Prosper Funding 10-Q 20 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	11-May-15
Document And Entity Information [Line Items]
Entity Registrant Name	PROSPER MARKETPLACE, INC
Entity Central Index Key	1416265
Current Fiscal Year End Date	-19
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		14,706,666
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Prosper Funding LLC [Member]
Document And Entity Information [Line Items]
Entity Registrant Name	Prosper Funding LLC
Current Fiscal Year End Date	-19
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		0

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Cash and Cash Equivalents	$38,332	$50,557
Restricted Cash	99,363	81,300
Short Term Investments	1,275	1,274
Accounts Receivable	1,268	3,152
Loans Held for Sale, at Fair Value	1,599	8,463
Borrower Loans, at Fair Value	280,404	273,243
Property and Equipment, Net	16,656	14,424
Prepaid and Other Assets	10,531	7,745
Goodwill and Intangibles	20,249
Total Assets	469,677	440,158
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities	21,368	17,239
Payable to Investors	87,706	64,494
Class Action Settlement Liability	5,880	7,861
Notes at Fair Value	280,801	273,783
Repurchase Liability for Unvested Restricted Stock Awards	946	1,010
Total Liabilities	396,701	364,387
Commitments and Contingencies (see Note 11)
Convertible Preferred Stock – $0.01 par value; 32,155,022 shares authorized; 30,699,957 issued and outstanding as of March 31, 2015 and December 31, 2014. Aggregate liquidation preference of $160,952 as of March 31, 2015 and December 31, 2014.	111,145	111,145
Stockholders' Deficit
Common Stock ($0.01 par value; 48,928,883 shares authorized; 14,878,514 issued and 14,691,327 outstanding as of March 31, 2015; and 47,928,883 shares authorized; 14,448,700 issued and 14,261,513 outstanding as of December 31, 2014)	110	102
Additional Paid-In Capital	90,239	86,340
Less: Treasury Stock	-303	-303
Accumulated Deficit	-128,215	-121,513
Total Stockholders' Deficit	-38,169	-35,374
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit	469,677	440,158
Prosper Funding LLC [Member]
Assets
Cash and Cash Equivalents	20,594	23,777
Restricted Cash	91,107	73,103
Short Term Investments	1,275	1,274
Loans Held for Sale, at Fair Value	1,599	8,463
Borrower Loans, at Fair Value	280,404	273,243
Property and Equipment, Net	3,964	1,125
Related party receivable	799	1,135
Other assets	4,801	3,120
Total Assets	404,543	385,240
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities	1,606	1,357
Payable to Investors	86,882	63,809
Notes at Fair Value	280,801	273,783
Total Liabilities	369,289	338,949
Stockholders' Deficit
Member's Equity	14,370	29,619
Accumulated Deficit	20,884	16,672
Total Stockholders' Deficit	35,254	46,291
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit	$404,543	$385,240

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share)	$0.01	$0.01
Convertible preferred stock, shares authorized (in shares)	32,155,022	32,155,022
Convertible preferred stock, shares issued (in shares)	30,699,957	30,699,957
Convertible preferred stock, shares outstanding (in shares)	30,699,957	30,699,957
Convertible preferred stock, aggregate liquidation preference	$160,952	$160,952
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized (in shares)	48,928,883	47,928,883
Common stock, shares issued (in shares)	14,878,514	14,448,700
Common stock, shares outstanding (in shares)	14,691,327	14,261,513

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating Revenue
Transaction Fees, Net	$25,342,000	$8,364,000
Servicing Fees, Net	2,569,000	414,000
Other Revenue	2,998,000	451,000
Total Operating Revenue	30,909,000	9,229,000
Interest Income
Interest Income on Borrower Loans	10,476,000	10,005,000
Interest Expense on Notes	-9,563,000	-9,422,000
Net Interest Income	913,000	583,000
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	-101,000	167,000
Total Net Revenue	31,721,000	9,979,000
Expenses
Origination and Servicing	6,852,000	2,291,000
Sales and Marketing	18,570,000	6,434,000
General and Administrative	13,502,000	3,972,000
Total Expenses	38,924,000	12,697,000
Net Loss Before Taxes	-7,203,000	-2,718,000
Income Tax Expense	73,000
Net Income (Loss)	-7,276,000	-2,718,000
Net Loss Per Share – Basic and Diluted	($0.69)	($0.34)
Weighted-Average Shares - Basic and Diluted	10,553,251	8,056,248
Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party	9,673,000	4,053,000
Servicing Fees, Net	2,265,000	423,000
Other Revenue	1,922,000	299,000
Total Operating Revenue	13,860,000	4,775,000
Interest Income
Interest Income on Borrower Loans	10,522,000	10,082,000
Interest Expense on Notes	-9,563,000	-9,423,000
Net Interest Income	959,000	659,000
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	-101,000	210,000
Total Net Revenue	14,718,000	5,644,000
Expenses
Origination and Servicing		398,000
Administration Fee – Related Party	9,295,000	3,494,000
Servicing	1,373,000	398,000
General and Administrative	266,000	104,000
Total Expenses	10,934,000	3,996,000
Income Tax Expense	0	0
Net Income (Loss)	$3,784,000	$1,648,000

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from Operating Activities:
Net Income (Loss)	($7,276)	($2,718)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	101	-167
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes	-205	-133
Depreciation and Amortization	1,850	400
Change in Servicing Rights	-1,256	-283
Stock-Based Compensation Expense	1,439	250
Loss on Impairment of Property and Equipment		215
Accretion of Class Action Settlement Liability	19	30
Purchase of Loans Held for Sale at Fair Value	-540,924	-150,787
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	547,673	150,510
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities	-19,922	-5,169
Accounts Receivable	2,031	-20
Prepaid and Other Assets	-850	-417
Accounts Payable and Accrued Liabilities	2,204	898
Class Action Settlement Liability	-2,000	-2,000
Payable to Investors	23,212	5,850
Net Cash Provided by (Used in) Operating Activities	6,096	-3,541
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	-47,714	-44,256
Principal Payments of Borrower Loans Held at Fair Value	36,063	28,245
Purchases of Property and Equipment	-3,537	-659
Maturities of Short Term Investments	1,274	1,271
Purchases of Short Term Investments	-1,275	-1,274
Acquisition of Business, Net of Cash Acquired	-19,000
Changes in Restricted Cash Related to Investing Activities	1,859	-771
Net Cash Used in Investing Activities	-32,330	-17,444
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	47,796	43,933
Payment of Notes Held at Fair Value	-36,069	-28,326
Proceeds from Early Exercise of Stock Options and Issuance of Restricted Stock	1,650	10
Proceeds from Exercise of Vested Stock Options	522	4
Repurchase of Restricted Stock	-1
Proceeds from Exercise of Common Stock Warrants	111
Net Cash Provided by Financing Activities	14,009	15,621
Net (Decrease) Increase in Cash and Cash Equivalents	-12,225	-5,364
Cash and Cash Equivalents at Beginning of the Period	50,557	18,339
Cash and Cash Equivalents at End of the Period	38,332	12,975
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	10,444	10,178
Non-Cash Investing Activity-Accrual for Property and Equipment, Net	321	28
Non-Cash Investing Activity-Amount Payable for the Acquisition of Business	840
Prosper Funding LLC [Member]
Cash flows from Operating Activities:
Net Income (Loss)	3,784	1,648
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	101	-210
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes	-205	-133
Depreciation and Amortization	1,220	277
Change in Servicing Rights	-1,443	-294
Purchase of Loans Held for Sale at Fair Value	-540,924	-150,787
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	547,673	150,510
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities	-19,864	-4,754
Other Assets	-15	3
Accounts Payable and Accrued Liabilities	205	89
Payable to Investors	23,073	5,684
Net Related Party Receivable/Payable	336	-516
Net Cash Provided by (Used in) Operating Activities	13,941	1,517
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	-47,714	-44,213
Principal Payments of Borrower Loans Held at Fair Value	36,063	28,245
Purchases of Property and Equipment	-4,059	-180
Maturities of Short Term Investments	1,274	1,271
Purchases of Short Term Investments	-1,275	-1,274
Changes in Restricted Cash Related to Investing Activities	1,860	-1,119
Net Cash Used in Investing Activities	-13,851	-17,270
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	47,796	43,933
Payment of Notes Held at Fair Value	-36,069	-28,326
Net Cash Included in Transfer of Assets from Parent	-15,000
Net Cash Provided by Financing Activities	-3,273	15,607
Net (Decrease) Increase in Cash and Cash Equivalents	-3,183	-146
Cash and Cash Equivalents at Beginning of the Period	23,777	5,789
Cash and Cash Equivalents at End of the Period	20,594	5,643
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	10,444	10,178
Non-Cash Financing Activity - Distribution to Parent	$249	$93

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Basis of Presentation	1. Basis of Presentation
	The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.
	Prosper did not have any items of other comprehensive income (loss) during any of the periods presented in the condensed consolidated financial statements as of and for the three months ended March 31, 2015 and 2014, respectively.
	The preparation of Prosper’s condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in Prosper’s financial statements and accompanying notes. Prosper bases its estimates on historical experience and on various other factors it believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material.
	The accompanying interim condensed consolidated financial statements include the accounts of PMI and its wholly-owned subsidiaries, PFL and PHL. All intercompany balances have been eliminated in consolidation.
	On January 23, 2015, Prosper acquired all of the outstanding limited liability company units of American HealthCare Lending, LLC (“AHL”), a company that operates a cloud-based patient financing platform, and merged AHL with and into PHL, with PHL surviving the merger. Prosper’s condensed consolidated financial statements include PHL's results of operations and financial position from this date forward (see Note 6 – American HealthCare Lending Acquisition).
	Reclassifications
	During the year ended December 31, 2014, Prosper changed the presentation of its revenue in the consolidated statements of operations. A new line called “Servicing fees” was created and the servicing fees related to Borrower Loans sold through Prosper’s Whole Loan Channel that were previously included in interest income were reclassified to this new line. Furthermore, the “Rebates and Promotions” line was removed, with the amounts in that line reclassified to the “Servicing fees” or “Origination fees” lines based on the underlying transactions. Also, the “Change in Fair Value of Borrower Loans, loans held for sale and Notes, Net” was moved into the “Total revenue” subtotal. Lastly, the subtotals were realigned to reflect the new presentation.
	Prosper also changed the definitions used to classify expenses.  Expenses were previously classified as cost of services, compensation and benefits, marketing and advertising, depreciation and amortization, professional services, facilities and maintenance, class action settlement, loss on impairment of fixed assets and other.   The revised classification approach replaces the previous classifications with origination and servicing, sales and marketing, and general and administration.  The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Lastly, the subtotals were realigned to reflect the new presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper’s competitors.
Prosper Funding LLC [Member]
Basis of Presentation	1. Basis of Presentation
	The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.
	Prosper Funding did not have any items of other comprehensive income (loss) during any of the periods presented in the condensed consolidated financial statements as of and for the three months ended March 31, 2015 and 2014, respectively.
	The preparation of Prosper Funding's condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in its condensed consolidated financial statements and accompanying notes. Prosper Funding based its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material.
	Reclassifications
	During the year ended December 31, 2014, Prosper Funding changed the presentation of its revenue in the statement of operations. A new line called “Servicing Fees, Net” was created and the servicing fees related to Borrower Loans sold through its Whole Loan Channel that were previously included in interest income were reclassified to this new line. Also, the “Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net” was moved into the total revenue subtotal.
	Prosper Funding also changed the definitions used to classify expenses. Expenses were previously classified as cost of services, administration fee, depreciation and amortization, professional services and other operating expenses. The revised classification approach replaces the previous classifications with servicing, administration fee –related party, and general and administration.   The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Prosper Funding believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper Funding’s competitors.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Significant Accounting Policies [Line Items]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies
	Prosper’s significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies in Prosper’s Annual Report on Form 10-K for the year ended December 31, 2014. There have been no changes to these accounting policies during the first three months of 2015 except for Loan Servicing Assets and Liabilities.
	Fair Value Measurements
	Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Short Term Investments, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature.
	Borrower Loans, Loans Held for Sale and Notes
	Borrower Loans, loans held for sale and Notes are recorded at fair value.  Prosper has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”). ASC Topic 825 permits companies to 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 reader of the financial statements and it allows both the Borrower Loans, loans held for sale 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.
	Loan Servicing Assets and Liabilities
	On January 1, 2015, Prosper elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities subsequent to initial recognition.  ASC 860-50, Servicing Assets and Liabilities allows the subsequent adoption of the fair value method at the beginning of any fiscal year.  The adoption of the fair value method for a particular class is irrevocable.  Prior to January 1, 2015, Prosper measured the servicing assets and liabilities using the amortized cost method. This change resulted in a $575 thousand decrease to accumulated deficit, a $546 thousand increase in net servicing assets and a $29 thousand decrease in net servicing liabilities.
	Recent Accounting Pronouncements
	In May 2014, as part of its ongoing efforts to assist in the convergence of U.S. GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers.” 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 2017. Early adoption is not permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40); Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” which requires management of a company to evaluate whether there is substantial doubt about the company’s ability to continue as a going concern. This ASU is effective for the annual reporting period ending after December 15, 2016, and for interim and annual reporting periods thereafter, with early adoption permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In November 2014, the FASB issued ASU 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity to eliminate the use of different methods in practice and thereby reduce existing diversity in the accounting for hybrid financial instruments issued in the form of a share. For hybrid financial instruments issued in the form of a share, an entity should determine the nature of the contract by considering the economic characteristics and risks of the entire hybrid financial instrument. The existence or omission of any single term or feature does not necessarily determine the economic characteristics and risks of the host contract. This standard will be effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In February 2015, the FASB issued ASU 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis." ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 is effective for periods beginning after December 15, 2015 with early adoption permitted. Prosper has decided to early adopt this guidance effective January 1, 2015, the adoption of this standard had no impact on Prosper’s financial statements.
Prosper Funding LLC [Member]
Significant Accounting Policies [Line Items]
Summary of Significant Accounting Policies	2. Significant Accounting Policies
	Prosper Funding's significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies in Prosper Funding’s Annual Report on Form 10-K for the year ended December 31, 2014. There have been no changes to these accounting policies during the first three months of 2015 except for Loan Servicing Assets and Liabilities.
	Fair Value Measurements
	Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Short Term Investments, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature.
	Borrower Loans, Loans Held for Sale and Notes
	Borrower Loans, loans held for sale and Notes are recorded at fair value.  Prosper Funding has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”). ASC Topic 825 permits companies to 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 reader of the financial statements and it allows both the Borrower Loans, loans held for sale 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.
	Loan Servicing Assets and Liabilities
	On January 1, 2015, Prosper Funding elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities, subsequent to initial recognition.  ASC 860, Servicing Assets and Liabilities allows the subsequent adoption of the fair value method at the beginning of any fiscal year.  The adoption of the fair value method for a particular class is irrevocable.  Prior to January 1, 2015, Prosper Funding measured the servicing assets and liabilities using the amortized cost method. This change resulted in a $428 thousand increase to retained earnings, a $399 thousand increase in net servicing assets and a $29 thousand decrease in net servicing liabilities.
	Recent Accounting Pronouncements
	In May 2014, as part of its ongoing efforts to assist in the convergence of U.S. GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers.” 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 2017. Early adoption is not permitted. Prosper Funding is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40); Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” which requires management of a company to evaluate whether there is substantial doubt about Prosper Funding’s ability to continue as a going concern. This ASU is effective for the annual reporting period ending after December 15, 2016, and for interim and annual reporting periods thereafter, with early adoption permitted. Prosper Funding is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In February 2015, the FASB issued ASU 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis." ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 is effective for periods beginning after December 15, 2015 with early adoption permitted. Prosper Funding has decided to early adopt this guidance effective January 1, 2015, the adoption of this standard had no impact on Prosper Funding’s financial statements.

Property_and_Equipment_Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2015
Property and Equipment, Net	3. Property and Equipment, Net
	Property and equipment consist of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Property and equipment:
	Computer equipment	$	6,178		$	3,824
	Internal-use software and website development costs		8,513			4,486
	Office equipment and furniture		1,961			1,904
	Leasehold improvements		5,564			5,274
	Assets not yet placed in service		1,589			4,361
	Property and equipment		23,805			19,849
	Less accumulated depreciation and amortization		(7,149	)		(5,425	)
	Total property and equipment, net	$	16,656		$	14,424
	Depreciation expense for the three months ended March 31, 2015 and 2014 was $1,850 thousand and $400 thousand respectively. Prosper capitalized internal-use software and website development costs in the amount of $1,215 thousand and $368 thousand for the three months ended March 31, 2015 and 2014, respectively. Prosper recorded internal-use software and website development impairment charges of $nil and $215 thousand for the three months ended March 31, 2015 and 2014 respectively, as a result of its decision to discontinue several software and website development projects.  These charges are included in general and administration expenses on the condensed consolidated statement of operations.
Prosper Funding LLC [Member]
Property and Equipment, Net	3. Property and Equipment
	Property and equipment consist of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Property and equipment:
	Internal-use software and web site development costs	$	8,022		$	4,042
	Less accumulated depreciation and amortization		(4,058	)		(2,917	)
	Total property and equipment, net	$	3,964		$	1,125
	Depreciation expense for the three months ended March 31, 2015 and 2014 was $1,220 thousand and $277 thousand, respectively.

