Prosper Marketplace 10-Q 13 Aug 19 2019 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2019	Aug. 07, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2019
Entity File Number	333-225797-01
Entity Registrant Name	PROSPER MARKETPLACE, INC.
Entity Central Index Key	0001416265
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	73-1733867
Entity Address, Address Line One	221 Main Street
Entity Address, Address Line Two	3rd Floor
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94105
City Area Code	415
Local Phone Number	593-5400
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		70,624,754
Prosper Funding LLC
Entity Information [Line Items]
Entity File Number	333-225797
Entity Registrant Name	PROSPER FUNDING LLC
Entity Central Index Key	0001542574
Current Fiscal Year End Date	--12-31
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-4526070
Entity Address, Address Line One	221 Main Street
Entity Address, Address Line Two	3rd Floor
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94105
City Area Code	415
Local Phone Number	593-5479
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		0

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Assets
Cash and Cash Equivalents		$ 68,124	$ 57,945
Restricted Cash (1)	[1]	160,990	149,114
Available for Sale Investments, at Fair Value		1,499	22,173
Accounts Receivable (1)	[1]	1,270	5,119
Loans Held for Sale, at Fair Value (1)	[1]	114,962	183,788
Borrower Loans Receivable at Fair Value	[1]	606,799	263,522
Property and Equipment, Net		31,169	15,273
Prepaid and Other Assets (1)	[1]	7,639	4,643
Servicing Assets		13,387	14,687
Goodwill		36,368	36,368
Intangible Assets, Net		859	999
Total Assets		1,043,066	753,631
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities		20,349	19,967
Payable to Investors		114,811	127,538
Notes, at Fair Value		253,425	264,003
Notes Issued by Securitization Trust (1)	[1]	313,111	0
Transfers of Financial Assets Accounted for as Sale, Initial Fair Value of Liabilities Incurred	[1]	44,090	0
Warehouse Lines (1)	[1]	101,406	162,488
Other Liabilities		24,207	10,629
Convertible Preferred Stock Warrant Liability		166,559	143,679
Total Liabilities		1,037,958	728,304
Commitments and Contingencies (see Note 18)
Temporary Equity, Carrying Amount, Attributable to Parent		323,793	323,793
Stockholders' Deficit
Common Stock – $0.01 par value; 625,000,000 shares authorized; 71,502,461 shares issued and 70,566,526 shares outstanding, as of June 30, 2019; 71,411,145 shares issued and 70,475,210 shares outstanding, as of December 31, 2018		230	229
Additional Paid-In Capital		148,528	145,486
Less: Treasury Stock		(23,417)	(23,417)
Retained Earnings (Accumulated Deficit)		(444,034)	(420,751)
Accumulated Other Comprehensive Loss		8	(13)
Total Stockholders' Deficit		(318,685)	(298,466)
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit		$ 1,043,066	$ 753,631
Convertible preferred stock, shares authorized (in shares)		444,760,848	444,760,848
Convertible preferred stock, shares issued (in shares)		214,637,925	214,637,925
Convertible preferred stock, shares outstanding (in shares)		214,637,925
Convertible preferred stock, aggregate liquidation preference		$ 375,952	$ 375,952
Common stock, shares authorized (in shares)		625,000,000	625,000,000
Common stock, shares issued (in shares)		71,502,461	71,411,145
Common stock, shares outstanding (in shares)		70,566,526	70,475,210
Primary Beneficiary
Assets
Restricted Cash (1)	[2]	$ 30,427	$ 0
Accounts Receivable (1)	[2]	249	3,902
Loans Held for Sale, at Fair Value (1)	[2]	114,963	183,788
Borrower Loans Receivable at Fair Value	[2]	348,898	0
Prepaid and Other Assets (1)	[2]	3,411	1,393
Total Assets	[2]	497,948	189,083
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Notes Issued by Securitization Trust (1)	[2]	313,111	0
Transfers of Financial Assets Accounted for as Sale, Initial Fair Value of Liabilities Incurred	[2]	44,090	0
Warehouse Lines (1)	[2]	101,406	162,488
Total Liabilities	[2]	458,187	162,488
Prosper Funding LLC
Assets
Cash and Cash Equivalents		12,269	11,163
Restricted Cash (1)		123,380	136,018
Borrower Loans Receivable at Fair Value		254,070	263,522
Related Party Receivable		914	0
Property and Equipment, Net		5,494	6,426
Servicing Assets		15,461	15,550
Other Assets		144	323
Total Assets		411,732	433,002
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Accounts Payable and Accrued Liabilities		2,224	4,690
Payable to Related Party		0	1,283
Payable to Investors		117,700	127,253
Notes, at Fair Value		253,425	264,003
Other Liabilities		4,617	4,528
Total Liabilities		377,966	401,757
Stockholders' Deficit
Member's Equity		24,904	24,904
Retained Earnings (Accumulated Deficit)		8,862	6,341
Total Stockholders' Deficit		33,766	31,245
Total Liabilities, Convertible Preferred Stock and Stockholders' Deficit		$ 411,732	$ 433,002
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.
[2]	The following table presents the assets and liabilities of consolidated variable interest entities (VIEs), which are included in the condensed consolidated balance sheets above. The assets in the table below may only be used to settle obligations of consolidated VIEs and are in excess of those obligations. Additionally, the assets and liabilities in the table below include third-party assets and liabilities of consolidated VIEs only and exclude intercompany balances that eliminate in consolidation. See Note 7 - Securitizations and Note 11 - Debt, to our Notes to Condensed Consolidated Financial Statements for add itional information.

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018	Sep. 20, 2017
Statement of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Revenues
Revenues	$ 36,990,000	$ 30,020,000	$ 63,472,000	$ 57,981,000
Gain (Loss) on Sale of Borrower Loans	3,559,000	4,200,000	6,256,000	7,512,000
Fair Value of Warrants Vested on Sale of Borrower Loans	(7,805,000)	(20,633,000)	(17,553,000)	(35,912,000)
Interest Income
Interest Income on Borrower Loans	23,543,000	14,556,000	41,972,000	26,916,000
Interest expense	(15,645,000)	(11,471,000)	(28,765,000)	(22,200,000)
Net Interest Income	7,898,000	3,085,000	13,207,000	4,716,000
Change in Fair Value of Financial Instruments, Net	(1,958,000)	(1,430,000)	(3,671,000)	(572,000)
Total Net Revenue	42,930,000	31,675,000	73,008,000	62,125,000
Expenses
Origination and Servicing	9,427,000	9,192,000	17,589,000	18,013,000
Sales and Marketing	21,450,000	20,907,000	37,791,000	39,735,000
General and Administrative	17,908,000	18,151,000	36,677,000	36,865,000
Restructuring Charges, Net	5,000	271,000	86,000	595,000
Change in Fair Value of Convertible Preferred Stock Warrants	(4,729,000)	(3,998,000)	5,327,000	(8,602,000)
Other Expenses (Income), Net	(591,000)	(258,000)	(1,237,000)	(500,000)
Total Expenses	43,470,000	44,265,000	96,233,000	86,106,000
Net Loss Before Taxes	(540,000)	(12,590,000)	(23,225,000)	(23,981,000)
Income Tax Expense	29,000	9,000	58,000	19,000
Net Loss	$ (569,000)	$ (12,599,000)	$ (23,283,000)	$ (24,000,000)
Net Loss Per Share – Basic and Diluted (in dollars per share)	$ (0.01)	$ (0.18)	$ (0.33)	$ (0.34)
Weighted-Average Shares - Basic and Diluted (in shares)	70,502,797	70,362,716	70,494,945	70,333,145
Prosper Funding LLC
Operating Revenues
Revenues	$ 18,804,000	$ 21,937,000	$ 35,655,000	$ 41,024,000
Gain (Loss) on Sale of Borrower Loans	(4,053,000)	(16,181,000)	(10,879,000)	(27,754,000)
Interest Income
Interest Income on Borrower Loans	10,403,000	10,907,000	20,734,000	21,859,000
Interest expense	(9,735,000)	(10,177,000)	(19,384,000)	(20,388,000)
Net Interest Income	668,000	730,000	1,350,000	1,471,000
Change in Fair Value on Borrower Loans, Loans Held for Sale and Notes, Net	(131,000)	(255,000)	(218,000)	(364,000)
Total Net Revenue	19,341,000	22,412,000	36,787,000	42,131,000
Expenses
Administration Fee - Related Party	16,773,000	20,285,000	31,765,000	38,175,000
Servicing	1,304,000	1,663,000	2,372,000	3,478,000
General and Administrative	34,000	182,000	129,000	365,000
Total Expenses	18,111,000	22,130,000	34,266,000	42,018,000
Income Tax Expense			0	0
Net Loss	1,230,000	282,000	2,521,000	113,000
Administration Fee Revenue - Related Party | Prosper Funding LLC
Operating Revenues
Revenues	16,640,000	30,836,000	33,615,000	54,620,000
Transaction Fees, Net
Operating Revenues
Revenues	33,876,000	37,988,000	60,171,000	69,343,000
Servicing Fees, Net
Operating Revenues
Revenues	5,172,000	7,487,000	11,375,000	14,671,000
Servicing Fees, Net | Prosper Funding LLC
Operating Revenues
Revenues	6,231,000	7,209,000	12,876,000	14,022,000
Other Revenue
Operating Revenues
Revenues	2,188,000	1,015,000	3,223,000	2,367,000
Other Revenue | Prosper Funding LLC
Operating Revenues
Revenues	$ (14,000)	$ 73,000	$ 43,000	$ 136,000

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Other Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net Loss	$ (569)	$ (12,599)	$ (23,283)	$ (24,000)
Other Comprehensive Income (Loss), Before Tax
Change in Net Unrealized Gain on Available for Sale Investments, at Fair Value	11	27	21	12
Realized (Gain) Loss on Sale of Available for Sale Investments, at Fair Value	0	0	0	0
Other Comprehensive Income (Loss), Before Tax	11	27	21	12
Income Tax Effect	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	11	27	21	12
Comprehensive Loss	$ (558)	$ (12,572)	$ (23,262)	$ (23,988)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from Operating Activities:
Net Loss	$ (23,283)	$ (24,000)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Financial Instruments, Net	5,045	572
Depreciation and Amortization	3,743	5,334
Amortization of Operating Lease Right-of-use Asset	1,632
Gain on Sales of Borrower Loans	(6,378)	(7,501)
Change in Fair Value of Servicing Rights	6,621	6,538
Stock-Based Compensation Expense	2,850	4,584
Restructuring Liability	0	595
Fair Value of Warrants Vested	17,553	35,912
Change in Fair Value of Warrants	5,327	(8,602)
Other, Net	1,303	(358)
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value	(1,161,237)	(1,324,100)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	1,108,814	1,207,916
