 ) (12 ) (10 ) Fair value $ 314,671 $ 297,273 $ (313,920 ) $ (297,405 ) $ 136 $ 32 At September 30, 2016 , outstanding Borrower Loans 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 2021 . At December 31, 2015 , outstanding Borrower Loans had original maturities 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 December 2020 . Approximately $0.4 million and $2.4 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, 2016 . As of September 30, 2016 , Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $2.7 million and a fair value of $0.8 million . As of December 31, 2015 , Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $2.3 million and a fair value of $0.9 million . Prosper places loans on non-accrual status when they are over 120 days past due. As of September 30, 2016 and December 31, 2015 , Borrower Loans in non-accrual status had a fair value of $0.2 million and $0.1 million , respectively.
Prosper Funding LLC
Entity Information [Line Items]
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	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, 2016 and December 31, 2015 , are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Aggregate principal balance outstanding $ 319,210 $ 296,945 $ (322,003 ) $ (294,331 ) $ 148 $ 42 Fair value adjustments (4,539 ) 328 8,083 (3,074 ) (12 ) (10 ) Fair value $ 314,671 $ 297,273 $ (313,920 ) $ (297,405 ) $ 136 $ 32 At September 30, 2016 , outstanding Borrower Loans 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 2021 . At December 31, 2015 , outstanding Borrower Loans had original maturities 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 December 2020 . Approximately $0.4 million and $2.4 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 ended September 30, 2016 . As of September 30, 2016 , Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $2.7 million and a fair value of $0.8 million . As of December 31, 2015 , Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $2.3 million and a fair value of $0.9 million . Prosper Funding places loans on non-accrual status when they are over 120 days past due. As of September 30, 2016 and December 31, 2015 , Borrower Loans in non-accrual status had a fair value of $0.2 million and $0.1 million , respectively.

Loan Servicing Assets and Liabi

Loan Servicing Assets and Liabilities	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Loan Servicing Assets and Liabilities	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 through the Whole Loan Channel and the servicing rights are retained. The servicing assets and liabilities are measured at fair value throughout the servicing period. The total gains recognized on the sale of such Borrower Loans were $0.8 million and $4.3 million for the three months ended September 30, 2016 and 2015 , respectively. The total gains recognized on the sale of such Borrower Loans were $3.9 million and $9.9 million for the nine months ended September 30, 2016 and 2015 , respectively. As of September 30, 2016 , Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $3.7 billion , original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 5.32% to 35.52% and various maturity dates through September 2021 . At December 31, 2015 , Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $3.8 billion , 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 December 2020 . $9.7 million and $6.3 million of contractually specified servicing fees and ancillary fees are included on our condensed consolidated statements of operations in Servicing Fees, Net for the three months ended September 30, 2016 and 2015 respectively. $29.8 million and $14.1 million of contractually specified servicing fees and ancillary fees are included on our condensed statements of operations in Servicing Fees, Net for the nine months ended September 30, 2016 and 2015 respectively. Fair value Valuation method – Prosper uses a discounted cash flow valuation methodology generally consisting of developing an estimate of future cash flows that are expected to occur over the life of a financial instrument and then discounting those cash flows at a rate of return that results in the fair value amount. Significant unobservable inputs presented in the table within Note 7 below are those that Prosper considers significant to the estimated fair values of the Level 3 servicing assets and liabilities. The following is a description of the significant unobservable inputs provided in the table. Market servicing rate – Prosper estimates adequate market servicing rates that would fairly compensate a substitute servicer should one be required, which includes the profit that would be demanded in the marketplace. This rate is stated as a fixed percentage of outstanding principal balance on a per annum basis. Prosper estimated these market servicing rates based on observable market rates for other loan types in the industry and bids from subservicing providers, adjusted for the unique loan attributes that are present in the specific loans that Prosper sells and services and information from a backup service provider. Discount rate – The discount rate is a rate of return used to discount future expected cash flows to arrive at a present value, which represents the fair value of the loan servicing rights. We used a range of discount rates for the servicing assets and liabilities based on comparable observed valuations of similar assets and publicly available disclosures related to servicing valuations, with comparability adjustments made to account for differences with Prosper’s servicing assets. Default Rate – The default rate presented in Note 7 is an annualized, average estimate considering all Borrower Loan categories (i.e. risk ratings and duration), and represents an aggregate of conditional default rate curves for each credit grade or Borrower Loan category. Each point on a particular Borrower Loan category’s curve represents the percentage of principal expected to default per period based on the term and age of the underlying Borrower Loans. The assumption regarding defaults directly reduces servicing revenues because the amount of servicing revenues received is based on the amount collected each period. Prepayment Rate – The prepayment rate presented in Note 7 is an annualized, average estimate considering all Borrower Loan categories (i.e. risk ratings and duration), and represents an aggregate of conditional prepayment rate curves for each credit grade or Borrower Loan category. Each point on a particular Borrower Loan category’s curve represents the percentage of principal expected to prepay per period based on the term and age of the underlying Borrower Loans. Prepayments reduce servicing revenues as they shorten the period over which we expect to collect fees on the Borrower Loans, which is used to project future servicing revenues.
Prosper Funding LLC
Entity Information [Line Items]
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 through the Whole Loan Channel and the servicing rights are retained. The servicing assets and liabilities are measured at fair value throughout the servicing period. The total gains recognized on the sale of such Borrower Loans were $0.8 million and $4.3 million for the three months ended September 30, 2016 and 2015 , respectively. The total gain recognized on the sale of such Borrower Loans was $3.9 million and $9.9 million for the nine months ended September 30, 2016 and 2015 , respectively. At September 30, 2016 , Borrower Loans that were sold, but for which Prosper Funding retained servicing rights, had a total outstanding principal balance of $3.6 billion , original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 5.32% to 35.52% and various maturity dates through September 2021 . At December 31, 2015 , Borrower Loans that were sold, but for which Prosper Funding retained servicing rights, had a total outstanding principal balance of $3.6 billion , 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 December 2020 . $9.6 million and $5.9 million of contractually specified servicing fees and ancillary fees are included on our condensed consolidated statements of operations in Servicing Fees, Net for the three months ended September 30, 2016 and 2015 respectively. $29.3 million and $12.7 million of contractually specified servicing fees and ancillary fees are included on our condensed consolidated statements of operations in Servicing Fees, Net for the nine months ended September 30, 2016 and 2015 respectively. Fair value Valuation method – Prosper Funding uses a discounted cash flow valuation methodology generally consisting of developing an estimate of future cash flows that are expected to occur over the life of a financial instrument and then discounting those cash flows at a rate of return that results in the fair value amount. Significant unobservable inputs presented in the table within Note 7 below are those that Prosper Funding considers significant to the estimated fair values of the Level 3 servicing assets and liabilities. The following is a description of the significant unobservable inputs provided in the table. Market servicing rate – Prosper Funding estimates adequate market servicing rates that would fairly compensate a substitute servicer should one be required, which includes the profit that would be demanded in the marketplace. This rate is stated as a fixed percentage of outstanding principal balance on a per annum basis. Prosper Funding estimated these market servicing rates based on observable market rates for other loan types in the industry and bids from subservicing providers, adjusted for the unique loan attributes that are present in the specific loans that Prosper Funding sells and services and information from a backup service provider. Discount rate – The discount rate is a rate of return used to discount future expected cash flows to arrive at a present value, which represents the fair value of the loan servicing rights. We used a range of discount rates for the servicing assets and liabilities based on comparable observed valuations of similar assets and publicly available disclosures related to servicing valuations, with comparability adjustments made to account for differences with Prosper Funding’s servicing assets. Default Rate – The default rate presented in Note 7 is an annualized, average estimate considering all Borrower Loan categories (i.e. risk ratings and duration), and represents an aggregate of conditional default rate curves for each credit grade or Borrower Loan category. Each point on a particular Borrower Loan category’s curve represents the percentage of principal expected to default per period based on the term and age of the underlying Borrower Loans. The assumption regarding defaults directly reduces servicing revenues because the amount of servicing revenues received is based on the amount collected each period. Prepayment Rate – The prepayment rate presented in Note 7 is an annualized, average estimate considering all Borrower Loan categories (i.e. risk ratings and duration), and represents an aggregate of conditional prepayment rate curves for each credit grade or Borrower Loan category. Each point on a particular Borrower Loan category’s curve represents the percentage of principal expected to prepay per period based on the term and age of the underlying Borrower Loans. Prepayments reduce servicing revenues as they shorten the period over which we expect to collect fees on the Borrower Loans, which is used to project future servicing revenues.

Available for Sale Investments,

Available for Sale Investments, at Fair Value	9 Months Ended
	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Available for Sale Investments, at Fair Value	Available for Sale Investments, at Fair Value 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, 2016 and December 31, 2015 , are as follows (in thousands): September 30, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Corporate debt securities $ 29,733 $ 16 $ (8 ) $ 29,741 US Treasury securities 10,525 14 (2 ) 10,537 Agency bonds 2,499 6 — 2,505 Total Available for Sale Investments $ 42,757 $ 36 $ (10 ) $ 42,783 December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Corporate debt securities $ 50,327 $ 1 $ (94 ) $ 50,234 Commercial paper 9,493 — — 9,493 US Treasury securities 8,512 — (41 ) 8,471 Agency bonds 2,499 — (8 ) 2,491 Total fixed maturity securities 70,831 1 (143 ) 70,689 Short term bond funds 2,500 — (2 ) 2,498 Total Available for Sale Investments $ 73,331 $ 1 $ (145 ) $ 73,187 A summary of available for sale investments with unrealized losses as of September 30, 2016 , and December 31, 2015 , aggregated by category and period of continuous unrealized loss, is as follows (in thousands): Less than 12 months 12 months or longer Total September 30, 2016 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturity securities: Corporate debt securities $ 12,075 $ (8 ) $ — $ — $ 12,075 $ (8 ) U.S. treasury securities 4,503 (2 ) — — 4,503 (2 ) Total Investments with Unrealized Losses $ 16,578 $ (10 ) $ — $ — $ 16,578 $ (10 ) Less than 12 months 12 months or longer Total December 31, 2015 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturity securities: Corporate debt securities $ 45,375 $ (94 ) $ — $ — $ 45,375 $ (94 ) U.S. treasury securities 8,471 (41 ) — — 8,471 (41 ) Agency bonds 2,491 (8 ) — — 2,491 (8 ) Total fixed maturity securities 56,337 (143 ) — — 56,337 (143 ) Short term bond funds 2,498 (2 ) — — 2,498 (2 ) Total Investments with Unrealized Losses $ 58,835 $ (145 ) $ — $ — $ 58,835 $ (145 ) There were no impairment charges recognized during the nine months ended September 30, 2016 . The maturities of available for sale investments at September 30, 2016 , and December 31, 2015 , are as follows (in thousands): September 30, 2016 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Corporate debt securities $ 25,235 $ 4,506 $ — $ — $ 29,741 US Treasury securities 6,532 4,005 — — 10,537 Agency bonds — 2,505 — — 2,505 Total Fair Value $ 31,767 $ 11,016 $ — $ — $ 42,783 Total Amortized Cost $ 31,763 $ 10,994 $ — $ — $ 42,757 December 31, 2015 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Corporate debt securities $ 26,289 $ 23,945 $ — $ — $ 50,234 Commercial paper 9,493 — — — 9,493 US Treasury securities — 8,471 — — 8,471 Agency bonds — 2,491 — — 2,491 Total Fair Value $ 35,782 $ 34,907 $ — $ — $ 70,689 Total Amortized Cost $ 35,831 $ 35,000 $ — $ — $ 70,831 During the nine months ended September 30, 2016 , Prosper sold $10.4 million of investments which resulted in a realized gain of $7 thousand .