Borrower_Loans_Loans_Held_for_

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	3 Months Ended
	Mar. 31, 2015
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	4. Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value
	The fair value of the Borrower Loans and Notes funded through the Note Channel 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 and Notes include default rates derived from historical performance and discount rates applied to each credit grade based on the perceived credit risk of each credit grade. The obligation to pay principal and interest on any series of Notes is equal to the loan payments, if any, received on the corresponding Borrower Loan, net of the servicing fee. As such, the fair value of the Notes is approximately equal to the fair value of the Borrower Loans funded through the Note Channel, adjusted for the servicing fee and the timing of borrower payments subsequently disbursed to the Note holders. The effective interest rate associated with a series of Notes will be less than the interest rate earned on the corresponding Borrower Loan due to the servicing fee.
	The aggregate principal balances outstanding and fair values of Borrower Loans, loans held for sale and Notes as of March 31, 2015 and December 31, 2014, are presented in the following table (in thousands):
			Borrower Loans								Notes						Loans Held for Sale
			March 31,				December 31,				March 31,			December 31,			March 31,		December 31,
			2015				2014				2015			2014			2015		2014
	Aggregate principal balance outstanding		$	275,879			$	268,598			$	(279,455	)	$	(272,267	)	$	1,573	$	8,295
	Fair value adjustments			4,525				4,645				(1,346	)		(1,516	)		26		168
	Fair value		$	280,404			$	273,243			$	(280,801	)	$	(273,783	)	$	1,599	$	8,463
	At March 31, 2015, Borrower Loans, loans held for sale and Notes had original terms to maturity of between 36 months and 60 months, had monthly payments with fixed interest rates ranging from 5.77% to 33.04% and had various maturity dates through March 2020. At December 31, 2014, Borrower Loans, Notes and loans held for sale had original maturities between 36 and 60 months, had monthly payments with fixed interest rates ranging from 5.77% to 33.04% and had various maturity dates through December 2019.
	Significant Unobservable Inputs
	The following table presents quantitative information about the significant unobservable inputs used for Prosper’s Borrower Loans, loans held for sale and Notes fair value measurements at March 31, 2015 and December 31, 2014:
			Range
	Unobservable Input		March 31, 2015		December 31, 2014
	Discount rate		2.8%-10.1%		3.3%-10.6%
	Default rate		2.6%-18.8%		2.5%-18.6%
	Key economic assumptions and the sensitivity of the current fair value to immediate adverse changes in those assumptions at March 31, 2015 Borrower Loans, loans held for sale and Notes funded through the Note Channel are presented in the following table (in thousands):
			Borrower Loans /				Notes
			Loans Held for Sale
	Discount rate assumption:		4.61			%*	4.61			%*
	Resulting fair value from:
	100 basis point increase		$	278,837			$	277,641
	200 basis point increase			275,756				274,567
	Resulting fair value from:
	100 basis point decrease		$	285,261			$	284,051
	200 basis point decrease			288,612				287,394
	Default rate assumption:		11.95			%*	11.95			%*
	Resulting fair value from:
	200 basis point decrease		$	289,030			$	287,800
	100 basis point decrease			285,527				284,310
	Resulting fair value from:
	100 basis point increase		$	278,513			$	277,324
	200 basis point increase			275,089				273,914
	*	Represents weighted average assumptions considering all credit grades.
	These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a 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.
	The changes in the Borrower Loans, loans held for sale and Notes, which are Level 3 assets measured at fair value on a recurring basis are as follows (in thousands):
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
			Borrower				Notes				Loans Held			Total
			Loans								for Sale
	Balance at January 1, 2014		$	233,105			$	(234,218	)		$	3,206		$	2,093
	Purchase of Borrower Loans/Issuance of Notes			44,256				(43,933	)			150,787			151,110
	Principal repayments			(28,245	)			28,326				-			81
	Borrower Loans sold to third parties			-				-				(150,510	)		(150,510	)
	Other changes			(39	)			173				(1	)		133
	Change in fair value			(4,150	)			4,317				-			167
	Balance at March 31, 2014		$	244,927			$	(245,335	)		$	3,482		$	3,074
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
			Borrower				Notes				Loans Held			Total
			Loans								for Sale
	Balance at January 1, 2015		$	273,243			$	(273,783	)		$	8,463		$	7,923
	Purchase of Borrower Loans/Issuance of Notes			47,714				(47,796	)			540,924			540,842
	Principal repayments			(36,063	)			36,069				(364	)		(358	)
	Borrower Loans sold to third parties			-				-				(547,309	)		(547,309	)
	Other changes			6				207				(8	)		205
	Change in fair value			(4,496	)			4,502				(107	)		(101	)
	Balance at March 31, 2015		$	280,404			$	(280,801	)		$	1,599		$	1,202
	Approximately $4.8 million and $4.6 million represents the aggregate adverse fair value adjustments that were recorded to charge off Borrower Loans during the three months ending March 31, 2015 and March 31, 2014 respectively.
	As of March 31, 2015, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $1.3 million and a fair value of $0.5 million. As of December 31, 2014, Borrower Loans that were 90 days or more delinquent, had an aggregate principal amount of $1.7 million and a fair value of $0.6 million. Prosper places loans on non-accrual status when they are over 120 days past due.  As of March 31, 2015 and December 31, 2014, Borrower Loans in non-accrual status had a fair value of $0.
Prosper Funding LLC [Member]
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	4. Borrower Loans, Loans Held For Sale and Notes Held at Fair Value
	The fair value of the Borrower Loans and Notes funded through the Note Channel 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 and Notes include default rates derived from historical performance and discount rates applied to each credit grade based on the perceived credit risk of each credit grade. The obligation to pay principal and interest on any series of Notes is equal to the loan payments, if any, received on the corresponding Borrower Loan, net of the servicing fee. As such, the fair value of the Notes is approximately equal to the fair value of the Borrower Loans funded through the Note Channel, adjusted for the servicing fee and the timing of borrower payments subsequently disbursed to the Note holders. The effective interest rate associated with a series of Notes will be less than the interest rate earned on the corresponding Borrower Loan due to the servicing fee.
	The aggregate principal balances outstanding and fair values of Borrower Loans, loans held for sale and Notes as of March 31, 2015 and December 31, 2014, are presented in the following table (in thousands):
			Borrower Loans								Notes						Loans Held for Sale
			March 31,				December 31,				March 31,			December 31,			March 31,		December 31,
			2015				2014				2015			2014			2015		2014
	Aggregate principal balance outstanding		$	275,879			$	268,593			$	(279,455	)	$	(272,270	)	$	1,573	$	8,295
	Fair value adjustments			4,525				4,650				(1,346	)		(1,513	)		26		168
	Fair value		$	280,404			$	273,243			$	(280,801	)	$	(273,783	)	$	1,599	$	8,463
	At March 31, 2015, Borrower Loans, loans held for sale and Notes had original terms to maturity of between 36 months and 60 months, had monthly payments with fixed interest rates ranging from 5.77% to 33.04 and had various maturity dates through March 2020. At December 31, 2014, Borrower Loans, Notes and loans held for sale had original maturities between 36 and 60 months, had monthly payments with fixed interest rates ranging from 5.77% to 33.04% and had various maturity dates through December 2019.
	Significant Unobservable Inputs
	The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding’s Borrower Loans, loans held for sale and Notes fair value measurements at March 31, 2015 and December 31, 2014:
			Range
	Unobservable Input		March 31, 2015		December 31, 2014
	Discount rate		2.8%-10.1%		3.3%-10.6%
	Default rate		2.6%-18.8%		2.5%-18.6%
	Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at March 31, 2015 for Borrower Loans, loans held for sale and Notes funded are presented in the following table (in thousands):
			Borrower				Notes
			Loans /
			Loans Held
			for Sale
	Discount rate assumption:		4.61			%*	4.61			%*
	Resulting fair value from:
	100 basis point increase		$	278,837			$	277,641
	200 basis point increase			275,756				274,567
	Resulting fair value from:
	100 basis point decrease		$	285,261			$	284,051
	200 basis point decrease			288,612				287,394
	Default rate assumption:		11.95			%*	11.95			%*
	Resulting fair value from:
	200 basis point decrease		$	289,030			$	287,800
	100 basis point decrease			285,527				284,310
	Resulting fair value from:
	100 basis point increase		$	278,513			$	277,324
	200 basis point increase			275,089				273,914
	*	Represents weighted average assumptions considering all credit grades.
	These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a 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.
	The changes in the Borrower Loans, loans held for sale and Notes, which are Level 3 assets measured at fair value on a recurring basis are as follows (in thousands):
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
											Loans
											Held for
			Borrower Loans				Notes				Sale			Total
	Balance at January 1, 2014		$	233,105			$	(234,218	)		$	3,206		$	2,093
	Originations			44,213				(43,933	)			150,787			151,067
	Principal repayments			(28,244	)			28,326				-			82
	Borrower Loans sold to third parties			-				-				(150,510	)		(150,510	)
	Other changes			(39	)			173				(1	)		133
	Change in fair value			(4,107	)			4,317				-			210
	Balance at March 31, 2014		$	244,928			$	(245,335	)	)	$	3,482		$	3,075
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
											Loans
											Held for
			Borrower Loans				Notes				Sale			Total
	Balance at January 1, 2015		$	273,243			$	(273,783	)		$	8,463		$	7,923
	Originations			47,714				(47,796	)			540,924			540,842
	Principal repayments			(36,063	)			36,069				(364	)		(358	)
	Borrower Loans sold to third parties			-				-				(547,309	)		(547,309	)
	Other changes			6				207				(8	)		205
	Change in fair value			(4,496	)			4,502				(107	)		(101	)
	Balance at March 31, 2015		$	280,404			$	(280,801	)		$	1,599		$	1,202
	Approximately $4.8 million and $4.6 million represents the aggregate adverse fair value adjustments that were recorded to charge off Borrower Loans during the three months ending March 31, 2015 and March 31, 2014 respectively.
	As March 31, 2015, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $1.3 million and a fair value of $0.5 million. As December 31, 2014, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $1.5 million and a fair value of $0.14 million. Prosper Funding places Borrower Loans on non-accrual status when they are over 120 days past due. As of March 31, 2015 and December 31, 2014, Borrower Loans in non-accrual status had a fair value of $0.

Loan_Servicing_Assets_and_Liab

Loan Servicing Assets and Liabilities	3 Months Ended
	Mar. 31, 2015
Loan Servicing Assets and Liabilities	5. Loan Servicing Assets and Liabilities
	Prosper accounts for servicing assets and liabilities at their estimated fair values with changes in fair values recorded in servicing fees.  The initial asset or liability is recognized when Prosper sells Borrower Loans to unrelated third-party buyers and the servicing rights are retained. Prior to January 1, 2015, the initial fair value of such servicing assets or liabilities was amortized in proportion to and over the servicing period. Subsequent to January 1, 2015, the servicing assets and liabilities are measured at fair value throughout the servicing period.  The total gain recognized on the sale of such Borrower Loans was $0.3 million for the three months ended March 31, 2014. The total gain recognized on the sale of Borrower Loans sold to unrelated third-party buyers was $1.9 million for the three months ended March 31, 2015.
	As of March 31, 2015, Borrower Loans that were facilitated and subsequently sold but for which Prosper retained servicing rights had a total outstanding principle balance of $1,796 million, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.00% to 31.90% and maturity dates through March 2020.  At December 31, 2014, Borrower Loans that were facilitated and subsequently sold but for which Prosper retained servicing rights had a total outstanding principle balance of $1.36 billion, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and maturity dates through December 2019.
	The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes the market servicing rate, the default rate and discount rate as important inputs.  For more details refer to Part IV - Item 15 – Exhibits, Financial Statement Schedules - Note 5 – Loan Servicing Assets and Liabilities Prosper’s Annual Report.
	Significant Unobservable Inputs
	The following table presents quantitative information about the significant unobservable inputs used for Prosper’s servicing asset/liability fair value measurements at March 31, 2015 and December 31, 2014:
		Range
	Unobservable Input	March 31, 2015		December 31, 2014
	Discount rate	15% - 25%		15% - 25%
	Default rate	2.0% - 19.8%		2.6% - 26.3%
	Market servicing rate	0.63%		0.625% - 0.70%
	Loan Servicing Asset and Liabilities Activity:
	The following table presents additional information about Level 3 servicing assets and liabilities measured at fair value for the three months ended March 31, 2015 (in thousands).
		Servicing			Servicing
		Assets			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		2,078			154
	Less: Changes in fair value		(753	)		(81	)
	Fair value at March 31, 2015	$	6,034		$	668
	Servicing Asset and Liability Fair Value Input Sensitivity:
	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 March 31, 2015 (in thousands, except percentages).
		Servicing			Servicing
		Assets			Liabilities
	Weighted average market servicing rate assumptions		0.625	%		0.625	%
	Resulting fair value from:
	Market servicing rate increase to 0.65%	$	5,594		$	(734	)
	Market servicing rate decrease to 0.60%	$	6,487		$	(601	)
	Weighted average default assumptions		13	%		13	%
	Resulting fair value from:
	100 basis point increase	$	5,930		$	(667	)
	100 basis point decrease	$	6,152		$	(669	)
	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.
Prosper Funding LLC [Member]
Loan Servicing Assets and Liabilities	5. Loan Servicing Assets and Liabilities
	Prosper Funding accounts for servicing assets and liabilities at their estimated fair values with changes in fair values recorded in servicing fees.  The initial asset or liability is recognized when Prosper Funding sells Borrower Loans to unrelated third-party buyers and the servicing rights are retained. Prior to January 1, 2015, the initial fair value of such servicing assets or liabilities was amortized in proportion to and over the servicing period. Subsequent to January 1, 2015, the servicing assets and liabilities are measured at fair value throughout the servicing period.  The total gain recognized on the sale of such Borrower Loans was $0.3 million for the three months ended March 31, 2014. Effective January 1, 2015, Prosper Funding elected to adopt the fair value method to measure the servicing assets and liabilities for all classes subsequent to initial recognition. The total gain recognized on the sale of the Borrower Loans sold to unrelated third-party buyers was $1.9 million for the three months ended March 31, 2015.
	At March 31, 2015, Borrower Loans that were facilitated and subsequently sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $1,448 million, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.00% to 31.90% and maturity dates through March 2020.  At December 31, 2014, Borrower Loans that were facilitated and subsequently sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $1,045 million, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and maturity dates through December 2019.
	The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes the market servicing rate, the default rate and discount rate as important inputs.  For more details refer to Part IV - Item 15 – Exhibits, Financial Statement Schedules - Note 5 – Loan Servicing Assets and Liabilities in the Prosper Funding’s Annual Report.
	Significant Unobservable Inputs
	The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding's servicing asset/liability fair value measurements at March 31, 2015 and December 31, 2014:
		Range
	Unobservable Input	31-Mar-15		31-Dec-14
	Discount rate	15% - 25%		15% - 25%
	Default rate	2.0% - 19.8%		2.6% - 26.3%
	Market servicing rate	0.63%		0.625% - 0.70%
	Loan Servicing Assets and Liabilities Activity:
	The following table presents additional information about Level 3 servicing assets and liabilities recorded at fair value for the three months ended March 31, 2015 (in thousands).
		Servicing			Servicing
		Assets			Liabilities
	Amortized cost at January 1, 2015	$	3,116		$	624
	Adjustment to adopt fair value measurement		399			(29	)
	Fair value at January 1, 2015		3,515			595
	Additions		2,078			154
	Less:  Transfers to PMI		(249	)		-
	Less: changes in fair value		(562	)		(81	)
	Fair value at March 31, 2015	$	4,782		$	668
	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 March 31, 2015 (in thousands, except percentages).
		Servicing			Servicing
		Assets			Liabilities
	Weighted average market servicing rate assumptions		0.625	%		0.625	%
	Resulting fair value from:
	Servicing rate increase to 0.65%	$	4,428		$	(734	)
	Servicing rate decrease to 0.60%	$	5,135		$	(601	)
	Weighted average default assumptions		13	%		13	%
	Resulting fair value from:
	100 basis point increase	$	4,694		$	(667	)
	100 basis point decrease	$	4,870		$	(669	)
	These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a 10% variation in assumptions generally cannot be determined because the relationship of the change in assumptions to the fair value may not be linear. Additionally, the impact of a variation in a particular assumption on the fair value is calculated while holding other assumptions constant. In reality, changes in one factor may lead to changes in other factors, which could impact the above hypothetical effects.

American_HealthCare_Lending_Ac

American HealthCare Lending Acquisition	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
American HealthCare Lending Acquisition	6. American HealthCare Lending Acquisition
	On January 23, 2015, Prosper acquired all of the outstanding limited liability company interests of AHL, and merged AHL with and into PHL, with PHL surviving the merger (the “Merger”). Under the terms of the purchase agreement, the sellers of AHL received an aggregate of $20.2 million in cash on the closing date and will receive $0.8M in cash one year after the closing date subject to general representations.
	PHL is a patient financing company for healthcare providers in the cosmetic, dentistry, bariatric surgery, fertility, plastic surgery and other markets. Prosper has included the financial results of PHL in the condensed consolidated financial statements from the date of acquisition.  The amounts of net revenue and loss of PHL included in Prosper’s condensed consolidated statement of operations from the merger date of January 23, 2015 to March 31, 2015 were $0.6 million and $0.3 million, respectively. Prosper recorded acquisition-related expenses of $0.2 million for the three months ended March 31, 2015, which is included in general and administrative expense.
	The preliminary purchase price allocation as of the merger date is as follows (in thousands):
		Fair Value
	Assets:
	Cash	$	1,219
	Accounts Receivable		147
	Property, equipment and software		6
	Other assets		63
	Identified intangible assets		3,520
	Goodwill		16,825
	Liabilities:
	Accrued expenses and other liabilities		708
	Total purchase consideration	$	21,072
	The allocation of the purchase price is preliminary and subject to further adjustment as information relative to closing date balances and related tax balances are finalized.
	The goodwill balance is primarily attributed to expected operational synergies and the combined workforce. Goodwill is expected to be deductible for U.S. income tax purposes.
	Intangible assets as of March 31, 2015 are as follows (in thousands):
		31-Mar-15
		Gross		Accumulated			Net		Remaining
		Carrying Value		Amortization			Carrying Value		Useful Life
									(In Years)
	Customer relationships	$	2,650	$	(41	)	$	2,609		10
	Technology		810		(45	)		765		3
	Brand name		60		(10	)		50		1
	Total intangible assets subject to amortization	$	3,520	$	(96	)	$	3,424
	The customer relationship intangible assets are being amortized on an accelerated basis over a 10 year period. The technology and brand name intangible assets are being amortized on a straight line basis over three and one years, respectively. Amortization expense associated with intangible assets for the three months ended March 31, 2015 was $96 thousand.
	Prosper valued customer relationships, technology and brand name using the income approach.  Significant assumptions include forecasts of revenues, costs of revenues, operating expenses and customer attrition rates for customers.

Net_Loss_Per_Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Net Loss Per Share	7. 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 March 31,
		2015			2014
	Numerator:
	Net loss available to common stockholders for basic	$	(7,276	)	$	(2,718	)
	and diluted EPS
	Denominator:
	Weighted average shares used in computing basic and		10,553,251			8,056,248
	diluted net loss per share
	Basic and diluted net loss per share	$	(0.69	)	$	(0.34	)
	Due to losses attributable to Prosper’s common shareholders for each of the periods below, the following potentially dilutive shares are excluded from the diluted net loss per share calculation because they were anti-dilutive under the treasury stock method, in accordance with ASC Topic 260:
		Three Months Ended March 31,
		2015			2014
		(shares)			(shares)
	Excluded securities:
	Convertible preferred stock issued and outstanding		30,699,957			27,274,068
	Stock options issued and outstanding		7,038,728			4,359,556
	Unvested stock options exercised		3,727,042			5,054,772
	Warrants issued and outstanding		125,293			218,810
	Total common stock equivalents excluded from		41,591,020			36,907,206
	diluted net loss per common share computation

Convertible_Preferred_Stock_an

Convertible Preferred Stock and Stockholders' Deficit	3 Months Ended
	Mar. 31, 2015
Stockholders Equity Note [Abstract]
Convertible Preferred Stock and Stockholders' Deficit	8. Convertible Preferred Stock and Stockholders’ Deficit
	Convertible Preferred Stock
	Under Prosper’s amended and restated certificate of incorporation, preferred stock is issuable in series, and the board of directors is authorized to determine the rights, preferences, and terms of each series.
	The number of authorized, issued and outstanding shares, their par value and liquidation preference for each series of convertible preferred stock as of March 31, 2015 are disclosed in the table below (amounts in thousands except share and per share amounts):
	Convertible Preferred Stock	Par Value		Authorized		Outstanding		Liquidation
				shares		and Issued		Preference
						shares
	New Series A	$	0.01		13,868,152		13,711,644	$	19,774
	Series A-1		0.01		5,117,182		4,952,183		49,522
	New Series B		0.01		8,288,734		7,155,176		21,581
	New Series C		0.01		4,880,954		4,880,954		70,075
					32,155,022		30,699,957	$	160,952
	Common Stock
	Prosper, through its amended and restated certificate of incorporation, is the sole issuer of common stock and related options and warrants. In May 2014, Prosper amended and restated its certificate of incorporation to effect an increase in the number of authorized shares of stock. The total number of shares of stock which Prosper has the authority to issue is 81,083,905, consisting of 48,928,883 shares of common stock, $0.01 par value per share, and 32,155,022 shares of preferred stock, $0.01 par value per share. As of March 31, 2015, 14,878,514 shares of common stock were issued and 14,691,237 shares of common stock were outstanding. As of December 31, 2014, 14,448,700 shares of common stock were issued and 14,261,513 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 three months ended March 31, 2015 Prosper issued 308,750 shares of common stock, upon the exercise of options for cash proceeds of $0.54 million, of which 9,459 shares were unvested. With the approval of Prosper’s board of directors, Prosper allows certain employees and directors to exercise stock options granted under the 2005 Plan prior to vesting. The unvested shares are subject to Prosper’s repurchase right at the original exercise price. Early exercises of options are not deemed to be substantive exercises for accounting purposes and therefore, amounts received for early exercises are initially recorded in repurchase liability for unvested restricted stock awards.  Such amounts are reclassified to common stock and additional paid-in capital as the underlying shares vest. At March 31, 2015 and December 31, 2014, there were 3,637,042 and 4,114,269 shares respectively of restricted stock outstanding that remain unvested and subject to Prosper’s right of repurchase.
	For the three months ended March 31, 2015, Prosper repurchased 1,875 shares of restricted stock for $1 thousand upon termination of employment of various employees.
	Common Stock Issued upon Exercise of Warrants
	For the three months ended March 31, 2015, Prosper issued 32,939 shares of common stock upon the exercise of warrants for aggregate proceeds of $111 thousand.