Accounts Receivable	4,035	(2,856)
Prepaid and Other Assets	(601)	1,448
Accounts Payable and Accrued Liabilities	601	2,540
Payable to Investors	(12,727)	(19,852)
Other Liabilities	(2,632)	(9)
Net Cash Used in Operating Activities	(49,334)	(121,839)
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	(86,064)	(91,075)
Principal Payments of Borrower Loans Held at Fair Value	106,940	90,963
Purchases of Property and Equipment	(5,032)	(2,715)
Purchases of Available for Sale Investments, at Fair Value	(1,488)	(5,448)
Maturities of Available for Sale Investments	22,271	24,000
Net Cash Provided by Investing Activities	36,627	15,725
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	86,713	90,693
Payments of Notes Held at Fair Value	(85,728)	(91,525)
Principal Payments on Notes Issued by Securitization Trust	(30,221)	0
Principal Payments on Certificates Issued by Securitization Trust	(4,272)	0
Proceeds from Securitization Issuance	5,454	0
Proceeds from Revolving Debt Facilities	69,411	103,097
Payment for Debt Issuance Costs	(6,608)	(1,428)
Proceeds from Exercise of Warrants and Stock Options including Early Exercise, and Issuance of Restricted Stock	13	18
Net Cash Provided by Financing Activities	34,762	100,855
Net Increase in Cash, Cash Equivalents and Restricted Cash	22,055	(5,259)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Period	207,059	198,463
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	229,114	193,204
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	27,560	22,252
Non-Cash Investing Activity - Accrual for Property and Equipment, Net	411	325
Non-Cash Investing Activity - Consolidation of Borrower Loans, at Fair Value	(262,565)	0
Non-Cash Financing Activity - Issuance of Securitization Notes and Certificates	395,544	0
Non-Cash Financing Activity - Derecognition of Warehouse Line Debt	(130,322)	0
Prosper Funding LLC
Cash flows from Operating Activities:
Net Loss	2,521	113
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Change in Fair Value of Financial Instruments, Net	217	364
Other Non-Cash Changes in Borrower Loans, Loans Held for Sale and Notes	(403)	(295)
Depreciation and Amortization	2,203	2,991
Gain on Sales of Borrower Loans	(6,796)	(8,147)
Change in Fair Value of Servicing Rights	6,877	6,552
Changes in Operating Assets and Liabilities:
Purchase of Loans Held for Sale at Fair Value	(1,161,237)	(1,324,100)
Proceeds from Sales and Principal Payments of Loans Held for Sale at Fair Value	1,161,237	1,324,114
Other Assets	179	(153)
Accounts Payable and Accrued Liabilities	(2,466)	708
Payable to Investors	(9,553)	(19,668)
Net Related Party Receivable/Payable	(1,131)	2,116
Other Liabilities	97	972
Net Cash Used in Operating Activities	(8,255)	(14,433)
Cash Flows from Investing Activities:
Purchase of Borrower Loans Held at Fair Value	(86,062)	(91,075)
Principal Payments of Borrower Loans Held at Fair Value	84,137	90,963
Purchases of Property and Equipment	(2,337)	(1,894)
Net Cash Provided by Investing Activities	(4,262)	(2,006)
Cash Flows from Financing Activities:
Proceeds from Issuance of Notes Held at Fair Value	86,713	90,693
Payments of Notes Held at Fair Value	(85,728)	(91,525)
Net Cash Provided by Financing Activities	985	(832)
Net Increase in Cash, Cash Equivalents and Restricted Cash	(11,532)	(17,271)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Period	147,181	148,315
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	135,649	131,044
Supplemental Disclosure of Cash Flow Information:
Cash Paid for Interest	19,986	22,252
Non-Cash Investing Activity - Accrual for Property and Equipment, Net	$ 35	$ (116)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders’ Deficit - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Retained Earnings (Accumulated Deficit)	Prosper Funding LLC	Prosper Funding LLCRetained Earnings (Accumulated Deficit)	Prosper Funding LLCMember's Equity
Beginning balance (in shares) at Dec. 31, 2017		214,637,925
Beginning balance at Dec. 31, 2017		$ 323,793
Ending balance (in shares) at Mar. 31, 2018		214,637,925
Ending balance at Mar. 31, 2018		$ 323,793
Beginning balance (in shares) at Dec. 31, 2017			75,468,234	(5,177,235)
Beginning balance at Dec. 31, 2017	$ (267,415)		$ 228	$ (23,417)	$ 136,653	$ (73)	$ (380,806)	$ 30,366	$ 5,462	$ 24,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of vested stock options (in shares)			43,746
Exercise of Vested Stock Options	8				8
Restricted Stock Vested	5				5
Exercise of warrants (in shares)			8,200
Stock-based Compensation Expense	2,425				2,425
Change in Net Unrealized Loss on Available for Sale Investments, at Fair Value	(16)					(16)
Net Loss	(11,401)						(11,401)	(169)	(169)
Ending balance (in shares) at Mar. 31, 2018			75,520,180	(5,177,235)
Ending balance at Mar. 31, 2018	(276,394)		$ 228	$ (23,417)	139,091	(89)	(392,207)	30,197	5,293	24,904
Beginning balance (in shares) at Dec. 31, 2017		214,637,925
Beginning balance at Dec. 31, 2017		$ 323,793
Beginning balance (in shares) at Dec. 31, 2017			75,468,234	(5,177,235)
Beginning balance at Dec. 31, 2017	(267,415)		$ 228	$ (23,417)	136,653	(73)	(380,806)	30,366	5,462	24,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Loss	(24,000)							113
Ending balance (in shares) at Jun. 30, 2018		214,637,925	75,559,226	(5,177,235)
Ending balance at Jun. 30, 2018	(286,594)	$ 323,793	$ 228	$ (23,417)	141,463	(62)	(404,806)	30,479	5,575	24,904
Beginning balance (in shares) at Mar. 31, 2018		214,637,925
Beginning balance at Mar. 31, 2018		$ 323,793
Beginning balance (in shares) at Mar. 31, 2018			75,520,180	(5,177,235)
Beginning balance at Mar. 31, 2018	(276,394)		$ 228	$ (23,417)	139,091	(89)	(392,207)	30,197	5,293	24,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of vested stock options (in shares)			39,046
Exercise of Vested Stock Options	8				8
Restricted Stock Vested	6				6
Stock-based Compensation Expense	2,356				2,356
Change in Net Unrealized Loss on Available for Sale Investments, at Fair Value	27					27
Net Loss	(12,599)						(12,599)	282	282
Ending balance (in shares) at Jun. 30, 2018		214,637,925	75,559,226	(5,177,235)
Ending balance at Jun. 30, 2018	(286,594)	$ 323,793	$ 228	$ (23,417)	141,463	(62)	(404,806)	30,479	5,575	24,904
Beginning balance (in shares) at Dec. 31, 2018		214,637,925
Beginning balance at Dec. 31, 2018	323,793	$ 323,793
Ending balance (in shares) at Mar. 31, 2019		214,637,925
Ending balance at Mar. 31, 2019		$ 323,793
Beginning balance (in shares) at Dec. 31, 2018			75,652,445	(5,177,235)
Beginning balance at Dec. 31, 2018	(298,466)		$ 229	$ (23,417)	145,486	(13)	(420,751)	31,245	6,341	24,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of vested stock options (in shares)			16,085
Exercise of Vested Stock Options	4				4
Stock-based Compensation Expense	1,714				1,714
Change in Net Unrealized Loss on Available for Sale Investments, at Fair Value	10					10
Net Loss	(22,714)						(22,714)	1,291	1,291
Ending balance (in shares) at Mar. 31, 2019			75,668,530	(5,177,235)
Ending balance at Mar. 31, 2019	(319,452)		$ 229	$ (23,417)	147,204	(3)	(443,465)	32,536	7,632	24,904
Beginning balance (in shares) at Dec. 31, 2018		214,637,925
Beginning balance at Dec. 31, 2018	$ 323,793	$ 323,793
Ending balance (in shares) at Jun. 30, 2019	214,637,925
Ending balance at Jun. 30, 2019	$ 323,793
Beginning balance (in shares) at Dec. 31, 2018			75,652,445	(5,177,235)
Beginning balance at Dec. 31, 2018	(298,466)		$ 229	$ (23,417)	145,486	(13)	(420,751)	31,245	6,341	24,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Loss	(23,283)							2,521
Ending balance (in shares) at Jun. 30, 2019		214,637,925	75,743,761	5,177,235
Ending balance at Jun. 30, 2019	$ (318,685)	$ 323,793	$ 230	$ (23,417)	148,528	8	(444,034)	33,766	8,862	24,904
Beginning balance (in shares) at Mar. 31, 2019		214,637,925
Beginning balance at Mar. 31, 2019		$ 323,793
Ending balance (in shares) at Jun. 30, 2019	214,637,925
Ending balance at Jun. 30, 2019	$ 323,793
Beginning balance (in shares) at Mar. 31, 2019			75,668,530	(5,177,235)
Beginning balance at Mar. 31, 2019	(319,452)		$ 229	$ (23,417)	147,204	(3)	(443,465)	32,536	7,632	24,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of vested stock options (in shares)			75,231
Exercise of Vested Stock Options	9		$ 1		8
Stock-based Compensation Expense	1,316				1,316
Change in Net Unrealized Loss on Available for Sale Investments, at Fair Value	11					11
Net Loss	(569)						(569)	1,230	1,230
Ending balance (in shares) at Jun. 30, 2019		214,637,925	75,743,761	5,177,235
Ending balance at Jun. 30, 2019	$ (318,685)	$ 323,793	$ 230	$ (23,417)	$ 148,528	$ 8	$ (444,034)	$ 33,766	$ 8,862	$ 24,904

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Marketplace, Inc. (“PMI”) was incorporated in the state of Delaware on March 22, 2005. Except as the context requires otherwise, as used in these notes to the condensed consolidated financial statements of PMI, “Prosper,” “we,” “us,” and “our” refer to PMI and its wholly-owned subsidiaries, on a consolidated basis. The unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2018. The balance sheet at December 31, 2018 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. The preparation of Prosper’s condensed consolidated financial statements and related disclosures in conformity with US GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in Prosper’s financial statements and accompanying notes. Management bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions. The accompanying interim condensed consolidated financial statements include the accounts of PMI, its wholly-owned subsidiaries and consolidated variable interest entities ("VIEs"). All intercompany balances have been eliminated in consolidation. Securitization Notes are notes held by certain third party investors pursuant to Prosper’s securitization transactions, and are distinguishable from the borrower payment dependent Notes available to investors through our Note Channel.