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities Prosper measures the fair value of assets and liabilities in accordance with its fair value hierarchy which prioritizes information used to measure fair value and the effect of fair value measurements on earnings and provides for enhanced disclosures determined by the level within the hierarchy of information used in the valuation. We apply this framework whenever other standards require (or permit) assets or liabilities to be measured at fair value. Assets and liabilities carried at fair value on the balance sheets are classified among three levels based on the observability of the inputs used to determine fair value: Level 1 — The valuation is based on quoted prices in active markets for identical instruments. Level 2 — The valuation is based on observable inputs such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation methodologies for which all significant assumptions are observable in the market. Level 3 — The valuation is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the instrument. Level 3 valuations are typically performed using pricing models, discounted cash flow methodologies, or similar methodologies, which incorporate management’s own estimates of assumptions that market participants would use in pricing the instrument or valuations that require significant management judgment or estimation. Fair values of assets or liabilities are determined based on the fair value hierarchy, which requires an entity to maximize the use of quoted prices and observable inputs and to minimize the use of unobservable inputs when measuring fair value. Various valuation methodologies are utilized, depending on the nature of the financial instrument, including the use of market prices for identical or similar instruments, or discounted cash flow models. When possible, active and observable market data for identical or similar financial instruments are utilized. Alternatively, fair value is determined using assumptions that management believes a market participant would use in pricing the asset or liability. Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Available for Sale Investments, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. Servicing Assets and Liabilities are also subject to fair value measurement within the financial statements of Prosper. 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. 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. Investments held at fair value consist of available for sale investments. The available for sale investments consist of corporate debt securities, commercial paper, U.S. treasury securities, agency bonds and short term bond funds. 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, 2016 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 314,671 $ 314,671 Loans Held for Sale — — 136 136 Available for Sale Investments, at Fair Value — 42,783 — 42,783 Servicing Assets — — 12,664 12,664 Total Assets — 42,783 327,471 370,254 Liabilities: Notes $ — $ — $ 313,920 $ 313,920 Servicing Liabilities — — 254 254 Contingent Consideration — — 4,994 4,994 Total Liabilities $ — $ — $ 319,168 $ 319,168 December 31, 2015 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 297,273 $ 297,273 Loans Held for Sale — — 32 32 Available for Sale Investments, at Fair Value — 73,187 — 73,187 Servicing Assets — — 14,363 14,363 Total Assets — 73,187 311,668 384,855 Liabilities: Notes $ — $ — $ 297,405 $ 297,405 Servicing Liabilities — — 484 484 Contingent Consideration — — 4,801 4,801 Total Liabilities $ — $ — $ 302,690 $ 302,690 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, 2016 and December 31, 2015 : Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 4.4% - 15.2% 4.3% - 14.5% Default rate 1.6% - 14.8% 1.4% - 14.4% Servicing Rights Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 15% - 25% 15% - 25% Default rate 1.4% - 15.0% 1.2% - 14.7% Prepayment rate 14.9% - 27.7% 14.3% - 25.6% Market servicing rate 0.625 % 0.625 % At September 30, 2016 , 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 borrower 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 (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2016 $ 297,273 $ (297,405 ) $ 32 $ (100 ) Purchase of Borrower Loans/Issuance of Notes 164,436 (165,727 ) 1,619,866 1,618,575 Principal repayments (125,419 ) 129,603 (269 ) 3,915 Borrower Loans sold to third parties (1,889 ) — (1,619,488 ) (1,621,377 ) Other changes 232 (229 ) (3 ) — Change in fair value (19,962 ) 19,838 (2 ) (126 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 July 1, 2016 $ 310,034 $ (309,530 ) $ 4,706 $ 5,210 Purchase of Borrower Loans/Issuance of Notes 55,221 (56,580 ) 261,855 260,496 Principal repayments (43,043 ) 45,403 (133 ) 2,227 Borrower Loans sold to third parties (751 ) — (266,286 ) (267,037 ) Other changes 238 (196 ) (4 ) 38 Change in fair value (7,028 ) 6,983 (2 ) (47 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 ) The following tables present additional information about level 3 servicing assets and liabilities measured at fair value on a recurring basis (in thousands): Servicing Assets Servicing Liabilities Fair Value at January 1, 2016 14,363 484 Additions 7,092 9 Less: Changes in fair value (8,791 ) (239 ) Fair Value at September 30, 2016 12,664 254 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 Servicing Assets Servicing Liabilities Fair Value at July 1, 2016 14,297 324 Additions 1,342 — Less: Changes in fair value (2,975 ) (70 ) Fair Value at September 30, 2016 12,664 254 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 Contingent Consideration: On October 9, 2015 , PMI, purchased 100% of the outstanding shares of BillGuard . The contingent consideration was primarily performance-based and will be determined over a one -year period from the date of purchase. Total contingent consideration due in October 2016 is based on revenues generated and other criteria. We measured the fair value of the contingent consideration using a probability-weighted discounted cash flow approach. Some of the significant inputs used for the valuation are not observable in the market and are thus Level 3 inputs. Contingent consideration is recorded in the condensed consolidated balance sheets under "Other Liabilities." Significant increases or decreases in certain underlying assumptions used to value the contingent consideration could significantly increase or decrease the fair value estimates recorded in the condensed consolidated balance sheets. During the three and nine month periods ended September 30, 2016 , there were fair value changes of $65 thousand and $192 thousand , respectively, resulting in a fair value of $5.0 million at September 30, 2016 from the opening fair value at January 1, 2016 of $4.8 million . 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, 2016 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: 7.59 % * 7.59 % * Resulting fair value from: 100 basis point increase $ 311,509 $ 310,760 200 basis point increase 308,426 307,680 Resulting fair value from: 100 basis point decrease $ 317,914 $ 317,161 200 basis point decrease 321,244 320,488 Default rate assumption: 11.50 % * 11.50 % * Resulting fair value from: 100 basis point increase $ 311,358 $ 310,601 200 basis point increase 308,142 307,380 Resulting fair value from: 100 basis point decrease $ 318,009 $ 317,264 200 basis point decrease 321,389 320,651 * Represents weighted average assumptions considering all credit grades. 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, 2016 (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% $ 11,744 $ 279 Market servicing rate decrease to 0.60% $ 13,583 $ 228 Weighted average prepayment assumptions 21.06 % 21.06 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate $ 12,426 $ 249 Applying a 0.9 multiplier to prepayment rate $ 12,904 $ 258 Weighted average default assumptions 11.64 % 11.64 % Resulting fair value from: Applying a 1.1 multiplier to default rate $ 12,451 $ 253 Applying a 0.9 multiplier to default rate $ 12,880 $ 254 These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a 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.
Prosper Funding LLC
Entity Information [Line Items]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities Prosper Funding measures the fair value of assets and liabilities in accordance with its fair value hierarchy which prioritizes information used to measure fair value and the effect of fair value measurements on earnings and provides for enhanced disclosures determined by the level within the hierarchy of information used in the valuation. We apply this framework whenever other standards require (or permit) assets or liabilities to be measured at fair value. Assets and liabilities carried at fair value on the balance sheets are classified among three levels based on the observability of the inputs used to determine fair value: Level 1 — The valuation is based on quoted prices in active markets for identical instruments. Level 2 — The valuation is based on observable inputs such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation methodologies for which all significant assumptions are observable in the market. Level 3 — The valuation is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the instrument. Level 3 valuations are typically performed using pricing models, discounted cash flow methodologies, or similar methodologies, which incorporate management’s own estimates of assumptions that market participants would use in pricing the instrument or valuations that require significant management judgment or estimation. Fair values of assets or liabilities are determined based on the fair value hierarchy, which requires an entity to maximize the use of quoted prices and observable inputs and to minimize the use of unobservable inputs when measuring fair value. Various valuation methodologies are utilized, depending on the nature of the financial instrument, including the use of market prices for identical or similar instruments, or discounted cash flow models. When possible, active and observable market data for identical or similar financial instruments are utilized. Alternatively, fair value is determined using assumptions that management believes a market participant would use in pricing the asset or liability. Financial instruments consist principally of cash and cash equivalents, restricted cash, Borrower Loans, accounts payable and accrued liabilities, and Notes. Servicing assets and liabilities are also subject to fair value measurement within the financial statements of Prosper Funding. The estimated fair values of cash and cash equivalents, restricted cash, accounts payable and accrued liabilities approximate their carrying values because of their short term nature. 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. Investments held at fair value consist of available for sale investments. The available for sale investments consist of corporate and government bonds. When available, Prosper Funding 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 Funding uses the price within the bid-ask spread that best represents fair value. When quoted prices do not exist, Prosper Funding uses prices obtained from independent third-party pricing services to measure the fair value of investment assets. Prosper Funding generally obtains prices from at least two independent pricing sources for assets recorded at fair value. Prosper Funding'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 Funding 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 Funding 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, 2016 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 314,671 $ 314,671 Loans Held for Sale — — 136 136 Servicing Assets — — 12,274 12,274 Total Assets — — 327,081 327,081 Liabilities: Notes $ — $ — $ 313,920 $ 313,920 Servicing Liabilities — — 254 254 Total Liabilities $ — $ — $ 314,174 $ 314,174 December 31, 2015 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 297,273 $ 297,273 Loans Held for Sale — — 32 32 Servicing Assets — — 13,605 13,605 Total Assets — — 310,910 310,910 Liabilities: Notes $ — $ — $ 297,405 $ 297,405 Servicing Liabilities — — 484 484 Total Liabilities $ — $ — $ 297,889 $ 297,889 As Prosper Funding’s Borrower Loans, Loans Held for Sale, Notes and loan servicing rights do not trade in an active market with readily observable prices, Prosper Funding 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 Funding’s level 3 fair value measurements at September 30, 2016 and December 31, 2015 : Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 4.4% - 15.2% 4.3% - 14.5% Default rate 1.6% - 14.8% 1.4% - 14.4% Servicing Rights Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 15% - 25% 15% - 25% Default rate 1.4% - 15.0% 1.2% - 14.7% Prepayment rate 14.9% - 27.7% 14.3% - 25.6% Market servicing rate 0.625 % 0.625 % 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) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2016 $ 297,273 $ (297,405 ) $ 32 $ (100 ) Originations 164,436 (165,727 ) 1,619,866 1,618,575 Principal repayments (125,419 ) 129,603 (269 ) 3,915 Borrower Loans sold to third parties (1,889 ) — (1,619,488 ) (1,621,377 ) Other changes 232 (229 ) (3 ) — Change in fair value (19,962 ) 19,838 (2 ) (126 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 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) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2016 $ 310,034 $ (309,530 ) $ 4,706 $ 5,210 Originations 55,221 (56,580 ) 261,855 260,496 Principal repayments (43,043 ) 45,403 (133 ) 2,227 Borrower Loans sold to third parties (751 ) — (266,286 ) (267,037 ) Other changes 238 (196 ) (4 ) 38 Change in fair value (7,028 ) 6,983 (2 ) (47 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 ) The following table presents additional information about Level 3 servicing assets and liabilities recorded at fair value for the three months ended September 30, 2016 (in thousands). Servicing Assets Servicing Liabilities Fair Value at January 1, 2016 13,605 484 Additions 7,092 9 Less: Changes in fair value (8,423 ) (239 ) Fair Value at September 30, 2016 12,274 254 Servicing Assets Servicing 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 Assets Servicing Liabilities Fair Value at July 1, 2016 13,798 324 Additions 1,342 — Less: Changes in fair value (2,866 ) (70 ) Fair Value at September 30, 2016 12,274 254 Servicing Assets Servicing 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 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, 2016 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: 7.59 % * 7.59 % * Resulting fair value from: 100 basis point increase $ 311,509 $ 310,760 200 basis point increase 308,426 307,680 Resulting fair value from: 100 basis point decrease $ 317,914 $ 317,161 200 basis point decrease 321,244 320,488 Default rate assumption: 11.50 % * 11.50 % * Resulting fair value from: 100 basis point increase $ 311,358 $ 310,601 200 basis point increase 308,142 307,380 Resulting fair value from: 100 basis point decrease $ 318,009 $ 317,264 200 basis point decrease 321,389 320,651 * Represents weighted average assumptions considering all credit grades. 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, 2016 (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% 11,509 279 Market servicing rate decrease to 0.60% 13,311 228 Weighted average prepayment assumptions 21.06 % 21.06 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate 12,043 249 Applying a 0.9 multiplier to prepayment rate 12,507 258 Weighted average default assumptions 11.64 % 11.64 % Resulting fair value from: Applying a 1.1 multiplier to default rate 12,068 253 Applying a 0.9 multiplier to default rate 12,484 254 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.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Acquisitions	Acquisitions On January 23, 2015 , PMI acquired all of the outstanding limited liability company interests of American HealthCare Lending, and merged American HealthCare Lending with and into PHL, with PHL surviving the merger. In January 2015, PMI completed the allocation of the purchase price of the acquisition of American HealthCare Lending to acquired assets and liabilities. On October 9, 2015 , PMI acquired all of the outstanding shares of BillGuard, Inc . PMI merged BillGuard with and into Beach Merger Sub, Inc., a newly established entity wholly owned by PMI, with BillGuard surviving the merger. 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.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill Prosper’s goodwill balance of $36.4 million at September 30, 2016 did not change during the nine months ended September 30, 2016 . We did not record any goodwill impairment expense for the nine months ended September 30, 2016 . Other Intangible Assets The following table presents the detail of other intangible assets for the period presented (dollars in thousands): September 30, 2016 Gross Carrying Value Accumulated Amortization Net Carrying Value Remaining Useful Life (In Years) User base and customer relationships $ 6,250 $ (2,541 ) $ 3,709 8.4 Developed technology 8,310 (1,950 ) $ 6,360 4.0 Brand name 60 (60 ) — — Total intangible assets subject to amortization $ 14,620 $ (4,551 ) $ 10,069 Prosper’s intangible asset balance was $10.1 million and $13.1 million at September 30, 2016 and December 31, 2015 , respectively. The user base and customer relationship intangible assets are being amortized on an accelerated basis over a three to ten year period. The technology and brand name intangible assets are being amortized on a straight line basis over three to five years and one year , respectively. Amortization expense for the three months ended September 30, 2016 and 2015 was $1.0 million and $0.2 million , respectively. Amortization expense for the nine months ended September 30, 2016 and 2015 was $3.0 million and $0.5 million , respectively. Estimated amortization of purchased intangible assets for future periods is as follows (in thousands): Year Ending December 31, 2016 $ 855 2017 3,260 2018 2,329 2019 1,779 2020 1,344 Thereafter 502 Total $ 10,069

Other Liabilities

Other Liabilities	9 Months Ended
	Sep. 30, 2016
Other Liabilities [Abstract]
Other Liabilities	Other Liabilities Other Liabilities includes the following: September 30, 2016 December 31, 2015 Class action settlement liability $ 2,984 $ 5,949 Repurchase liability for unvested restricted stock awards 180 473 Contingent consideration 4,994 4,801 Deferred revenue 285 1,591 Servicing liabilities 254 484 Deferred rent 4,563 5,240 Restructuring liability 5,107 — Other 2,587 2,197 Total Other Liabilities $ 20,954 $ 20,735

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Net Loss Per Share	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, 2016 2015 2016 2015 Numerator: Net loss available to common stockholders for basic and diluted EPS $ (17,417 ) $ (3,843 ) $ (70,509 ) $ (17,324 ) Denominator: Weighted average shares used in computing basic and diluted net loss per share 65,393,175 55,907,765 63,015,616 54,746,980 Basic and diluted net loss per share $ (0.27 ) $ (0.07 ) $ (1.12 ) $ (0.32 ) 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, 2016 2015 2016 2015 (shares) (shares) (shares) (shares) Excluded securities: Convertible preferred stock issued and outstanding 177,388,425 177,388,425 177,388,425 177,388,425 Stock options issued and outstanding 50,387,360 35,063,150 44,617,487 32,592,610 Unvested stock options exercised 3,209,345 11,906,925 3,209,345 11,906,925 Warrants issued and outstanding 1,203,344 602,355 910,945 602,355 Total common stock equivalents excluded from diluted net loss per common share computation 232,188,474 224,960,855 226,126,202 222,490,315 The number of shares issued and outstanding reflect a 5 -for- 1 forward stock split effected by PMI on February 16, 2016.

Convertible Preferred Stock and

Convertible Preferred Stock and Stockholders' Deficit	9 Months Ended
	Sep. 30, 2016
Stockholders' Equity Note [Abstract]
Convertible Preferred Stock and Stockholders' Deficit	Convertible Preferred Stock and Stockholders’ Deficit 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, 2016 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 68,558,220 68,558,220 $ 19,774 Series A-1 0.01 24,760,915 24,760,915 49,522 New Series B 0.01 35,775,880 35,775,880 21,581 New Series C 0.01 24,404,770 24,404,770 70,075 New Series D 0.01 23,888,640 23,888,640 165,000 177,388,425 177,388,425 $ 325,952 The number of shares issued and outstanding reflect a 5 -for-1 forward stock split effected by PMI on February 16, 2016. Common Stock PMI, through its amended and restated certificate of incorporation, as amended, is the sole issuer of common stock and related options, RSUs and warrants. On February 16, 2016, PMI amended and restated its certificate of incorporation to, among other things, effect a 5 -for-1 forward stock split. On May 31, 2016, PMI further amended its amended and restated certificate of incorporation to increase the number of shares of common stock authorized for issuance. The total number of shares of stock which PMI has the authority to issue is 475,610,528 , consisting of 298,222,103 shares of common stock, $0.01 par value per share, and 177,388,425 shares of preferred stock, $0.01 par value per share. As of September 30, 2016 , 70,708,055 shares of common stock were issued and 69,772,120 shares of common stock were outstanding. As of December 31, 2015 , 70,367,425 shares of common stock were issued and 69,431,490 shares of common stock were outstanding. Each holder of common stock is entitled to one vote for each share of common stock held. Common Stock Issued upon Exercise of Stock Options During the nine months ended September 30, 2016 , PMI issued 386,720 shares of common stock upon the exercise of vested options for cash proceeds of $0.3 million . Certain options are eligible for exercise prior to vesting. These unvested options may be exercised for restricted shares of common stock that have the same vesting schedule as the options. Prosper records a liability for the exercise price paid upon the exercise of unvested options, which is reclassified to common stock and additional paid-in capital as the shares vest. Should the holder’s employment be terminated, the unvested restricted shares are subject to repurchase by PMI at an amount equal to the exercise price paid for such shares. At September 30, 2016 and December 31, 2015 , there were 3,209,345 and 9,806,170 shares, respectively, of restricted stock outstanding that remain unvested and subject to Prosper’s right of repurchase. For the nine months ended September 30, 2016 , PMI repurchased 288,520 shares of restricted stock for $70 thousand upon termination of employment of various employees. Common Stock Issued upon Exercise of Warrants For the nine months ended September 30, 2016 , PMI issued 51,915 shares of common stock upon the exercise of warrants for aggregate proceeds of $11 thousand .