Stock_Option_Plan_and_Compensa

Stock Option Plan and Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Option Plan and Compensation	9. Stock Option Plan and Compensation
	In 2005, Prosper’s stockholders approved the adoption of the 2005 Stock Plan. In December 2010, Prosper’s stockholders approved the adoption of the Amended and Restated 2005 Stock Plan (the “2005 Plan”). As of March 31, 2015 under the 2005 Plan, options to purchase up to 15,195,255 shares of common stock are reserved and may be granted to employees, directors, and consultants by Prosper’s board of directors and stockholders to promote the success of its business. Options generally vest 25% one year from the vesting commencement date and 1/48th per month thereafter.  In no event are options exercisable more than ten years after the date of grant.
	At March 31, 2015, there were 138,289 stock options available for grant under the 2005 Plan.
	Early Exercised Stock Options
	The activity of options that were early exercised under the 2005 Plan for the three months ended March 31, 2015 is below:
			Early exercised			Weighted average
			options, unvested			exercise price
	Balance as of January 1, 2015			4,112,269		$	0.25
	Exercise of non-vested stock options			9,459			2.18
	Repurchase of restricted stock			(1,875	)		0.57
	Restricted stock vested			(482,811	)		0.17
	Balance as of March 31, 2015			3,637,042		$	0.26
	Additional information regarding the unvested early exercised stock options outstanding as of March 31, 2015 is as follows:
			Options Outstanding
	Range of
	Exercise		Number			Weighted –Avg.			Weighted –Avg.
	Prices		Outstanding			Remaining Life			Exercise Price
	$0.10 - $0.10			3,111,922			1.89		$	0.1
	0.57 - 0.57			458,981			2.97			0.57
	5.65-5.65			66,139			3.33			5.65
	$0.10 - $5.65			3,637,042			2.06		$	0.26
	Stock Option Activity
	Stock option activity under the 2005 Plan is summarized for the three months ended March 31, 2015 below:
			Options			Weighted-
			Issued and			Average
			Outstanding			Exercise
						Price
	Balance as of January 1, 2015			4,994,998		$	1.85
	Options granted			2,469,314			18.11
	Options exercised – vested			(299,291	)		1.74
	Options exercised – nonvested			(9,459	)		2.18
	Options forfeited			(116,834	)		6.02
	Balance as of March 31, 2015			7,038,728			7.49
	Options vested and exercisable at March 31, 2015			6,006,329			8.1
	For the three months ended March 31, 2015, Prosper granted stock options to purchase 2,469,314 shares of common stock with a weighted average exercise price of $18.11 per share, a weighted average grant date fair value of $16.04 per share and an estimated aggregate fair value of approximately $39.6 million.
	Other Information Regarding Stock Options
	Additional information regarding common stock options outstanding as of March 31, 2015 is as follows:
			Options Outstanding								Options Vested and Exercisable
						Weighted –			Weighted –				Weighted -
	Range of					Avg.			Avg.				Avg.
	Exercise		Number			Remaining			Exercise		Number		Exercise
	Prices		Outstanding			Life			Price		Vested		Price
	$0.10 - $0.10			157,040			8.38		$	0.1		73,756	$	0.1
	0.57 - 0.57			3,100,551			8.87			0.57		2,120,600		0.57
	1.20 – 1.20			70,999			6.45			1.2		63,742		1.2
	1.70 – 1.70			48,019			7.01			1.7		36,990		1.7
	2.00 – 2.00			90,310			5.34			2		90,310		2
	5.00 - 5.00			7,000			1.5			5		7,000		5
	5.60 - 5.60			18,250			4.46			5.6		18,250		5.6
	5.65-5.65			1,105,245			9.46			5.65		2,884		5.65
	$18.11-$18.11			2,441,314			9.89			18.11		-		18.11
	$0.10 - $18.11			7,038,728			8.1		$	7.49		2,413,532	$	0.7
	The fair value of options granted to employees is estimated on the grant date using the Black-Scholes option valuation model. This valuation model for stock-based compensation expense requires Prosper to make assumptions and judgments about the variables used in the calculation, including the fair value of its common stock, the expected term (the period of time that the options granted are expected to be outstanding), the volatility of its common stock, a risk-free interest rate, and expected dividends.
	Given the absence of a publicly traded market, Prosper considered numerous objective and subjective factors to determine the fair value of its common stock at each grant date. These factors included, but were not limited to, (i) contemporaneous valuations of common stock performed by unrelated third-party specialists; (ii) the prices for its preferred stock sold to outside investors; (iii) the rights, preferences and privileges of its preferred stock relative to its common stock; (iv) the lack of marketability of its common stock; (v) developments in its business; (vi) secondary transactions of its common and preferred shares and (vii) the likelihood of achieving a liquidity event, such as an initial public offering or a merger or acquisition of Prosper, given prevailing market conditions.
	Prosper also estimates forfeitures of unvested stock options. To the extent actual forfeitures differ from the estimates, the difference will be recorded as a cumulative adjustment in the period estimates are revised. No compensation cost is recorded for options that do not vest.
	As Prosper’s stock is not publically traded, the expected volatility of its stock 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 and contractual terms 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. Expected forfeitures are based on Prosper’s historical experience.
	The fair value of Prosper’s stock option awards for the three months ended March 31, 2015 and 2014 was estimated at the date of grant using the Black-Scholes model with the following average assumptions:
		Three months ended
			March 31,
			2015			2014
	Volatility of common stock			55.59	%		73.31	%
	Risk-free interest rate			1.61	%		1.92	%
	Expected life	5.7 years				6.1 years
	Dividend yield			0	%		0	%
During the three months ended March 31, 2015, Prosper issued 90,000 shares of restricted stock to employees at a purchase price of $18.11 per share.  One third of these shares vest on the annual anniversary date of the grant over the three year term of the agreement.
The following table presents the amount of stock-based compensation related to stock-based awards granted to employees recognized in Prosper’s condensed consolidated statements of operations during the three months ended March 31, 2015 and 2014 (in thousands):
		Three months ended
		March 31,
		2015			2014
Origination and servicing		$	144		$	63
Sales and marketing			388			16
General and administrative			907			171
Total stock based compensation		$	1,439		$	250
During the three months ended March 31, 2015 and 2014, Prosper capitalized $122 thousand and $5 thousand respectively, of stock-based compensation as internal use software and website development costs. As of March 31, 2015, the unamortized stock-based compensation expense related to Prosper’s employees’ unvested stock-based awards was approximately $32.8 million, which will be recognized over the remaining weighted-average vesting period of approximately 3.8 years.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Taxes	10. Income Taxes
	For the three months ended March 31, 2015, Prosper recognized $73 thousand of income tax expense. The $73 thousand of tax expense relates to the amortization of goodwill from the Acquisition for tax purposes which gives rise to an indefinite-lived deferred tax liability.  No other income tax expense or benefit was recorded for the three months ended March 31, 2015 and 2014 due to a full valuation allowance recorded against our deferred tax assets.
	Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to utilize our existing deferred tax assets. On the basis of this evaluation, a full valuation allowance has been recorded to recognize only deferred tax assets that are more likely than not to be realized.
	Prosper files U.S. Federal and multiple state tax returns. Prosper is currently not subject to any income tax examinations in any jurisdiction. Due to the Prosper’s losses, generally income tax returns related to all years remain open to examination.
	The net amount of unrecognized tax benefits as of March 31, 2015 is $4.9 million related to the uncertainty of whether Prosper will be allowed to utilize certain California NOL carryforwards to offset future taxable income due to Section 382 and the uncertainty relate to our utilization of certain R&D credits. Prosper does not expect any material changes in the next 12 months to its unrecognized tax benefits.
	Subsequent to the issuance of the consolidated financial statements for the year ended December 31, 2014, Prosper identified an error that affected the disclosure of Unrecognized Tax Benefits as of December 31, 2014.  The error was the result of presenting a portion of the unrecognized tax benefit gross of the application of the applicable tax rate, this overstated the amount.  The amount of unrecognized tax benefits as of January 1, 2015 has been revised to reflect the correction of the error.  All unrecognized tax benefits are netted against deferred tax assets with a full valuation allowance.  If these amounts are recognized there will be no effect on Prosper's effective tax rate due to the full valuation allowance.
	The following table summarizes Prosper’s activity related to its unrecognized tax benefits (in thousands):
	Beginning balance as of January 1, 2015		4,927
	Decrease related to prior year positions		-
	Increase related to current year positions		-
	Ending balance as of March 31, 2015	$	4,927
	Prosper recognizes interest and/or penalties related to uncertain tax positions. To the extent accrued interest and penalties do not ultimately become payable, amounts accrued will be reduced and reflected in the period that such determination is made.  The interest and penalties are recognized as other expense in the income statement.  Prosper currently has no interest and penalties related to uncertain tax positions.
Prosper Funding LLC [Member]
Income Taxes	6. Income Taxes
	Prosper Funding incurred no income tax provision for the three months ended March 31, 2015 and 2014. Prosper Funding is a US disregarded entity and its income and loss is included in the return of its parent, PMI. Since PMI is in a loss position, not currently subject to income taxes, and has fully reserved its deferred tax asset, the net effective tax rate for Prosper Funding is 0%.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies	11. Commitments and Contingencies
	Future Minimum Lease Payments
	During 2014, Prosper entered into leases for its new corporate headquarters at 221 Main Street in San Francisco California and for its co-location facility.  These are non-cancelable operating leases that expire in February 2023 and August 2015, respectively. In 2014, Prosper entered into a lease for office space in Phoenix, Arizona under an operating lease that expires in June 2022.
	Future minimum rental payments under these leases as of March 31, 2015 are as follows:
	Remaining nine months of 2015		2,742
	2016		4,239
	2017		3,866
	2018		3,977
	2019		4,093
	2020		4,210
	Thereafter		8,808
	Total future operating lease obligations	$	31,935
	Rental expense under operating lease arrangements was $0.8 million and $0.1 million for the three months ended March 31, 2015 and 2014, respectively.
	Operating Commitments
	Prosper amended and restated its agreement with WebBank, under which all Borrower Loans originated through Prosper’s marketplace are made by WebBank under its bank charter. The arrangement allows for Borrower Loans to be offered to borrowers nationwide on uniform terms. Prosper is required to pay the greater of a monthly minimum fee or a fee calculated based on a certain percentage of monthly Borrower Loan origination volume. The minimum annual fee for the year ended December 31, 2015 is $1.4 million.
	Loan Purchase Commitments
	Prosper has entered into an agreement with WebBank to purchase $26.2 million of Borrower Loans that WebBank is originating within the first two business days of the three months ended June 30, 2015.
	Repurchase and Indemnification Contingency
	Under the terms of the loan purchase agreements between Prosper and investor members that participate in the Whole Loan Channel, Prosper may, in certain circumstances, become obligated to repurchase a Borrower Loan from an investor member. Generally, these circumstances include the occurrence of verifiable identity theft, the failure to properly follow loan listing or bidding protocols, or a violation of the applicable federal, state, or local lending laws. The fair value of the indemnification and repurchase obligation is estimated based on historical experience and the initial fair value is insignificant. Prosper recognizes a liability for the repurchase and indemnification obligation when the Borrower Loans are issued. Indemnified or repurchased Borrower Loans associated with violations of federal, state, or local lending laws or verifiable identity theft are written off at the time of repurchase or at the time an indemnification payment is made.  The maximum potential amount of future payments associated under this obligation is the outstanding balances of the Borrower Loans issued through the Whole Loan Channel, which at March 31, 2015 is $1,796 million. Prosper has accrued $212 thousand and $171 thousand as of March 31, 2015 and December 31, 2014, respectively in regard to this obligation.
	Securities Law Compliance
	From inception through October 16, 2008, Prosper sold approximately $178.0 million of Borrower Loans to investor members through its old platform structure, whereby Prosper assigned promissory notes directly to investor members. Prosper did not register the offer and sale of the promissory notes corresponding to these Borrower Loans under the Securities Act or under the registration or qualification provisions of any state securities laws. Prosper believes that the question of whether or not the operation of the platform during this period constituted an offer or sale of “securities” involved a complicated factual and legal analysis and was uncertain. If the sales of promissory notes offered through the platform during this period were viewed as a securities offering, Prosper would have failed to comply with the registration and qualification requirements of federal and state laws.
	Prosper’s decision to restructure the platform and cease sales of promissory notes offered through the platform effective October 16, 2008 limited this contingent liability to the period covering its activities prior to October 16, 2008.
	On April 21, 2009, Prosper and the North American Securities Administrators Association (“NASAA”) reached agreement on the terms of a model consent order between Prosper and the states in which it, under its initial platform structure, offered promissory notes for sale directly to investor members prior to November 2008. The consent order involves payment by Prosper of up to an aggregate of $1million in penalties, which have been allocated among the states based on Prosper’s promissory note sale transaction volume in each state prior to November 2008. A state that enters into a consent order receives its portion of the $1 million in exchange for its agreement to terminate, or refrain from initiating, any investigation of our promissory note sale activities prior to November 2008. Penalties are paid promptly after a state enters into a consent order. NASAA has recommended that each state enter into a consent order; however, no state is obliged to do so, and there is no deadline by which a state must make its decision. Prosper is not required to pay any portion of the penalty to those states that do not elect to enter into a consent order. If a state does not enter into a consent order, it is free to pursue its own remedies against Prosper, subject to any applicable statute of limitations. As of March 31, 2015, Prosper has entered into consent orders with 34 states and has paid an aggregate of $0.47 million in penalties to those states.
	As of March 31, 2015 and December 31, 2014, Prosper has accrued approximately $0.25 million and $0.25 million, respectively, in connection with the contingent liability associated with the states that have not entered into consent orders, in accordance with ASC Topic 450, Contingencies. The methodology applied to estimate the accrual was to divide the $1 million maximum fee pro-rata by state, using Prosper’s promissory note sales from inception through November 2008. A weighting was then applied by state to each state that has not entered into a consent order, assigning a likelihood that the penalty will be claimed. In estimating the probability of a claim being made by a state, Prosper considered factors such as the standard terms of the consent orders; whether the state ever gave any indication of concern regarding the sale of promissory notes through the platform; the probability of a state electing not to enter into a consent order in order to pursue its own litigation against Prosper; whether the penalty is sufficient to compensate a state for the cost of processing the settlement consent order; and finally the impact that current economic conditions have had on state governments. Prosper will continue to evaluate this accrual and related assumptions as new information becomes known.
	In 2008, plaintiffs filed a class action lawsuit against Prosper and certain of its executive officers and directors in the Superior Court of California, County of San Francisco, California. The suit was brought on behalf of all promissory note purchasers on the platform from January 1, 2006 through October 14, 2008. The lawsuit alleged that Prosper offered and sold unqualified and unregistered securities in violation of the California and federal securities laws. On July 19, 2013 solely to avoid the costs, risks and uncertainties inherent in litigation, and without admitting any liability or wrongdoing, the parties to the class action litigation agreed to enter into a settlement to resolve all claims related thereto (the “Settlement”). In connection with the Settlement, Prosper agreed to pay an aggregate amount of $10 million into a settlement fund, split into four annual installments of $2 million in 2014, $2 million in 2015, $3 million in 2016 and $3 million in 2017. The Settlement received final approval in a final order and judgment entered by the Superior Court on April 16, 2014. Pursuant to the final order and judgment, the claims in the class action were dismissed, and the defendants were released by the plaintiffs from all claims that were or could have been asserted concerning the issues alleged in the class action lawsuit. The reserve for the class action settlement liability is $5.9 million in the condensed consolidated balance sheet as of March 31, 2015.
Prosper Funding LLC [Member]
Commitments and Contingencies	7. Commitments and Contingencies
	Operating Commitments
	Prosper Funding and PMI entered into an amended and restated agreement with WebBank, pursuant to which Prosper Funding is required to pay WebBank the greater of a monthly minimum fee or a fee calculated based on a certain percentage of Borrower Loans purchased by Prosper Funding. The minimum annual fee for the year ended December 31, 2015 is $1.4 million.
	Loan Purchase Commitments
	Under the terms of Prosper Funding’s agreement with WebBank, Prosper Funding is committed to purchase $26.2 million of Borrower Loans that WebBank will originate within the first two business days of April 2015.
	Repurchase and Indemnification Contingency
	Under the terms of the loan purchase agreements between Prosper Funding and investor members that participate in the Whole Loan Channel, Prosper Funding may, in certain circumstances, become obligated to repurchase a Borrower Loan from an investor member. Generally, these circumstances include the occurrence of verifiable identity theft, the failure to properly follow loan listing or bidding protocols, or a violation of the applicable federal, state, or local lending laws. The fair value of the indemnification and repurchase obligation is estimated based on historical experience and the initial fair value is insignificant. 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 March 31, 2015 is $1.4 billion. Prosper Funding had accrued $161 thousand and $171 thousand as of March 31, 2015 and December 31, 2014 in regard to this obligation, respectively.

Related_Parties

Related Parties	3 Months Ended
	Mar. 31, 2015
Related Parties	12. Related Parties
	Since Prosper’s inception, it has engaged in various transactions with its directors, executive officers and holders of more than 10% of its voting securities, and immediate family members and other affiliates of its directors, executive officers and 10% stockholders. Prosper believes that all of the transactions described below were made on terms no less favorable to Prosper than could have been obtained from unaffiliated third parties.
	Prosper’s executive officers, directors who are not executive officers and certain affiliates participate in its marketplace by placing bids and purchasing Notes. The aggregate amount of the Notes purchased and the income earned by parties deemed to be affiliates and related parties of Prosper for the three months ended March 31, 2015 and 2014, as well as the Notes outstanding as of March 31, 2015 and December 31, 2014 are summarized below (in thousands):
		Aggregate Amount of				Interest Earned on Notes
		Notes Purchased
		Three Months Ended				Three Months Ended
		March 31,				31-Mar
	Related Party	2015		2014		2015		2014
	Executive officers and management	$	479	$	214	$	47	$	36
	Directors		10	$	2	$	2	$	3
	Total	$	489	$	216	$	49	$	39
		Notes Balance as of
	Related Party	March 31,		December 31,
		2015		2014
	Executive officers and management	$	1,842	$	1,614
	Directors		96		76
		$	1,938	$	1,690
	Prosper has earned approximately $4 thousand and $6 thousand in servicing fee revenue related to these Notes for the three months ended  March 31, 2015 and 2014, respectively.
Prosper Funding LLC [Member]
Related Parties	8. Related Parties
	Since inception, Prosper Funding has engaged in various transactions with its directors, executive officers and sole member, and immediate family members and other affiliates of its directors, executive officers and sole member. Prosper Funding believes that all of the transactions described below were made on terms no less favorable to Prosper Funding than could have been obtained from unaffiliated third parties.
	Prosper Funding’s executive officers, directors who are not executive officers participate in its marketplace by placing bids and purchasing Notes. The aggregate amount of the Notes purchased and the income earned by parties deemed to be related parties of Prosper as of March 31, 2015 and December 31, 2014 are summarized below (in thousands):
		Aggregate Amount of				Interest Earned on Notes
		Notes Purchased
		Three Months Ended				Three Months Ended
		March 31,				31-Mar
	Related Party	2015		2014		2015		2014
	Executive officers and management	$	479	$	214	$	47	$	36
	Directors		-		-		-		-
	Total	$	479	$	214	$	47	$	36
		Note Balance as of
	Related Party	March 31,		December 31,
		2015		2014
	Executive officers and management	$	1,842	$	1,614
	Directors		-		-
		$	1,842	$	1,614
	Prosper Funding has earned approximately $4 thousand and $6 thousand in servicing fee revenue related to these Notes for the three months ended March 31, 2015 and 2014, respectively.

Postretirement_Benefit_Plans

Postretirement Benefit Plans	3 Months Ended
	Mar. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Postretirement Benefit Plans	13. Postretirement Benefit Plans
	Prosper has a 401(k) plan that covers all employees meeting certain eligibility requirements. The 401(k) plan is designed to provide tax-deferred retirement benefits in accordance with the provisions of Section 401(k) of the Internal Revenue Code. Eligible employees may defer up to 90% of eligible compensation up to the annual maximum as determined by the Internal Revenue Service. Prosper’s contributions to the 401(k) plan are discretionary. During the three months ended March 31, 2015 and 2014, Prosper has contributed $0.4 million and $nil to the 401 (k) plan.

Segments

Segments	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segments	14. Segments
	Prosper’s chief operating decision maker reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. As such, Prosper has a single reporting segment and operating unit structure.