Prosper Funding LLC
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Funding LLC (“PFL”) was formed in the state of Delaware on February 17, 2012 as a limited liability company with the sole equity member being Prosper Marketplace, Inc. (“PMI”). Except as the context otherwise requires, as used in these Notes to the condensed consolidated financial statements of Prosper Funding LLC, “Prosper Funding,” “we,” “us,” and “our” refers to PFL and its wholly owned subsidiaries, Prosper Asset Holdings LLC (“PAH”), a Delaware limited liability company, and Prosper Depositor LLC, a Delaware limited liability company, on a consolidated basis. PAH was dissolved on November 28, 2018. As a result, references to Prosper Funding do not include PAH for periods subsequent to the year ended December 31, 2018. The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2018. The balance sheet at December 31, 2018 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 six months ended June 30, 2019 and June 30, 2018. The preparation of Prosper Funding's condensed consolidated financial statements and related disclosures in conformity with US GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in its condensed consolidated financial statements and accompanying notes. Management bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Prosper’s significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies in Prosper’s Annual Report on Form 10-K for the year ended December 31, 2018. There have been no changes to these accounting policies during the first six months of 2019 other than the changes noted below. Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Available for Sale Investments at Fair Value, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors, Convertible Preferred Stock Warrant Liability, Certificates Issued by Securitization Trust 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. Restricted Cash Restricted Cash consists primarily of cash deposits and short term certificate of deposit accounts held as collateral as required for long term leases, loan funding and servicing activities, and cash that investors or Prosper have on our marketplace that has not yet been invested in Borrower Loans or disbursed to the investor. The following table provides a reconciliation of Cash, Cash Equivalents, and Restricted Cash reported within the condensed consolidated balance sheets that sum to the total of the same such amount shown in the condensed consolidated statements of cash flows: June 30, 2019 December 31, 2018 June 30, 2018 December 31, 2017 Cash and Cash Equivalents $ 68,124 57,945 $ 58,652 $ 45,795 Restricted Cash 160,990 149,114 134,552 152,668 Total Cash, Cash Equivalents and Restricted Cash shown in the consolidated statements of cash flows $ 229,114 $ 207,059 $ 193,204 $ 198,463 Borrower Loans, Loans Held for Sale and Notes Through the Note Channel, Prosper purchases Borrower Loans from WebBank, then issues Notes and holds the Borrower Loans until maturity. The obligation to repay a series of Notes issued through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans funded and Notes issued through the Note Channel are carried on Prosper’s condensed consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes. Leases We determine if an arrangement is a lease at inception. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are included on our consolidated balance sheets in the Property and Equipment, Net and the Other Liabilities sections, respectively. If a contract contains a lease, we evaluate whether it should be classified as an operating or finance lease. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. For certain leases with original terms of twelve months or less we recognize the lease expense as incurred and we do not recognize ROU assets and lease liabilities. Consolidation of Variable Interest Entities The determination of whether to consolidate a variable interest entity (“VIE”) in which we have a variable interest requires a significant amount of analysis and judgment regarding whether we are the primary beneficiary of a VIE due to our holding a controlling financial interest in the VIE. A controlling financial interest in a VIE exists if we have both the power to direct the VIE’s activities that most significantly affect the VIE’s economic performance and a potentially significant economic interest in the VIE. The determination of whether an entity is a VIE considers factors, such as (i) whether the entity’s equity investment at risk is insufficient to allow the entity to finance its activities without additional subordinated financial support and (ii) whether a holder’s equity investment at risk lacks any of the following characteristics of a controlling financial interest: the direct or indirect ability through voting rights or similar rights to make decisions about a legal entity’s activities that have a significant effect on the entity’s success, the obligation to absorb the expected losses of the entity or the right to receive the expected residual returns of the legal entity. Management regularly reviews and reconsiders its previous conclusions regarding the status of an entity as a VIE and whether we are required to consolidate such VIE in the consolidated financial statements. Recent Accounting Pronouncements Accounting Standards Adopted In The Current Period In June 2018, the FASB issued ASU No. 2018-07, "Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting." The ASU is intended to reduce the cost and complexity and to improve financial reporting for nonemployee share-based payments. The ASU expands the scope of Topic 718, Compensation-Stock Compensation, which currently only includes share-based payments to employees, to include share-based payments issued to nonemployees for goods or services. Consequently, the accounting for share-based payments to nonemployees and employees will be substantially aligned. Prosper adopted the standard effective January 1, 2019. The adoption of this standard did not have a material impact on Prosper’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)," which requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases, along with additional qualitative and quantitative disclosures. Prosper adopted the standard effective January 1, 2019. In accordance with ASU 2018-11, "Leases (Topic 842), Target Improvements", Prosper has elected not to restate prior periods and has presented the cumulative effect of applying the new standard as an adjustment to the opening balance of retained earnings on January 1, 2019. The standard had a material impact on our consolidated balance sheets, but did not materially impact our consolidated statement of operations. The most significant impact is the recognition of ROU assets and lease obligation liabilities for operating leases. Additionally, Prosper recorded an impairment charge to its ROU asset upon adoption due to existing sublease arrangements that were entered into at a loss. The impairment charge did not have a material impact as it will be offset by a reduction of the existing restructuring liability for those leases. Prosper has elected the package of practical expedients, which allows the Company not to reassess (1) whether any expired or existing contracts as of the adoption date are or contain a lease, (2) lease classification for any expired or existing leases as of the adoption date and (3) initial direct costs for any existing leases as of the adoption date. The Company did not elect to apply the hindsight practical expedient when determining lease term and assessing impairment of right-of-use assets. The Company also elected a practical expedient that allowed it to not separate non-lease components from lease components and instead to account for each lease and non-lease component as a single lease component. The adoption of ASU 2016-02 on January 1, 2019 resulted in the recognition of ROU assets of approximately $16.1 million, lease liabilities for operating leases of approximately $21.6 million, a reduction in existing other liabilities of $5.1 million related to deferred rent and restructuring liabilities, and no cumulative-effect adjustment on retained earnings on Prosper's Consolidated Balance Sheets, with no material impact to its Consolidated Statements of Operations. Accounting Standards Issued, To Be Adopted By The Company In Future Periods In June 2016, the FASB amended guidance related to impairment of financial instruments as part of ASU 2016-13, "Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments", which will be effective for interim and annual periods beginning after December 15, 2019. The guidance replaces the incurred loss impairment methodology with an expected credit loss model for which a company recognizes an allowance based on the estimate of expected credit loss. Prosper accounts for its Borrower Loans at fair value through net income, which is outside the scope of Topic 326. For certain available for sale investments, the guidance will require recognition of expected credit losses through recording an allowance for credit losses. The recognition of this allowance is limited to the difference between the security’s amortized cost basis and fair value. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment." The standard eliminates Step 2 from the goodwill impairment test, which requires a hypothetical purchase price allocation. Prosper will continue to have the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The standard is effective for interim and annual periods beginning after December 15, 2019 and early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The standard should be applied on a prospective basis. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, "Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement." Entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, but public companies will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. ASU No. 2018-13 is effective for all entities for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, but entities are permitted to early adopt either the entire standard or only the provisions that eliminate or modify the requirements. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, "Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract." This ASU aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within that fiscal year and early adoption is permitted. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements.