Shared Based Incentive Plan and

Shared Based Incentive Plan and Compensation	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shared Based Incentive Plan and Compensation	Share Based Incentive Plan and Compensation In 2005, PMI’s stockholders approved the adoption of the 2005 Stock Plan. On December 1, 2010, PMI’s stockholders approved the adoption of the Amended and Restated 2005 Stock Plan (the “2005 Plan”). The 2005 Plan expired during the year ending December 31, 2015 and PMI’s stockholders approved the adoption of the 2015 Equity Incentive Plan. On February 15, 2016, PMI’s stockholders approved the adoption of an Amendment No. 1 to the 2015 Equity Incentive Plan, and on May 31, 2016, PMI’s stockholders approved the adoption of an Amendment No. 2 to the 2015 Equity Incentive Plan (as amended to date, the “2015 Plan”). As of September 30, 2016 under the 2005 Plan, up to 56,902,925 shares of common stock are reserved and may be issued to employees, directors, and consultants by PMI’s board of directors and stockholders to promote the success of Prosper’s business. As of September 30, 2016 under the 2015 Plan, up to 54,336,473 shares of common stock are reserved and may be granted to employees, directors, and consultants by PMI’s board of directors and stockholders to promote the success of Prosper’s business. Options generally vest 25% one year from the vesting commencement date and 1/48t h per month thereafter or vest 50% two years from the vesting commencement date and 1/48t h per month thereafter or vest 1/36t h per month from the vesting commencement date. In no event are options exercisable more than ten years after the date of grant. At September 30, 2016 , there were 20,684,495 shares available for grant under the 2015 Plan and zero shares available for grant under the 2005 Plan. The number of options, restricted stock units and amounts per share reflects a 5 -for-1 forward stock split effected by PMI on February 16, 2016. Stock Option Reprice On May 3, 2016, the Compensation Committee of the Board of Directors of PMI approved a stock option repricing program, (the “Reprice”) authorizing PMI’s officers to reprice certain outstanding stock options held by employees and directors that have exercise prices above the current fair market value of PMI’s common stock. The repricing was effected on May 16, 2016 for eligible directors and employees located in the United States and on May 19, 2016 for eligible employees located in Israel. Prosper believes the repricing of such stock options will encourage the continued service of valued employees and directors, and motivate such service providers to perform at high levels, both of which are critical to Prosper’s continued success. Prosper expects to incur additional stock based compensation charges as a result of this repricing. The financial statement impact of this repricing is $0.8 million in the three months ended September 30, 2016 , $2.0 million in the nine months ended September 30, 2016 and $2.9 million (net of forfeitures) that will be recognized over the remaining weighted average vesting period of 2.5 years . Early Exercised Stock Options The activity of options that were early exercised under the 2005 Plan for the nine months ended September 30, 2016 is below: Early exercised options, unvested Weighted average exercise price Balance as of January 1, 2016 9,806,170 $ 0.05 Repurchase of restricted stock (288,520 ) 0.24 Restricted stock vested (6,308,305 ) 0.04 Balance as of September 30, 2016 3,209,345 $ 0.06 Additional information regarding the unvested early exercised stock options outstanding as of September 30, 2016 is as follows: Options Outstanding Range of Exercise Prices Number Outstanding Weighted –Avg. Remaining Life Weighted –Avg. Exercise Price 0.02 2,910,435 0.4 $ 0.02 0.11 212,710 1.3 0.11 1.13 86,200 1.9 1.13 $0.02 - $1.13 3,209,345 0.5 $ 0.06 Stock Option Activity Stock option activity under the 2005 Plan and 2015 Plan is summarized for the nine months ended September 30, 2016 below: Options Issued and Outstanding Weighted- Average Exercise Price Balance as of January 1, 2016 40,425,605 $ 2.64 Options issued 19,655,338 2.14 Options exercised – vested (386,720 ) 0.75 Options forfeited (12,886,025 ) 1.60 Balance as of September 30, 2016 46,808,198 $ 1.55 Options vested and/or exercisable at September 30, 2016 26,701,173 1.13 Due to the timing of the Reprice, the ending weighted average exercise price shown above reflects repriced options while the opening weighted average exercise price does not. Other Information Regarding Stock Options Additional information regarding common stock options outstanding as of September 30, 2016 is as follows: Options Outstanding Options Vested and Exercisable Range of Exercise Prices Number Outstanding Weighted – Avg. Remaining Life Weighted –Avg. Exercise Price Number Vested Weighted – Avg. Exercise Price $ 0.02 - 0.99 12,919,025 7.15 $ 0.12 12,919,025 $ 0.12 1.00 - 2.99 33,208,863 9.09 2.04 13,101,838 1.97 3.00 - 4.99 463,490 8.38 3.62 463,490 3.62 5.00 - 5.52 216,820 8.67 5.46 216,820 5.46 $ 0.02 - 5.52 46,808,198 8.54 $ 1.55 26,701,173 $ 1.13 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 PMI’s common stock, the expected term (the period of time that the options granted are expected to be outstanding), the volatility of PMI’s common stock, 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 PMI’s 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 PMI’s preferred stock sold to outside investors; (iii) the rights, preferences and privileges of PMI’s preferred stock relative to PMI’s common stock; (iv) the lack of marketability of PMI’s common stock; (v) developments in the business; (vi) secondary transactions of PMI’s 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. As PMI’s stock is not publically traded volatility for stock options 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 were determined based on the vesting terms, exercise terms and contractual lives of the options using the simplified method. 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. Prosper also estimates forfeitures of unvested stock options. Expected forfeitures are based on Prosper’s historical experience. 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. The fair value of PMI’s stock option awards granted during the three months ended September 30, 2016 and 2015 was estimated at the date of grant using the Black-Scholes model with the following average assumptions: Three Months Ended Nine Months Ended 2016 2015 2016 2015 Volatility of common stock n/a 50.71 % 50.88 % 56.14 % Risk-free interest rate n/a 1.70 % 1.29 % 1.71 % Expected life n/a 6.0 years 5.8 years 6.0 years Dividend yield n/a 0 % 0 % 0 % Restricted Stock Unit Activity During the nine months ended September 30, 2016 , PMI granted restricted stock units (“RSUs”) to certain employees that are subject to three -year vesting terms or four year vesting terms and the occurrence of a liquidity event. The aggregate fair value of the RSUs granted was $10.7 million . The following table summarizes the activities for PMI’s RSUs during the nine months ending September 30, 2016 : Number of Shares Weighted-Average Grant Date Fair Value Unvested - December 31, 2015 1,835,510 $ 5.52 Granted 3,580,220 2.14 Vested — — Forfeited (2,255,350 ) 2.97 Unvested - September 30, 2016 3,160,380 $ 2.15 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 months ended September 30, 2016 and 2015 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Origination and servicing $ 518 $ 369 $ 1,536 $ 805 Sales and marketing 639 669 2,271 1,734 General and administrative 4,513 2,209 13,329 4,900 Restructuring — — 45 — Total stock based compensation $ 5,670 $ 3,247 $ 17,181 $ 7,439 During the three months ended September 30, 2016 and 2015 , Prosper capitalized $156 thousand and $202 thousand respectively, of stock-based compensation as internal use software and website development costs. During the nine months ended September 30, 2016 and 2015 , Prosper capitalized $592 thousand and $499 thousand respectively, of stock-based compensation as internal use software and website development costs. As of September 30, 2016 , the unamortized stock-based compensation expense adjusted for forfeiture estimates related to Prosper’s employees’ unvested stock-based awards was approximately $43.8 million , which will be recognized over the remaining weighted-average vesting period of approximately 2.52 years.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2016
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring Summary of Restructuring Plan On May 3, 2016, Prosper adopted a strategic restructuring of its business. This restructuring is intended to streamline our operations and support future growth efforts. Under this restructuring, Prosper closed its Salt Lake City, Utah location. As a result of this restructuring, Prosper terminated 167 employees across all locations. In connection with the restructuring, Prosper has recognized employee severance and benefits charges of approximately $396 thousand in the third quarter which were included in “Restructuring Charges” within the condensed consolidated statements of operations. In addition to the employment costs associated with the restructuring, Prosper is also engaged in marketing for sublease, space in our existing office space that is no longer needed due to the reduction in headcount. During the quarter ended September 30, 2016 Prosper executed the termination of one lease. The termination penalties associated with this lease was less than the accrued lease exit liability. Additionally, during negotiations to terminate another lease, Prosper obtained additional information that resulted in Prosper revising its estimate of future sublease income for that lease. These events resulted in an aggregate reduction of the lease exit liability of $1.5 million . This reduction has been recognized within “Restructuring Charges, Net” within the condensed consolidated statements of operations. In connection with the lease termination, Prosper also wrote off $ 0.4 million in leasehold improvements and incurred $0.2 million of other restructuring charges. The following table summarizes the activities related to Prosper's restructuring plan (in thousands): Severance Related Facilities Related Total Balance July 1, 2016 $ 2,038 $ 8,492 $ 10,530 Adjustments to expense 396 (1,314 ) (918 ) Less: Cash paid (2,423 ) (2,071 ) (4,494 ) Balance September 30, 2016 $ 11 $ 5,107 $ 5,118

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Income Taxes	Income Taxes For the three months ended September 30, 2016 and 2015 , Prosper recognized $74 thousand and $35 thousand of income tax expense, respectively. For the nine months ended September 30, 2016 and 2015 , Prosper recognized $344 thousand and $284 thousand of income tax expense, respectively. 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 nine month periods ended September 30, 2016 and 2015 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 recorded.
Prosper Funding LLC
Entity Information [Line Items]
Income Taxes	Income Taxes Prosper Funding incurred no income tax provision for the nine months ended September 30, 2016 and 2015 . 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, is 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, 2016
Entity Information [Line Items]
Commitments and Contingencies	Commitments and Contingencies Future Minimum Lease Payments Prosper has entered into various non-cancelable operating leases for certain offices with contractual lease periods expiring between 2022 and 2027 . Future minimum rental payments under these leases as of September 30, 2016 are as follows (in thousands): Remaining three months of 2016 1,731 2017 7,721 2018 8,328 2019 8,620 2020 8,862 2021 8,916 Thereafter 18,178 Total future operating lease obligations $ 62,356 Rental expense under operating lease arrangements was $1.6 million and $1.0 million for the three months ended September 30, 2016 and 2015 , respectively. Rental expense under operating lease arrangements was $5.3 million and $2.7 million for the nine months ended September 30, 2016 and 2015 , respectively. Operating Commitments Prosper has entered into an agreement with WebBank, under which all Borrower Loans originated through the marketplace are made by WebBank under its bank charter. Pursuant to the agreement, the marketing fee that Prosper receives in connection with the origination of each loan is partially reduced by an amount (the “Designated Amount”) calculated as a percentage of the principal amount of such loan based on the aggregate principal amount of loans originated for the applicable month. To the extent the aggregate Designated Amount for all loans originated during any month is less than $143,500 , Prosper is required to pay WebBank an amount equal to such deficiency. Accordingly, t he minimum fee for the remaining three months ended December 31, 2016 is $0.4 million . The minimum fee is $1.7 million , $1.7 million and $1.0 million in each of the years 2017, 2018 and 2019, respectively. Additionally, under the agreement with WebBank, Prosper is required to maintain a minimum net liquidity of $15 million at all times during the term of the agreement. Net liquidity is defined as the sum of Cash, Cash Equivalents and Available for Sale Investments. Violation of this covenant can result in termination of the contract with WebBank. At September 30, 2016 the Company was in compliance with the covenant. Loan Purchase Commitments Prosper has entered into an agreement with WebBank to purchase $16.5 million of Borrower Loans that WebBank originated during the last two business days of the quarter ended September 30, 2016 and the first business day of the quarter ending December 31, 2016. Prosper will purchase these Borrower Loans within the first three business days of the quarter ended December 31, 2016. Repurchase and Indemnification Contingency Under the terms of the loan purchase agreements between Prosper and investors that participate in the Whole Loan Channel, Prosper may, in certain circumstances, become obligated to repurchase a Borrower Loan from an investor. 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, 2016 is $3,737 million . Prosper has accrued $487 thousand and $510 thousand as of September 30, 2016 and December 31, 2015 , 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 investors through its old platform structure, whereby Prosper assigned promissory notes directly to investors. 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. 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 first three annual installments have been made prior to September 30, 2016 and the reserve for the class action settlement liability is $3.0 million in the condensed consolidated balance sheet as of September 30, 2016 .
Prosper Funding LLC
Entity Information [Line Items]
Commitments and Contingencies	8. Commitments and Contingencies Operating Commitments Prosper has entered into an agreement with WebBank, under which all Borrower Loans originated through the marketplace are made by WebBank under its bank charter. Pursuant to the agreement, the marketing fee that Prosper receives in connection with the origination of each loan is partially reduced by an amount (the “Designated Amount”) calculated as a percentage of the principal amount of such loan based on the aggregate principal amount of loans originated for the applicable month. To the extent the aggregate Designated Amount for all loans originated during any month is less than $143,500, Prosper is required to pay WebBank an amount equal to such deficiency. Accordingly, the minimum fee for the remaining three months of 2016 is $0.4 million . The minimum fee is $1.7 million , $1.7 million and $1.0 million for years 2017 , 2018 and 2019 respectively. Loan Purchase Commitments Under the terms of Prosper Funding’s agreement with WebBank, Prosper Funding is committed to purchase $16.5 million of Borrower Loans that WebBank originated during the last two business days of the quarter ended September 30, 2016 and first business day of the quarter ended December 31, 2016. Prosper Funding will purchase these Borrower Loans within the first three business days of the quarter ended December 31, 2016. 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, 2016 is $3,615 million . Prosper Funding had accrued $437 thousand and $460 thousand as of September 30, 2016 and December 31, 2015 , respectively, in regard to this obligation.

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Related Parties	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 and Borrower Loans. The aggregate amount of the Notes and Borrower Loans 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, 2016 and 2015 , as well as the Notes and Borrower Loans outstanding as of September 30, 2016 and December 31, 2015 are summarized below (in thousands): Aggregate Amount of Notes and Borrower Loans Purchased Nine Months Ended September 30, Interest Earned on Notes and Borrower Loans Nine Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 1,039 $ 1,232 $ 170 $ 152 Directors (excluding executive officers and management) 427 31 25 6 Total $ 1,466 $ 1,263 $ 195 $ 158 Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended September 30, Interest Earned on Notes and Borrower Loans Three Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 245 $ 386 $ 62 $ 53 Directors (excluding executive officers and management) 77 10 10 2 Total $ 322 $ 396 $ 72 $ 55 Notes and Borrower Loans Balance as of Related Party September 30, 2016 December 31, 2015 Executive officers and management $ 1,966 $ 2,173 Directors (excluding executive officers and management) 535 99 $ 2,501 $ 2,272
Prosper Funding LLC
Entity Information [Line Items]
Related Parties	9. 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 and directors who are not executive officers participate in its marketplace by placing bids and purchasing Notes and Borrower Loans. The aggregate amount of the Notes and Borrower Loans purchased and the income earned by parties deemed to be related parties of Prosper Funding as of September 30, 2016 and December 31, 2015 are summarized below (in thousands): Aggregate Amount of Notes and Borrower Loans Purchased Interest Earned on Notes and Borrower Loans Nine Months Ended September 30, Nine Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 1,039 $ 1,232 $ 170 $ 152 Directors (excluding executive officers and management) — — — — Total $ 1,039 $ 1,232 $ 170 $ 152 Aggregate Amount of Notes and Borrower Loans Purchased Interest Earned on Notes and Borrower Loans Three Months Ended September 30, Three Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 245 $ 386 $ 62 $ 53 Directors (excluding executive officers and management) — — — — Total $ 245 $ 386 $ 62 $ 53 Note and Borrower Loan Balance as of Related Party September 30, 2016 December 31, 2015 Executive officers and management $ 1,966 $ 2,173 Directors (excluding executive officers and management) — — $ 1,966 $ 2,173

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Prosper and Colchis Capital Management, L.P. (“Colchis”) entered into a Supplementary Agreement, dated June 1, 2013, and Addendum to the Supplementary Agreement, dated November 18, 2013 (together, the “Colchis Agreement”), pursuant to which Prosper agreed to give Colchis certain incentives to encourage Colchis to invest in Borrower Loans and Notes through the platform. On April 21, 2015, Colchis filed a demand for arbitration to resolve interpretative questions relating to the Colchis Agreement, including, for example, whether certain rights given to Colchis extended beyond the term of the Colchis Agreement. On October 17, 2016, the arbitrator issued a final award in favor of Colchis. On November 17, 2016, Prosper and Colchis entered into a Settlement and Release Agreement, pursuant to which Colchis has agreed to terminate the Colchis Agreement and waive all rights conferred under such agreement in exchange for a $9 million cash payment by Prosper and an agreement by Prosper to issue a warrant to purchase shares of a new series of preferred stock representing 7% of Prosper’s capitalization on a fully diluted basis as of the date of the issuance of the warrant (the “New Series”) for $.01 per share (the “Equity Payment”). Prosper’s obligation to make the Equity Payment is subject to Prosper obtaining the requisite stockholder approval. This will be accounted for as a termination of a contract.