Restatement_of_Condensed_Conso

Restatement of Condensed Consolidated Financial Statements	3 Months Ended
	Mar. 31, 2015
Condensed Financial Statements Captions [Line Items]
Restatement of Condensed Consolidated Financial Statements	15. Restatement of Condensed Consolidated Financial Statements
	Subsequent to the issuance of the condensed consolidated financial statements for the three months ended March 31, 2014, Prosper identified errors that affected the interim condensed financial statements as of and for the three months ended March 31, 2014. Financial statements presented herein have been restated to correct for these errors that are described below and summarized in the tables that follow.
	Prosper discovered that certain fees that Prosper pays to WebBank were incorrectly classified as expenses.  Since WebBank is a customer of Prosper and Prosper earns transaction fees from WebBank any cash consideration paid to WebBank should be recorded as a reduction of the transaction fees earned by Prosper.   This resulted in an overstatement of transaction fee revenues and origination and servicing expenses of $389 thousand.
	Prosper also discovered that certain rebates offered on the sale of loans and Notes were incorrectly classified as transaction fee revenue and should have been classified as other revenue or change in fair value of Borrower Loans, loans held for sale and Notes.   This resulted in an understatement of transaction fee revenues of $232 thousand, an overstatement of other revenues of $188 thousand and an overstatement of change in fair values of Borrower Loans, loans held for sale and Notes of $44 thousand.
	Additionally, Prosper discovered certain errors in its valuation of servicing assets and liabilities which resulted in an overstatement of net loan servicing rights and an overstatement of the gain recognized on the sale of Borrower Loans which was included in other revenues of $20 thousand.  Furthermore, Prosper inappropriately classified loan servicing rights in “Borrower Loans Receivable at Fair Value”.  Prosper corrected this error by reclassifying the gross serving assets to “Prepaid and Other Assets and recognized the servicing liabilities in “Accounts Payable and Other Liabilities.
	Prosper also discovered errors related to internal use software and web site development costs including an impairment that was not recorded when the project was abandoned in the prior year and assets were being amortized over a time period that exceeded their useful life which understated amortization included in origination and servicing expense for $42 thousand.  As well property and equipment was overstated.
	In addition to the restatements described above, Prosper has made other corrections, some of which were previously identified, but were not corrected because management had determined they were not material, individually or in the aggregate, to our consolidated financial statements. These corrections related to the fair value of loans held for investment, reclassification of certain loans from loans held for investment to Borrower Loans, amortization of prepaid assets, estimation of various accruals and a correction for vesting of options that were early exercised.
	Prosper also discovered the following classification errors within its Condensed Consolidated Statement of Cash Flows:
	●	Changes in certain Restricted Cash balances related to investing activities were inappropriately classified as changes in cash flows from operating activities rather than changes in cash flows from investing activities.
	●	Cash flows from the principal payments and proceeds from sale related to Borrower Loans held for sale were inappropriately classified within cash flows from investing activities rather than cash flows from operating activities.
	●	A portion of the change in fair value of Borrower Loans and Notes was inappropriately reflected as a cash flow from investing and financing activities, respectively, rather than an adjustment to reconcile net income to net cash used in operating activities.
	●	The proceeds from sale of borrower loans held at fair value were netted against purchase of borrower loans at fair value.
	●	Other changes related to the correction of errors in the balance sheet and statement of operations as described above.
	Lastly, Prosper corrected its calculation of basic and diluted earnings (loss) per share for the changes to net income (loss) and errors in the calculation of the weighted average basic and diluted shares which was understated by 1,188,095 shares.
	The following tables present the impact of these corrections and corrections of other immaterial errors on three months ended March 31, 2014 ($ in thousands):
	Consolidated Statement of Operations – Three months ended March 31, 2014
			As previously			Reclassifications*			As			Adjustments			As
			reported						reclassified						corrected
	Revenue
	Operating Revenue
	Transaction Fees,  Net		$	8,701		$	(231	)	$	8,470		$	(106	)	$	8,364
	Rebates and Promotions			(361	)		361			-			-			-
	Servicing Fees, Net			-			99			99			315			414
	Other Revenue			696			-			696			(245	)		451
	Total Operating Revenue			9,036			229			9,265			(36	)		9,229
	Interest Income on Borrower Loans			10,109			(228	)		9,881			124			10,005
	Interest Expense on Notes			(9,269	)					(9,269	)		(153	)		(9,422	)
	Net Interest Income			840			(228	)		612			(29	)		583
	Change in Fair Value on Borrower Loans, Loans Held for			298			-			298			(131	)		167
	Sale and Notes, net
	Total Net Revenue			10,174			1			10,175			(196	)		9,979
	Cost of Revenue
	Cost of Services			(525	)		525			-			-			-
	Provision for repurchase and indemnification obligation			(62	)		62			-			-			-
				(587	)		587			-			-			-
	Expenses
	Compensation and benefits			3,901			(3,901	)		-			-			-
	Marketing and advertising			5,986			(5,986	)		-			-			-
	Depreciation and amortization			363			(363	)		-			-			-
	Professional services			176			(176	)		-			-			-
	Facilities and maintenance			445			(445	)		-			-
	Loss on impairment			215			(215	)		-			-			-
	Other			668			(668	)		-			-			-
	Origination and Servicing			-			2,131			2,131			160			2,291
	Sales and Marketing			-			6,424			6,424			10			6,434
	General and Administrative			-			3,786			3,786			186			3,972
	Total  Expenses			11,754			587			12,341			356			12,697
	Other income			1			(1	)		-			-			-
	Total Net Income		$	(2,166	)	$	-		$	(2,166	)	$	(552	)	$	(2,718	)
	*See note 1 for a description of the reclassifications.
	Condensed Consolidated Statements of Cash Flows – Three months ended March 31, 2014
			As previously
			reported			Adjustments			As corrected
	Cash flows from operating activities:
	Net Loss		$	(2,166	)	$	(552	)	$	(2,718	)
	Adjustments to Reconcile Net Income (Loss) to Net Cash Used in
	Operating Activities:
	Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes			-			(167	)		(167	)
	Change in Fair Value of Notes			32			(32	)		-
	Change in Fair Value of Borrower Loans Receivable			(332	)		332			-
	Change in Fair Value of Loans Held for Sale			2			(2	)		-
	Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes			-			(133	)		(133	)
	Depreciation and Amortization			363			37			400
	Stock-Based Compensation			255			(5	)		250
Loss on Impairment of Property and Equipment			215			-			215
Accretion of Class Action Settlement Liability			-			30			30
Change in Servicing Rights			-			(283	)		(283	)
Purchase of  loans held for sale at fair value			-			(150,787	)		(150,787	)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value			-			150,510			150,510
Changes in Operating Assets and Liabilities:						-
Restricted Cash			(1,189	)		(3,980	)		(5,169	)
Accounts Receivable			36			(56	)		(20	)
Prepaid and Other Assets			(445	)		28			(417	)
Accounts Payable and Accrued Liabilities			1,511			(613	)		898
Repurchase liability for unvested stock awards			(105	)		105			-
Payable to Investors			-			5,850			5,850
Class Action Settlement Liability			(2,000	)		-			(2,000	)
Net Cash Used in Operating Activities			(3,823	)		282			(3,541	)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Receivable Held at Fair Value			(166,608	)		122,352			(44,256	)
Principal Payment of Borrower Loans Receivable Held at Fair Value			32,642			(4,397	)		28,245
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value			121,864			(121,864	)		-
Repayment of Loans Held for Investment at Fair Value			100			(100	)		-
Origination of Loans Held for Investment at Fair Value			(28,858	)		28,858			-
Proceeds from sale of Borrower Loans at Fair Value			28,602			(28,602	)		-
Purchases of Property and Equipment			(692	)		33			(659	)
Maturities of Short Term Investments			-			1,271			1,271
Purchases of Short Investments			-			(1,274	)		(1,274	)
Changes in Restricted Cash Related to Investing Activities			-			(771	)		(771	)
Net Cash Used in Investing Activities			(12,950	)		(4,494	)		(17,444	)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value			44,199			(266	)		43,933
Payment of Notes Held at Fair Value			(32,910	)		4,584			(28,326	)
Proceeds from Early Exercise of Stock Options			12			(2	)		10
Proceeds of Restricted Stock Vested			104			(104	)		-
Proceeds from Exercise of Vested Stock Options			4			-			4
Net Cash Provided by Financing Activities		$	11,409		$	4,212		$	15,621
Net Decrease in Cash and Cash Equivalents			(5,364	)		-			(5,364	)
Cash and Cash Equivalents at Beginning of the Period			18,339			-			18,339
Cash and Cash Equivalents at End of the Period		$	12,975		$	-		$	12,975
Prosper Funding LLC [Member]
Condensed Financial Statements Captions [Line Items]
Restatement of Condensed Consolidated Financial Statements	9. Restatement of Condensed Consolidated Financial Statements
	Subsequent to the issuance of the condensed consolidated financial statements for the three months ended March 31, 2014, Prosper Funding identified errors that affected the interim condensed financial statements as of and for the three months ended March 31, 2014.  The financial statements presented herein have been restated to correct for these errors that are described below.
	Prosper Funding discovered certain errors in its valuation of servicing assets and liabilities which resulted in an overstatement of net loan servicing rights and an overstatement of the gain recognized on the sale of Borrower Loans which was included in other revenues of $20 thousand.  Furthermore, Prosper Funding inappropriately classified loan servicing rights in Borrower Loans Receivable at Fair Value.  Prosper Funding corrected this error by reclassifying the gross serving assets to Prepaid and Other Assets and recognized the servicing liabilities in Accounts Payable and Other Liabilities.
	Prosper Funding also discovered that the Administration Fee Related Party Expense was understated by $328 thousand, servicing expenses were overstated by $381 thousand and the Related Party Receivable was understated by $53 thousand due to an error in the calculation of the fee and misclassification of certain expenses.
	Prosper Funding also discovered errors related to internal use software including an overstatement of assets transferred from PMI and assets that were being amortized over their original estimated useful life after Prosper Funding decided to replace the assets before the originally estimated useful life which understated amortization by $42 thousand which is included in servicing expenses. As well Property and Equipment was overstated.
	In addition to the restatements described above, Prosper Funding has made other corrections, some of which were previously identified, but were not corrected because management had determined they were not material, individually or in the aggregate, to our consolidated financial statements. These corrections related to the fair value of loans held for investment, and reclassification of certain Borrower Loans from loans held for investment to Borrower Loans.
	Lastly, Prosper Funding discovered the following classification errors within its Condensed Consolidated Statement of Cash Flows:
	●	Changes in certain Restricted Cash balances related to investing activities were inappropriately classified as changes in cash flows from operating activities rather than changes in cash flows from investing activities.
	●	Cash flows from the principal payments and proceeds from sale related to Borrower Loans held for sale were inappropriately classified within cash flows from investing activities rather than cash flows from operating activities.
	●	A portion of the change in fair value of Borrower Loans and Notes was inappropriately reflected as a cash flow from investing and financing activities, respectively, rather than an adjustment to reconcile net income to net cash used in operating activities.
	Other changes related to the correction of errors in the balance sheet and statement of operations as described above.
	The following tables present the impact of these corrections and corrections of other immaterial errors on the interim periods in the three months ended March 31, 2014 (in thousands):
	Consolidated Statement of Operations – Three months ended March 31, 2014
			As previously			Reclassifications*			As			Adjustments			As
			reported						reclassified						corrected
	Revenue
	Operating Revenue
	Administration Fee Revenue – Related Party		$	4,053		$	—		$	4,053		$	—		$	4,053
	Servicing Income, Net			—			170			170			253			423
	Other Revenue			356			—			356			(57	)		299
	Total Operating Revenue			4,409			170			4,579			196			4,775
	Interest Income on Borrower Loans			10,057			(176	)		9,881			201			10,082
	Interest Expense on Notes			(9,269	)		-			(9,269	)		(154	)		(9,423	)
	Net Interest Income			788			(176	)		612			47			659
	Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net			298			(1	)		297			(87	)		210
	Total Net Revenue			5,495			(7	)		5,488			156			5,644
	Cost of Revenue
	Cost of Services			(397	)		397			—			—			—
	Provision for repurchase and indemnification obligation			(62	)		62			—			—			—
				(459	)		459			—			—			—
	Expenses
	Servicing			—			694			694			(296	)		398
	Administration Fee – Related Party			2,606			—			2,606			888			3,494
	Depreciation and Amortization			235			(235	)		—			—			—
	Professional Services			12			(12	)		—			—			—
	Other Operating Expenses			88			(88	)		—			—			—
	General and Administration			—			100			100			4			104
	Total  Expenses			2,941			459			3,400			596			3,996
	Other income			(7	)		7			—			—			—
	Total Net Income		$	2,088		$	—		$	2,088		$	(440	)	$	1,648
	*See note 1 for further details on the reclassifications.
	Condensed Consolidated Statements of Cash Flows – Three months ended March 31, 2014
			As previously
			reported			Adjustments			As corrected
	Cash flows from operating activities:
	Net Income		$	2,088		$	(440	)	$	1,648
	Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
	Change in Fair Value of Notes			32			(32	)		-
	Change in Fair Value of Borrower Loans Receivable			(332	)		332			-
	Change in Fair Value of Loans Held for Sale			2			(2	)		-
	Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes			-			(210	)		(210	)
	Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes			-			(133	)		(133	)
	Depreciation and Amortization			235			42			277
	Change in Servicing Rights			-			(294	)		(294	)
	Purchase of Loans Held for Sale at Fair Value			-			(150,787	)		(150,787	)
	Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value			-			150,510			150,510
	Changes in Operating Assets and Liabilities:						-
	Restricted Cash			(1,122	)		(3,632	)		(4,754	)
	Other Assets			3			-			3
	Accounts Payable and Accrued Liabilities			563			(474	)		89
	Payable to Investors			-			5,684			5,684
	Net Related Party Payable			(463	)		(53	)		(516	)
	Net Cash Used in Operating Activities			1,006			511			1,517
	Cash Flows From Investing Activities:
Purchase of Borrower Loans Receivable Held at Fair Value			(166,608	)		122,395			(44,213	)
Principal Payment of Borrower Loans Receivable Held at Fair Value			32,642			(4,397	)		28,245
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value			121,864			(121,864	)		-
Repayment of Loans Held for Investment at Fair Value			100			(100	)		-
Origination of Loans Held for Investment at Fair Value			(28,858	)		28,858			-
Proceeds from Sale of Borrower Loans at Fair Value			28,602			(28,602	)		-
Maturities of Short Term Investments			-			1,271			1,271
Purchases of Property and Equipment			-			(1,274	)		(1,274	)
Purchases of Property and Equipment			(183	)		3			(180	)
Changes in Restricted Cash Related to Investing Activities			-			(1,119	)		(1,119	)
Net Cash Used in Investing Activities			(12,441	)		(4,829	)		(17,270	)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value			44,199			(266	)		43,933
Payment of Notes Held at Fair Value			(32,910	)		4,584			(28,326	)
Net Cash Provided by Financing Activities			11,289			4,318			15,607
Net Decrease in Cash and Cash Equivalents			(146	)		-			(146	)
Cash and Cash Equivalents at Beginning of the Period			5,789			-			5,789
Cash and Cash Equivalents at End of the Period		$	5,643		$	-		$	5,643

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events
	On April 7, 2015, Prosper entered into a Series D Preferred Stock Purchase Agreement with several new investors, pursuant to which Prosper issued and sold to such purchasers 4,777,728 shares of Prosper’s new Series D convertible preferred stock for an aggregate purchase price of $165 million.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Significant Accounting Policies [Line Items]
Basis of Presentation	The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.
	Prosper did not have any items of other comprehensive income (loss) during any of the periods presented in the condensed consolidated financial statements as of and for the three months ended March 31, 2015 and 2014, respectively.
	The preparation of Prosper’s condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in Prosper’s financial statements and accompanying notes. Prosper bases its estimates on historical experience and on various other factors it believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material.
	The accompanying interim condensed consolidated financial statements include the accounts of PMI and its wholly-owned subsidiaries, PFL and PHL. All intercompany balances have been eliminated in consolidation.
	On January 23, 2015, Prosper acquired all of the outstanding limited liability company units of American HealthCare Lending, LLC (“AHL”), a company that operates a cloud-based patient financing platform, and merged AHL with and into PHL, with PHL surviving the merger. Prosper’s condensed consolidated financial statements include PHL's results of operations and financial position from this date forward (see Note 6 – American HealthCare Lending Acquisition).
Reclassifications	Reclassifications
	During the year ended December 31, 2014, Prosper changed the presentation of its revenue in the consolidated statements of operations. A new line called “Servicing fees” was created and the servicing fees related to Borrower Loans sold through Prosper’s Whole Loan Channel that were previously included in interest income were reclassified to this new line. Furthermore, the “Rebates and Promotions” line was removed, with the amounts in that line reclassified to the “Servicing fees” or “Origination fees” lines based on the underlying transactions. Also, the “Change in Fair Value of Borrower Loans, loans held for sale and Notes, Net” was moved into the “Total revenue” subtotal. Lastly, the subtotals were realigned to reflect the new presentation.
	Prosper also changed the definitions used to classify expenses.  Expenses were previously classified as cost of services, compensation and benefits, marketing and advertising, depreciation and amortization, professional services, facilities and maintenance, class action settlement, loss on impairment of fixed assets and other.   The revised classification approach replaces the previous classifications with origination and servicing, sales and marketing, and general and administration.  The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Lastly, the subtotals were realigned to reflect the new presentation. Management believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper’s competitors.
Fair Value Measurement	Fair Value Measurements
	Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Short Term Investments, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature.
Borrower Loans, Loans Held for Sale and Notes	Borrower Loans, Loans Held for Sale and Notes
	Borrower Loans, loans held for sale and Notes are recorded at fair value.  Prosper has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”). ASC Topic 825 permits companies to 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 reader of the financial statements and it allows both the Borrower Loans, loans held for sale 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.
Loan Servicing Assets and Liabilities	Loan Servicing Assets and Liabilities
	On January 1, 2015, Prosper elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities subsequent to initial recognition.  ASC 860-50, Servicing Assets and Liabilities allows the subsequent adoption of the fair value method at the beginning of any fiscal year.  The adoption of the fair value method for a particular class is irrevocable.  Prior to January 1, 2015, Prosper measured the servicing assets and liabilities using the amortized cost method. This change resulted in a $575 thousand decrease to accumulated deficit, a $546 thousand increase in net servicing assets and a $29 thousand decrease in net servicing liabilities.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In May 2014, as part of its ongoing efforts to assist in the convergence of U.S. GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers.” 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 2017. Early adoption is not permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40); Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” which requires management of a company to evaluate whether there is substantial doubt about the company’s ability to continue as a going concern. This ASU is effective for the annual reporting period ending after December 15, 2016, and for interim and annual reporting periods thereafter, with early adoption permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In November 2014, the FASB issued ASU 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity to eliminate the use of different methods in practice and thereby reduce existing diversity in the accounting for hybrid financial instruments issued in the form of a share. For hybrid financial instruments issued in the form of a share, an entity should determine the nature of the contract by considering the economic characteristics and risks of the entire hybrid financial instrument. The existence or omission of any single term or feature does not necessarily determine the economic characteristics and risks of the host contract. This standard will be effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. Prosper is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In February 2015, the FASB issued ASU 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis." ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 is effective for periods beginning after December 15, 2015 with early adoption permitted. Prosper has decided to early adopt this guidance effective January 1, 2015, the adoption of this standard had no impact on Prosper’s financial statements.
Prosper Funding LLC [Member]
Significant Accounting Policies [Line Items]
Basis of Presentation	The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Rule 8-03 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2014. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.
	Prosper Funding did not have any items of other comprehensive income (loss) during any of the periods presented in the condensed consolidated financial statements as of and for the three months ended March 31, 2015 and 2014, respectively.
	The preparation of Prosper Funding's condensed consolidated financial statements and related disclosures in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in its condensed consolidated financial statements and accompanying notes. Prosper Funding based its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material.
Reclassifications	Reclassifications
	During the year ended December 31, 2014, Prosper Funding changed the presentation of its revenue in the statement of operations. A new line called “Servicing Fees, Net” was created and the servicing fees related to Borrower Loans sold through its Whole Loan Channel that were previously included in interest income were reclassified to this new line. Also, the “Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net” was moved into the total revenue subtotal.
	Prosper Funding also changed the definitions used to classify expenses. Expenses were previously classified as cost of services, administration fee, depreciation and amortization, professional services and other operating expenses. The revised classification approach replaces the previous classifications with servicing, administration fee –related party, and general and administration.   The changes had no impact to the total expenses or net income. Prior period amounts have been reclassified to conform to the current presentation. Prosper Funding believes these changes make the income statement more useful for the readers of the financial statements and comparable with Prosper Funding’s competitors.
Fair Value Measurement	Fair Value Measurements
	Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Short Term Investments, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors and Notes. The estimated fair values of Cash and Cash Equivalents, Restricted Cash, Accounts Receivable, Accounts Payable and Accrued Liabilities, and Payable to Investors approximate their carrying values because of their short term nature.
Borrower Loans, Loans Held for Sale and Notes	Borrower Loans, Loans Held for Sale and Notes
	Borrower Loans, loans held for sale and Notes are recorded at fair value.  Prosper Funding has adopted the provisions of ASC Topic 825, Financial Instruments (“ASC Topic 825”). ASC Topic 825 permits companies to 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 reader of the financial statements and it allows both the Borrower Loans, loans held for sale 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.
Loan Servicing Assets and Liabilities	Loan Servicing Assets and Liabilities
	On January 1, 2015, Prosper Funding elected to adopt the fair value method to measure the servicing assets and liabilities for all classes of servicing assets and liabilities, subsequent to initial recognition.  ASC 860, Servicing Assets and Liabilities allows the subsequent adoption of the fair value method at the beginning of any fiscal year.  The adoption of the fair value method for a particular class is irrevocable.  Prior to January 1, 2015, Prosper Funding measured the servicing assets and liabilities using the amortized cost method. This change resulted in a $428 thousand increase to retained earnings, a $399 thousand increase in net servicing assets and a $29 thousand decrease in net servicing liabilities.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In May 2014, as part of its ongoing efforts to assist in the convergence of U.S. GAAP and International Financial Reporting Standards (“IFRS”), the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers.” 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 2017. Early adoption is not permitted. Prosper Funding is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40); Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” which requires management of a company to evaluate whether there is substantial doubt about Prosper Funding’s ability to continue as a going concern. This ASU is effective for the annual reporting period ending after December 15, 2016, and for interim and annual reporting periods thereafter, with early adoption permitted. Prosper Funding is currently assessing the potential impact on its financial statements from adopting this new guidance.
	In February 2015, the FASB issued ASU 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis." ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 is effective for periods beginning after December 15, 2015 with early adoption permitted. Prosper Funding has decided to early adopt this guidance effective January 1, 2015, the adoption of this standard had no impact on Prosper Funding’s financial statements.