Prosper Funding LLC
Entity Information [Line Items]
Summary of Significant Accounting Policies	Significant Accounting Policies Prosper Funding's significant accounting policies are included in Note 2 – Summary of Significant Accounting Policies in Prosper Funding’s Annual Report on Form 10-K for the year ended December 31, 2018. There have been no changes to these accounting policies during the first six months of 2019. 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. Restricted Cash Restricted cash consists primarily of cash deposits and short term certificate of deposit accounts held as collateral as required for long term leases, loan funding and servicing activities, and cash that investors or Prosper has on our marketplace that has not yet been invested in Borrower Loans or disbursed to the investor. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amount shown in the consolidated statements of cash flows: June 30, 2019 December 31, 2018 June 30, 2018 December 31, 2017 Cash and Cash Equivalents $ 12,269 11,163 $ 10,892 $ 8,223 Restricted Cash 123,380 136,018 120,152 140,092 Total Cash, Cash Equivalents and Restricted Cash show in the consolidated statements of cash flows $ 135,649 $ 147,181 $ 131,044 $ 148,315 Borrower Loans, Loans Held for Sale and Notes Through the Note Channel, Prosper Funding purchases Borrower Loans from WebBank, then issues Notes and holds the Borrower Loans until maturity. The obligation to repay a series of Notes funded through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans and Notes funded through the Note Channel are carried on Prosper Funding’s condensed consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper Funding estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper Funding maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes. Recent Accounting Pronouncements Accounting Standards Adopted In The Current Period No accounting standards were adopted in the current period for Prosper Funding LLC. Accounting Standards Issued, To Be Adopted By The Company In Future Periods In August 2018, the FASB issued ASU No. 2018-13, " Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement ." Entities will no longer be required to disclose the amount of and reasons for transfers between level 1 and level 2 of the fair value hierarchy, but public companies will be required to disclose the range and weighted average used to develop significant unobservable inputs for level 3 fair value measurements. ASU No. 2018-13 is effective for all entities for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, but entities are permitted to early adopt either the entire standard or only the provisions that eliminate or modify the requirements. Prosper Funding is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Property and Equipment, Net

Property and Equipment, Net	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Property and Equipment, Net	Property and Equipment, Net Property and equipment consist of the following (in thousands): June 30, 2019 December 31, 2018 Property and Equipment: Operating lease right-of-use assets $ 16,138 $ — Computer equipment 12,790 15,193 Internal-use software and website development costs 24,621 22,505 Office equipment and furniture 2,995 3,015 Leasehold improvements 7,158 7,157 Assets not yet placed in service 3,268 2,745 Property and equipment 66,970 50,615 Less accumulated depreciation and amortization (35,801) (35,342) Total Property and Equipment, Net $ 31,169 $ 15,273 Depreciation and amortization expense for Property and Equipment for the three months ended June 30, 2019 and June 30, 2018 was $1.8 million and $2.4 million, respectively. Depreciation and amortization expense for property and equipment for the six months ended June 30, 2019 and June 30, 2018 was $3.6 million and $5.1 million, respectively. These charges are included in General and Administrative expenses on the condensed consolidated statements of operations. Prosper capitalized internal-use software and website development costs in the amount of $2.3 million and $1.4 million for the three months ended June 30, 2019 and June 30, 2018, respectively. Prosper capitalized internal-use software and website development costs in the amount of $4.3 million and $2.5 million for the six months ended June 30, 2019 and June 30, 2018, respectively. Additionally, disclosures around the operating lease right-of-use assets are included in Note 17.
Prosper Funding LLC
Entity Information [Line Items]
Property and Equipment, Net	Property and Equipment Property and equipment consist of the following (in thousands): June 30, 2019 December 31, 2018 Property and equipment: Internal-use software and web site development costs $ 22,075 $ 22,505 Less accumulated depreciation and amortization (16,581) (16,079) Total property and equipment, net $ 5,494 $ 6,426 Depreciation expense for the three months ended June 30, 2019 and June 30, 2018 was $1.1 million and $1.4 million, respectively. Depreciation expense for the six months ended June 30, 2019 and June 30, 2018 was $2.2 million and $3.0 million, respectively.

Borrower Loans, Loans Held for

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	Borrower Loans, Loans Held for Sale, and Notes, Held at Fair Value The aggregate principal balances outstanding and fair values of Borrower Loans, Loans Held for Sale, and Notes as of June 30, 2019 and December 31, 2018, are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 Aggregate principal balance outstanding $ 614,678 $ 269,093 $ (259,954) $ (272,430) $ 115,098 $ 185,657 Fair value adjustments (7,879) (5,571) 6,529 8,427 (136) (1,869) Fair value $ 606,799 $ 263,522 $ (253,425) $ (264,003) $ 114,962 $ 183,788 Borrower Loans At June 30, 2019, outstanding Borrower Loans had original terms to maturity of either 36 or 60 months, had monthly payments with fixed interest rates ranging from 5.31% to 31.92%, and had various maturity dates through June 2024. At December 31, 2018, outstanding Borrower Loans had original maturities of either 36 or 60 months, had monthly payments with fixed interest rates ranging from 5.31% to 31.92%, and had various maturity dates through December 2023. Approximately $0.4 million and $0.6 million represents the loss that is attributable to changes in the instrument-specific credit risks related to Borrower Loans that were recorded in the change in fair value during the six months ending June 30, 2019 and June 30, 2018, respectively, as recorded on the Condensed Consolidated Statement of Operations. As of June 30, 2019, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $4.1 million and a fair value of $1.6 million. As of December 31, 2018, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $2.5 million and a fair value of $1.1 million. Prosper places loans on non-accrual status when they are over 120 days past due. As of June 30, 2019 and December 31, 2018, Borrower Loans in non-accrual status had a fair value of $0.4 million and $0.3 million, respectively. Loans Held for Sale At June 30, 2019, outstanding Loans Held for Sale had original terms to maturity of either 36 or 60 months, had monthly payments with fixed interest rates ranging from 5.31% to 31.82%, and had various maturity dates through June 2024. At December 31, 2018, outstanding Loans Held for Sale had original terms to maturity of either 36 or 60 months, had monthly payments with fixed interest rates ranging from 5.31% to 31.82% and had various maturity dates through December 2023. Fair value adjustments recorded in earnings on loans invested in by the Company resulted in a net loss of $0.1 million during the six months ended June 30, 2019. Interest income earned on Loans Held for Sale by the Company was $7.5 million and $5.1 million during the six months ended June 30, 2019 and June 30, 2018, respectively. As of June 30, 2019, Loans Held for Sale that were 90 days or more delinquent, had an aggregate principal amount of $0.4 million and a fair value of $0.1 million. As of December 31, 2018, Loans Held for S ale that were 90 days or more delinquent had an aggregate principal amount of $0.8 million and a fair value of $0.3 million .
Prosper Funding LLC
Entity Information [Line Items]
Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value	Borrower Loans and Notes Held at Fair Value The aggregate principal balances outstanding and fair values of Borrower Loans and Notes as of June 30, 2019 and December 31, 2018, are presented in the following table (in thousands): Borrower Loans Notes June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 Aggregate principal balance outstanding $ 257,921 $ 269,093 $ (259,954) $ (272,430) Fair value adjustments (3,851) (5,571) 6,529 8,427 Fair value $ 254,070 $ 263,522 $ (253,425) $ (264,003) At June 30, 2019, outstanding Borrower Loans had original terms to maturity of either 36 or 60 months, had monthly payments with fixed interest rates ranging from 5.31% to 31.92% and had various maturity dates through June 2024. At December 31, 2018, outstanding Borrower Loans had original maturities of either 36 or 60 months, monthly payments with fixed interest rates ranging from 5.31% to 31.92%, and had various maturity dates through December 2023. Within the change in fair value of Borrower Loans, Prosper Funding recorded a loss of approximately $0.2 million that is attributable to changes in the credit risks related to Borrower Loans during the six months ended June 30, 2019. As of June 30, 2019, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $2.2 million and a fair value of $0.9 million. As of December 31, 2018, Borrower Loans that were 90 days or more delinquent had an aggregate principal amount of $2.5 million and a fair value of $1.1 million. Prosper Funding places loans on non-accrual status when they are over 120 days past due. As of June 30, 2019 and December 31, 2018, Borrower Loans in non-accrual status had a fair value of $0.4 million and $0.3 million, respectively.