Summary of Significant Accoun26

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Marketplace, Inc. (“PMI”) was incorporated in the state of Delaware on March 22, 2005. Except as the context requires otherwise, as used in these notes to the condensed consolidated financial statements of Prosper Marketplace, Inc., “Prosper,” “we,” “us,” and “our” refer to PMI and its wholly-owned subsidiaries, on a consolidated basis. 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 Article 10 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, 2015 . The balance sheet at December 31, 2015 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. Management 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. The accompanying interim condensed consolidated financial statements include the accounts of PMI and its wholly-owned subsidiaries. All intercompany balances have been eliminated in consolidation. On January 23, 2015, PMI acquired all of the outstanding limited liability company units of American HealthCare Lending, LLC (“American HealthCare Lending”), a company that operated a patient financing platform, and merged American HealthCare Lending with and into Prosper Healthcare Lending LLC (“PHL”), a newly established entity surviving the merger. Prosper’s condensed consolidated financial statements include PHL’s results of operations and financial position from the date of acquisition forward. On October 9, 2015, PMI acquired all of the outstanding stock of BillGuard, Inc. (“BillGuard”), a company incorporated in Delaware in 2010 that developed applications that help consumers manage their identity, finances and credit. PMI merged BillGuard with and into Beach Merger Sub, Inc., a newly established entity wholly owned by PMI, with BillGuard surviving the merger. Prosper’s condensed consolidated financial statements include BillGuard’s results of operations and financial position from the date of acquisition forward.
Reclassifications	Reclassifications Due to the early adoption of ASU 2016-09 on January 1, 2016, reclassifications were made to the financing section of the condensed consolidated statements of cash flows to reflect taxes paid for awards vested under equity incentive plans. Prior period amounts have been reclassified to conform to the current presentation.
Fair Value Measurements	Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Available for Sale 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.
Restructuring Charges	Restructuring Charges Restructuring charges consist of severance and contract termination related costs. A liability for severance costs is typically recognized when the plan of termination has been communicated to the affected employees and is measured at its fair value at the communication date. Contract termination costs consist primarily of costs that will continue to be incurred under operating leases for their remaining terms without economic benefit to the Company. A liability for contract termination costs is recognized at the date the Company ceases using the rights conveyed by the lease contract and is measured at its fair value, which is determined based on the remaining contractual lease rentals reduced by estimated sublease rentals.
Borrower Loans, Loans Held for Sale and Notes	Borrower Loans, Loans Held for Sale and Notes Through the Note Channel, Prosper purchases Borrower Loans from WebBank then issues Notes, and holds the Borrower Loans until maturity. The obligation to repay a series of Notes issued through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans funded and Notes issued through the Note Channel are carried on Prosper’s condensed consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes.
Loan Trailing Fee	Loan Trailing Fee On July 1, 2016, Prosper signed a series of agreements with WebBank to include an additional program fee (Loan Trailing Fee). These agreements are effective August 1, 2016. The Loan Trailing Fee is dependent on the amount and timing of principal and interest payments made by borrowers of the underlying loans, irrespective of whether the loans are sold by Prosper, and gives the issuing bank an ongoing financial interest in the performance of the loans it originates. This fee is paid by Prosper to the issuing bank partner over the term of the respective loans and is a function of the principal and interest payments. In the event that principal and interest payments are not made, Prosper is not required to make this Loan Trailing Fee payment. The obligation to pay the Loan Trailing Fee is recorded at fair value at the time of the origination of the loan with Other Liabilities and recorded as a reduction of Transaction Fees, net. Any changes in the fair value of this liability are recorded in changes in fair value of Borrower Loans, Loans Held for Sale and Notes, Net on the statements of operations. The fair value of the Loan Trailing Fee represents the present value of the expected monthly Loan Trailing Fee payments, which considers assumptions of expected prepayment rates and defaults rates.
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 .” The new guidance sets forth a new five-step revenue recognition model which replaces the prior revenue recognition guidance in its entirety and is intended to eliminate numerous industry-specific pieces of revenue recognition guidance that have historically existed in U.S. GAAP. The underlying principle of the new standard is that a business or other organization will recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects what it expects in exchange for the goods or services. The standard also requires more detailed disclosures and provides additional guidance for transactions that were not addressed completely in the prior accounting guidance. The standard will be effective for Prosper in the first quarter of fiscal 2018. In August 2015, the FASB issued ASU No. 2015-14, which amended the standard to provide a one-year deferral of the effective date, as well as providing the option to early adopt the standard on the original effective date. Accordingly, Prosper may adopt the standard in either Prosper’s fiscal year ending December 31, 2017 or 2018. The guidance can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. In March 2016, April 2016 and May 2016, the FASB further amended the guidance to clarify the implementation on principal versus agent considerations, the identification of performance obligation and the licensing implementation guidance, and to provide narrow-scope improvements and practical expedients. Prosper has not yet selected a transition method and is evaluating the impact of adopting this new accounting standard update on the consolidated financial statements and related disclosures. 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. Prosper adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In April 2015, the FASB issued ASU 2015-05 “ Customers’ Accounting for Fees Paid in Cloud Computing Arrangement ”, which became effective for the annual reporting period beginning 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 adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In September 2015, the FASB issued ASU 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, and interim periods within those fiscal years, beginning after December 15, 2015. Prosper adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , which requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases, along with additional qualitative and quantitative disclosures. This guidance will be effective for us in the first quarter of our fiscal year 2019, and early adoption is permitted. Prosper will be required to recognize and measure leases at the beginning off the earliest period presented using a modified retrospective approach. Prosper anticipates that this standard will have a material impact on our consolidated financial statements. While Prosper is continuing to assess all potential impacts of the standard, Prosper currently believes the most significant impact relates to our accounting for office operating leases. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting (Topic 718). This guidance makes several modifications to Topic 718 related to the accounting for forfeitures, employer tax withholding on share-based compensation and the financial statement presentation of excess tax benefits or deficiencies. ASU 2016-09 also clarifies the statement of cash flows presentation for certain components of share-based awards. This guidance will be effective for us in the first quarter of our fiscal year 2017, and early adoption is permitted. Prosper has decided to early adopt this guidance effective January 1, 2016, the adoption of this standard did not have a material impact on Prosper’s condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” The standard provides guidance for eight targeted changes with respect to how cash receipts and cash payments are classified in the statements of cash flows, with the objective of reducing diversity in practice. This guidance will be effective for Prosper in the first quarter of our fiscal year 2018, and early adoption is permitted. Prosper is currently evaluating the impacts the adoption of this accounting standard will have on Prosper's cash flows.
Prosper Funding LLC
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Funding LLC (“PFL”) was formed in the state of Delaware on February 17, 2012 as a limited liability company with the sole equity member being Prosper Marketplace, Inc. (“PMI”, "Parent"). Except as the context otherwise requires, as used in these Notes to the condensed consolidated financial statements of Prosper Funding LLC, “Prosper Funding,” “we,” “us,” and “our” refers to PFL and its wholly owned subsidiary, Prosper Asset Holdings LLC (“PAH”), a Delaware limited liability company, on a consolidated basis. 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 Article 10 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, 2015 . The balance sheet at December 31, 2015 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 no t 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 nine months ended September 30, 2016 and 2015 . 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. Management 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.
Fair Value Measurements	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 Through the Note Channel, Prosper Funding purchases Borrower Loans from WebBank then issues Notes, and holds the Borrower Loans until maturity. The obligation to repay a series of Notes funded through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans and Notes funded through the Note Channel are carried on Prosper Funding’s consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper Funding estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper Funding maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes.
Loan Trailing Fee	Loan Trailing Fee On July 1, 2016, Prosper Funding signed a series of agreements with WebBank to include an additional program fee (Loan Trailing Fee). These agreements are effective August 1, 2016. The Loan Trailing Fee is dependent on the amount and timing of principal and interest payments made by borrowers of the underlying loans, irrespective of whether the loans are sold by Propser and gives the issuing bank an ongoing financial interest in the performance of the loans it originates. This fee is paid by Prosper Funding to the issuing bank partner over the term of the respective loans and is a function of the principal and interest payments. In the event that principal and interest payments are not made, Prosper Funding is not required to make this Loan Trailing Fee payment. The obligation to pay the Loan Trailing Fee is recorded at fair value at the time of the origination of the loan within Other Liabilities and is recorded as a reduction in related party expenses on the statement of operations. Any changes in the fair value of this liability are recorded in changes in fair value of Borrower Loans, Loans Held for Sale and Notes, Net on the statements of operations. The fair value of the Loan Trailing Fee represents the present value of the expected monthly Loan Trailing Fee payments, which considers assumptions of expected prepayment rates and defaults rates.
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.” The new guidance sets forth a new five-step revenue recognition model which replaces the prior revenue recognition guidance in its entirety and is intended to eliminate numerous industry-specific pieces of revenue recognition guidance that have historically existed in U.S. GAAP. The underlying principle of the new standard is that a business or other organization will recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects what it expects in exchange for the goods or services. The standard also requires more detailed disclosures and provides additional guidance for transactions that were not addressed completely in the prior accounting guidance. The standard will be effective for Prosper Funding in the first quarter of fiscal 2018. In August 2015, the FASB issued ASU No. 2015-14, which amended the standard to provide a one-year deferral of the effective date, as well as providing the option to early adopt the standard on the original effective date. Accordingly, Prosper Funding may adopt the standard in either Prosper Funding’s fiscal year ending December 31, 2017 or 2018. The guidance can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. In March 2016, April 2016 and May 2016, the FASB further amended the guidance to clarify the implementation on principal versus agent considerations, the identification of performance obligation and the licensing implementation guidance, and to provide narrow-scope improvements and practical expedients. Prosper Funding has not yet selected a transition method and is evaluating the impact of adopting this new accounting standard update on the consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-05 “Customers’ Accounting for Fees Paid in Cloud Computing Arrangement”, which became effective for the annual reporting period beginning 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 Funding adopted this guidance on January 1, 2016, and the adoption of this standard did not have a material impact on Prosper Funding’s condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” The standard provides guidance for eight targeted changes with respect to how cash receipts and cash payments are classified in the statements of cash flows, with the objective of reducing diversity in practice. This guidance will be effective for Prosper Funding in the first quarter of our fiscal year 2018, and early adoption is permitted. Prosper Funding is currently evaluating the impacts the adoption of this accounting standard will have on the Prosper Funding's cash flows.

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Property and Equipment, Net	Property and equipment consist of the following (in thousands): September 30, December 31, Property and equipment: Computer equipment $ 14,241 $ 10,522 Internal-use software and website development costs 15,144 10,990 Office equipment and furniture 3,064 2,442 Leasehold improvements 7,071 5,719 Assets not yet placed in service 2,121 3,242 Property and equipment 41,641 32,915 Less accumulated depreciation and amortization (14,963 ) (7,950 ) Total property and equipment, net $ 26,678 $ 24,965
Prosper Funding LLC
Entity Information [Line Items]
Property and Equipment, Net	Property and equipment consist of the following (in thousands): September 30, December 31, Property and equipment: Internal-use software and web site development costs $ 15,143 $ 10,990 Less accumulated depreciation and amortization (5,511 ) (2,571 ) Total property and equipment, net $ 9,632 $ 8,419

Borrower Loans, Loans Held fo28

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value (Tables)	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
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, 2016 and December 31, 2015 , are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, December 31, September 30, December 31, September 30, December 31, Aggregate principal balance outstanding $ 319,210 $ 296,945 $ (322,003 ) $ (294,331 ) $ 148 $ 42 Fair value adjustments (4,539 ) 328 8,083 (3,074 ) (12 ) (10 ) Fair value $ 314,671 $ 297,273 $ (313,920 ) $ (297,405 ) $ 136 $ 32
Prosper Funding LLC
Entity Information [Line Items]
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, 2016 and December 31, 2015 , are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Aggregate principal balance outstanding $ 319,210 $ 296,945 $ (322,003 ) $ (294,331 ) $ 148 $ 42 Fair value adjustments (4,539 ) 328 8,083 (3,074 ) (12 ) (10 ) Fair value $ 314,671 $ 297,273 $ (313,920 ) $ (297,405 ) $ 136 $ 32

Available for Sale Investment29

Available for Sale Investments, at Fair Value (Tables)	9 Months Ended
	Sep. 30, 2016
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, 2016 and December 31, 2015 , are as follows (in thousands): September 30, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Corporate debt securities $ 29,733 $ 16 $ (8 ) $ 29,741 US Treasury securities 10,525 14 (2 ) 10,537 Agency bonds 2,499 6 — 2,505 Total Available for Sale Investments $ 42,757 $ 36 $ (10 ) $ 42,783 December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Corporate debt securities $ 50,327 $ 1 $ (94 ) $ 50,234 Commercial paper 9,493 — — 9,493 US Treasury securities 8,512 — (41 ) 8,471 Agency bonds 2,499 — (8 ) 2,491 Total fixed maturity securities 70,831 1 (143 ) 70,689 Short term bond funds 2,500 — (2 ) 2,498 Total Available for Sale Investments $ 73,331 $ 1 $ (145 ) $ 73,187
Summary of Securities Available for Sale of Continuous Unrealized Loss	A summary of available for sale investments with unrealized losses as of September 30, 2016 , and December 31, 2015 , aggregated by category and period of continuous unrealized loss, is as follows (in thousands): Less than 12 months 12 months or longer Total September 30, 2016 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturity securities: Corporate debt securities $ 12,075 $ (8 ) $ — $ — $ 12,075 $ (8 ) U.S. treasury securities 4,503 (2 ) — — 4,503 (2 ) Total Investments with Unrealized Losses $ 16,578 $ (10 ) $ — $ — $ 16,578 $ (10 ) Less than 12 months 12 months or longer Total December 31, 2015 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturity securities: Corporate debt securities $ 45,375 $ (94 ) $ — $ — $ 45,375 $ (94 ) U.S. treasury securities 8,471 (41 ) — — 8,471 (41 ) Agency bonds 2,491 (8 ) — — 2,491 (8 ) Total fixed maturity securities 56,337 (143 ) — — 56,337 (143 ) Short term bond funds 2,498 (2 ) — — 2,498 (2 ) Total Investments with Unrealized Losses $ 58,835 $ (145 ) $ — $ — $ 58,835 $ (145 )
Schedule of Maturities of Securities Available for Sale	The maturities of available for sale investments at September 30, 2016 , and December 31, 2015 , are as follows (in thousands): September 30, 2016 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Corporate debt securities $ 25,235 $ 4,506 $ — $ — $ 29,741 US Treasury securities 6,532 4,005 — — 10,537 Agency bonds — 2,505 — — 2,505 Total Fair Value $ 31,767 $ 11,016 $ — $ — $ 42,783 Total Amortized Cost $ 31,763 $ 10,994 $ — $ — $ 42,757 December 31, 2015 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Corporate debt securities $ 26,289 $ 23,945 $ — $ — $ 50,234 Commercial paper 9,493 — — — 9,493 US Treasury securities — 8,471 — — 8,471 Agency bonds — 2,491 — — 2,491 Total Fair Value $ 35,782 $ 34,907 $ — $ — $ 70,689 Total Amortized Cost $ 35,831 $ 35,000 $ — $ — $ 70,831