Property_and_Equipment_Net_Tab

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2015
Property and Equipment, Net	Property and equipment consist of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Property and equipment:
	Computer equipment	$	6,178		$	3,824
	Internal-use software and website development costs		8,513			4,486
	Office equipment and furniture		1,961			1,904
	Leasehold improvements		5,564			5,274
	Assets not yet placed in service		1,589			4,361
	Property and equipment		23,805			19,849
	Less accumulated depreciation and amortization		(7,149	)		(5,425	)
	Total property and equipment, net	$	16,656		$	14,424
Prosper Funding LLC [Member]
Property and Equipment, Net	Property and equipment consist of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Property and equipment:
	Internal-use software and web site development costs	$	8,022		$	4,042
	Less accumulated depreciation and amortization		(4,058	)		(2,917	)
	Total property and equipment, net	$	3,964		$	1,125

Borrower_Loans_Loans_Held_for_1

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value (Tables)	3 Months Ended
	Mar. 31, 2015
Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale
	The aggregate principal balances outstanding and fair values of Borrower Loans, loans held for sale and Notes as of March 31, 2015 and December 31, 2014, are presented in the following table (in thousands):
			Borrower Loans								Notes						Loans Held for Sale
			March 31,				December 31,				March 31,			December 31,			March 31,		December 31,
			2015				2014				2015			2014			2015		2014
	Aggregate principal balance outstanding		$	275,879			$	268,598			$	(279,455	)	$	(272,267	)	$	1,573	$	8,295
	Fair value adjustments			4,525				4,645				(1,346	)		(1,516	)		26		168
	Fair value		$	280,404			$	273,243			$	(280,801	)	$	(273,783	)	$	1,599	$	8,463
Quantitative Information About Significant Unobservable Inputs	The following table presents quantitative information about the significant unobservable inputs used for Prosper’s Borrower Loans, loans held for sale and Notes fair value measurements at March 31, 2015 and December 31, 2014:
			Range
	Unobservable Input		March 31, 2015		December 31, 2014
	Discount rate		2.8%-10.1%		3.3%-10.6%
	Default rate		2.6%-18.8%		2.5%-18.6%
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 adverse changes in those assumptions at March 31, 2015 Borrower Loans, loans held for sale and Notes funded through the Note Channel are presented in the following table (in thousands):
			Borrower Loans /				Notes
			Loans Held for Sale
	Discount rate assumption:		4.61			%*	4.61			%*
	Resulting fair value from:
	100 basis point increase		$	278,837			$	277,641
	200 basis point increase			275,756				274,567
	Resulting fair value from:
	100 basis point decrease		$	285,261			$	284,051
	200 basis point decrease			288,612				287,394
	Default rate assumption:		11.95			%*	11.95			%*
	Resulting fair value from:
	200 basis point decrease		$	289,030			$	287,800
	100 basis point decrease			285,527				284,310
	Resulting fair value from:
	100 basis point increase		$	278,513			$	277,324
	200 basis point increase			275,089				273,914
	*	Represents weighted average assumptions considering all credit grades.
Changes in Borrower Loans, Loans Held for Sale and Notes, and Level 3 Assets 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 measured at fair value on a recurring basis are as follows (in thousands):
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
			Borrower				Notes				Loans Held			Total
			Loans								for Sale
	Balance at January 1, 2014		$	233,105			$	(234,218	)		$	3,206		$	2,093
	Purchase of Borrower Loans/Issuance of Notes			44,256				(43,933	)			150,787			151,110
	Principal repayments			(28,245	)			28,326				-			81
	Borrower Loans sold to third parties			-				-				(150,510	)		(150,510	)
	Other changes			(39	)			173				(1	)		133
	Change in fair value			(4,150	)			4,317				-			167
	Balance at March 31, 2014		$	244,927			$	(245,335	)		$	3,482		$	3,074
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
			Borrower				Notes				Loans Held			Total
			Loans								for Sale
	Balance at January 1, 2015		$	273,243			$	(273,783	)		$	8,463		$	7,923
	Purchase of Borrower Loans/Issuance of Notes			47,714				(47,796	)			540,924			540,842
	Principal repayments			(36,063	)			36,069				(364	)		(358	)
	Borrower Loans sold to third parties			-				-				(547,309	)		(547,309	)
	Other changes			6				207				(8	)		205
	Change in fair value			(4,496	)			4,502				(107	)		(101	)
	Balance at March 31, 2015		$	280,404			$	(280,801	)		$	1,599		$	1,202
Prosper Funding LLC [Member]
Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale	The aggregate principal balances outstanding and fair values of Borrower Loans, loans held for sale and Notes as of March 31, 2015 and December 31, 2014, are presented in the following table (in thousands):
			Borrower Loans								Notes						Loans Held for Sale
			March 31,				December 31,				March 31,			December 31,			March 31,		December 31,
			2015				2014				2015			2014			2015		2014
	Aggregate principal balance outstanding		$	275,879			$	268,593			$	(279,455	)	$	(272,270	)	$	1,573	$	8,295
	Fair value adjustments			4,525				4,650				(1,346	)		(1,513	)		26		168
	Fair value		$	280,404			$	273,243			$	(280,801	)	$	(273,783	)	$	1,599	$	8,463
Quantitative Information About Significant Unobservable Inputs	The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding’s Borrower Loans, loans held for sale and Notes fair value measurements at March 31, 2015 and December 31, 2014:
			Range
	Unobservable Input		March 31, 2015		December 31, 2014
	Discount rate		2.8%-10.1%		3.3%-10.6%
	Default rate		2.6%-18.8%		2.5%-18.6%
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 March 31, 2015 for Borrower Loans, loans held for sale and Notes funded are presented in the following table (in thousands):
			Borrower				Notes
			Loans /
			Loans Held
			for Sale
	Discount rate assumption:		4.61			%*	4.61			%*
	Resulting fair value from:
	100 basis point increase		$	278,837			$	277,641
	200 basis point increase			275,756				274,567
	Resulting fair value from:
	100 basis point decrease		$	285,261			$	284,051
	200 basis point decrease			288,612				287,394
	Default rate assumption:		11.95			%*	11.95			%*
	Resulting fair value from:
	200 basis point decrease		$	289,030			$	287,800
	100 basis point decrease			285,527				284,310
	Resulting fair value from:
	100 basis point increase		$	278,513			$	277,324
	200 basis point increase			275,089				273,914
	*	Represents weighted average assumptions considering all credit grades.
Changes in Borrower Loans, Loans Held for Sale and Notes, and Level 3 Assets 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 measured at fair value on a recurring basis are as follows (in thousands):
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
											Loans
											Held for
			Borrower Loans				Notes				Sale			Total
	Balance at January 1, 2014		$	233,105			$	(234,218	)		$	3,206		$	2,093
	Originations			44,213				(43,933	)			150,787			151,067
	Principal repayments			(28,244	)			28,326				-			82
	Borrower Loans sold to third parties			-				-				(150,510	)		(150,510	)
	Other changes			(39	)			173				(1	)		133
	Change in fair value			(4,107	)			4,317				-			210
	Balance at March 31, 2014		$	244,928			$	(245,335	)	)	$	3,482		$	3,075
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
											Loans
											Held for
			Borrower Loans				Notes				Sale			Total
	Balance at January 1, 2015		$	273,243			$	(273,783	)		$	8,463		$	7,923
	Originations			47,714				(47,796	)			540,924			540,842
	Principal repayments			(36,063	)			36,069				(364	)		(358	)
	Borrower Loans sold to third parties			-				-				(547,309	)		(547,309	)
	Other changes			6				207				(8	)		205
	Change in fair value			(4,496	)			4,502				(107	)		(101	)
	Balance at March 31, 2015		$	280,404			$	(280,801	)		$	1,599		$	1,202

Loan_Servicing_Assets_and_Liab1

Loan Servicing Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2015
Significant Unobservable Inputs Fair Value	The following table presents quantitative information about the significant unobservable inputs used for Prosper’s servicing asset/liability fair value measurements at March 31, 2015 and December 31, 2014:
		Range
	Unobservable Input	March 31, 2015		December 31, 2014
	Discount rate	15% - 25%		15% - 25%
	Default rate	2.0% - 19.8%		2.6% - 26.3%
	Market servicing rate	0.63%		0.625% - 0.70%
Schedule of Servicing Assets and Liabilities Measured at Fair Value	The following table presents additional information about Level 3 servicing assets and liabilities measured at fair value for the three months ended March 31, 2015 (in thousands).
		Servicing			Servicing
		Assets			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		2,078			154
	Less: Changes in fair value		(753	)		(81	)
	Fair value at March 31, 2015	$	6,034		$	668
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 March 31, 2015 (in thousands, except percentages).
		Servicing			Servicing
		Assets			Liabilities
	Weighted average market servicing rate assumptions		0.625	%		0.625	%
	Resulting fair value from:
	Market servicing rate increase to 0.65%	$	5,594		$	(734	)
	Market servicing rate decrease to 0.60%	$	6,487		$	(601	)
	Weighted average default assumptions		13	%		13	%
	Resulting fair value from:
	100 basis point increase	$	5,930		$	(667	)
	100 basis point decrease	$	6,152		$	(669	)
Prosper Funding LLC [Member]
Significant Unobservable Inputs Fair Value	The following table presents quantitative information about the significant unobservable inputs used for Prosper Funding's servicing asset/liability fair value measurements at March 31, 2015 and December 31, 2014:
		Range
	Unobservable Input	31-Mar-15		31-Dec-14
	Discount rate	15% - 25%		15% - 25%
	Default rate	2.0% - 19.8%		2.6% - 26.3%
	Market servicing rate	0.63%		0.625% - 0.70%
Schedule of Servicing Assets and Liabilities Measured at Fair Value	The following table presents additional information about Level 3 servicing assets and liabilities recorded at fair value for the three months ended March 31, 2015 (in thousands).
		Servicing			Servicing
		Assets			Liabilities
	Amortized cost at January 1, 2015	$	3,116		$	624
	Adjustment to adopt fair value measurement		399			(29	)
	Fair value at January 1, 2015		3,515			595
	Additions		2,078			154
	Less:  Transfers to PMI		(249	)		-
	Less: changes in fair value		(562	)		(81	)
	Fair value at March 31, 2015	$	4,782		$	668
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 March 31, 2015 (in thousands, except percentages).
		Servicing			Servicing
		Assets			Liabilities
	Weighted average market servicing rate assumptions		0.625	%		0.625	%
	Resulting fair value from:
	Servicing rate increase to 0.65%	$	4,428		$	(734	)
	Servicing rate decrease to 0.60%	$	5,135		$	(601	)
	Weighted average default assumptions		13	%		13	%
	Resulting fair value from:
	100 basis point increase	$	4,694		$	(667	)
	100 basis point decrease	$	4,870		$	(669	)

American_HealthCare_Lending_Ac1

American HealthCare Lending Acquisition - (Tables)	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Preliminary Purchase Price Allocation	The preliminary purchase price allocation as of the merger date is as follows (in thousands):
		Fair Value
	Assets:
	Cash	$	1,219
	Accounts Receivable		147
	Property, equipment and software		6
	Other assets		63
	Identified intangible assets		3,520
	Goodwill		16,825
	Liabilities:
	Accrued expenses and other liabilities		708
	Total purchase consideration	$	21,072
Schedule of Intangible Assets	Intangible assets as of March 31, 2015 are as follows (in thousands):
		31-Mar-15
		Gross		Accumulated			Net		Remaining
		Carrying Value		Amortization			Carrying Value		Useful Life
									(In Years)
	Customer relationships	$	2,650	$	(41	)	$	2,609		10
	Technology		810		(45	)		765		3
	Brand name		60		(10	)		50		1
	Total intangible assets subject to amortization	$	3,520	$	(96	)	$	3,424

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Basic and Diluted Loss Per Share	Basic and diluted net loss per share was calculated as follows:
		Three Months Ended March 31,
		2015			2014
	Numerator:
	Net loss available to common stockholders for basic	$	(7,276	)	$	(2,718	)
	and diluted EPS
	Denominator:
	Weighted average shares used in computing basic and		10,553,251			8,056,248
	diluted net loss per share
	Basic and diluted net loss per share	$	(0.69	)	$	(0.34	)
Dilutive Shares Excluded from the Diluted Net Loss Per Share Calculation	Due to losses attributable to Prosper’s common shareholders for each of the periods below, the following potentially dilutive shares are excluded from the diluted net loss per share calculation because they were anti-dilutive under the treasury stock method, in accordance with ASC Topic 260:
		Three Months Ended March 31,
		2015			2014
		(shares)			(shares)
	Excluded securities:
	Convertible preferred stock issued and outstanding		30,699,957			27,274,068
	Stock options issued and outstanding		7,038,728			4,359,556
	Unvested stock options exercised		3,727,042			5,054,772
	Warrants issued and outstanding		125,293			218,810
	Total common stock equivalents excluded from		41,591,020			36,907,206
	diluted net loss per common share computation

Convertible_Preferred_Stock_an1

Convertible Preferred Stock and Stockholders' Deficit (Tables)	3 Months Ended
	Mar. 31, 2015
Stockholders Equity Note [Abstract]
Summary of Shares Authorized, Issued, Outstanding, Par Value and Liquidation Preference of Convertible Preferred Stock	The number of authorized, issued and outstanding shares, their par value and liquidation preference for each series of convertible preferred stock as of March 31, 2015 are disclosed in the table below (amounts in thousands except share and per share amounts):
	Convertible Preferred Stock	Par Value		Authorized		Outstanding		Liquidation
				shares		and Issued		Preference
						shares
	New Series A	$	0.01		13,868,152		13,711,644	$	19,774
	Series A-1		0.01		5,117,182		4,952,183		49,522
	New Series B		0.01		8,288,734		7,155,176		21,581
	New Series C		0.01		4,880,954		4,880,954		70,075
					32,155,022		30,699,957	$	160,952

Stock_Option_Plan_and_Compensa1

Stock Option Plan and Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Activity of Options that were Early Exercised under the Plan	The activity of options that were early exercised under the 2005 Plan for the three months ended March 31, 2015 is below:
			Early exercised			Weighted average
			options, unvested			exercise price
	Balance as of January 1, 2015			4,112,269		$	0.25
	Exercise of non-vested stock options			9,459			2.18
	Repurchase of restricted stock			(1,875	)		0.57
	Restricted stock vested			(482,811	)		0.17
	Balance as of March 31, 2015			3,637,042		$	0.26
Additional Information Regarding the Unvested Early Exercised Stock Options Outstanding	Additional information regarding the unvested early exercised stock options outstanding as of March 31, 2015 is as follows:
			Options Outstanding
	Range of
	Exercise		Number			Weighted –Avg.			Weighted –Avg.
	Prices		Outstanding			Remaining Life			Exercise Price
	$0.10 - $0.10			3,111,922			1.89		$	0.1
	0.57 - 0.57			458,981			2.97			0.57
	5.65-5.65			66,139			3.33			5.65
	$0.10 - $5.65			3,637,042			2.06		$	0.26
Summarized Option Activity under Option Plan	Stock option activity under the 2005 Plan is summarized for the three months ended March 31, 2015 below:
			Options			Weighted-
			Issued and			Average
			Outstanding			Exercise
						Price
	Balance as of January 1, 2015			4,994,998		$	1.85
	Options granted			2,469,314			18.11
	Options exercised – vested			(299,291	)		1.74
	Options exercised – nonvested			(9,459	)		2.18
	Options forfeited			(116,834	)		6.02
	Balance as of March 31, 2015			7,038,728			7.49
	Options vested and exercisable at March 31, 2015			6,006,329			8.1
Additional Information Regarding Common Stock Options Outstanding	Additional information regarding common stock options outstanding as of March 31, 2015 is as follows:
			Options Outstanding								Options Vested and Exercisable
						Weighted –			Weighted –				Weighted -
	Range of					Avg.			Avg.				Avg.
	Exercise		Number			Remaining			Exercise		Number		Exercise
	Prices		Outstanding			Life			Price		Vested		Price
	$0.10 - $0.10			157,040			8.38		$	0.1		73,756	$	0.1
	0.57 - 0.57			3,100,551			8.87			0.57		2,120,600		0.57
	1.20 – 1.20			70,999			6.45			1.2		63,742		1.2
	1.70 – 1.70			48,019			7.01			1.7		36,990		1.7
	2.00 – 2.00			90,310			5.34			2		90,310		2
	5.00 - 5.00			7,000			1.5			5		7,000		5
	5.60 - 5.60			18,250			4.46			5.6		18,250		5.6
	5.65-5.65			1,105,245			9.46			5.65		2,884		5.65
	$18.11-$18.11			2,441,314			9.89			18.11		-		18.11
	$0.10 - $18.11			7,038,728			8.1		$	7.49		2,413,532	$	0.7
Fair Value of Stock Option Awards	The fair value of Prosper’s stock option awards for the three months ended March 31, 2015 and 2014 was estimated at the date of grant using the Black-Scholes model with the following average assumptions:
		Three months ended
			March 31,
			2015			2014
	Volatility of common stock			55.59	%		73.31	%
	Risk-free interest rate			1.61	%		1.92	%
	Expected life	5.7 years				6.1 years
	Dividend yield			0	%		0	%
Stock Based Compensation Included in Consolidated Statements of Operations	The following table presents the amount of stock-based compensation related to stock-based awards granted to employees recognized in Prosper’s condensed consolidated statements of operations during the three months ended March 31, 2015 and 2014 (in thousands):
			Three months ended
			March 31,
			2015			2014
	Origination and servicing		$	144		$	63
	Sales and marketing			388			16
	General and administrative			907			171
	Total stock based compensation		$	1,439		$	250

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	The following table summarizes Prosper’s activity related to its unrecognized tax benefits (in thousands):
	Beginning balance as of January 1, 2015		4,927
	Decrease related to prior year positions		-
	Increase related to current year positions		-
	Ending balance as of March 31, 2015	$	4,927