Loan Servicing Assets and Liabi

Loan Servicing Assets and Liabilities	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Loan Servicing Assets and Liabilities	Loan Servicing Assets and Liabilities Prosper accounts for servicing assets and liabilities at their estimated fair values with changes in fair values recorded in servicing fees. The initial asset or liability is recognized when Prosper sells Borrower Loans to unrelated third-party buyers through the Whole Loan Channel and the servicing rights are retained. The servicing assets and liabilities are measured at fair value throughout the servicing period. The total gains and losses recognized on the sale of such Borrower Loans for the three months ended June 30, 2019 was a gain of $3.6 million and a loss of $7.8 million from the Fair Value of Warrants Vested on the Sale of Borrower Loans to the Consortium. The total gains recognized on the sale of such Borrower Loans were $4.2 million during the three months ended June 30, 2018, and a loss of $20.6 million from the Fair Value of Warrants Vested on the Sale of Borrower Loans to the Consortium. The total gains and losses recognized on the sale of such Borrower Loans for the six months ended June 30, 2019 was a gain of $6.3 million and a loss of $17.6 million from the Fair Value of Warrants Vested on the Sale of Borrower Loans to the Consortium. The total gains recognized on the sale of such Borrower Loans were $7.5 million during the six months ended June 30, 2018, and a loss of $35.9 million from the Fair Value of Warrants Vested on the Sale of Borrower Loans to the Consortium. As of June 30, 2019, Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $3.3 billion, original terms of either 36 or 60 months, monthly payments with fixed interest rates ranging from 5.31% to 35.52%, and various maturity dates through June 2024. At December 31, 2018, Borrower Loans that were sold but for which Prosper retained servicing rights had a total outstanding principal balance of $3.6 billion, original terms of either 36 or 60 months, monthly payments with fixed interest rates ranging from 5.31% to 35.52%, and various maturity dates through December 2023. $18.5 million and $21.6 million of contractually specified servicing fees and ancillary fees are included on our condensed consolidated statements of operations in Servicing Fees, Net for the six months ended June 30, 2019 and June 30, 2018, respectively. Fair Value Valuation Method . Prosper uses a discounted cash flow valuation methodology generally consisting of developing an estimate of future cash flows that are expected to occur over the life of a financial instrument and then discounting those cash flows at a rate of return that results in the fair value amount. Significant unobservable inputs presented in the table within Note 8 below are those that Prosper considers significant to the estimated fair values of the level 3 servicing assets and liabilities. The following is a description of the significant unobservable inputs provided in the table. Market Servicing Rate . Prosper estimates adequate market servicing rates that would fairly compensate a substitute servicer should one be required, which includes the profit that would be demanded in the marketplace. This rate is stated as a fixed percentage of outstanding principal balance on a per annum basis. Prosper estimated these market servicing rates based on observable market rates for other loan types in the industry and bids from subservicing providers, adjusted for the unique loan attributes that are present in the specific loans that Prosper sells and services and information from a backup service provider. Discount Rate . The discount rate is a rate of return used to discount future expected cash flows to arrive at a present value, which represents the fair value of the loan servicing rights. We used a range of discount rates for the servicing assets and liabilities based on comparable observed valuations of similar assets and publicly available disclosures related to servicing valuations, with comparability adjustments made to account for differences with Prosper’s servicing assets. Default Rate . The default rate presented in Note 8 is an annualized, average estimate considering all Borrower Loan categories (i.e., risk ratings and duration), and represents an aggregate of conditional default rate curves for each credit grade or Borrower Loan category. Each point on a particular Borrower Loan category’s curve represents the percentage of principal expected to default per period based on the term and age of the underlying Borrower Loans. The assumption regarding defaults directly reduces servicing revenues because the amount of servicing revenues received is based on the amount collected each period. Prepayment Rate . The prepayment rate presented in Note 8 is an annualized, average estimate considering all Borrower Loan categories (i.e., risk ratings and duration), and represents an aggregate of conditional prepayment rate curves for each credit grade or Borrower Loan category. Each point on a particular Borrower Loan category’s curve represents the percentage of principal expected to prepay per period based on the term and age of the underlying Borrower Loans. Prepayments reduce servicing revenues as they shorten the period over which we expect to collect fees on the Borrower Loans, which is used to project future servicing revenues.
Prosper Funding LLC
Entity Information [Line Items]
Loan Servicing Assets and Liabilities	Loan Servicing Assets and Liabilities Prosper Funding accounts for servicing assets and liabilities at their estimated fair values with changes in fair values recorded in servicing fees. The initial asset or liability is recognized when Prosper Funding sells Borrower Loans to unrelated third-party buyers through the Whole Loan Channel and the servicing rights are retained. The total losses recognized on the sale of such Borrower Loans were a loss of $4.1 million and $16.2 million for the three months ended June 30, 2019 and June 30, 2018, respectively. The total losses recognized on the sale of such Borrower Loans were a loss of $10.9 million and $27.8 million for the six months ended June 30, 2019 and June 30, 2018, respectively. As of June 30, 2019, Borrower Loans that were sold, but for which Prosper Funding retained servicing rights, had a total outstanding principal balance of $3.7 billion, original terms of either 36 or 60 months, monthly payments with fixed interest rates ranging from 5.31% to 35.52%, and various maturity dates through June 2024. At December 31, 2018, Borrower Loans that were sold, but for which Prosper Funding retained servicing rights, had a total outstanding principal balance of $3.7 billion, original terms of either 36 or 60 months, monthly payments with fixed interest rates ranging from 5.31% to 35.52%, and various maturity dates through December 2023. $10.2 million and $11.2 million of contractually specified servicing fees and ancillary fees are included on our condensed consolidated statements of operations in Servicing Fees, Net for the three months ended June 30, 2019 and June 30, 2018, respectively. $20.2 million and $21.8 million of contractually specified servicing fees and ancillary fees are included on our condensed consolidated statements of operations in Servicing Fees, Net for the six months ended June 30, 2019 and June 30, 2018, respectively. Fair Value Valuation Method . Prosper Funding uses a discounted cash flow valuation methodology generally consisting of developing an estimate of future cash flows that are expected to occur over the life of a financial instrument and then discounting those cash flows at a rate of return that results in the fair value amount. Significant unobservable inputs presented in the table within Note 7 below are those that Prosper Funding considers significant to the estimated fair values of the level 3 servicing assets and liabilities. The following is a description of the significant unobservable inputs provided in the table. Market Servicing Rate . Prosper Funding estimates adequate market servicing rates that would fairly compensate a substitute servicer should one be required, which includes the profit that would be demanded in the marketplace. This rate is stated as a fixed percentage of outstanding principal balance on a per annum basis. Prosper Funding estimated these market servicing rates based on observable market rates for other loan types in the industry and bids from subservicing providers, adjusted for the unique loan attributes that are present in the specific loans that Prosper Funding sells and services and information from a backup service provider. Discount Rate . The discount rate is a rate of return used to discount future expected cash flows to arrive at a present value, which represents the fair value of the loan servicing rights. We used a range of discount rates for the servicing assets and liabilities based on comparable observed valuations of similar assets and publicly available disclosures related to servicing valuations, with comparability adjustments made to account for differences with Prosper Funding’s servicing assets. Default Rate . The default rate presented in Note 7 is an annualized, average estimate considering all Borrower Loan categories (i.e. risk ratings and duration), and represents an aggregate of conditional default rate curves for each credit grade or Borrower Loan category. Each point on a particular Borrower Loan category’s curve represents the percentage of principal expected to default per period based on the term and age of the underlying Borrower Loans. The assumption regarding defaults directly reduces servicing revenues because the amount of servicing revenues received is based on the amount collected each period.

Available for Sale Investments,

Available for Sale Investments, at Fair Value	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Available for Sale Investments, at Fair Value	Available for Sale Investments, at Fair Value Available for sale investments are recorded at fair value and unrealized gains and losses are reported, net of taxes, in accumulated other comprehensive income (loss) included in stockholders' equity unless management determines that an investment is other-than-temporarily impaired. The amortized cost, gross unrealized gains and losses, and fair value of available for sale investments as of June 30, 2019 and December 31, 2018, are as follows (in thousands): June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Treasury Bills — — — — US Treasury securities 1,492 7 — 1,499 Total Available for Sale Investments $ 1,492 $ 7 $ — $ 1,499 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Treasury Bills $ 17,940 $ — $ (3) $ 17,937 US Treasury securities 4,246 — (10) 4,236 Total Available for Sale Investments $ 22,186 $ — $ (13) $ 22,173 The Company did not hold any available for sale investments with unrealized losses as of June 30, 2019. A summary of available for sale investments with unrealized losses as of December 31, 2018, aggregated by category and period of continuous unrealized loss, is as follows (in thousands): Less than 12 months 12 months or longer Total December 31, 2018 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturity securities: Treasury Bills $ 17,937 $ (3) $ — $ — $ 17,937 $ (3) US Treasury securities $ — $ — $ 4,236 $ (10) $ 4,236 $ (10) Total Investments with Unrealized Losses $ 17,937 $ (3) $ 4,236 $ (10) $ 22,173 $ (13) There were no impairment charges recognized during the six months ended June 30, 2019. The maturities of available for sale investments at June 30, 2019 and December 31, 2018 are as follows (in thousands): June 30, 2019 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Treasury Bills — — — — — US Treasury securities 1,499 — — — 1,499 Total Fair Value $ 1,499 $ — $ — $ — $ 1,499 Total Amortized Cost $ 1,492 $ — $ — $ — $ 1,492 December 31, 2018 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Treasury Bills 17,937 — — — 17,937 US Treasury securities 4,236 — — — 4,236 Total Fair Value $ 22,173 $ — $ — $ — $ 22,173 Total Amortized Cost $ 22,186 $ — $ — $ — $ 22,186 During the six months ended June 30, 2019, Prosper sold $0 of investments.