Fair Value of Assets and Liab30

Fair Value of Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
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, 2016 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 314,671 $ 314,671 Loans Held for Sale — — 136 136 Available for Sale Investments, at Fair Value — 42,783 — 42,783 Servicing Assets — — 12,664 12,664 Total Assets — 42,783 327,471 370,254 Liabilities: Notes $ — $ — $ 313,920 $ 313,920 Servicing Liabilities — — 254 254 Contingent Consideration — — 4,994 4,994 Total Liabilities $ — $ — $ 319,168 $ 319,168 December 31, 2015 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 297,273 $ 297,273 Loans Held for Sale — — 32 32 Available for Sale Investments, at Fair Value — 73,187 — 73,187 Servicing Assets — — 14,363 14,363 Total Assets — 73,187 311,668 384,855 Liabilities: Notes $ — $ — $ 297,405 $ 297,405 Servicing Liabilities — — 484 484 Contingent Consideration — — 4,801 4,801 Total Liabilities $ — $ — $ 302,690 $ 302,690
Quantitative Information About Significant Unobservable Inputs	Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 4.4% - 15.2% 4.3% - 14.5% Default rate 1.6% - 14.8% 1.4% - 14.4%
Significant Unobservable Inputs Fair Value	Servicing Rights Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 15% - 25% 15% - 25% Default rate 1.4% - 15.0% 1.2% - 14.7% Prepayment rate 14.9% - 27.7% 14.3% - 25.6% Market servicing rate 0.625 % 0.625 %
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 (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2016 $ 297,273 $ (297,405 ) $ 32 $ (100 ) Purchase of Borrower Loans/Issuance of Notes 164,436 (165,727 ) 1,619,866 1,618,575 Principal repayments (125,419 ) 129,603 (269 ) 3,915 Borrower Loans sold to third parties (1,889 ) — (1,619,488 ) (1,621,377 ) Other changes 232 (229 ) (3 ) — Change in fair value (19,962 ) 19,838 (2 ) (126 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 July 1, 2016 $ 310,034 $ (309,530 ) $ 4,706 $ 5,210 Purchase of Borrower Loans/Issuance of Notes 55,221 (56,580 ) 261,855 260,496 Principal repayments (43,043 ) 45,403 (133 ) 2,227 Borrower Loans sold to third parties (751 ) — (266,286 ) (267,037 ) Other changes 238 (196 ) (4 ) 38 Change in fair value (7,028 ) 6,983 (2 ) (47 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 )
Schedule of Servicing Assets and Liabilities Measured at Fair Value	The following tables present additional information about level 3 servicing assets and liabilities measured at fair value on a recurring basis (in thousands): Servicing Assets Servicing Liabilities Fair Value at January 1, 2016 14,363 484 Additions 7,092 9 Less: Changes in fair value (8,791 ) (239 ) Fair Value at September 30, 2016 12,664 254 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 Servicing Assets Servicing Liabilities Fair Value at July 1, 2016 14,297 324 Additions 1,342 — Less: Changes in fair value (2,975 ) (70 ) Fair Value at September 30, 2016 12,664 254 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
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, 2016 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: 7.59 % * 7.59 % * Resulting fair value from: 100 basis point increase $ 311,509 $ 310,760 200 basis point increase 308,426 307,680 Resulting fair value from: 100 basis point decrease $ 317,914 $ 317,161 200 basis point decrease 321,244 320,488 Default rate assumption: 11.50 % * 11.50 % * Resulting fair value from: 100 basis point increase $ 311,358 $ 310,601 200 basis point increase 308,142 307,380 Resulting fair value from: 100 basis point decrease $ 318,009 $ 317,264 200 basis point decrease 321,389 320,651 * 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, 2016 (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% $ 11,744 $ 279 Market servicing rate decrease to 0.60% $ 13,583 $ 228 Weighted average prepayment assumptions 21.06 % 21.06 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate $ 12,426 $ 249 Applying a 0.9 multiplier to prepayment rate $ 12,904 $ 258 Weighted average default assumptions 11.64 % 11.64 % Resulting fair value from: Applying a 1.1 multiplier to default rate $ 12,451 $ 253 Applying a 0.9 multiplier to default rate $ 12,880 $ 254
Prosper Funding LLC
Entity Information [Line Items]
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, 2016 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 314,671 $ 314,671 Loans Held for Sale — — 136 136 Servicing Assets — — 12,274 12,274 Total Assets — — 327,081 327,081 Liabilities: Notes $ — $ — $ 313,920 $ 313,920 Servicing Liabilities — — 254 254 Total Liabilities $ — $ — $ 314,174 $ 314,174 December 31, 2015 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 297,273 $ 297,273 Loans Held for Sale — — 32 32 Servicing Assets — — 13,605 13,605 Total Assets — — 310,910 310,910 Liabilities: Notes $ — $ — $ 297,405 $ 297,405 Servicing Liabilities — — 484 484 Total Liabilities $ — $ — $ 297,889 $ 297,889
Quantitative Information About Significant Unobservable Inputs	The following tables present quantitative information about the significant unobservable inputs used for Prosper Funding’s level 3 fair value measurements at September 30, 2016 and December 31, 2015 : Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 4.4% - 15.2% 4.3% - 14.5% Default rate 1.6% - 14.8% 1.4% - 14.4%
Significant Unobservable Inputs Fair Value	Servicing Rights Range Unobservable Input September 30, 2016 December 31, 2015 Discount rate 15% - 25% 15% - 25% Default rate 1.4% - 15.0% 1.2% - 14.7% Prepayment rate 14.9% - 27.7% 14.3% - 25.6% Market servicing rate 0.625 % 0.625 %
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) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2016 $ 297,273 $ (297,405 ) $ 32 $ (100 ) Originations 164,436 (165,727 ) 1,619,866 1,618,575 Principal repayments (125,419 ) 129,603 (269 ) 3,915 Borrower Loans sold to third parties (1,889 ) — (1,619,488 ) (1,621,377 ) Other changes 232 (229 ) (3 ) — Change in fair value (19,962 ) 19,838 (2 ) (126 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 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) Borrower Loans Notes Loans Held for Sale Total Balance at July 1, 2016 $ 310,034 $ (309,530 ) $ 4,706 $ 5,210 Originations 55,221 (56,580 ) 261,855 260,496 Principal repayments (43,043 ) 45,403 (133 ) 2,227 Borrower Loans sold to third parties (751 ) — (266,286 ) (267,037 ) Other changes 238 (196 ) (4 ) 38 Change in fair value (7,028 ) 6,983 (2 ) (47 ) Balance at September 30, 2016 $ 314,671 $ (313,920 ) $ 136 $ 887 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 )
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 September 30, 2016 (in thousands). Servicing Assets Servicing Liabilities Fair Value at January 1, 2016 13,605 484 Additions 7,092 9 Less: Changes in fair value (8,423 ) (239 ) Fair Value at September 30, 2016 12,274 254 Servicing Assets Servicing 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 Assets Servicing Liabilities Fair Value at July 1, 2016 13,798 324 Additions 1,342 — Less: Changes in fair value (2,866 ) (70 ) Fair Value at September 30, 2016 12,274 254 Servicing Assets Servicing 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
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, 2016 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: 7.59 % * 7.59 % * Resulting fair value from: 100 basis point increase $ 311,509 $ 310,760 200 basis point increase 308,426 307,680 Resulting fair value from: 100 basis point decrease $ 317,914 $ 317,161 200 basis point decrease 321,244 320,488 Default rate assumption: 11.50 % * 11.50 % * Resulting fair value from: 100 basis point increase $ 311,358 $ 310,601 200 basis point increase 308,142 307,380 Resulting fair value from: 100 basis point decrease $ 318,009 $ 317,264 200 basis point decrease 321,389 320,651
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, 2016 (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% 11,509 279 Market servicing rate decrease to 0.60% 13,311 228 Weighted average prepayment assumptions 21.06 % 21.06 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate 12,043 249 Applying a 0.9 multiplier to prepayment rate 12,507 258 Weighted average default assumptions 11.64 % 11.64 % Resulting fair value from: Applying a 1.1 multiplier to default rate 12,068 253 Applying a 0.9 multiplier to default rate 12,484 254

Goodwill and Other Intangible31

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Other Intangible Assets for the Period Presented	The following table presents the detail of other intangible assets for the period presented (dollars in thousands): September 30, 2016 Gross Carrying Value Accumulated Amortization Net Carrying Value Remaining Useful Life (In Years) User base and customer relationships $ 6,250 $ (2,541 ) $ 3,709 8.4 Developed technology 8,310 (1,950 ) $ 6,360 4.0 Brand name 60 (60 ) — — Total intangible assets subject to amortization $ 14,620 $ (4,551 ) $ 10,069
Summary of Estimated Amortization of Purchased Intangible Assets	Estimated amortization of purchased intangible assets for future periods is as follows (in thousands): Year Ending December 31, 2016 $ 855 2017 3,260 2018 2,329 2019 1,779 2020 1,344 Thereafter 502 Total $ 10,069

Other Liabilities (Tables)

Other Liabilities (Tables)	9 Months Ended
	Sep. 30, 2016
Other Liabilities [Abstract]
Schedule of Other Liabilities	Other Liabilities includes the following: September 30, 2016 December 31, 2015 Class action settlement liability $ 2,984 $ 5,949 Repurchase liability for unvested restricted stock awards 180 473 Contingent consideration 4,994 4,801 Deferred revenue 285 1,591 Servicing liabilities 254 484 Deferred rent 4,563 5,240 Restructuring liability 5,107 — Other 2,587 2,197 Total Other Liabilities $ 20,954 $ 20,735

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2016
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, 2016 2015 2016 2015 Numerator: Net loss available to common stockholders for basic and diluted EPS $ (17,417 ) $ (3,843 ) $ (70,509 ) $ (17,324 ) Denominator: Weighted average shares used in computing basic and diluted net loss per share 65,393,175 55,907,765 63,015,616 54,746,980 Basic and diluted net loss per share $ (0.27 ) $ (0.07 ) $ (1.12 ) $ (0.32 )
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, 2016 2015 2016 2015 (shares) (shares) (shares) (shares) Excluded securities: Convertible preferred stock issued and outstanding 177,388,425 177,388,425 177,388,425 177,388,425 Stock options issued and outstanding 50,387,360 35,063,150 44,617,487 32,592,610 Unvested stock options exercised 3,209,345 11,906,925 3,209,345 11,906,925 Warrants issued and outstanding 1,203,344 602,355 910,945 602,355 Total common stock equivalents excluded from diluted net loss per common share computation 232,188,474 224,960,855 226,126,202 222,490,315

Convertible Preferred Stock a34

Convertible Preferred Stock and Stockholders' Deficit (Tables)	9 Months Ended
	Sep. 30, 2016
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, 2016 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 68,558,220 68,558,220 $ 19,774 Series A-1 0.01 24,760,915 24,760,915 49,522 New Series B 0.01 35,775,880 35,775,880 21,581 New Series C 0.01 24,404,770 24,404,770 70,075 New Series D 0.01 23,888,640 23,888,640 165,000 177,388,425 177,388,425 $ 325,952

Shared Based Incentive Plan a35

Shared Based Incentive Plan and Compensation (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based 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, 2016 is below: Early exercised options, unvested Weighted average exercise price Balance as of January 1, 2016 9,806,170 $ 0.05 Repurchase of restricted stock (288,520 ) 0.24 Restricted stock vested (6,308,305 ) 0.04 Balance as of September 30, 2016 3,209,345 $ 0.06
Additional Information Regarding the Unvested Early Exercised Stock Options Outstanding	Additional information regarding the unvested early exercised stock options outstanding as of September 30, 2016 is as follows: Options Outstanding Range of Exercise Prices Number Outstanding Weighted –Avg. Remaining Life Weighted –Avg. Exercise Price 0.02 2,910,435 0.4 $ 0.02 0.11 212,710 1.3 0.11 1.13 86,200 1.9 1.13 $0.02 - $1.13 3,209,345 0.5 $ 0.06
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, 2016 below: Options Issued and Outstanding Weighted- Average Exercise Price Balance as of January 1, 2016 40,425,605 $ 2.64 Options issued 19,655,338 2.14 Options exercised – vested (386,720 ) 0.75 Options forfeited (12,886,025 ) 1.60 Balance as of September 30, 2016 46,808,198 $ 1.55 Options vested and/or exercisable at September 30, 2016 26,701,173 1.13
Additional Information Regarding Common Stock Options Outstanding	Additional information regarding common stock options outstanding as of September 30, 2016 is as follows: Options Outstanding Options Vested and Exercisable Range of Exercise Prices Number Outstanding Weighted – Avg. Remaining Life Weighted –Avg. Exercise Price Number Vested Weighted – Avg. Exercise Price $ 0.02 - 0.99 12,919,025 7.15 $ 0.12 12,919,025 $ 0.12 1.00 - 2.99 33,208,863 9.09 2.04 13,101,838 1.97 3.00 - 4.99 463,490 8.38 3.62 463,490 3.62 5.00 - 5.52 216,820 8.67 5.46 216,820 5.46 $ 0.02 - 5.52 46,808,198 8.54 $ 1.55 26,701,173 $ 1.13
Fair Value of Stock Option Awards	The fair value of PMI’s stock option awards granted during the three months ended September 30, 2016 and 2015 was estimated at the date of grant using the Black-Scholes model with the following average assumptions: Three Months Ended Nine Months Ended 2016 2015 2016 2015 Volatility of common stock n/a 50.71 % 50.88 % 56.14 % Risk-free interest rate n/a 1.70 % 1.29 % 1.71 % Expected life n/a 6.0 years 5.8 years 6.0 years Dividend yield n/a 0 % 0 % 0 %
Summarized Activities for RSU's	The following table summarizes the activities for PMI’s RSUs during the nine months ending September 30, 2016 : Number of Shares Weighted-Average Grant Date Fair Value Unvested - December 31, 2015 1,835,510 $ 5.52 Granted 3,580,220 2.14 Vested — — Forfeited (2,255,350 ) 2.97 Unvested - September 30, 2016 3,160,380 $ 2.15
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 months ended September 30, 2016 and 2015 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Origination and servicing $ 518 $ 369 $ 1,536 $ 805 Sales and marketing 639 669 2,271 1,734 General and administrative 4,513 2,209 13,329 4,900 Restructuring — — 45 — Total stock based compensation $ 5,670 $ 3,247 $ 17,181 $ 7,439

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2016
Restructuring and Related Activities [Abstract]
Summary of Activities Related to Prosper's Restructuring Plan	The following table summarizes the activities related to Prosper's restructuring plan (in thousands): Severance Related Facilities Related Total Balance July 1, 2016 $ 2,038 $ 8,492 $ 10,530 Adjustments to expense 396 (1,314 ) (918 ) Less: Cash paid (2,423 ) (2,071 ) (4,494 ) Balance September 30, 2016 $ 11 $ 5,107 $ 5,118

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	Prosper has entered into various non-cancelable operating leases for certain offices with contractual lease periods expiring between 2022 and 2027 . Future minimum rental payments under these leases as of September 30, 2016 are as follows (in thousands): Remaining three months of 2016 1,731 2017 7,721 2018 8,328 2019 8,620 2020 8,862 2021 8,916 Thereafter 18,178 Total future operating lease obligations $ 62,356

Related Parties (Tables)

Related Parties (Tables)	9 Months Ended
	Sep. 30, 2016
Entity Information [Line Items]
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes and Borrower Loans 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, 2016 and 2015 , as well as the Notes and Borrower Loans outstanding as of September 30, 2016 and December 31, 2015 are summarized below (in thousands): Aggregate Amount of Notes and Borrower Loans Purchased Nine Months Ended September 30, Interest Earned on Notes and Borrower Loans Nine Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 1,039 $ 1,232 $ 170 $ 152 Directors (excluding executive officers and management) 427 31 25 6 Total $ 1,466 $ 1,263 $ 195 $ 158 Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended September 30, Interest Earned on Notes and Borrower Loans Three Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 245 $ 386 $ 62 $ 53 Directors (excluding executive officers and management) 77 10 10 2 Total $ 322 $ 396 $ 72 $ 55 Notes and Borrower Loans Balance as of Related Party September 30, 2016 December 31, 2015 Executive officers and management $ 1,966 $ 2,173 Directors (excluding executive officers and management) 535 99 $ 2,501 $ 2,272
Prosper Funding LLC
Entity Information [Line Items]
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes and Borrower Loans purchased and the income earned by parties deemed to be related parties of Prosper Funding as of September 30, 2016 and December 31, 2015 are summarized below (in thousands): Aggregate Amount of Notes and Borrower Loans Purchased Interest Earned on Notes and Borrower Loans Nine Months Ended September 30, Nine Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 1,039 $ 1,232 $ 170 $ 152 Directors (excluding executive officers and management) — — — — Total $ 1,039 $ 1,232 $ 170 $ 152 Aggregate Amount of Notes and Borrower Loans Purchased Interest Earned on Notes and Borrower Loans Three Months Ended September 30, Three Months Ended September 30, Related Party 2016 2015 2016 2015 Executive officers and management $ 245 $ 386 $ 62 $ 53 Directors (excluding executive officers and management) — — — — Total $ 245 $ 386 $ 62 $ 53 Note and Borrower Loan Balance as of Related Party September 30, 2016 December 31, 2015 Executive officers and management $ 1,966 $ 2,173 Directors (excluding executive officers and management) — — $ 1,966 $ 2,173