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	During 2014, Prosper entered into leases for its new corporate headquarters at 221 Main Street in San Francisco California and for its co-location facility.  These are non-cancelable operating leases that expire in February 2023 and August 2015, respectively. In 2014, Prosper entered into a lease for office space in Phoenix, Arizona under an operating lease that expires in June 2022.
	Future minimum rental payments under these leases as of March 31, 2015 are as follows:
	Remaining nine months of 2015		2,742
	2016		4,239
	2017		3,866
	2018		3,977
	2019		4,093
	2020		4,210
	Thereafter		8,808
	Total future operating lease obligations	$	31,935

Related_Parties_Tables

Related Parties (Tables)	3 Months Ended
	Mar. 31, 2015
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes purchased and the income earned by parties deemed to be affiliates and related parties of Prosper for the three months ended March 31, 2015 and 2014, as well as the Notes outstanding as of March 31, 2015 and December 31, 2014 are summarized below (in thousands):
		Aggregate Amount of				Interest Earned on Notes
		Notes Purchased
		Three Months Ended				Three Months Ended
		March 31,				31-Mar
	Related Party	2015		2014		2015		2014
	Executive officers and management	$	479	$	214	$	47	$	36
	Directors		10	$	2	$	2	$	3
	Total	$	489	$	216	$	49	$	39
		Notes Balance as of
	Related Party	March 31,		December 31,
		2015		2014
	Executive officers and management	$	1,842	$	1,614
	Directors		96		76
		$	1,938	$	1,690
Prosper Funding LLC [Member]
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes purchased and the income earned by parties deemed to be related parties of Prosper as of March 31, 2015 and December 31, 2014 are summarized below (in thousands):
		Aggregate Amount of				Interest Earned on Notes
		Notes Purchased
		Three Months Ended				Three Months Ended
		March 31,				31-Mar
	Related Party	2015		2014		2015		2014
	Executive officers and management	$	479	$	214	$	47	$	36
	Directors		-		-		-		-
	Total	$	479	$	214	$	47	$	36
		Note Balance as of
	Related Party	March 31,		December 31,
		2015		2014
	Executive officers and management	$	1,842	$	1,614
	Directors		-		-
		$	1,842	$	1,614

Restatement_of_Condensed_Conso1

Restatement of Condensed Consolidated Financial Statements (Tables)	3 Months Ended
	Mar. 31, 2015
Condensed Financial Statements Captions [Line Items]
Restatement of Consolidated Balance Sheets, Consolidated Statements of Operations and Consolidated Statements of Cash Flows	The following tables present the impact of these corrections and corrections of other immaterial errors on three months ended March 31, 2014 ($ in thousands):
	Consolidated Statement of Operations – Three months ended March 31, 2014
		As previously			Reclassifications*			As			Adjustments			As
		reported						reclassified						corrected
	Revenue
	Operating Revenue
	Transaction Fees,  Net	$	8,701		$	(231	)	$	8,470		$	(106	)	$	8,364
	Rebates and Promotions		(361	)		361			-			-			-
	Servicing Fees, Net		-			99			99			315			414
	Other Revenue		696			-			696			(245	)		451
	Total Operating Revenue		9,036			229			9,265			(36	)		9,229
	Interest Income on Borrower Loans		10,109			(228	)		9,881			124			10,005
	Interest Expense on Notes		(9,269	)					(9,269	)		(153	)		(9,422	)
	Net Interest Income		840			(228	)		612			(29	)		583
	Change in Fair Value on Borrower Loans, Loans Held for		298			-			298			(131	)		167
	Sale and Notes, net
	Total Net Revenue		10,174			1			10,175			(196	)		9,979
	Cost of Revenue
	Cost of Services		(525	)		525			-			-			-
	Provision for repurchase and indemnification obligation		(62	)		62			-			-			-
			(587	)		587			-			-			-
	Expenses
	Compensation and benefits		3,901			(3,901	)		-			-			-
	Marketing and advertising		5,986			(5,986	)		-			-			-
	Depreciation and amortization		363			(363	)		-			-			-
	Professional services		176			(176	)		-			-			-
	Facilities and maintenance		445			(445	)		-			-
	Loss on impairment		215			(215	)		-			-			-
	Other		668			(668	)		-			-			-
	Origination and Servicing		-			2,131			2,131			160			2,291
	Sales and Marketing		-			6,424			6,424			10			6,434
	General and Administrative		-			3,786			3,786			186			3,972
	Total  Expenses		11,754			587			12,341			356			12,697
	Other income		1			(1	)		-			-			-
	Total Net Income	$	(2,166	)	$	-		$	(2,166	)	$	(552	)	$	(2,718	)
	*See note 1 for a description of the reclassifications.
	Condensed Consolidated Statements of Cash Flows – Three months ended March 31, 2014
		As previously
		reported			Adjustments			As corrected
	Cash flows from operating activities:
	Net Loss	$	(2,166	)	$	(552	)	$	(2,718	)
	Adjustments to Reconcile Net Income (Loss) to Net Cash Used in
	Operating Activities:
	Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		-			(167	)		(167	)
	Change in Fair Value of Notes		32			(32	)		-
	Change in Fair Value of Borrower Loans Receivable		(332	)		332			-
	Change in Fair Value of Loans Held for Sale		2			(2	)		-
	Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes		-			(133	)		(133	)
	Depreciation and Amortization		363			37			400
	Stock-Based Compensation		255			(5	)		250
	Loss on Impairment of Property and Equipment		215			-			215
	Accretion of Class Action Settlement Liability		-			30			30
	Change in Servicing Rights		-			(283	)		(283	)
	Purchase of  loans held for sale at fair value		-			(150,787	)		(150,787	)
	Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value		-			150,510			150,510
	Changes in Operating Assets and Liabilities:					-
	Restricted Cash		(1,189	)		(3,980	)		(5,169	)
	Accounts Receivable		36			(56	)		(20	)
	Prepaid and Other Assets		(445	)		28			(417	)
	Accounts Payable and Accrued Liabilities		1,511			(613	)		898
	Repurchase liability for unvested stock awards		(105	)		105			-
	Payable to Investors		-			5,850			5,850
	Class Action Settlement Liability		(2,000	)		-			(2,000	)
	Net Cash Used in Operating Activities		(3,823	)		282			(3,541	)
Cash Flows From Investing Activities:
Purchase of Borrower Loans Receivable Held at Fair Value		(166,608	)		122,352			(44,256	)
Principal Payment of Borrower Loans Receivable Held at Fair Value		32,642			(4,397	)		28,245
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value		121,864			(121,864	)		-
Repayment of Loans Held for Investment at Fair Value		100			(100	)		-
Origination of Loans Held for Investment at Fair Value		(28,858	)		28,858			-
Proceeds from sale of Borrower Loans at Fair Value		28,602			(28,602	)		-
Purchases of Property and Equipment		(692	)		33			(659	)
Maturities of Short Term Investments		-			1,271			1,271
Purchases of Short Investments		-			(1,274	)		(1,274	)
Changes in Restricted Cash Related to Investing Activities		-			(771	)		(771	)
Net Cash Used in Investing Activities		(12,950	)		(4,494	)		(17,444	)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value		44,199			(266	)		43,933
Payment of Notes Held at Fair Value		(32,910	)		4,584			(28,326	)
Proceeds from Early Exercise of Stock Options		12			(2	)		10
Proceeds of Restricted Stock Vested		104			(104	)		-
Proceeds from Exercise of Vested Stock Options		4			-			4
Net Cash Provided by Financing Activities	$	11,409		$	4,212		$	15,621
Net Decrease in Cash and Cash Equivalents		(5,364	)		-			(5,364	)
Cash and Cash Equivalents at Beginning of the Period		18,339			-			18,339
Cash and Cash Equivalents at End of the Period	$	12,975		$	-		$	12,975
Prosper Funding LLC [Member]
Condensed Financial Statements Captions [Line Items]
Restatement of Consolidated Balance Sheets, Consolidated Statements of Operations and Consolidated Statements of Cash Flows	The following tables present the impact of these corrections and corrections of other immaterial errors on the interim periods in the three months ended March 31, 2014 (in thousands):
	Consolidated Statement of Operations – Three months ended March 31, 2014
		As previously			Reclassifications*			As			Adjustments			As
		reported						reclassified						corrected
	Revenue
	Operating Revenue
	Administration Fee Revenue – Related Party	$	4,053		$	—		$	4,053		$	—		$	4,053
	Servicing Income, Net		—			170			170			253			423
	Other Revenue		356			—			356			(57	)		299
	Total Operating Revenue		4,409			170			4,579			196			4,775
	Interest Income on Borrower Loans		10,057			(176	)		9,881			201			10,082
	Interest Expense on Notes		(9,269	)		-			(9,269	)		(154	)		(9,423	)
	Net Interest Income		788			(176	)		612			47			659
	Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, net		298			(1	)		297			(87	)		210
	Total Net Revenue		5,495			(7	)		5,488			156			5,644
	Cost of Revenue
	Cost of Services		(397	)		397			—			—			—
	Provision for repurchase and indemnification obligation		(62	)		62			—			—			—
			(459	)		459			—			—			—
	Expenses
	Servicing		—			694			694			(296	)		398
	Administration Fee – Related Party		2,606			—			2,606			888			3,494
	Depreciation and Amortization		235			(235	)		—			—			—
	Professional Services		12			(12	)		—			—			—
	Other Operating Expenses		88			(88	)		—			—			—
	General and Administration		—			100			100			4			104
	Total  Expenses		2,941			459			3,400			596			3,996
	Other income		(7	)		7			—			—			—
	Total Net Income	$	2,088		$	—		$	2,088		$	(440	)	$	1,648
	*See note 1 for further details on the reclassifications.
	Condensed Consolidated Statements of Cash Flows – Three months ended March 31, 2014
		As previously
		reported			Adjustments			As corrected
	Cash flows from operating activities:
	Net Income	$	2,088		$	(440	)	$	1,648
	Adjustments to Reconcile Net Income (Loss) to Net Cash Used in Operating Activities:
	Change in Fair Value of Notes		32			(32	)		-
	Change in Fair Value of Borrower Loans Receivable		(332	)		332			-
	Change in Fair Value of Loans Held for Sale		2			(2	)		-
	Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		-			(210	)		(210	)
	Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes		-			(133	)		(133	)
	Depreciation and Amortization		235			42			277
	Change in Servicing Rights		-			(294	)		(294	)
	Purchase of Loans Held for Sale at Fair Value		-			(150,787	)		(150,787	)
	Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value		-			150,510			150,510
	Changes in Operating Assets and Liabilities:					-
	Restricted Cash		(1,122	)		(3,632	)		(4,754	)
	Other Assets		3			-			3
	Accounts Payable and Accrued Liabilities		563			(474	)		89
	Payable to Investors		-			5,684			5,684
	Net Related Party Payable		(463	)		(53	)		(516	)
	Net Cash Used in Operating Activities		1,006			511			1,517
	Cash Flows From Investing Activities:
	Purchase of Borrower Loans Receivable Held at Fair Value		(166,608	)		122,395			(44,213	)
	Principal Payment of Borrower Loans Receivable Held at Fair Value		32,642			(4,397	)		28,245
	Proceeds from Sale of Borrower Loans Receivable Held at Fair Value		121,864			(121,864	)		-
	Repayment of Loans Held for Investment at Fair Value		100			(100	)		-
	Origination of Loans Held for Investment at Fair Value		(28,858	)		28,858			-
	Proceeds from Sale of Borrower Loans at Fair Value		28,602			(28,602	)		-
	Maturities of Short Term Investments		-			1,271			1,271
	Purchases of Property and Equipment		-			(1,274	)		(1,274	)
	Purchases of Property and Equipment		(183	)		3			(180	)
	Changes in Restricted Cash Related to Investing Activities		-			(1,119	)		(1,119	)
	Net Cash Used in Investing Activities		(12,441	)		(4,829	)		(17,270	)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value		44,199			(266	)		43,933
Payment of Notes Held at Fair Value		(32,910	)		4,584			(28,326	)
Net Cash Provided by Financing Activities		11,289			4,318			15,607
Net Decrease in Cash and Cash Equivalents		(146	)		-			(146	)
Cash and Cash Equivalents at Beginning of the Period		5,789			-			5,789
Cash and Cash Equivalents at End of the Period	$	5,643		$	-		$	5,643

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Significant Accounting Policies [Line Items]
Decrease to accumulated deficit	($575)
Increase in net servicing asset	546
Decrease in net servicing liabilities	-29
Prosper Funding LLC [Member]
Significant Accounting Policies [Line Items]
Increase in net servicing asset	399
Decrease in net servicing liabilities	-29
Increase to retained earnings	$428

Property_and_Equipment_Net_Det

Property and Equipment, Net (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$23,805	$19,849
Less accumulated depreciation and amortization	-7,149	-5,425
Total property and equipment, net	16,656	14,424
Prosper Funding LLC [Member]
Property, Plant and Equipment [Line Items]
Less accumulated depreciation and amortization	-4,058	-2,917
Total property and equipment, net	3,964	1,125
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	6,178	3,824
Internal-use Software and Website Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	8,513	4,486
Internal-use Software and Website Development Costs [Member] | Prosper Funding LLC [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	8,022	4,042
Office Equipment and Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	1,961	1,904
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	5,564	5,274
Assets Not Yet Placed in Service [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$1,589	$4,361

Property_and_Equipment_Net_Add

Property and Equipment, Net - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation expense	$1,850,000	$400,000
Capitalized internal-use software and website development costs	1,215,000	368,000
Recorded internal-use software and website development impairment charges	0	215,000
Prosper Funding LLC [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	$1,220,000	$277,000

Borrower_Loans_Loans_Held_for_2

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 $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Borrower Loans [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding	$275,879	$268,598
Fair value adjustments	4,525	4,645
Fair value	280,404	273,243
Borrower Loans [Member] | Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding	275,879	268,593
Fair value adjustments	4,525	4,650
Fair value	280,404	273,243
Loans Held for Sale [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding	1,573	8,295
Fair value adjustments	26	168
Fair value	1,599	8,463
Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding	1,573	8,295
Fair value adjustments	26	168
Fair value	1,599	8,463
Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding	-279,455	-272,267
Fair value adjustments	-1,346	-1,516
Fair value	-280,801	-273,783
Notes [Member] | Prosper Funding LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding	-279,455	-272,270
Fair value adjustments	-1,346	-1,513
Fair value	($280,801)	($273,783)

Borrower_Loans_Loans_Held_for_3

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Additional Information (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Debt Instrument [Line Items]
Fixed interest rate, Minimum	5.77%		5.77%
Fixed interest rate, Maximum	33.04%		33.04%
Loans maturity date	31-Mar-20		31-Dec-19
Aggregate fair value adjustments	$4,800,000	$4,600,000
Minimum number of days for which loans originated were delinquent	90 days		90 days
Aggregate principal amount of loans originated	1,300,000		1,700,000
Fair value of loans originated	500,000		600,000
Borrower Loans receivable	0		0
Prosper Funding LLC [Member]
Debt Instrument [Line Items]
Fixed interest rate, Minimum	5.77%		5.77%
Fixed interest rate, Maximum	33.04%		33.04%
Loans maturity date	31-Mar-20		31-Dec-19
Aggregate fair value adjustments	4,800,000	4,600,000
Minimum number of days for which loans originated were delinquent	90 days		90 days
Aggregate principal amount of loans originated	1,300,000		1,500,000
Fair value of loans originated	500,000		140,000
Borrower Loans receivable	$0		$0
Minimum [Member]
Debt Instrument [Line Items]
Underlying notes and certificates original terms	36 months		36 months
Minimum [Member] | Prosper Funding LLC [Member]
Debt Instrument [Line Items]
Underlying notes and certificates original terms	36 months		36 months
Maximum [Member]
Debt Instrument [Line Items]
Underlying notes and certificates original terms	60 months		60 months
Maximum [Member] | Prosper Funding LLC [Member]
Debt Instrument [Line Items]
Underlying notes and certificates original terms	60 months		60 months

Recovered_Sheet1

Borrower Loans, Loans Held For Sale and Notes Held at Fair Value - Quantitative Information about the Significant Unobservable Inputs (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Minimum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	2.80%	3.30%
Default rate	2.60%	2.50%
Minimum [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	2.80%	3.30%
Default rate	2.60%	2.50%
Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	10.10%	10.60%
Default rate	18.80%	18.60%
Maximum [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	10.10%	10.60%
Default rate	18.80%	18.60%

Borrower_Loans_Loans_Held_for_4

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Fair Value Assumptions for Borrower Loans, Loans Held for Sale and Notes (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Discount rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.61%	[1]
Discount rate assumption [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.61%	[1]
Discount rate assumption [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.61%	[1]
Discount rate assumption [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	4.61%	[1]
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	277,641
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	277,641
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	278,837
Discount rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	278,837
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	274,567
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	274,567
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	275,756
Discount rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	275,756
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	284,051
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	284,051
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	285,261
Discount rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	285,261
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	287,394
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	287,394
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	288,612
Discount rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	288,612
Default rate assumption [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	11.95%	[1]
Default rate assumption [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate assumption (in hundredths)	11.95%	[1]
Default rate assumption [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	11.95%	[1]
Default rate assumption [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Default rate assumption (in hundredths)	11.95%	[1]
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	277,324
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	277,324
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	278,513
Default rate assumption [Member] | 100 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	278,513
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	273,914
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	273,914
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	275,089
Default rate assumption [Member] | 200 Basis Point Increase [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	275,089
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	284,310
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	284,310
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	285,527
Default rate assumption [Member] | 100 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	285,527
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	287,800
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Notes [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	287,800
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	289,030
Default rate assumption [Member] | 200 Basis Point Decrease [Member] | Borrower Loans/Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	289,030
[1]	Represents weighted average assumptions considering all credit grades.