Securitization

Securitization	6 Months Ended
	Jun. 30, 2019
Transfers and Servicing [Abstract]
Securitization and Variable Interest Entities	Securitizations PMIT 2019-1 On February 7, 2019, Prosper completed a securitization of approximately $205.1 million in unsecured personal whole loans facilitated through the Company’s platform through a securitization trust ("PMIT 2019-1") which Prosper consolidated. PMIT 2019-1 issued notes, residual certificates and a risk retention interest to finance the purchase of Borrower Loans. The resulting notes were sold to third party investors for $171.7 million in net proceeds. Prosper retained 65.5% of the resulting residual certificates. The remaining residual certificates and the risk retention interests are held by third party investors. PMIT 2019-1 was deemed a VIE that the Company consolidates because the Company is the primary beneficiary of the VIE. The creditors of PMIT 2019-1 have no recourse to the general credit of PMI as the primary beneficiary of the VIEs and the liabilities of the VIEs can only be settled by the respective VIE’s assets. Additionally, Prosper's continued involvement includes loan servicing responsibilities over the life of the underlying loans. As a result, Prosper has included PMIT 2019-1's Borrower Loans under "Borrower Loans, at Fair Value", the notes held by third party investors under "Notes Issued by Securitization Trust" and the risk retention and residual certificates held by third party investors under "Certificates Issued by Securitization Trust, at Fair Value" in Prosper's condensed consolidated balance sheets. The notes under the PMIT 2019-1 were issued in three classes: Class A in the amount of $127.3 million, Class B in the amount of $25.0 million and Class C in the amount of $19.3 million (collectively, the “2019-1 Notes”). The Class A, Class B and Class C notes bear interest at a fixed rate of 3.54%, 4.03% and 5.27%, respectively. Principal and interest payments began in March 2019 and are payable monthly. These notes are recorded at amortized cost on the balance sheet. The associated debt issuance costs of $2.3 million are deferred and amortized into interest expense over the contractual life of the notes. The notes held by third-party investors and the unamortized debt issuance costs are included in “Notes Issued by Securitization Trust” with a balance of $140.0 million on the condensed consolidated balance sheets as of June 30, 2019 and are secured by an aggregate outstanding principal balance of $158.9 million of borrower loans included in “Borrower Loans, at Fair Value” on the condensed consolidated balance sheets as of June 30, 2019. The risk retention and residual certificates are carried at fair value and the risk retention interest represents the right to receive 5.0% of all amounts collected on the Borrower Loans held by PMIT 2019-1, net of its pro-rata share of ongoing fees and expenses of PMIT 2019-1. PMIT 2019-2 On May 23, 2019, Prosper completed a securitization of approximately $203.5 million in unsecured personal whole loans facilitated through the Company’s platform through a securitization trust ("PMIT 2019-2") which Prosper consolidated. PMIT 2019-2 issued notes, residual certificates and a risk retention interest to finance the purchase of Borrower Loans. The resulting notes were sold to third party investors for $174.2 million in net proceeds. Prosper retained 16.4% of the resulting residual certificates. The remaining residual certificates and the risk retention interests are held by third party investors. PMIT 2019-2 was deemed a VIE that the Company consolidates because the Company is the primary beneficiary of the VIE. The creditors of PMIT 2019-2 have no recourse to the general credit of PMI as the primary beneficiary of the VIEs and the liabilities of the VIEs can only be settled by the respective VIE’s assets. Additionally, Prosper's continued involvement includes loan servicing responsibilities over the life of the underlying loans. As a result, Prosper has included PMIT 2019-2's Borrower Loans under "Borrower Loans, at Fair Value", the notes held by third party investors under "Notes Issued by Securitization Trust" and the risk retention and residual certificates held by third party investors under "Certificates Issued by Securitization Trust, at Fair Value" in Prosper's condensed consolidated balance sheets. The notes under the PMIT 2019-2 were issued in three classes: Class A in the amount of $110.1 million, Class B in the amount of $31.4 million and Class C in the amount of $32.7 million (collectively, the “2019-2 Notes”). The Class A, Class B and Class C notes bear interest at a fixed rate of 3.20%, 3.69% and 5.05%, respectively. Principal and interest payments begin in July 2019 and are payable monthly. These notes are recorded at amortized cost on the balance sheet. The associated debt issuance costs of $1.9 million are deferred and amortized into interest expense over the contractual life of the notes. The notes held by third-party investors and the unamortized debt issuance costs are included in “Notes Issued by Securitization Trust” with a balance of $173.1 million on the condensed consolidated balance sheets as of June 30, 2019 and are secured by an aggregate outstanding principal balance of $192.8 million of borrower loans included in “Borrower Loans, at Fair Value” on the condensed consolidated balance sheets as of June 30, 2019. The risk retention and residual certificates are carried at fair value and the risk retention interest represents the right to receive 5.0% of all amounts collected on the Borrower Loans held by PMIT 2019-2, net of its pro-rata share of ongoing fees and expenses of PMIT 2019-2.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities Prosper measures the fair value of assets and liabilities in accordance with its fair value hierarchy which prioritizes information used to measure fair value and the effect of fair value measurements on earnings and provides for enhanced disclosures determined by the level within the hierarchy of information used in the valuation. We apply this framework whenever other standards require (or permit) assets or liabilities to be measured at fair value. Assets and liabilities carried at fair value on the balance sheets are classified among three levels based on the observability of the inputs used to determine fair value: Level 1 — The valuation is based on quoted prices in active markets for identical instruments. Level 2 — The valuation is based on observable inputs such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation methodologies for which all significant assumptions are observable in the market. Level 3 — The valuation is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the instrument. Level 3 valuations are typically performed using pricing models, discounted cash flow methodologies, or similar methodologies, which incorporate management’s own estimates of assumptions that market participants would use in pricing the instrument or valuations that require significant management judgment or estimation. Fair values of assets or liabilities are determined based on the fair value hierarchy, which requires an entity to maximize the use of quoted prices and observable inputs and to minimize the use of unobservable inputs when measuring fair value. Various valuation methodologies are utilized, depending on the nature of the financial instrument, including the use of market prices for identical or similar instruments, or discounted cash flow models. When possible, active and observable market data for identical or similar financial instruments are utilized. Alternatively, fair value is determined using assumptions that management believes a market participant would use in pricing the asset or liability. Financial Instruments Recorded at Fair Value The fair value of the Borrower Loans, Loans Held for Sale, Certificates Issued by Securitization Trust and Notes are estimated using discounted cash flow methodologies based upon a set of valuation assumptions. The primary cash flow assumptions used to value such Borrower Loans, Loans Held for Sale, Certificates Issued by Securitization Trust, and Notes include default rates derived from historical performance and discount rates applied to each credit grade based on the perceived credit risk of each credit grade. Investments held at fair value consist of Available for Sale Investments. The Available for Sale Investments may consist of corporate debt securities, commercial paper, U.S. Treasury securities, Treasury bills, agency bonds and short term bond funds. When available, Prosper uses quoted prices in active markets to measure the fair value of securities available for sale. When utilizing market data and bid-ask spreads, Prosper uses the price within the bid-ask spread that best represents fair value. When quoted prices do not exist, Prosper uses prices obtained from independent third-party pricing services to measure the fair value of investment assets. Prosper's primary independent pricing service provides prices based on observable trades and discounted cash flows that incorporate observable information, such as yields for similar types of securities (a benchmark interest rate plus observable spreads) and weighted-average maturity for the same or similar securities. Prosper compares the prices obtained from its primary independent pricing service to the prices obtained from the additional independent pricing services to determine if the price obtained from the primary independent pricing service is reasonable. Prosper does not adjust the prices received from independent third-party pricing services unless such prices are inconsistent with the definition of fair value and result in a material difference in the recorded amounts. The Convertible Preferred Stock Warrant Liability is valued using a Black-Scholes option pricing model. Refer to Note 13 for further details. The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands): June 30, 2019 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 606,799 $ 606,799 Loans Held for Sale — — 114,962 114,962 Available for Sale Investments, at Fair Value — 1,499 — 1,499 Servicing Assets — — 13,387 13,387 Total Assets $ — $ 1,499 $ 735,148 $ 736,647 Liabilities: Notes $ — $ — $ 253,425 $ 253,425 Servicing Liabilities — — 4 4 Certificates Issued by Securitization Trust, at Fair Value — — 44,090 44,090 Convertible Preferred Stock Warrant Liability — — 166,559 166,559 Loan Trailing Fee Liability — — 3,249 3,249 Total Liabilities $ — $ — $ 467,327 $ 467,327 December 31, 2018 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 263,522 $ 263,522 Loans Held for Sale — — 183,788 183,788 Available for Sale Investments, at Fair Value — 22,173 — 22,173 Servicing Assets — — 14,687 14,687 Total Assets $ — $ 22,173 $ 461,997 $ 484,170 Liabilities: Notes $ — $ — $ 264,003 $ 264,003 Servicing Liabilities — — 12 12 Convertible Preferred Stock Warrant Liability — — 143,679 143,679 Loan Trailing Fee Liability — — 3,118 3,118 Total Liabilities $ — $ — $ 410,812 $ 410,812 As Prosper’s Borrower Loans, Loans Held for Sale, Certificates Issued by Securitization Trust, Notes, and loan servicing rights do not trade in an active market with readily observable prices, Prosper uses significant unobservable inputs to measure the fair value of these assets and liabilities. Financial instruments are categorized in the level 3 valuation hierarchy based on the significance of unobservable factors in the overall fair value measurement. These fair value estimates may also include observable, actively quoted components derived from external sources. As a result, the realized and unrealized gains and losses for assets and liabilities within the level 3 category may include changes in fair value that were attributable to both observable and unobservable inputs. Significant Unobservable Inputs The following tables present quantitative information about the significant unobservable inputs used for Prosper’s level 3 fair value measurements at June 30, 2019 and December 31, 2018: Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 4.9% - 12.9% 4.7% - 13.8% Default rate 2.0% - 16.6% 2.0% - 15.8% Servicing Rights: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1% Market servicing rate 0.625 % 0.625 % Loan Trailing Fee Liability: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1% At June 30, 2019, the discounted cash flow methodology used to estimate the Note fair values used the same projected cash flows as the related Borrower Loans. The following tables present additional information about level 3 Borrower Loans, Loans Held for Sale and Notes measured at fair value on a recurring basis (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Certificates Issued by Securitization Trust Loans Held for Sale Total Balance at January 1, 2019 $ 263,522 $ (264,003) $ — $ 183,788 $ 183,307 Purchase of Borrower Loans/Issuance of Notes 348,629 (86,713) (51,595) 1,161,237 1,371,558 Transfers in (Transfers out) 147,773 — — (147,773) — Principal repayments (134,031) 85,728 4,272 (26,529) (70,560) Borrower Loans sold to third parties (1,886) — — (1,053,308) (1,055,194) Other changes 91 603 (603) 89 180 Change in fair value (17,299) 10,960 3,836 (2,542) (5,045) Balance at June 30, 2019 $ 606,799 $ (253,425) $ (44,090) $ 114,962 $ 424,246 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2018 $ 293,005 $ (293,948) $ 49 $ (894) Purchase of Borrower Loans/Issuance of Notes 91,075 (90,693) 1,324,100 1,324,482 Principal repayments (88,947) 91,525 (14,265) (11,687) Borrower Loans sold to third parties (2,016) — (1,193,651) (1,195,667) Other changes (338) 633 796 1,091 Change in fair value (15,418) 15,058 (212) (572) Balance at June 30, 2018 $ 277,361 $ (277,425) $ 116,817 $ 116,753 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Certificates Issued by Securitization Trust Loans Held for Sale Total Balance at April 1, 2019 $ 448,710 $ (258,722) $ (19,134) $ 106,640 $ 277,494 Purchase of Borrower Loans/Issuance of Notes 213,370 (41,774) (30,979) 670,382 810,999 Transfers in (Transfers out) 33,457 — — (33,457) — Principal repayments (77,402) 41,611 3,139 (11,790) (44,442) Borrower Loans sold to third parties (912) — — (615,835) (616,747) Other changes (48) 2 (436) 255 (227) Change in fair value (10,376) 5,458 3,320 (1,233) (2,831) Balance at June 30, 2019 $ 606,799 $ (253,425) $ (44,090) $ 114,962 $ 424,246 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at April 1, 2018 $ 285,584 $ (285,095) $ 82,803 $ 83,292 Purchase of Borrower Loans/Issuance of Notes 44,799 (44,468) 728,901 729,232 Principal repayments (43,990) 44,423 (10,416) (9,983) Borrower Loans sold to third parties (950) — (683,547) (684,497) Other changes (202) 86 255 139 Change in fair value (7,880) 7,629 (1,179) (1,430) Balance at June 30, 2018 $ 277,361 $ (277,425) $ 116,817 $ 116,753 The following tables present additional information about level 3 servicing assets measured at fair value on a recurring basis (in thousands): Servicing Assets Fair Value at January 1, 2019 14,687 Additions 6,378 Derecognition (1,049) Less: Changes in fair value (6,629) Fair Value at June 30, 2019 13,387 Servicing Assets Fair Value at January 1, 2018 14,711 Additions 7,502 Less: Changes in fair value (6,569) Fair Value at June 30, 2018 15,644 Servicing Assets Fair Value at April 1, 2019 13,814 Additions 3,636 Derecognition (685) Less: Changes in fair value (3,378) Fair Value at June 30, 2019 13,387 Servicing Assets Fair Value at April 1, 2018 14,754 Additions 4,163 Less: Changes in fair value (3,273) Fair Value at June 30, 2018 15,644 The following table presents additional information about level 3 Preferred Stock Warrant Liability measured at fair value on a recurring basis (in thousands): Preferred Stock Balance as of January 1, 2019 $ 143,679 Add Issuances of Preferred Stock Warrant 17,553 Change in Fair Value of the Preferred Stock Warrant Liability 5,327 Balance as of June 30, 2019 $ 166,559 Preferred Stock Balance as of January 1, 2018 $ 116,366 Add Issuances of Preferred Stock Warrant 35,912 Change in Fair Value of the Preferred Stock Warrant Liability (8,602) Balance as of June 30, 2018 $ 143,676 Preferred Stock Balance as of April 1, 2019 $ 163,483 Add Issuances of Preferred Stock Warrant 7,805 Change in Fair Value of the Preferred Stock Warrant Liability (4,729) Balance as of June 30, 2019 $ 166,559 Preferred Stock Balance as of April 1, 2018 $ 127,041 Add Issuances of Preferred Stock Warrant 20,633 Change in Fair Value of the Preferred Stock Warrant Liability (3,998) Balance as of June 30, 2018 $ 143,676 Loan Trailing Fee The fair value of the Loan Trailing Fee represents the present value of the expected monthly Loan Trailing Fee payments, which takes into consideration certain assumptions related to expected prepayment rates and defaults rates using a discounted cash flow model. The following table presents additional information about level 3 Loan Trailing Fee Liability measured at fair value on a recurring basis (in thousands): Loan Trailing Fee Balance at January 1, 2019 3,118 Issuances 1,297 Cash Payment of Loan Trailing Fee (1,298) Change in Fair Value 132 Balance at June 30, 2019 3,249 Significant Recurring Level 3 Fair Value Asset and Liability Input Sensitivity Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at June 30, 2019 for Borrower Loans, Loans Held for Sale and Notes funded through the Note Channel are presented in the following table (in thousands, except percentages): Borrower Loans and Loans Held for Sale Notes Fair Value as of June 30, 2019 $721,761 $253,425 Discount rate assumption: 7.44 % * 7.87 % * Resulting fair value from: 100 basis point increase $ 715,006 $ 251,050 200 basis point increase 708,411 248,730 Resulting fair value from: 100 basis point decrease $ 728,682 $ 255,859 200 basis point decrease 735,775 258,354 Default rate assumption: 12.19 % * 12.55 % * Resulting fair value from: 100 basis point increase $ 713,132 $ 250,379 200 basis point increase 704,794 247,437 Resulting fair value from: 100 basis point decrease $ 730,554 $ 256,527 200 basis point decrease 739,384 259,643 * Represents weighted average assumptions considering all credit grades. The following table presents the estimated impact on Prosper’s estimated fair value of servicing assets and liabilities, calculated using different market servicing rates and different default rates as of June 30, 2019 (in thousands, except percentages). Servicing Assets Fair Value as of June 30, 2019 $13,387 Market servicing rate assumptions 0.625 % Resulting fair value from: Market servicing rate increase to 0.65% $ 12,560 Market servicing rate decrease to 0.60% $ 14,214 Weighted average prepayment assumptions 20.59 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate $ 13,220 Applying a 0.9 multiplier to prepayment rate $ 13,556 Weighted average default assumptions 11.72 % Resulting fair value from: Applying a 1.1 multiplier to default rate $ 13,237 Applying a 0.9 multiplier to default rate $ 13,541 These sensitivities are hypothetical and should be evaluated with care. The effect on fair value of a variation in assumptions generally cannot be determined because the relationship of the change in assumptions to the fair value may not be linear. Additionally, the impact of a variation in a particular assumption on the fair value is calculated while holding other assumptions constant. In reality, changes in one factor may lead to changes in other factors, which could impact the above hypothetical effects. Financial Instruments, Assets and Liabilities not Recorded at Fair Value The following tables present the fair value hierarchy for financial instruments, assets, and liabilities not recorded at fair value (in thousands): June 30, 2019 Carrying Amount Level 1 Inputs Level 2 Inputs Level 3 Inputs Balance at Fair Value Assets: Cash and Cash Equivalents $ 68,124 $ 68,124 $ — $ — $ 68,124 Restricted Cash 160,990 — 160,990 — 160,990 Accounts Receivable 1,270 — 1,270 — 1,270 Total Assets $ 230,384 $ 68,124 $ 162,260 $ — $ 230,384 Liabilities: Accounts Payable and Accrued Liabilities $ 20,349 $ — $ 20,349 $ — $ 20,349 Payable to Investors 114,811 — 114,811 — 114,811 Notes Issued by Securitization Trust 313,111 — $ 318,304 — 318,304 Warehouse Lines 101,406 — 101,406 — 101,406 Total Liabilities $ 549,677 $ — $ 554,870 $ — $ 554,870
Prosper Funding LLC