Basis of Presentation (Addition

Basis of Presentation (Additional Information) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Prosper Funding LLC
Entity Information [Line Items]
Other comprehensive income (loss)	$ 0	$ 0

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment	$ 41,641	$ 32,915
Less accumulated depreciation and amortization	(14,963)	(7,950)
Total property and equipment, net	26,678	24,965
Prosper Funding LLC
Property, Plant and Equipment [Line Items]
Less accumulated depreciation and amortization	(5,511)	(2,571)
Total property and equipment, net	9,632	8,419
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	14,241	10,522
Internal-use software and website development costs
Property, Plant and Equipment [Line Items]
Property and equipment	15,144	10,990
Internal-use software and website development costs | Prosper Funding LLC
Property, Plant and Equipment [Line Items]
Property and equipment	15,143	10,990
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Property and equipment	3,064	2,442
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	7,071	5,719
Assets not yet placed in service
Property, Plant and Equipment [Line Items]
Property and equipment	$ 2,121	$ 3,242

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Depreciation expense			$ 9,892	$ 4,967
Prosper Funding LLC
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 1,076	$ 587	2,940	2,483
Property Plant And Equipment
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	2,500	1,300	6,900	4,400
Internal-use software and website development costs
Property, Plant and Equipment [Line Items]
Capitalized internal-use software and website development costs	$ 1,300	$ 2,000	5,200	5,900
Recorded internal-use software and website development impairment charges			$ 672	$ 0

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, 2016	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower Loans, at Fair Value	$ 314,671	$ 297,273
Notes, at Fair Value	(313,920)	(297,405)
Loans Held for Sale, at Fair Value	136	32
Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower Loans, at Fair Value	314,671	297,273
Notes, at Fair Value	(313,920)	(297,405)
Loans Held for Sale, at Fair Value	136	32
Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Notes	(322,003)	(294,331)
Fair value adjustments, Notes	8,083	(3,074)
Notes, at Fair Value	(313,920)	(297,405)
Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Notes	(322,003)	(294,331)
Fair value adjustments, Notes	8,083	(3,074)
Notes, at Fair Value	(313,920)	(297,405)
Borrower Loans
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Borrower Loans	319,210	296,945
Fair value adjustments, Borrower Loans, Loans Held for Sale	(4,539)	328
Borrower Loans, at Fair Value	314,671	297,273
Borrower Loans | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Borrower Loans	319,210	296,945
Fair value adjustments, Borrower Loans, Loans Held for Sale	(4,539)	328
Borrower Loans, at Fair Value	314,671	297,273
Loans Held for Sale
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value adjustments, Borrower Loans, Loans Held for Sale	(12)	(10)
Aggregate principal balance outstanding, Loans Held for Sale	148	42
Loans Held for Sale, at Fair Value	136	32
Loans Held for Sale | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value adjustments, Borrower Loans, Loans Held for Sale	(12)	(10)
Aggregate principal balance outstanding, Loans Held for Sale	148	42
Loans Held for Sale, at Fair Value	$ 136	$ 32

Borrower Loans, Loans Held fo43

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Gain (loss) related to credit risks on borrower loans	$ (0.4)	$ (2.4)
Minimum number of days for which loans originated were delinquent		90 days	90 days
Aggregate principal amount of loans originated	2.7	$ 2.7	$ 2.3
Fair value of loans originated	0.8	$ 0.8	0.9
Non accrual status past due date		120 days
Borrower loans receivable	0.2	$ 0.2	$ 0.1
Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Gain (loss) related to credit risks on borrower loans	(0.4)	$ (2.4)
Minimum number of days for which loans originated were delinquent		90 days	90 days
Aggregate principal amount of loans originated	2.7	$ 2.7	$ 2.3
Fair value of loans originated	0.8	$ 0.8	0.9
Non accrual status past due date		120 days
Borrower loans receivable	$ 0.2	$ 0.2	$ 0.1
Loans Held For Sale Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed interest rate, minimum		5.32%
Fixed interest rate, maximum		33.04%
Loans Held For Sale Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed interest rate, minimum		5.32%
Fixed interest rate, maximum		33.04%
Outstanding Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed interest rate, minimum			5.32%
Fixed interest rate, maximum			33.04%
Outstanding Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed interest rate, minimum			5.32%
Fixed interest rate, maximum			33.04%
Minimum | Loans Held For Sale Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		36 months
Minimum | Loans Held For Sale Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		36 months
Minimum | Outstanding Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months			36 months
Minimum | Outstanding Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months			36 months
Maximum | Loans Held For Sale Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		60 months
Maximum | Loans Held For Sale Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		60 months
Maximum | Outstanding Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months			60 months
Maximum | Outstanding Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months			60 months

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Servicing Assets And Liabilities Fair Value [Line Items]
Gain (loss) on sale of borrower loans	$ 761	$ 4,263	$ 3,865	$ 9,881
Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Gain (loss) on sale of borrower loans	761	4,263	3,865	9,881
Borrower Loans
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	3,700,000		$ 3,700,000		$ 3,800,000
Fixed interest rate, minimum			5.32%		5.32%
Fixed interest rate, maximum			35.52%		31.90%
Contractually specified servicing fees, late charges and ancillary fees	9,700	6,300	$ 29,800	14,100
Borrower Loans | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	3,600,000		$ 3,600,000		$ 3,600,000
Fixed interest rate, minimum			5.32%		5.32%
Fixed interest rate, maximum			35.52%		31.90%
Debt instrument servicing rights, description			At September 30, 2016 , Borrower Loans that were sold, but for which Prosper Funding retained servicing rights, had a total outstanding principal balance of $3.6 billion , original terms of either 36 or 60 months and had monthly payments with fixed interest rates ranging from 5.32% to 35.52% and various maturity dates through September 2021 . At December 31, 2015 , Borrower Loans that were sold, but for which Prosper Funding retained servicing rights, had a total outstanding principal balance of $3.6 billion , 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 December 2020 .
Contractually specified servicing fees, late charges and ancillary fees	$ 9,600	$ 5,900	$ 29,300	$ 12,700
Minimum | Borrower Loans
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months			36 months		36 months
Minimum | Borrower Loans | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months			36 months		36 months
Maximum | Borrower Loans
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months			60 months		60 months
Maximum | Borrower Loans | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months			60 months		60 months

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) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 42,757	$ 73,331
Gross Unrealized Gains	36	1
Gross Unrealized Losses	(10)	(145)
Fair Value	42,783	73,187
Short term bond funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		2,500
Gross Unrealized Losses		(2)
Fair Value		2,498
Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		70,831
Gross Unrealized Gains		1
Gross Unrealized Losses		(143)
Fair Value		70,689
Fixed Maturity Securities | Corporate debt securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	29,733	50,327
Gross Unrealized Gains	16	1
Gross Unrealized Losses	(8)	(94)
Fair Value	29,741	50,234
Fixed Maturity Securities | Commercial paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		9,493
Fair Value		9,493
Fixed Maturity Securities | US Treasury securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	10,525	8,512
Gross Unrealized Gains	14
Gross Unrealized Losses	(2)	(41)
Fair Value	10,537	8,471
Fixed Maturity Securities | Agency bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,499	2,499
Gross Unrealized Gains	6
Gross Unrealized Losses		(8)
Fair Value	$ 2,505	$ 2,491

Available for Sale Investment46

Available for Sale Investments at Fair Value - Summary of Available for Sale Investments of Continuous Unrealized Loss (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	$ 16,578	$ 58,835
Unrealized losses, less than 12 months	(10)	(145)
Fair value, 12 months or longer	0	0
Unrealized losses, 12 months or longer	0	0
Fair Value	16,578	58,835
Unrealized Losses	(10)	(145)
Short term bond funds
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months		2,498
Unrealized losses, less than 12 months		(2)
Fair value, 12 months or longer		0
Unrealized losses, 12 months or longer		0
Fair Value		2,498
Unrealized Losses		(2)
Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months		56,337
Unrealized losses, less than 12 months		(143)
Fair value, 12 months or longer	0	0
Unrealized losses, 12 months or longer	0	0
Fair Value		56,337
Unrealized Losses		(143)
Fixed Maturity Securities | Corporate debt securities
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	12,075	45,375
Unrealized losses, less than 12 months	(8)	(94)
Fair value, 12 months or longer	0	0
Unrealized losses, 12 months or longer	0	0
Fair Value	12,075	45,375
Unrealized Losses	(8)	(94)
Fixed Maturity Securities | US Treasury securities
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	4,503	8,471
Unrealized losses, less than 12 months	(2)	(41)
Fair value, 12 months or longer		0
Unrealized losses, 12 months or longer		0
Fair Value	4,503	8,471
Unrealized Losses	$ (2)	(41)
Fixed Maturity Securities | Agency bonds
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months		2,491
Unrealized losses, less than 12 months		(8)
Fair value, 12 months or longer		0
Unrealized losses, 12 months or longer		0
Fair Value		2,491
Unrealized Losses		$ (8)

Available for Sale Investment47

Available for Sale Investments at Fair Value - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Impairment charges recognized during period	$ 0
Proceeds from Sale of Available for Sale Investments	10,444,000	$ 0
Available-for-sale investments, realized gains	$ 7,000

Available for Sale Investment48

Available for Sale Investments at Fair Value - Schedule of Maturities of Available for Sale Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Within 1 year	$ 31,767	$ 35,782
After 1 year through 5 years	11,016	34,907
After 5 years to 10 years	0	0
After 10 years	0	0
Fair value	42,783	70,689
Amortized cost within 1 year	31,763	35,831
Amortized cost after 1 year through 5 years	10,994	35,000
Amortized cost after 5 years to 10 years	0	0
Amortized cost after 10 years	0	0
Amortized cost	42,757	70,831
Corporate debt securities
Schedule Of Available For Sale Securities [Line Items]
Within 1 year	25,235	26,289
After 1 year through 5 years	4,506	23,945
After 5 years to 10 years	0	0
After 10 years	0	0
Fair value	29,741	50,234
Commercial paper
Schedule Of Available For Sale Securities [Line Items]
Within 1 year		9,493
After 1 year through 5 years		0
After 5 years to 10 years		0
After 10 years		0
Fair value		9,493
US Treasury securities
Schedule Of Available For Sale Securities [Line Items]
Within 1 year	6,532	0
After 1 year through 5 years	4,005	8,471
After 5 years to 10 years	0	0
After 10 years	0	0
Fair value	10,537	8,471
Agency bonds
Schedule Of Available For Sale Securities [Line Items]
Within 1 year	0	0
After 1 year through 5 years	2,505	2,491
After 5 years to 10 years	0	0
After 10 years	0	0
Fair value	$ 2,505	$ 2,491

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, 2016	Jan. 01, 2016	Dec. 31, 2015
Assets:
Borrower Loans	$ 314,671		$ 297,273
Loans Held for Sale	136		32
Available for Sale Investments, at Fair Value	42,783		73,187
Servicing Assets	12,664		14,363
Total Assets	370,254		384,855
Liabilities:
Notes	313,920		297,405
Servicing Liabilities	254		484
Contingent Consideration	4,994	$ 4,800	4,801
Total Liabilities	319,168		302,690
Prosper Funding LLC
Assets:
Borrower Loans	314,671		297,273
Loans Held for Sale	136		32
Servicing Assets	12,274		13,605
Total Assets	327,081		310,910
Liabilities:
Notes	313,920		297,405
Servicing Liabilities	254		484
Total Liabilities	314,174		297,889
Level 2 Inputs
Assets:
Available for Sale Investments, at Fair Value	42,783		73,187
Total Assets	42,783		73,187
Level 3 Inputs
Assets:
Borrower Loans	314,671		297,273
Loans Held for Sale	136		32
Servicing Assets	12,664		14,363
Total Assets	327,471		311,668
Liabilities:
Notes	313,920		297,405
Servicing Liabilities	254		484
Contingent Consideration	4,994		4,801
Total Liabilities	319,168		302,690
Level 3 Inputs | Prosper Funding LLC
Assets:
Borrower Loans	314,671		297,273
Loans Held for Sale	136		32
Servicing Assets	12,274		13,605
Total Assets	327,081		310,910
Liabilities:
Notes	313,920		297,405
Servicing Liabilities	254		484
Total Liabilities	$ 314,174		$ 297,889

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, 2016	Dec. 31, 2015
Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.40%	4.30%
Default rate	1.60%	1.40%
Minimum | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.40%	4.30%
Default rate	1.60%	1.40%
Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	15.20%	14.50%
Default rate	14.80%	14.40%
Maximum | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	15.20%	14.50%
Default rate	14.80%	14.40%

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, 2016	Dec. 31, 2015
Servicing Liabilities at Fair Value [Line Items]
Market servicing rate	0.625%	0.625%
Prosper Funding LLC
Servicing Liabilities at Fair Value [Line Items]
Market servicing rate	0.625%	0.625%
Minimum
Servicing Liabilities at Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	1.40%	1.20%
Prepayment rate	14.90%	14.30%
Minimum | Prosper Funding LLC
Servicing Liabilities at Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	1.40%	1.20%
Prepayment rate	14.90%	14.30%
Maximum
Servicing Liabilities at Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	15.00%	14.70%
Prepayment rate	27.70%	25.60%
Maximum | Prosper Funding LLC
Servicing Liabilities at Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	15.00%	14.70%
Prepayment rate	27.70%	25.60%