Borrower_Loans_Loans_Held_for_5

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Changes in Borrower Loans, Loans Held for Sale and Notes, which are Level 3 Assets Measured at Fair Value on a Recurring Basis (Details) (Recurring [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Total	$2,093	$7,923
Purchase of Borrower Loans/Issuance of Notes, Total	151,110	540,842
Principal repayments, Total	81	-358
Borrower Loans sold to third parties, Total	-150,510	-547,309
Other changes, Total	133	205
Change in fair value, Total	167	-101
Ending balance, Total	3,074	1,202
Prosper Funding LLC [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Total	2,093	7,923
Originations, Total	151,067	540,842
Principal repayments, Total	82	-358
Other changes, Total	133	205
Ending balance, Total	3,075	1,202
Borrower loans sold to third parties, Total	-150,510	-547,309
Change in fair value of loans held for sale, Total	210	-101
Notes [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Liabilities	-234,218	-273,783
Purchase of Borrower Loans/Issuance of Notes, Liabilities	-43,933	-47,796
Principal repayments, Liabilities	28,326	36,069
Borrower Loans sold to third parties, Liabilities	0	0
Other changes, Liabilities	173	207
Change in fair value, Liabilities	4,317	4,502
Ending balance, Liabilities	-245,335	-280,801
Notes [Member] | Prosper Funding LLC [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Liabilities	-234,218	-273,783
Originations, Liabilities	-43,933	-47,796
Principal repayments, Liabilities	28,326	36,069
Other changes, Liabilities	173	207
Change in fair value, Liabilities	4,317	4,502
Ending balance, Liabilities	-245,335	-280,801
Borrower loans sold to third parties, Liabilities	0	0
Borrower Loans [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	233,105	273,243
Purchase of Borrower Loans/Issuance of Notes, Assets	44,256	47,714
Principal repayments, Assets	-28,245	-36,063
Borrower Loans sold to third parties, Assets		0
Other changes, Assets	-39	6
Change in fair value, Assets	-4,150	-4,496
Ending balance, Assets	244,927	280,404
Borrower Loans [Member] | Prosper Funding LLC [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	233,105	273,243
Originations, Assets	44,213	47,714
Principal repayments, Assets	-28,244	-36,063
Borrower Loans sold to third parties, Assets	0	0
Other changes, Assets	-39	6
Change in fair value, Assets	-4,107	-4,496
Ending balance, Assets	244,928	280,404
Loans Held for Sale [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	3,206	8,463
Purchase of Borrower Loans/Issuance of Notes, Assets	150,787	540,924
Principal repayments, Assets	0	-364
Borrower Loans sold to third parties, Assets	-150,510	-547,309
Other changes, Assets	-1	-8
Change in fair value, Assets	0	-107
Ending balance, Assets	3,482	1,599
Loans Held for Sale [Member] | Prosper Funding LLC [Member]
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	3,206	8,463
Originations, Assets	150,787	540,924
Principal repayments, Assets	0	-364
Borrower Loans sold to third parties, Assets	-150,510	-547,309
Other changes, Assets	-1	-8
Change in fair value, Assets	0	-107
Ending balance, Assets	$3,482	$1,599

Loan_Servicing_Assets_and_Liab2

Loan Servicing Assets and Liabilities - Additional Information (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Servicing Assets And Liabilities Fair Value [Line Items]
Gain on sales of whole loans	$1.90	$0.30
Fixed interest rate, Minimum	5.77%		5.77%
Fixed interest rate, Maximum	33.04%		33.04%
Loans maturity date	31-Mar-20		31-Dec-19
Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Gain on sales of whole loans	1.9	0.3
Fixed interest rate, Minimum	5.77%		5.77%
Fixed interest rate, Maximum	33.04%		33.04%
Loans maturity date	31-Mar-20		31-Dec-19
Borrower Loans [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	1,796		1,360
Fixed interest rate, Minimum	6.00%		6.05%
Fixed interest rate, Maximum	31.90%		31.34%
Loans maturity date	31-Mar-20		31-Dec-19
Debt instrument, Description	As of March 31, 2015, Borrower Loans that were facilitated and subsequently sold but for which Prosper retained servicing rights had a total outstanding principle balance of $1,796 million, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.00% to 31.90% and maturity dates through March 2020. At December 31, 2014, Borrower Loans that were facilitated and subsequently sold but for which Prosper retained servicing rights had a total outstanding principle balance of $1.36 billion, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and maturity dates through December 2019. The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes the market servicing rate, the default rate and discount rate as important inputs. For more details refer to Part IV - Item 15 – Exhibits, Financial Statement Schedules - Note 5 – Loan Servicing Assets and Liabilities Prosper’s Annual Report.
Borrower Loans [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	$1,448		1,045
Fixed interest rate, Minimum	6.00%		6.05%
Fixed interest rate, Maximum	31.90%		31.34%
Loans maturity date	31-Mar-20		31-Dec-19
Debt instrument, Description	At March 31, 2015, Borrower Loans that were facilitated and subsequently sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $1,448 million, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.00% to 31.90% and maturity dates through March 2020. At December 31, 2014, Borrower Loans that were facilitated and subsequently sold, but for which Prosper Funding retained servicing rights had a total outstanding principal balance of $1,045 million, original terms between 36 and 60 months and had monthly payments with fixed interest rates ranging from 6.05% to 31.34% and maturity dates through December 2019. The fair value of the loan servicing assets and liabilities is determined using a discounted cash flow model that includes the market servicing rate, the default rate and discount rate as important inputs. For more details refer to Part IV - Item 15 – Exhibits, Financial Statement Schedules - Note 5 – Loan Servicing Assets and Liabilities in the Prosper Funding’s Annual Report.
Minimum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	36 months		36 months
Minimum [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	36 months		36 months
Minimum [Member] | Borrower Loans [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	36 months		36 months
Minimum [Member] | Borrower Loans [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	36 months		36 months
Maximum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	60 months		60 months
Maximum [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	60 months		60 months
Maximum [Member] | Borrower Loans [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	60 months		60 months
Maximum [Member] | Borrower Loans [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Borrower loans original maturity term	60 months		60 months

Loan_Servicing_Assets_and_Liab3

Loan Servicing Assets and Liabilities - Significant Unobservable Inputs (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate	0.63%
Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Market servicing rate	0.63%
Minimum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	2.00%	2.60%
Market servicing rate		0.63%
Minimum [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	2.00%	2.60%
Market servicing rate		0.63%
Maximum [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	19.80%	26.30%
Market servicing rate		0.70%
Maximum [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	19.80%
Market servicing rate		0.70%

Loan_Servicing_Assets_and_Liab4

Loan Servicing Assets and Liabilities - Schedule of Servicing Assets and Liabilities Measured at Fair Value (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Loan servicing assets [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Amortized cost at beginning of period	$4,163
Adjustment to adopt fair value measurement	546
Fair value at beginning of period	4,709
Additions	2,078
Less: Changes in fair value	-753
Fair Value at end of period	6,034
Loan servicing assets [Member] | Prosper Funding LLC [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Amortized cost at beginning of period	3,116
Adjustment to adopt fair value measurement	399
Fair value at beginning of period	3,515
Additions	2,078
Less: Changes in fair value	-562
Fair Value at end of period	4,782
Less: Transfers to PMI	-249
Loan servicing liabilities [Member]
Servicing Liability at Amortized Cost [Roll Forward]
Amortized cost at beginning of the period	624
Fair value adjustments	-29
Fair value at beginning of the period	595
Additions	154
Less: Changes in fair value	-81
Fair value at end of the period	668
Loan servicing liabilities [Member] | Prosper Funding LLC [Member]
Servicing Liability at Amortized Cost [Roll Forward]
Amortized cost at beginning of the period	624
Fair value adjustments	-29
Fair value at beginning of the period	595
Additions	154
Less: Changes in fair value	-81
Fair value at end of the period	$668

Loan_Servicing_Assets_and_Liab5

Loan Servicing Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Loan servicing assets [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Weighted average market servicing rate assumptions	0.63%
Resulting fair value from:
Market servicing rate increase to 0.65%	$5,594
Market servicing rate decrease to 0.60%	6,487
100 basis point increase	5,930
100 basis point decrease	6,152
Weighted average default assumptions	13.00%
Loan servicing assets [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Weighted average market servicing rate assumptions	0.63%
Resulting fair value from:
Market servicing rate increase to 0.65%	4,428
Market servicing rate decrease to 0.60%	5,135
100 basis point increase	4,694
100 basis point decrease	4,870
Weighted average default assumptions	13.00%
Loan servicing liabilities [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Weighted average market servicing rate assumptions	0.63%
Resulting fair value from:
Market servicing rate increase to 0.65%	-734
Market servicing rate decrease to 0.60%	-601
100 basis point increase	-667
100 basis point decrease	-669
Weighted average default assumptions	13.00%
Loan servicing liabilities [Member] | Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Weighted average market servicing rate assumptions	0.63%
Resulting fair value from:
Market servicing rate increase to 0.65%	-734
Market servicing rate decrease to 0.60%	-601
100 basis point increase	-667
100 basis point decrease	($669)
Weighted average default assumptions	13.00%

Loan_Servicing_Assets_and_Liab6

Loan Servicing Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Parenthetical) (Details)	3 Months Ended
	Mar. 31, 2015
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Default rate increase	1.00%
Default rate decrease	1.00%
Prosper Funding LLC [Member]
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Default rate increase	1.00%
Default rate decrease	1.00%

American_HealthCare_Lending_Ac2

American HealthCare Lending Acquisition - Additional Information (Details) (USD $)	0 Months Ended	3 Months Ended
	Jan. 23, 2015	Mar. 31, 2015
Business Acquisition [Line Items]
Amortization of intangible assets		$96,000
Customer Relationships [member]
Business Acquisition [Line Items]
Remaining useful life (in years)		10 years
Technology [Member]
Business Acquisition [Line Items]
Remaining useful life (in years)		3 years
Brand Name [Member]
Business Acquisition [Line Items]
Remaining useful life (in years)		1 year
American HealthCare [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	20,200,000	800,000
Business Acquisition, Effective Date of Acquisition		23-Jan-15
Business Acquisition, Name of Acquired Entity		American HealthCare Lending LLC
Net revenue		600,000
Net earnings		300,000
Acquisition expenses		$200,000

American_HealthCare_Lending_Ac3

American HealthCare Lending Acquisition - Preliminary Purchase Price Allocation (Details) (American HealthCare [Member], USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
American HealthCare [Member]
Assets:
Cash	$1,219
Accounts Receivable	147
Property, equipment and software	6
Other assets	63
Identified intangible assets	3,520
Goodwill	16,825
Liabilities:
Accrued expenses and other liabilities	708
Total purchase consideration	$21,072

American_HealthCare_Lending_Ac4

American HealthCare Lending Acquisition - Schedule of Intangible Assets (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	$3,520
Accumulated amortization	-96
Net carrying value	3,424
Customer Relationships [member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	2,650
Accumulated amortization	-41
Net carrying value	2,609
Remaining useful life (in years)	10 years
Technology [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	810
Accumulated amortization	-45
Net carrying value	765
Remaining useful life (in years)	3 years
Brand Name [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	60
Accumulated amortization	-10
Net carrying value	$50
Remaining useful life (in years)	1 year

Net_Loss_Per_Share_Basic_and_D

Net Loss Per Share - Basic and Diluted Loss Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Numerator [Abstract]
Net loss available to common stockholders for basic and diluted EPS	($7,276)	($2,718)
Denominator [Abstract]
Weighted-Average Shares - Basic and Diluted Net Loss Per Share	10,553,251	8,056,248
Basic and diluted net loss per share (in dollars per share)	($0.69)	($0.34)

Net_Loss_Per_Share_Dilutive_Sh

Net Loss Per Share - Dilutive Shares Excluded from the Diluted Net Loss Per Share Calculation (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	41,591,020	36,907,206
Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	30,699,957	27,274,068
Stock Options Issued and Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	7,038,728	4,359,556
Unvested Stock Options Exercised [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	3,727,042	5,054,772
Warrants Issued and Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	125,293	218,810

Convertible_Preferred_Stock_an2

Convertible Preferred Stock and Stockholders' Deficit - Summary of Shares Authorized, Issued, Outstanding, Par Value and Liquidation Preference of Convertible Preferred Stock (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
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)	32,155,022	32,155,022
Convertible preferred stock, shares outstanding and issued (in shares)	30,699,957
Convertible preferred stock, liquidation preference	$160,952	$160,952
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$0.01
Convertible preferred stock, shares authorized (in shares)	13,868,152
Convertible preferred stock, shares outstanding and issued (in shares)	13,711,644
Convertible preferred stock, liquidation preference	19,774
Series A 1 [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$0.01
Convertible preferred stock, shares authorized (in shares)	5,117,182
Convertible preferred stock, shares outstanding and issued (in shares)	4,952,183
Convertible preferred stock, liquidation preference	49,522
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$0.01
Convertible preferred stock, shares authorized (in shares)	8,288,734
Convertible preferred stock, shares outstanding and issued (in shares)	7,155,176
Convertible preferred stock, liquidation preference	21,581
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$0.01
Convertible preferred stock, shares authorized (in shares)	4,880,954
Convertible preferred stock, shares outstanding and issued (in shares)	4,880,954
Convertible preferred stock, liquidation preference	$70,075

Convertible_Preferred_Stock_an3

Convertible Preferred Stock and Stockholders' Deficit - Additional Information (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	31-May-14
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	48,928,883		47,928,883
Preferred stock, shares authorized (in shares)	32,155,022		32,155,022
Common stock, par value (in dollars per share)	$0.01		$0.01
Common stock, shares issued (in shares)	14,878,514		14,448,700
Common stock, shares outstanding (in shares)	14,691,327		14,261,513
Proceeds from Exercise of Vested Stock Options	$522	$4
Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)				81,083,905
Exercise of stock options (in shares)	308,750
Proceeds from Exercise of Vested Stock Options	540
Exercise of nonvested stock options (in shares)	9,459
Unvested restricted stock outstanding (in shares)	3,637,042		4,114,269
Stock repurchase upon termination of employment (in shares)	1,875
Stock repurchase upon termination of employment	1
Exercise of common stock warrants (in shares)	32,939
Exercise of warrants aggregate proceeds	$111
Warrants Issued and Outstanding [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)				48,928,883
Common stock, par value (in dollars per share)				0.01
Common stock, shares issued (in shares)	14,878,514		14,448,700
Common stock, shares outstanding (in shares)	14,691,237		14,261,513
Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				32,155,022
Common stock, par value (in dollars per share)				0.01

Stock_Option_Plan_and_Compensa2

Stock Option Plan and Compensation - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
Vesting period of the options	1 year
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights	Options generally vest 25% one year from the vesting commencement date and 1/48th per month thereafter.
Options exercisable, maximum period	10 years
Unrecognized cost of unvested share-based compensation awards.	$0
Dividend yield	0.00%	0.00%
Stock-Based Compensation Expense	1,439,000	250,000
Unamortized expense related to unvested stock-based awards	32,800,000
Remaining weighted average vesting period	3 years 9 months 18 days
Internal-use Software and Website Development Costs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation Expense	122,000	5,000
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	90,000
Shares Issued, Price Per Share	$18.11
Restricted Stock | Vesting 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	33.33%
Restricted Stock | Vesting 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	33.33%
Restricted Stock | Vesting 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	33.33%
2005 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options made available in pool (in shares)	15,195,255
Shares available for grant under the plan	138,289
Options Issued and Outstanding, Options granted	2,469,314
Weighted-Average Exercise Price, Options granted	$18.11
Weighted average grant fair value	$16.04
Stock options estimated aggregate fair value	$39,600,000

Stock_Option_Plan_and_Compensa3

Stock Option Plan and Compensation - Schedule of Activity of Options that were Early Exercised under the Plan (Details) (Early Exercised Stock Options Under 2005 Stock Option Plan [Member], USD $)	3 Months Ended
	Mar. 31, 2015
Early Exercised Stock Options Under 2005 Stock Option Plan [Member]
Early exercised options, unvested [Roll Forward]
Beginning balance	4,112,269
Exercise of non-vested stock options	9,459
Repurchase of restricted stock	-1,875
Restricted stock vested	-482,811
Ending balance	3,637,042
Weighted average exercise price [Abstract]
Weighted-Average Exercise Price, Beginning balance	$0.25
Exercise of non-vested stock options	$2.18
Repurchase of restricted stock	$0.57
Restricted stock vested	$0.17
Weighted-Average Exercise Price, Ending balance	$0.26

Stock_Option_Plan_and_Compensa4

Stock Option Plan and Compensation - Additional Information Regarding Unvested Early exercised stock options outstanding (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
$0.10 - $0.10 [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.10
Range of Exercise Prices, Maximum	$0.10
Number Outstanding	3,111,922
Weighted Avg. Remaining Life	1 year 10 months 21 days
Weighted Avg. Exercise Price	$0.10
$0.57 - $0.57 [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.57
Range of Exercise Prices, Maximum	$0.57
Number Outstanding	458,981
Weighted Avg. Remaining Life	2 years 11 months 19 days
Weighted Avg. Exercise Price	$0.57
$5.65 - $5.65 [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$5.65
Range of Exercise Prices, Maximum	$5.65
Number Outstanding	66,139
Weighted Avg. Remaining Life	3 years 3 months 29 days
Weighted Avg. Exercise Price	$5.65
$0.10 - $5.65 [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.01
Range of Exercise Prices, Maximum	$5.65
Number Outstanding	3,637,042
Weighted Avg. Remaining Life	2 years 22 days
Weighted Avg. Exercise Price	$0.26

Stock_Option_Plan_and_Compensa5

Stock Option Plan and Compensation - Summarized Option Activity under Option Plan (Details) (2005 Stock Option Plan [Member], USD $)	3 Months Ended
	Mar. 31, 2015
2005 Stock Option Plan [Member]
Options Issued and Outstanding [Roll Forward]
Options Issued and Outstanding, Options granted	2,469,314
Options Issued and Outstanding, Options exercised – vested	-299,291
Options Issued and Outstanding, Options exercised – nonvested	-9,459
Options Issued and Outstanding, Ending balance	7,038,728
Options Issued and Outstanding, Options vested and exercisable at March 31, 2015	6,006,329
Weighted-Average Exercise Price [Roll Forward]
Weighted-Average Exercise Price, Options granted	$18.11
Weighted-Average Exercise Price, Options exercised – vested	$1.74
Weighted-Average Exercise Price, Options exercised – nonvested	$2.18
Weighted-Average Exercise Price, Ending balance	$7.49
Weighted-Average Exercise Price, Options vested and exercisable at March 31, 2015	$8.10

Stock_Option_Plan_and_Compensa6

Stock Option Plan and Compensation - Additional Information Regarding Common Stock Options Outstanding (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
$0.10 - $0.10 [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.10
Range of Exercise Prices, Maximum	$0.10
Number Outstanding	3,111,922
Weighted Avg. Remaining Life	1 year 10 months 21 days
Weighted Avg. Exercise Price	$0.10
$0.10 - $0.10 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.10
Range of Exercise Prices, Maximum	$0.10
Number Outstanding	157,040
Weighted Avg. Remaining Life	8 years 4 months 17 days
Weighted Avg. Exercise Price	$0.10
Options Exercisable [Abstract]
Number Exercisable	73,756
Weighted Avg. Exercise Price	$0.10
$0.57 - $0.57 [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.57
Range of Exercise Prices, Maximum	$0.57
Number Outstanding	458,981
Weighted Avg. Remaining Life	2 years 11 months 19 days
Weighted Avg. Exercise Price	$0.57
$0.57 - $0.57 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.57
Range of Exercise Prices, Maximum	$0.57
Number Outstanding	3,100,551
Weighted Avg. Remaining Life	8 years 10 months 13 days
Weighted Avg. Exercise Price	$0.57
Options Exercisable [Abstract]
Number Exercisable	2,120,600
Weighted Avg. Exercise Price	$0.57
$1.20 - $1.20 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$1.20
Range of Exercise Prices, Maximum	$1.20
Number Outstanding	70,999
Weighted Avg. Remaining Life	6 years 5 months 12 days
Weighted Avg. Exercise Price	$1.20
Options Exercisable [Abstract]
Number Exercisable	63,742
Weighted Avg. Exercise Price	$1.20
$1.70 - $1.70 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$1.70
Range of Exercise Prices, Maximum	$1.70
Number Outstanding	48,019
Weighted Avg. Remaining Life	7 years 4 days
Weighted Avg. Exercise Price	$1.70
Options Exercisable [Abstract]
Number Exercisable	36,990
Weighted Avg. Exercise Price	$1.70
$2.00 - $2.00 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$2
Range of Exercise Prices, Maximum	$2
Number Outstanding	90,310
Weighted Avg. Remaining Life	5 years 4 months 2 days
Weighted Avg. Exercise Price	$2
Options Exercisable [Abstract]
Number Exercisable	90,310
Weighted Avg. Exercise Price	$2
$5.00 - $5.00 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$5
Range of Exercise Prices, Maximum	$5
Number Outstanding	7,000
Weighted Avg. Remaining Life	1 year 6 months
Weighted Avg. Exercise Price	$5
Options Exercisable [Abstract]
Number Exercisable	7,000
Weighted Avg. Exercise Price	$5
$5.60 - $5.60 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$5.60
Range of Exercise Prices, Maximum	$5.60
Number Outstanding	18,250
Weighted Avg. Remaining Life	4 years 5 months 16 days
Weighted Avg. Exercise Price	$5.60
Options Exercisable [Abstract]
Number Exercisable	18,250
Weighted Avg. Exercise Price	$5.60
$5.65 - $5.65 [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$5.65
Range of Exercise Prices, Maximum	$5.65
Number Outstanding	66,139
Weighted Avg. Remaining Life	3 years 3 months 29 days
Weighted Avg. Exercise Price	$5.65
$5.65 - $5.65 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$5.65
Range of Exercise Prices, Maximum	$5.65
Number Outstanding	1,105,245
Weighted Avg. Remaining Life	9 years 5 months 16 days
Weighted Avg. Exercise Price	$5.65
Options Exercisable [Abstract]
Number Exercisable	2,884
Weighted Avg. Exercise Price	$5.65
$18.11 - $18.11 | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$18.11
Range of Exercise Prices, Maximum	$18.11
Number Outstanding	2,441,314
Weighted Avg. Remaining Life	9 years 10 months 21 days
Weighted Avg. Exercise Price	$18.11
Options Exercisable [Abstract]
Weighted Avg. Exercise Price	$18.11
$0.10 - $18.11 [Member] | Stock Options Issued and Outstanding [Member]
Options Outstanding [Abstract]
Range of Exercise Prices, Minimum	$0.10
Range of Exercise Prices, Maximum	$18.11
Number Outstanding	7,038,728
Weighted Avg. Remaining Life	8 years 1 month 6 days
Weighted Avg. Exercise Price	$7.49
Options Exercisable [Abstract]
Number Exercisable	2,413,532
Weighted Avg. Exercise Price	$0.70