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 - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Asset And Liability [Roll Forward]
Beginning balance, Total	$ 5,210	$ 1,004	$ (100)	$ 7,923
Purchase of Borrower Loans/Issuance of Notes, Total	260,496	1,024,385	1,618,575	2,426,820
Principal repayments, Total	2,227	(209)	3,915	(699)
Borrower Loans sold to third parties, Total	(267,037)	(1,025,846)	(1,621,377)	(2,434,729)
Other changes, Total	38	(5)	0	(7)
Change in fair value, Total	(47)	(87)	(126)	(66)
Ending balance, Total	887	(758)	887	(758)
Prosper Funding LLC
Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Asset And Liability [Roll Forward]
Beginning balance, Total	5,210	1,004	(100)	7,923
Purchase of Borrower Loans/Issuance of Notes, Total		1,024,385
Originations, Total	260,496		1,618,575	2,426,820
Principal repayments, Total	2,227	(209)	3,915	(699)
Borrower Loans sold to third parties, Total	(267,037)	(1,025,846)	(1,621,377)	(2,434,729)
Other changes, Total	38	(5)	0	(7)
Change in fair value, Total	(47)	(87)	(126)	(66)
Ending balance, Total	887	(758)	887	(758)
Notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, Liabilities	(309,530)	(284,627)	(297,405)	(273,783)
Purchase of Borrower Loans/Issuance of Notes, Liabilities	(56,580)	(47,670)	(165,727)	(142,246)
Principal repayments, Liabilities	45,403	38,202	129,603	111,711
Borrower Loans sold to third parties, Liabilities	0	425	0	425
Other changes, Liabilities	(196)	(18)	(229)	119
Change in fair value, Liabilities	6,983	6,434	19,838	16,520
Ending balance, Liabilities	(313,920)	(287,254)	(313,920)	(287,254)
Notes | Prosper Funding LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, Liabilities	(309,530)	(284,627)	(297,405)	(273,783)
Purchase of Borrower Loans/Issuance of Notes, Liabilities		(47,670)
Originations, Liabilities	(56,580)		(165,727)	(142,246)
Principal repayments, Liabilities	45,403	38,202	129,603	111,711
Borrower Loans sold to third parties, Liabilities	0	425	0	425
Other changes, Liabilities	(196)	(18)	(229)	119
Change in fair value, Liabilities	6,983	6,434	19,838	16,520
Ending balance, Liabilities	(313,920)	(287,254)	(313,920)	(287,254)
Borrower Loans
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	310,034	284,200	297,273	273,243
Purchase of Borrower Loans/Issuance of Notes, Assets	55,221	47,591	164,436	142,103
Principal repayments, Assets	(43,043)	(38,407)	(125,419)	(111,864)
Borrower Loans sold to third parties, Assets	(751)	(447)	(1,889)	(447)
Other changes, Assets	238	21	232	(108)
Change in fair value, Assets	(7,028)	(6,496)	(19,962)	(16,465)
Ending balance, Assets	314,671	286,462	314,671	286,462
Borrower Loans | Prosper Funding LLC
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	310,034	284,200	297,273	273,243
Purchase of Borrower Loans/Issuance of Notes, Assets		47,591
Originations, Assets	55,221		164,436	142,103
Principal repayments, Assets	(43,043)	(38,407)	(125,419)	(111,864)
Borrower Loans sold to third parties, Assets	(751)	(447)	(1,889)	(447)
Other changes, Assets	238	21	232	(108)
Change in fair value, Assets	(7,028)	(6,496)	(19,962)	(16,465)
Ending balance, Assets	314,671	286,462	314,671	286,462
Loans Held for Sale
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	4,706	1,431	32	8,463
Purchase of Borrower Loans/Issuance of Notes, Assets	261,855	1,024,464	1,619,866	2,426,963
Principal repayments, Assets	(133)	(4)	(269)	(546)
Borrower Loans sold to third parties, Assets	(266,286)	(1,025,824)	(1,619,488)	(2,434,707)
Other changes, Assets	(4)	(8)	(3)	(18)
Change in fair value, Assets	(2)	(25)	(2)	(121)
Ending balance, Assets	136	34	136	34
Loans Held for Sale | Prosper Funding LLC
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	4,706	1,431	32	8,463
Purchase of Borrower Loans/Issuance of Notes, Assets		1,024,464
Originations, Assets	261,855		1,619,866	2,426,963
Principal repayments, Assets	(133)	(4)	(269)	(546)
Borrower Loans sold to third parties, Assets	(266,286)	(1,025,824)	(1,619,488)	(2,434,707)
Other changes, Assets	(4)	(8)	(3)	(18)
Change in fair value, Assets	(2)	(25)	(2)	(121)
Ending balance, Assets	136	$ 34	136	$ 34
Scenario, Previously Reported | Prosper Funding LLC
Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Asset And Liability [Roll Forward]
Ending balance, Total	887		887
Scenario, Previously Reported | Notes | Prosper Funding LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Ending balance, Liabilities	(313,920)		(313,920)
Scenario, Previously Reported | Borrower Loans | Prosper Funding LLC
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Ending balance, Assets	314,671		314,671
Scenario, Previously Reported | Loans Held for Sale | Prosper Funding LLC
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Ending balance, Assets	$ 136		$ 136

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance			$ 14,363
Servicing Asset at Fair Value, Ending Balance	$ 12,664		12,664
Servicing Liability at Amortized Cost [Roll Forward]
Servicing Liability at Fair Value, Beginning Balance			484
Servicing Liability at Fair Value, Ending Balance	254		254
Prosper Funding LLC
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance			13,605
Servicing Asset at Fair Value, Ending Balance	12,274		12,274
Servicing Liability at Amortized Cost [Roll Forward]
Servicing Liability at Fair Value, Beginning Balance			484
Servicing Liability at Fair Value, Ending Balance	254		254
Servicing Assets
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Amortized cost at beginning of period				$ 4,163
Adjustment to Adopt Fair Value Measurement				546
Servicing Asset at Fair Value, Beginning Balance	14,297	$ 8,682	14,363	4,709
Additions	1,342	4,370	7,092	10,204
Less: Changes in fair value	(2,975)	(1,752)	(8,791)	(3,613)
Servicing Asset at Fair Value, Ending Balance	12,664	11,300	12,664	11,300
Servicing Assets | Prosper Funding LLC
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Amortized cost at beginning of period				3,116
Adjustment to Adopt Fair Value Measurement				399
Servicing Asset at Fair Value, Beginning Balance	13,798	7,634	13,605	3,515
Additions	1,342	4,367	7,092	10,204
Less: Changes in fair value	(2,866)	(1,580)	(8,423)	(3,049)
Less: Transfers to PMI				(249)
Servicing Asset at Fair Value, Ending Balance	12,274	10,421	12,274	10,421
Servicing Liabilities
Servicing Liability at Amortized Cost [Roll Forward]
Amortized cost at beginning of period				624
Adjustment to Adopt Fair Value Measurement				(29)
Servicing Liability at Fair Value, Beginning Balance	324	606	484	595
Additions	0	53	9	246
Less: Changes in fair value	(70)	(109)	(239)	(291)
Servicing Liability at Fair Value, Ending Balance	254	550	254	550
Servicing Liabilities | Prosper Funding LLC
Servicing Liability at Amortized Cost [Roll Forward]
Amortized cost at beginning of period				624
Adjustment to Adopt Fair Value Measurement				(29)
Servicing Liability at Fair Value, Beginning Balance	324	606	484	595
Additions	0	53	9	246
Less: Changes in fair value	(70)	(109)	(239)	(291)
Servicing Liability at Fair Value, Ending Balance	$ 254	$ 550	$ 254	$ 550

Fair Value of Assets and Liab54

Fair Value of Assets and Liabilities - Additional Information (Details) - USD ($) $ in Thousands	Oct. 09, 2015	Sep. 30, 2016	Sep. 30, 2016	Jan. 01, 2016	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Changes in fair value		$ 65	$ 192
Contingent Consideration		$ 4,994	$ 4,994	$ 4,800	$ 4,801
BillGuard Inc
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Outstanding shares purchased by parent company	100.00%
Duration of payment for purchase of outstanding shares	1 year

Fair Value of Assets and Liab55

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, 2016USD ($)
Discount rate assumption | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	7.59%
Discount rate assumption | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	7.59%
Discount rate assumption | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	7.59%
Discount rate assumption | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	7.59%
Discount rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 311,509
Discount rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	311,509
Discount rate assumption | 100 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	310,760
Discount rate assumption | 100 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	310,760
Discount rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	308,426
Discount rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	308,426
Discount rate assumption | 200 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	307,680
Discount rate assumption | 200 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	307,680
Discount rate assumption | Resulting fair value from: | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	317,914
Discount rate assumption | Resulting fair value from: | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	317,914
Discount rate assumption | Resulting fair value from: | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	317,161
Discount rate assumption | Resulting fair value from: | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	317,161
Discount rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	321,244
Discount rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	321,244
Discount rate assumption | 200 basis point decrease | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	320,488
Discount rate assumption | 200 basis point decrease | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 320,488
Default rate assumption | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate	11.50%
Default rate assumption | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate	11.50%
Default rate assumption | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate	11.50%
Default rate assumption | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate	11.50%
Default rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 311,358
Default rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	311,358
Default rate assumption | 100 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	310,601
Default rate assumption | 100 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	310,601
Default rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	308,142
Default rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	308,142
Default rate assumption | 200 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	307,380
Default rate assumption | 200 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	307,380
Default rate assumption | Resulting fair value from: | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	318,009
Default rate assumption | Resulting fair value from: | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	318,009
Default rate assumption | Resulting fair value from: | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	317,264
Default rate assumption | Resulting fair value from: | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	317,264
Default rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	321,389
Default rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	321,389
Default rate assumption | 200 basis point decrease | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	320,651
Default rate assumption | 200 basis point decrease | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	$ 320,651

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 (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%	0.625%
Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%	0.625%
Servicing Assets
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%
Resulting fair value from:
Servicing Asset, Market servicing rate increase to 0.65%	$ 11,744
Servicing Asset, Market servicing rate decrease to 0.60%	$ 13,583
Weighted average prepayment assumptions	21.06%
Weighted average default assumptions	11.64%
Servicing Assets | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%
Resulting fair value from:
Servicing Asset, Market servicing rate increase to 0.65%	$ 11,509
Servicing Asset, Market servicing rate decrease to 0.60%	$ 13,311
Weighted average prepayment assumptions	21.06%
Weighted average default assumptions	11.64%
Servicing Liabilities
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%
Resulting fair value from:
Servicing Liabilities, Market servicing rate increase to 0.65%	$ 279
Servicing Liabilities, Market servicing rate decrease to 0.60%	$ 228
Weighted average prepayment assumptions	21.06%
Weighted average default assumptions	11.64%
Servicing Liabilities | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate assumptions	0.625%
Resulting fair value from:
Servicing Asset, Market servicing rate increase to 0.65%	$ 279
Servicing Asset, Market servicing rate decrease to 0.60%	$ 228
Weighted average prepayment assumptions	21.06%
Weighted average default assumptions	11.64%
Prepayment rate assumption | Servicing Assets | Applying a 1.1 multiplier to prepayment rate
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to prepayment rate	$ 12,426
Prepayment rate assumption | Servicing Assets | Applying a 1.1 multiplier to prepayment rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to prepayment rate	12,043
Prepayment rate assumption | Servicing Assets | Applying a 0.9 multiplier to prepayment rate
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to prepayment rate	12,904
Prepayment rate assumption | Servicing Assets | Applying a 0.9 multiplier to prepayment rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to prepayment rate	12,507
Prepayment rate assumption | Servicing Liabilities | Applying a 1.1 multiplier to prepayment rate
Resulting fair value from:
Servicing Liabilities, Applying a 1.1 multiplier to prepayment rate	249
Prepayment rate assumption | Servicing Liabilities | Applying a 1.1 multiplier to prepayment rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to prepayment rate	249
Prepayment rate assumption | Servicing Liabilities | Applying a 0.9 multiplier to prepayment rate
Resulting fair value from:
Servicing Liabilities, Applying a 0.9 multiplier to prepayment rate	258
Prepayment rate assumption | Servicing Liabilities | Applying a 0.9 multiplier to prepayment rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to prepayment rate	258
Default rate assumption | Servicing Assets | Applying a 1.1 multiplier to default rate
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to default rate	12,451
Default rate assumption | Servicing Assets | Applying a 1.1 multiplier to default rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to default rate	12,068
Default rate assumption | Servicing Assets | Applying a 0.9 multiplier to default rate
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to default rate	12,880
Default rate assumption | Servicing Assets | Applying a 0.9 multiplier to default rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to default rate	12,484
Default rate assumption | Servicing Liabilities | Applying a 1.1 multiplier to default rate
Resulting fair value from:
Servicing Liabilities, Applying a 1.1 multiplier to default rate	253
Default rate assumption | Servicing Liabilities | Applying a 1.1 multiplier to default rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to default rate	253
Default rate assumption | Servicing Liabilities | Applying a 0.9 multiplier to default rate
Resulting fair value from:
Servicing Liabilities, Applying a 0.9 multiplier to default rate	254
Default rate assumption | Servicing Liabilities | Applying a 0.9 multiplier to default rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to default rate	$ 254

Fair Value of Assets and Liab57

Fair Value of Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities(Details)	9 Months Ended
	Sep. 30, 2016
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Prepayment rate assumption
Servicing Assets And Liabilities Fair Value [Line Items]
Prepayment rate increase	1.10%
Prepayment rate decrease	0.90%
Prepayment rate assumption | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Prepayment rate increase	1.10%
Prepayment rate decrease	0.90%
Default rate assumption
Servicing Assets And Liabilities Fair Value [Line Items]
Default rate increase	1.10%
Default rate decrease	0.90%
Default rate assumption | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Default rate increase	1.10%
Default rate decrease	0.90%

Goodwill And Other Intangible58

Goodwill And Other Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Goodwill And Other Intangible Assets [Line Items]
Goodwill	$ 36,368		$ 36,368		$ 36,368
Intangible assets	10,069		10,069		$ 13,051
Amortization of intangible assets	1,000	$ 200	$ 3,000	$ 500
User Base and Customer Relationships | Minimum
Goodwill And Other Intangible Assets [Line Items]
Intangible assets amortized period (in years)			3 years
User Base and Customer Relationships | Maximum
Goodwill And Other Intangible Assets [Line Items]
Intangible assets amortized period (in years)			10 years
Developed technology
Goodwill And Other Intangible Assets [Line Items]
Intangible assets	$ 6,360		$ 6,360
Intangible assets amortized period (in years)			4 years
Developed technology | Minimum
Goodwill And Other Intangible Assets [Line Items]
Intangible assets amortized period (in years)			3 years
Developed technology | Maximum
Goodwill And Other Intangible Assets [Line Items]
Intangible assets amortized period (in years)			5 years
Brand name
Goodwill And Other Intangible Assets [Line Items]
Intangible assets amortized period (in years)			1 year

Goodwill And Other Intangible59

Goodwill And Other Intangible Assets - Summary of Other Intangible for the Period Presented (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 14,620
Accumulated Amortization	(4,551)
Net Carrying Value	10,069	$ 13,051
User base and customer relationships
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	6,250
Accumulated Amortization	(2,541)
Net Carrying Value	$ 3,709
Remaining Useful Life (In Years)	8 years 4 months 24 days
Developed technology
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 8,310
Accumulated Amortization	(1,950)
Net Carrying Value	$ 6,360
Remaining Useful Life (In Years)	4 years
Brand name
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 60
Accumulated Amortization	$ (60)
Remaining Useful Life (In Years)	1 year
Remaining Useful Life (In Years)	0 years

Goodwill And Other Intangible60

Goodwill And Other Intangible Assets - Summary of Estimated Amortization of Purchased Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
2,016	$ 855
2,017	3,260
2,018	2,329
2,019	1,779
2,020	1,344
Thereafter	502
Net Carrying Value	$ 10,069	$ 13,051

Other Liabilities - Schedule of

Other Liabilities - Schedule of Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Other Liabilities [Abstract]
Class action settlement liability	$ 2,984	$ 5,949
Repurchase liability for unvested restricted stock awards	180	473
Contingent consideration	4,994	4,801
Deferred revenue	285	1,591
Servicing liabilities	254	484
Deferred rent	4,563	5,240
Restructuring liability	5,107	0
Other	2,587	2,197
Total Other Liabilities	$ 20,954	$ 20,735

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net loss available to common stockholders for basic and diluted EPS	$ (17,417)	$ (3,843)	$ (70,509)	$ (17,324)
Denominator:
Weighted average shares used in computing basic and diluted net loss per share (in shares)	65,393,175	55,907,765	63,015,616	54,746,980
Basic and diluted net loss per share (in dollars per share)	$ (0.27)	$ (0.07)	$ (1.12)	$ (0.32)

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
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)	232,188,474	224,960,855	226,126,202	222,490,315
Convertible preferred stock issued and outstanding
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)	177,388,425	177,388,425	177,388,425	177,388,425
Stock options issued and outstanding
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)	50,387,360	35,063,150	44,617,487	32,592,610
Unvested stock options exercised
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)	3,209,345	11,906,925	3,209,345	11,906,925
Warrants issued and outstanding
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)	1,203,344	602,355	910,945	602,355

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Details)	Feb. 16, 2016shares
Earnings Per Share [Abstract]
Forward stock split, shares issued (in shares)	5

Convertible Preferred Stock a65

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, 2016	May 31, 2016	Dec. 31, 2015
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)	177,388,425	177,388,425	177,388,425
Convertible preferred stock, shares outstanding (in shares)	177,388,425		177,388,425
Convertible preferred stock, shares issued (in shares)	177,388,425		177,388,425
Convertible preferred stock, aggregate liquidation preference	$ 325,952		$ 325,952
New Series A
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	68,558,220
Convertible preferred stock, shares outstanding (in shares)	68,558,220
Convertible preferred stock, aggregate liquidation preference	$ 19,774
Series A-1
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	24,760,915
Convertible preferred stock, shares outstanding (in shares)	24,760,915
Convertible preferred stock, aggregate liquidation preference	$ 49,522
New Series B
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	35,775,880
Convertible preferred stock, shares outstanding (in shares)	35,775,880
Convertible preferred stock, aggregate liquidation preference	$ 21,581
New Series C
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	24,404,770
Convertible preferred stock, shares outstanding (in shares)	24,404,770
Convertible preferred stock, aggregate liquidation preference	$ 70,075
New Series D
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	23,888,640
Convertible preferred stock, shares outstanding (in shares)	23,888,640
Convertible preferred stock, aggregate liquidation preference	$ 165,000