Stock_Option_Plan_and_Compensa7

Stock Option Plan and Compensation - Fair Value of Stock Option Awards (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Fair value of stock option awards [Abstract]
Volatility of common stock	55.59%	73.31%
Risk-free interest rate	1.61%	1.92%
Expected life	5 years 8 months 12 days	6 years 1 month 6 days
Dividend yield	0.00%	0.00%

Stock_Option_Plan_and_Compensa8

Stock Option Plan and Compensation - Stock Based Compensation Included in Consolidated Statements of Operations (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	$1,439	$250
Origination and Servicing [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	144	63
Sales and Marketing [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	388	16
General and Administrative [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation	$907	$171

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Income Taxes [Line Items]
Income Tax Expense	$73,000
Unrecognized Tax Benefits	4,927,000		4,927,000
Interest and penalties related to uncertain tax positions	0
Prosper Funding LLC [Member]
Income Taxes [Line Items]
Income Tax Expense	0	0
Net effective tax rate	0.00%	0.00%
Valuation Allowance of Deferred Tax Assets
Income Taxes [Line Items]
Income Tax Expense	$0	$0

Income_Taxes_Unrecognized_Tax_

Income Taxes - Unrecognized Tax Benefits (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]
Beginning balance as of January 1, 2015	$4,927	$4,927
Ending balance as of March 31, 2015	$4,927	$4,927

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2015	Nov. 30, 2008	Oct. 16, 2008
	Installment
	State
Commitments And Contingencies [Line Items]
Non cancelable operating lease expiration	2015-08
Office lease expiration	2022-06
Rental expense under operating lease arrangements	$800,000	$100,000
Minimum annual fee				1,400,000
Purchase of borrower loans	26,200,000
Maximum potential future payments	1,796,000,000
Accrued repurchase and indemnification obligation	212,000		171,000
Securities Law Compliance [Abstract]
Amount of loans sold to lender members						178,000,000
Aggregate amount of payment for penalties					1,000,000
Number of states with which company entered into consent order	34
Aggregate amount paid by entity for penalties to states	470,000
Accrued contingent liability associated with states not entered into consent orders	250,000		250,000
Maximum fee liability taken to estimate accrued contingent liability	1,000,000
Agreed amount of settlement liability payable to plaintiffs	10,000,000
Number of annual installments paid to plaintiffs	4
Other commitment paid	2,000,000		2,000,000
Settlement installment due in 2016	3,000,000
Settlement installment due in 2017	3,000,000
Class action settlement liability	5,880,000		7,861,000
Prosper Funding LLC [Member]
Commitments And Contingencies [Line Items]
Minimum annual fee	1,400,000
Purchase of borrower loans	26,200,000
Maximum potential future payments	1,400,000,000
Accrued repurchase and indemnification obligation	$161,000		$171,000
San Francisco California
Commitments And Contingencies [Line Items]
Non cancelable operating lease expiration	2023-02

Commitments_and_Contingencies_2

Commitments and Contingencies - Future Minimum Lease Payments (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Operating Leases Future Minimum Payments Due [Abstract]
Remaining nine months of 2015	$2,742
2016	4,239
2017	3,866
2018	3,977
2019	4,093
2020	4,210
Thereafter	8,808
Total future operating lease obligations	$31,935

Related_Parties_Additional_Inf

Related Parties - Additional Information (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Related Party Transaction [Line Items]
Minimum percentage of voting securities considered for related parties	10.00%
Servicing fees revenue earned by entity	$4	$6
Prosper Funding LLC [Member]
Related Party Transaction [Line Items]
Servicing fees revenue earned by entity	$4	$6

Related_Parties_Aggregate_Amou

Related Parties - Aggregate Amount of Notes Purchased and the Income Earned (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	$489	$216
Interest earned on Notes	49	39
Notes balance	1,938		1,690
Prosper Funding LLC [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	479	214
Interest earned on Notes	47	36
Notes balance	1,842		1,614
Executive Officers & Management [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	479	214
Interest earned on Notes	47	36
Notes balance	1,842		1,614
Executive Officers & Management [Member] | Prosper Funding LLC [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	479	214
Interest earned on Notes	47	36
Notes balance	1,842		1,614
Directors [Member]
Related Party Transaction [Line Items]
Aggregate amount of notes purchased	10	2
Interest earned on Notes	2	3
Notes balance	$96		$76

Postretirement_Benefit_Plans_A

Postretirement Benefit Plans - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Compensation And Retirement Disclosure [Abstract]
Deferred compensation arrangement with eligible employees, percentage	90.00%
Employer contribution during the period	$400,000	$0

Segments_Additional_Informatio

Segments - Additional Information (Details)	3 Months Ended
	Mar. 31, 2015
	Segment
Segment Reporting [Abstract]
Number of Reportable Segments	1

Restatement_of_Condensed_Conso2

Restatement of Condensed Consolidated Financial Statements - Consolidated Statements of Operations (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Revenue
Transaction Fees, Net	$25,342	$8,364
Servicing Fees, Net	2,569	414
Other Revenue	2,998	451
Total Operating Revenue	30,909	9,229
Interest Income on Borrower Loans	10,476	10,005
Interest Expense on Notes	-9,563	-9,422
Net Interest Income	913	583
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	-101	167
Total Net Revenue	31,721	9,979
Expenses
Depreciation and Amortization	1,850	400
Origination and Servicing	6,852	2,291
Sales and Marketing	18,570	6,434
General and Administrative	13,502	3,972
Total Expenses	38,924	12,697
Net Income (Loss)	-7,276	-2,718
Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party	9,673	4,053
Servicing Fees, Net	2,265	423
Other Revenue	1,922	299
Total Operating Revenue	13,860	4,775
Interest Income on Borrower Loans	10,522	10,082
Interest Expense on Notes	-9,563	-9,423
Net Interest Income	959	659
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net	-101	210
Total Net Revenue	14,718	5,644
Cost of Revenue
Cost of Services	-1,373	-398
Expenses
Depreciation and Amortization	1,220	277
Origination and Servicing		398
General and Administrative	266	104
Total Expenses	10,934	3,996
Administration Fee – Related Party	9,295	3,494
Net Income (Loss)	3,784	1,648
Previously Stated [Member]
Operating Revenue
Transaction Fees, Net		8,701
Rebates and Promotions		-361
Other Revenue		696
Total Operating Revenue		9,036
Interest Income on Borrower Loans		10,109
Interest Expense on Notes		-9,269
Net Interest Income		840
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		298
Total Net Revenue		10,174
Cost of Revenue
Cost of Services		-525
Provision for repurchase and indemnification obligation		-62
Net revenues		-587
Expenses
Compensation and benefits		3,901
Marketing and advertising		5,986
Depreciation and Amortization		363
Professional services		176
Facilities and maintenance		445
Loss on impairment		215
Other		668
Total Expenses		11,754
Other income		1
Net Income (Loss)		-2,166
Previously Stated [Member] | Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party		4,053
Other Revenue		356
Total Operating Revenue		4,409
Interest Income on Borrower Loans		10,057
Interest Expense on Notes		-9,269
Net Interest Income		788
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		298
Total Net Revenue		5,495
Cost of Revenue
Cost of Services		-397
Provision for repurchase and indemnification obligation		-62
Net revenues		-459
Expenses
Depreciation and Amortization		235
Professional services		12
Total Expenses		2,941
Administration Fee – Related Party		2,606
Other Operating Expenses		88
Other income		-7
Net Income (Loss)		2,088
Reclassification
Operating Revenue
Transaction Fees, Net		-231
Rebates and Promotions		361
Servicing Fees, Net		99
Total Operating Revenue		229
Interest Income on Borrower Loans		-228
Net Interest Income		-228
Total Net Revenue		1
Cost of Revenue
Cost of Services		525
Provision for repurchase and indemnification obligation		62
Net revenues		587
Expenses
Compensation and benefits		-3,901
Marketing and advertising		-5,986
Depreciation and Amortization		-363
Professional services		-176
Facilities and maintenance		-445
Loss on impairment		-215
Other		-668
Origination and Servicing		2,131
Sales and Marketing		6,424
General and Administrative		3,786
Total Expenses		587
Other income		-1
Reclassification | Prosper Funding LLC [Member]
Operating Revenue
Servicing Fees, Net		170
Total Operating Revenue		170
Interest Income on Borrower Loans		-176
Net Interest Income		-176
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		-1
Total Net Revenue		-7
Cost of Revenue
Cost of Services		397
Provision for repurchase and indemnification obligation		62
Net revenues		459
Expenses
Depreciation and Amortization		-235
Professional services		-12
Origination and Servicing		694
General and Administrative		100
Total Expenses		459
Other Operating Expenses		-88
Other income		7
As Reclassified
Operating Revenue
Transaction Fees, Net		8,470
Servicing Fees, Net		99
Other Revenue		696
Total Operating Revenue		9,265
Interest Income on Borrower Loans		9,881
Interest Expense on Notes		-9,269
Net Interest Income		612
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		298
Total Net Revenue		10,175
Expenses
Origination and Servicing		2,131
Sales and Marketing		6,424
General and Administrative		3,786
Total Expenses		12,341
Net Income (Loss)		-2,166
As Reclassified | Prosper Funding LLC [Member]
Operating Revenue
Administration Fee Revenue - Related Party		4,053
Servicing Fees, Net		170
Other Revenue		356
Total Operating Revenue		4,579
Interest Income on Borrower Loans		9,881
Interest Expense on Notes		-9,269
Net Interest Income		612
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		297
Total Net Revenue		5,488
Expenses
Origination and Servicing		694
General and Administrative		100
Total Expenses		3,400
Administration Fee – Related Party		2,606
Net Income (Loss)		2,088
Adjustment [Member]
Operating Revenue
Transaction Fees, Net		-106
Servicing Fees, Net		315
Other Revenue		-245
Total Operating Revenue		-36
Interest Income on Borrower Loans		124
Interest Expense on Notes		-153
Net Interest Income		-29
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		-131
Total Net Revenue		-196
Expenses
Depreciation and Amortization		37
Origination and Servicing		160
Sales and Marketing		10
General and Administrative		186
Total Expenses		356
Net Income (Loss)		-552
Adjustment [Member] | Prosper Funding LLC [Member]
Operating Revenue
Servicing Fees, Net		253
Other Revenue		-57
Total Operating Revenue		196
Interest Income on Borrower Loans		201
Interest Expense on Notes		-154
Net Interest Income		47
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes, Net		-87
Total Net Revenue		156
Expenses
Depreciation and Amortization		42
Origination and Servicing		-296
General and Administrative		4
Total Expenses		596
Administration Fee – Related Party		888
Net Income (Loss)		($440)

Restatement_of_Condensed_Conso3

Restatement of Condensed Consolidated Financial Statements - Condensed Consolidated Statements of Cash Flows (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net Income (Loss)	($7,276)	($2,718)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	101	-167
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes		-133
Depreciation and Amortization	1,850	400
Stock-Based Compensation	1,439	250
Loss on Impairment of Property and Equipment		215
Accretion of Class Action Settlement Liability	19	30
Change in Servicing Rights	-1,256	-283
Purchase of Loans Held for Sale at Fair Value	-540,924	-150,787
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	547,673	150,510
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities	-19,922	-5,169
Accounts Receivable	2,031	-20
Prepaid and Other Assets	-850	-417
Accounts Payable and Accrued Liabilities	2,204	898
Payable to Investors	23,212	5,850
Class Action Settlement Liability	-2,000	-2,000
Net Cash Used in Operating Activities		-3,541
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value	-47,714	-44,256
Principal Payments of Borrower Loans Held at Fair Value	36,063	28,245
Purchases of Property and Equipment	-3,537	-659
Maturities of Short Term Investments	1,274	1,271
Purchases of Short Term Investments	-1,275	-1,274
Changes in Restricted Cash Related to Investing Activities	1,859	-771
Net Cash Used in Investing Activities		-17,444
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	47,796	43,933
Payment of Notes Held at Fair Value	-36,069	-28,326
Proceeds from Early Exercise of Stock Options		10
Proceeds from Exercise of Vested Stock Options	522	4
Net Cash Provided by Financing Activities		15,621
Net (Decrease) Increase in Cash and Cash Equivalents	-12,225	-5,364
Cash and Cash Equivalents at Beginning of the Period	50,557	18,339
Cash and Cash Equivalents at End of the Period	38,332	12,975
Prosper Funding LLC [Member]
Cash flows from operating activities:
Net Income (Loss)	3,784	1,648
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes	101	-210
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes		-133
Depreciation and Amortization	1,220	277
Change in Servicing Rights	-1,443	-294
Purchase of Loans Held for Sale at Fair Value	-540,924	-150,787
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	547,673	150,510
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities	-19,864	-4,754
Accounts Payable and Accrued Liabilities	205	89
Payable to Investors	23,073	5,684
Other Assets	-15	3
Net Related Party Payable		-516
Net Cash Used in Operating Activities		1,517
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value	-47,714	-44,213
Principal Payments of Borrower Loans Held at Fair Value	36,063	28,245
Purchases of Property and Equipment	-4,059	-180
Maturities of Short Term Investments	1,274	1,271
Purchases of Short Term Investments	-1,275	-1,274
Changes in Restricted Cash Related to Investing Activities	1,860	-1,119
Net Cash Used in Investing Activities		-17,270
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	47,796	43,933
Payment of Notes Held at Fair Value	-36,069	-28,326
Net Cash Provided by Financing Activities		15,607
Net (Decrease) Increase in Cash and Cash Equivalents	-3,183	-146
Cash and Cash Equivalents at Beginning of the Period	23,777	5,789
Cash and Cash Equivalents at End of the Period	20,594	5,643
Prosper Funding LLC [Member] | Property Plant and Equipment One [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment		-1,274
Prosper Funding LLC [Member] | Property Plant and Equipment Two [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment		-180
Previously Stated [Member]
Cash flows from operating activities:
Net Income (Loss)		-2,166
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Notes		32
Change in Fair Value of Borrower Loans Receivable		-332
Change in Fair Value of Loans Held for Sale		2
Depreciation and Amortization		363
Stock-Based Compensation		255
Loss on Impairment of Property and Equipment		215
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities		-1,189
Accounts Receivable		36
Prepaid and Other Assets		-445
Accounts Payable and Accrued Liabilities		1,511
Repurchase liability for unvested stock awards		-105
Class Action Settlement Liability		-2,000
Net Cash Used in Operating Activities		-3,823
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value		-166,608
Principal Payments of Borrower Loans Held at Fair Value		32,642
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value		121,864
Repayment of Loans Held for Investment at Fair Value		100
Origination of Loans Held for Investment at Fair Value		-28,858
Proceeds from sale of Borrower Loans at Fair Value		28,602
Purchases of Property and Equipment		-692
Net Cash Used in Investing Activities		-12,950
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value		44,199
Payment of Notes Held at Fair Value		-32,910
Proceeds from Early Exercise of Stock Options		12
Proceeds of Restricted Stock Vested		104
Proceeds from Exercise of Vested Stock Options		4
Net Cash Provided by Financing Activities		11,409
Net (Decrease) Increase in Cash and Cash Equivalents		-5,364
Cash and Cash Equivalents at Beginning of the Period		18,339
Cash and Cash Equivalents at End of the Period		12,975
Previously Stated [Member] | Prosper Funding LLC [Member]
Cash flows from operating activities:
Net Income (Loss)		2,088
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Notes		32
Change in Fair Value of Borrower Loans Receivable		-332
Change in Fair Value of Loans Held for Sale		2
Depreciation and Amortization		235
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities		-1,122
Accounts Payable and Accrued Liabilities		563
Other Assets		3
Net Related Party Payable		-463
Net Cash Used in Operating Activities		1,006
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value		-166,608
Principal Payments of Borrower Loans Held at Fair Value		32,642
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value		121,864
Repayment of Loans Held for Investment at Fair Value		100
Origination of Loans Held for Investment at Fair Value		-28,858
Proceeds from sale of Borrower Loans at Fair Value		28,602
Net Cash Used in Investing Activities		-12,441
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value		44,199
Payment of Notes Held at Fair Value		-32,910
Net Cash Provided by Financing Activities		11,289
Net (Decrease) Increase in Cash and Cash Equivalents		-146
Cash and Cash Equivalents at Beginning of the Period		5,789
Cash and Cash Equivalents at End of the Period		5,643
Previously Stated [Member] | Prosper Funding LLC [Member] | Property Plant and Equipment Two [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment		-183
Adjustment [Member]
Cash flows from operating activities:
Net Income (Loss)		-552
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		-167
Change in Fair Value of Notes		-32
Change in Fair Value of Borrower Loans Receivable		332
Change in Fair Value of Loans Held for Sale		-2
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes		-133
Depreciation and Amortization		37
Stock-Based Compensation		-5
Accretion of Class Action Settlement Liability		30
Change in Servicing Rights		-283
Purchase of Loans Held for Sale at Fair Value		-150,787
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value		150,510
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities		-3,980
Accounts Receivable		-56
Prepaid and Other Assets		28
Accounts Payable and Accrued Liabilities		-613
Repurchase liability for unvested stock awards		105
Payable to Investors		5,850
Net Cash Used in Operating Activities		282
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value		122,352
Principal Payments of Borrower Loans Held at Fair Value		-4,397
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value		-121,864
Repayment of Loans Held for Investment at Fair Value		-100
Origination of Loans Held for Investment at Fair Value		28,858
Proceeds from sale of Borrower Loans at Fair Value		-28,602
Purchases of Property and Equipment		33
Maturities of Short Term Investments		1,271
Purchases of Short Term Investments		-1,274
Changes in Restricted Cash Related to Investing Activities		-771
Net Cash Used in Investing Activities		-4,494
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value		-266
Payment of Notes Held at Fair Value		4,584
Proceeds from Early Exercise of Stock Options		-2
Proceeds of Restricted Stock Vested		-104
Net Cash Provided by Financing Activities		4,212
Adjustment [Member] | Prosper Funding LLC [Member]
Cash flows from operating activities:
Net Income (Loss)		-440
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Borrower Loans, Loans Held for Sale and Notes		-210
Change in Fair Value of Notes		-32
Change in Fair Value of Borrower Loans Receivable		332
Change in Fair Value of Loans Held for Sale		-2
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes		-133
Depreciation and Amortization		42
Change in Servicing Rights		-294
Purchase of Loans Held for Sale at Fair Value		-150,787
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value		150,510
Changes in Operating Assets and Liabilities:
Restricted Cash Except for those Related to Investing Activities		-3,632
Accounts Payable and Accrued Liabilities		-474
Payable to Investors		5,684
Net Related Party Payable		-53
Net Cash Used in Operating Activities		511
Cash Flows From Investing Activities:
Purchase of Borrower Loans Held at Fair Value		122,395
Principal Payments of Borrower Loans Held at Fair Value		-4,397
Proceeds from Sale of Borrower Loans Receivable Held at Fair Value		-121,864
Repayment of Loans Held for Investment at Fair Value		-100
Origination of Loans Held for Investment at Fair Value		28,858
Proceeds from sale of Borrower Loans at Fair Value		-28,602
Maturities of Short Term Investments		1,271
Changes in Restricted Cash Related to Investing Activities		-1,119
Net Cash Used in Investing Activities		-4,829
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value		-266
Payment of Notes Held at Fair Value		4,584
Net Cash Provided by Financing Activities		4,318
Adjustment [Member] | Prosper Funding LLC [Member] | Property Plant and Equipment One [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment		-1,274
Adjustment [Member] | Prosper Funding LLC [Member] | Property Plant and Equipment Two [Member]
Cash Flows From Investing Activities:
Purchases of Property and Equipment		$3

Subsequent_Events_Details

Subsequent Events (Details) (Subsequent Event [Member], Series D Convertible Preferred Stock [Member], USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Apr. 07, 2015
Subsequent Event [Member] | Series D Convertible Preferred Stock [Member]
Subsequent Event [Line Items]
Shares issued (in shares)	4,777,728
Proceeds from issuance of preferred stock	$165