Convertible Preferred Stock a66

Convertible Preferred Stock and Stockholders' Deficit - Additional Information (Details) $ / shares in Units, $ in Thousands	Feb. 16, 2016	Sep. 30, 2016USD ($)$ / sharesshares	Dec. 31, 2015vote / shares$ / sharesshares	May 31, 2016$ / sharesshares
Class of Stock [Line Items]
Stock split conversion ratio	5	5
Common and preferred stock, shares authorized (in shares)				475,610,528
Common stock, shares authorized (in shares)		298,222,103	270,326,075	298,222,103
Common stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)		177,388,425	177,388,425	177,388,425
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.01
Common stock, shares issued (in shares)		70,708,055	70,367,425
Common stock, shares outstanding (in shares)		69,772,120	69,431,490
Common stock, vote per share | vote / shares			1
Common Stock
Class of Stock [Line Items]
Stock split conversion ratio	5
Exercise of stock options (in shares)		386,720
Proceeds from Exercise of Vested Stock Options | $		$ 300
Unvested restricted stock outstanding (in shares)		3,209,345	9,806,170
Stock repurchase upon termination of employment (in shares)		288,520
Aggregate price for repurchase of common stock | $		$ 70
Warrants
Class of Stock [Line Items]
Shares issued (in shares)		51,915
Exercise of warrants aggregate proceeds | $		$ 11

Shared Based Incentive Plan a67

Shared Based Incentive Plan and Compensation - Additional Information (Details)	Feb. 16, 2016	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options exercisable, maximum period				10 years
Stock split conversion ratio	5			5
Financial statement impact amount				$ 17,181,000	$ 7,439,000
Unamortized expense related to unvested stock-based awards		$ 43,800,000		$ 43,800,000
Dividend yield			0.00%	0.00%	0.00%
Unrecognized cost of unvested share-based compensation awards.		0		$ 0
Remaining weighted average vesting period				2 years 6 months 7 days
Internal-use software and website development costs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation capitalized		156,000	$ 202,000	$ 592,000	$ 499,000
Stock Option Repricing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Financial statement impact amount		800,000		2,000,000
Unamortized expense related to unvested stock-based awards		$ 2,900,000		$ 2,900,000
Weighted average vesting period				2 years 6 months 18 days
Restricted Stock Unit (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate fair value				$ 10,700,000
Vesting Period One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percent				25.00%
Vesting period of the options				1 year
Incremental vesting percent				2.08%
Vesting Period One | Restricted Stock Unit (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of the options				3 years
Vesting Period Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percent				50.00%
Vesting period of the options				2 years
Incremental vesting percent				2.08%
Vesting Period Two | Restricted Stock Unit (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of the options				4 years
Vesting period three
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental vesting percent				2.78%
2005 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options made available in pool (in shares) | shares		56,902,925		56,902,925
2005 Stock Plan | Stock options issued and outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant under the plan (in shares) | shares		0		0
2015 Stock Option Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options made available in pool (in shares) | shares		54,336,473		54,336,473
Shares available for grant under the plan (in shares) | shares		20,684,495		20,684,495

Shared Based Incentive Plan a68

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	9 Months Ended
	Sep. 30, 2016$ / sharesshares
Early exercised options, unvested [Roll Forward]
Beginning balance (shares) | shares	9,806,170
Repurchase of restricted stock (shares) | shares	(288,520)
Restricted stock vested (shares) | shares	(6,308,305)
Ending balance (shares) | shares	3,209,345
Weighted average exercise price [Abstract]
Weighted-Average Exercise Price, Beginning balance (in dollars per share) | $ / shares	$ 0.05
Repurchase of restricted stock (in dollars per share) | $ / shares	0.24
Restricted stock vested (in dollars per share) | $ / shares	0.04
Weighted-Average Exercise Price, Ending balance (in dollars per share) | $ / shares	$ 0.06

Shared Based Incentive Plan a69

Shared Based Incentive Plan and Compensation - Additional Information Regarding Unvested Early exercised stock options outstanding (Details)	9 Months Ended
	Sep. 30, 2016$ / sharesshares
$ 0.02
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices (in dollars per share)	$ 0.02
Number Outstanding (in shares) | shares	2,910,435
Weighted Avg. Remaining Life (in years)	4 months 24 days
Weighted Avg. Exercise Price (in dollars per share)	$ 0.02
$ 0.11
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices (in dollars per share)	$ 0.11
Number Outstanding (in shares) | shares	212,710
Weighted Avg. Remaining Life (in years)	1 year 3 months 18 days
Weighted Avg. Exercise Price (in dollars per share)	$ 0.11
$ 1.13
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices (in dollars per share)	$ 1.13
Number Outstanding (in shares) | shares	86,200
Weighted Avg. Remaining Life (in years)	1 year 10 months 24 days
Weighted Avg. Exercise Price (in dollars per share)	$ 1.13
$0.02 - $1.13
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	0.02
Range of Exercise Prices, Maximum (in dollars per share)	$ 1.13
Number Outstanding (in shares) | shares	3,209,345
Weighted Avg. Remaining Life (in years)	6 months
Weighted Avg. Exercise Price (in dollars per share)	$ 0.06

Shared Based Incentive Plan a70

Shared Based Incentive Plan and Compensation - Summarized Option Activity under Option Plan (Details) - 2005 Stock Plan and 2015 Stock Option Plan	9 Months Ended
	Sep. 30, 2016$ / sharesshares
Options Issued and Outstanding [Roll Forward]
Options Issued and Outstanding, Beginning Balance (in shares) | shares	40,425,605
Options Issued and Outstanding, Options issued (in shares) | shares	19,655,338
Options Issued and Outstanding, Options exercised - vested (in shares) | shares	(386,720)
Options Issued and Outstanding, Options forfeited (in shares) | shares	(12,886,025)
Options Issued and Outstanding, Ending balance (in shares) | shares	46,808,198
Options Issued and Outstanding, Options vested and/or exercisable (in shares) | shares	26,701,173
Weighted-Average Exercise Price [Roll Forward]
Weighted-Average Exercise Price, Beginning balance (in dollars per share) | $ / shares	$ 2.64
Weighted-Average Exercise Price, Options issued (in dollars per share) | $ / shares	2.14
Weighted-Average Exercise Price, Options exercised - vested (in dollars per share) | $ / shares	0.75
Weighted-Average Exercise Price, Options forfeited (in dollars per share) | $ / shares	1.60
Weighted-Average Exercise Price, Ending balance (in dollars per share) | $ / shares	1.55
Weighted-Average Exercise Price, Options vested and/or exercisable (in dollars per share) | $ / shares	$ 1.13

Shared Based Incentive Plan a71

Shared Based Incentive Plan and Compensation - Additional Information Regarding Common Stock Options Outstanding (Details) - Stock options issued and outstanding	9 Months Ended
	Sep. 30, 2016$ / sharesshares
$0.02 - 0.99
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	$ 0.02
Range of Exercise Prices, Maximum (in dollars per share)	$ 0.99
Number Outstanding (in shares) | shares	12,919,025
Weighted Avg. Remaining Life (in years)	7 years 1 month 24 days
Weighted Avg. Exercise Price (in dollars per share)	$ 0.12
Number Exercisable (in shares) | shares	12,919,025
Weighted-Avg. Exercise Price (in dollars per share)	$ 0.12
$1.00 -2.99
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	1
Range of Exercise Prices, Maximum (in dollars per share)	$ 2.99
Number Outstanding (in shares) | shares	33,208,863
Weighted Avg. Remaining Life (in years)	9 years 1 month 2 days
Weighted Avg. Exercise Price (in dollars per share)	$ 2.04
Number Exercisable (in shares) | shares	13,101,838
Weighted-Avg. Exercise Price (in dollars per share)	$ 1.97
$3.00 - 4.99
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	3
Range of Exercise Prices, Maximum (in dollars per share)	$ 4.99
Number Outstanding (in shares) | shares	463,490
Weighted Avg. Remaining Life (in years)	8 years 4 months 17 days
Weighted Avg. Exercise Price (in dollars per share)	$ 3.62
Number Exercisable (in shares) | shares	463,490
Weighted-Avg. Exercise Price (in dollars per share)	$ 3.62
$5.00- 5.52
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	5
Range of Exercise Prices, Maximum (in dollars per share)	$ 5.52
Number Outstanding (in shares) | shares	216,820
Weighted Avg. Remaining Life (in years)	8 years 8 months 1 day
Weighted Avg. Exercise Price (in dollars per share)	$ 5.46
Number Exercisable (in shares) | shares	216,820
Weighted-Avg. Exercise Price (in dollars per share)	$ 5.46
$0.02 - 5.52
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	0.02
Range of Exercise Prices, Maximum (in dollars per share)	$ 5.52
Number Outstanding (in shares) | shares	46,808,198
Weighted Avg. Remaining Life (in years)	8 years 6 months 15 days
Weighted Avg. Exercise Price (in dollars per share)	$ 1.55
Number Exercisable (in shares) | shares	26,701,173
Weighted-Avg. Exercise Price (in dollars per share)	$ 1.13

Shared Based Incentive Plan a72

Shared Based Incentive Plan and Compensation - Fair Value of Stock Option Awards (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair value of stock option awards [Abstract]
Volatility of common stock	50.71%	50.88%	56.14%
Risk-free interest rate	1.70%	1.29%	1.71%
Expected life	6 years	5 years 9 months 18 days	6 years 6 days
Dividend yield	0.00%	0.00%	0.00%

Shared Based Incentive Plan a73

Shared Based Incentive Plan and Compensation - Summarized Activities for the Company's RSU's (Details) - Restricted Stock Unit (RSUs)	9 Months Ended
	Sep. 30, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock unit ,Unvested ,Beginning Balance (in shares) | shares	1,835,510
Granted (in shares) | shares	3,580,220
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(2,255,350)
Restricted stock unit ,Unvested ,Ending Balance (in shares) | shares	3,160,380
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock unit, Unvested, Beginning Balance (in dollars per share) | $ / shares	$ 5.52
Granted (in dollars per share) | $ / shares	2.14
Vested (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	2.97
Restricted stock unit, Unvested, Ending Balance (in dollars per share) | $ / shares	$ 2.15

Shared Based Incentive Plan a74

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	$ 5,670	$ 3,247	$ 17,181	$ 7,439
Origination and servicing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	518	369	1,536	805
Sales and marketing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	639	669	2,271	1,734
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	4,513	$ 2,209	13,329	$ 4,900
Restructuring
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	$ 0		$ 45

Restructuring - Additional Info

Restructuring - Additional Information (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2016USD ($)lease	May 03, 2016Employee
Restructuring Cost and Reserve [Line Items]
Number of employees terminated due to restructuring | Employee		167
Employee severance and benefits charges	$ 396
Number of leases terminated | lease	1
Leasehold improvements	$ 400
Other restructuring charges	200
Restructuring Charges, Net
Restructuring Cost and Reserve [Line Items]
Gain on extinguishment of liabilities	$ 1,500

Restructuring - Summary of Acti

Restructuring - Summary of Activities Related to Prosper's Restructuring Plan (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2016USD ($)
Restructuring Cost and Reserve [Line Items]
Balance July 1, 2016	$ 10,530
Adjustments to expense	(918)
Less: Cash paid	(4,494)
September 30, 2016	5,118
Severance Related
Restructuring Cost and Reserve [Line Items]
Balance July 1, 2016	2,038
Adjustments to expense	396
Less: Cash paid	(2,423)
September 30, 2016	11
Facilities Related
Restructuring Cost and Reserve [Line Items]
Balance July 1, 2016	8,492
Adjustments to expense	(1,314)
Less: Cash paid	(2,071)
September 30, 2016	$ 5,107

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Taxes [Line Items]
Income Tax Expense	$ 74,000	$ 35,000	$ 344,000	$ 284,000
Prosper Funding LLC
Income Taxes [Line Items]
Income Tax Expense			$ 0	0
Net effective tax rate			0.00%
Valuation ​Allowance of Deferred ​Tax ​Assets
Income Taxes [Line Items]
Income Tax Expense			$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	Jul. 19, 2013USD ($)Installment	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)Installment	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Aug. 01, 2016USD ($)	Oct. 16, 2008USD ($)
Commitments And Contingencies [Line Items]
Rental expense under operating lease arrangements		$ 1,600,000	$ 1,000,000	$ 5,300,000	$ 2,700,000
Designated Amount for loans (less than)								$ 143,500
Minimum fee, remaining six months of 2016		400,000		400,000
Minimum fee, 2017		1,700,000		1,700,000
Minimum fee, 2018		1,700,000		1,700,000
Minimum fee, 2019		1,000,000		1,000,000
Minimum liquidity covenant								$ 15,000,000
Purchase of borrower loans				16,500,000
Maximum potential future payments		3,737,000,000		3,737,000,000
Accrued repurchase and indemnification obligation		487,000		$ 487,000		$ 510,000
Amount of loans sold to lender members									$ 178,000,000
Settlement amount	$ 10,000,000
Number of annual installments paid to plaintiffs | Installment	4			3
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		2,984,000		2,984,000		5,949,000
Prosper Funding LLC
Commitments And Contingencies [Line Items]
Minimum fee, remaining six months of 2016		400,000		400,000
Minimum fee, 2017		1,700,000		1,700,000
Minimum fee, 2018		1,700,000		1,700,000
Minimum fee, 2019		1,000,000		1,000,000
Purchase of borrower loans				16,500,000
Maximum potential future payments		3,615,000,000		3,615,000,000
Accrued repurchase and indemnification obligation		$ 437,000		$ 437,000		$ 460,000

Commitments and Contingencies79

Commitments and Contingencies - Future Minimum Lease Payments (Details) $ in Thousands	Sep. 30, 2016USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remaining three months of 2016	$ 1,731
2,017	7,721
2,018	8,328
2,019	8,620
2,020	8,862
2,021	8,916
Thereafter	18,178
Total future operating lease obligations	$ 62,356

Related Parties - Additional In

Related Parties - Additional Information (Details)	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Minimum percentage of voting securities considered for related parties	10.00%
Minimum percentage of stock holders considered for related parties	10.00%

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Nine Months Ended September 30,	$ 322	$ 396	$ 1,466	$ 1,263
Interest Earned on Notes and Borrower Loans Nine Months Ended September 30,	72	55	195	158
Notes and Borrower Loans Balance as of	2,501		2,501		$ 2,272
Prosper Funding LLC
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Nine Months Ended September 30,	245	386	1,039	1,232
Interest Earned on Notes and Borrower Loans Nine Months Ended September 30,	62	53	170	152
Notes and Borrower Loans Balance as of	1,966		1,966		2,173
Executive officers and management
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Nine Months Ended September 30,	245	386	1,039	1,232
Interest Earned on Notes and Borrower Loans Nine Months Ended September 30,	62	53	170	152
Notes and Borrower Loans Balance as of	1,966		1,966		2,173
Executive officers and management | Prosper Funding LLC
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Nine Months Ended September 30,	245	386	1,039	1,232
Interest Earned on Notes and Borrower Loans Nine Months Ended September 30,	62	53	170	152
Notes and Borrower Loans Balance as of	1,966		1,966		2,173
Directors (excluding executive officers and management)
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Nine Months Ended September 30,	77	10	427	31
Interest Earned on Notes and Borrower Loans Nine Months Ended September 30,	10	$ 2	25	$ 6
Notes and Borrower Loans Balance as of	$ 535		$ 535		$ 99

Subsequent Events (Details)

Subsequent Events (Details) $ / shares in Units, $ in Millions	Nov. 16, 2015USD ($)$ / shares
Subsequent Event [Line Items]
Cash payment | $	$ 9
Preferred Stock
Subsequent Event [Line Items]
Percent of capitalization	7.00%
Share price (in dollars per share) | $ / shares	$ 0.01