Entity Information [Line Items]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities Prosper Funding measures the fair value of assets and liabilities in accordance with its fair value hierarchy which prioritizes information used to measure fair value and the effect of fair value measurements on earnings and provides for enhanced disclosures determined by the level within the hierarchy of information used in the valuation. We apply this framework whenever other standards require (or permit) assets or liabilities to be measured at fair value. Assets and liabilities carried at fair value on the balance sheets are classified among three levels based on the observability of the inputs used to determine fair value: Level 1 — The valuation is based on quoted prices in active markets for identical instruments. Level 2 — The valuation is based on observable inputs such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation methodologies for which all significant assumptions are observable in the market. Level 3 — The valuation is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the instrument. Level 3 valuations are typically performed using pricing models, discounted cash flow methodologies, or similar methodologies, which incorporate management’s own estimates of assumptions that market participants would use in pricing the instrument or valuations that require significant management judgment or estimation. Fair values of assets or liabilities are determined based on the fair value hierarchy, which requires an entity to maximize the use of quoted prices and observable inputs and to minimize the use of unobservable inputs when measuring fair value. Various valuation methodologies are utilized, depending on the nature of the financial instrument, including the use of market prices for identical or similar instruments, or discounted cash flow models. When possible, active and observable market data for identical or similar financial instruments are utilized. Alternatively, fair value is determined using assumptions that management believes a market participant would use in pricing the asset or liability. Financial Instruments Recorded at Fair Value The fair value of the Borrower Loans, Loans Held for Sale and Notes are estimated using discounted cash flow methodologies based upon a set of valuation assumptions. The primary cash flow assumptions used to value such Borrower Loans, Loans Held for Sale and Notes include default rates derived from historical performance and discount rates applied to each credit grade based on the perceived credit risk of each credit grade. The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands): June 30, 2019 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 254,070 $ 254,070 Servicing Assets — — 15,461 15,461 Total Assets — — 269,531 269,531 Liabilities: Notes $ — $ — $ 253,425 $ 253,425 Servicing Liabilities — — 4 4 Loan Trailing Fee Liability — — 3,249 3,249 Total Liabilities $ — $ — $ 256,678 $ 256,678 December 31, 2018 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 263,522 $ 263,522 Servicing Assets — — 15,550 15,550 Total Assets — — 279,072 279,072 Liabilities: Notes $ — $ — $ 264,003 $ 264,003 Servicing Liabilities — — 12 12 Loan Trailing Fee Liability — — 3,118 3,118 Total Liabilities $ — $ — $ 267,133 $ 267,133 As Prosper Funding’s Borrower Loans, Loans Held for Sale, Notes and loan servicing rights do not trade in an active market with readily observable prices, Prosper Funding uses significant unobservable inputs to measure the fair value of these assets and liabilities. Financial instruments are categorized in the level 3 valuation hierarchy based on the significance of unobservable factors in the overall fair value measurement. These fair value estimates may also include observable, actively quoted components derived from external sources. As a result, the realized and unrealized gains and losses for assets and liabilities within the level 3 category may include changes in fair value that were attributable to both observable and unobservable inputs. Significant Unobservable Inputs The following tables present quantitative information about the significant unobservable inputs used for Prosper Funding’s level 3 fair value measurements at June 30, 2019 and December 31, 2018: Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 4.9% - 12.9% 4.7% - 13.8% Default rate 2.0% - 16.6% 2.0% - 15.8% Servicing Assets and Liabilities: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1% Market servicing rate 0.625 % 0.625 % Loan Trailing Fee Liability: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1% The changes in the Borrower Loans, Loans Held for Sale and Notes, which are level 3 assets and liabilities measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2019 $ 263,522 $ (264,003) $ — $ (481) Originations 86,062 (86,713) 1,161,237 1,160,586 Principal repayments (82,414) 85,728 — 3,314 Borrower Loans sold to third parties (1,723) — (1,161,237) (1,162,960) Other changes (200) 603 — 403 Change in fair value (11,177) 10,960 — (217) Balance at June 30, 2019 $ 254,070 $ (253,425) $ — $ 645 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2018 $ 293,005 $ (293,948) $ 49 $ (894) Originations 91,075 (90,693) 1,324,100 1,324,482 Principal repayments (88,947) 91,525 (14) 2,564 Borrower Loans sold to third parties (2,016) — (1,324,100) (1,326,116) Other changes (338) 633 — 295 Change in fair value (15,418) 15,058 (4) (364) Balance at June 30, 2018 $ 277,361 $ (277,425) $ 31 $ (33) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at April 1, 2019 $ 259,899 $ (258,722) $ — $ 1,177 Originations 41,839 (41,774) 670,382 670,447 Principal repayments (41,215) 41,611 — 396 Borrower Loans sold to third parties (749) — (670,382) (671,131) Other changes (115) 2 — (113) Change in fair value (5,589) 5,458 — (131) Balance at June 30, 2019 $ 254,070 $ (253,425) $ — $ 645 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at April 1, 2018 $ 285,584 $ (285,095) $ 41 $ 530 Originations 44,799 (44,468) 728,901 729,232 Principal repayments (43,990) 44,423 (6) 427 Borrower Loans sold to third parties (950) — (728,901) (729,851) Other changes (202) 86 — (116) Change in fair value (7,880) 7,629 (4) (255) Balance at June 30, 2018 $ 277,361 $ (277,425) $ 31 $ (33) The following table presents additional information about level 3 servicing assets recorded at fair value (in thousands): Servicing Assets Fair Value at January 1, 2019 15,550 Additions 6,796 Less: Changes in fair value (6,885) Fair Value at June 30, 2019 15,461 Servicing Assets Fair Value at January 1, 2018 14,598 Additions 8,147 Less: Changes in fair value (6,583) Fair Value at June 30, 2018 16,162 Servicing Assets Fair Value at April 1, 2019 15,174 Additions 3,830 Less: Changes in fair value (3,543) Fair Value at June 30, 2019 15,461 Servicing Assets Fair Value at April 1, 2018 15,023 Additions 4,452 Less: Changes in fair value (3,313) Fair Value at June 30, 2018 16,162 Loan Trailing Fee The fair value of the Loan Trailing Fee represents the present value of the expected monthly Loan Trailing Fee payments, which takes into consideration certain assumptions related to expected prepayment rates and defaults rates using a discounted cash flow model. The following table presents additional information about level 3 Loan Trailing Fee Liability measured at fair value on a recurring basis (in thousands): Loan Trailing Fee Liability Fair Value at January 1, 2019 3,118 Issuances 1,297 Cash payment of Loan Trailing Fee (1,298) Change in fair value 132 Fair Value at June 30, 2019 3,249 Significant Recurring Level 3 Fair Value Asset and Liability Input Sensitivity Key economic assumptions and the sensitivity of the current fair value to immediate changes in those assumptions at June 30, 2019 for Borrower Loans, Loans Held for Sale and Notes funded are presented in the following table (in thousands, except percentages): Borrower Loans Notes Fair Value at June 30, 2019 $ 254,070 $ 253,425 Discount rate assumption: 7.87 % * 7.87 % * Resulting fair value from: 100 basis point increase $ 251,692 $ 251,050 200 basis point increase 249,371 248,730 Resulting fair value from: 100 basis point decrease $ 256,507 $ 255,859 200 basis point decrease 259,004 258,354 Default rate assumption: 12.55 % * 12.55 % * Resulting fair value from: 100 basis point increase $ 251,033 $ 250,379 200 basis point increase 248,098 247,437 Resulting fair value from: 100 basis point decrease $ 257,166 $ 256,527 200 basis point decrease 260,274 259,643 * Represents weighted average assumptions considering all credit grades. The following table presents the estimated impact on Prosper Funding’s estimated fair value of servicing assets, calculated using different market servicing rates and different default rates as of June 30, 2019 (in thousands, except percentages). Servicing Assets Fair Value at June 30, 2019 $ 15,461 Market servicing rate assumptions 0.625 % Resulting fair value from: Market servicing rate increase to 0.65% 14,506 Market servicing rate decrease to 0.60% 16,415 Weighted average prepayment assumptions 20.59 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate 15,267 Applying a 0.9 multiplier to prepayment rate 15,655 Weighted average default assumptions 11.72 % Resulting fair value from: Applying a 1.1 multiplier to default rate 15,287 Applying a 0.9 multiplier to default rate 15,638 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.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill Prosper’s goodwill balance of $36.4 million at June 30, 2019 did not change during the six months ended June 30, 2019. We did not record any goodwill impairment expense for the six months ended June 30, 2019. Other Intangible Assets The following table presents the detail of other intangible assets for the period presented (dollars in thousands): June 30, 2019 Gross Carrying Value Accumulated Amortization Net Carrying Value Remaining Useful Life (In Years) Developed technology $ 3,060 $ (3,060) $ — — User base and customer relationships 5,050 (4,191) $ 859 5.8 Brand name 60 (60) — — Total Intangible Assets Subject to Amortization $ 8,170 $ (7,311) $ 859 Prosper’s intangible asset balance was $0.9 million and $1.0 million at June 30, 2019 and December 31, 2018, respectively. The user base and customer relationships intangible assets are being amortized on an accelerated basis over a three to ten years period. Amortization expense for the three months ended June 30, 2019 and June 30, 2018 was $0.1 million and $0.1 million, respectively. Amortization expense for the six months ended June 30, 2019 and June 30, 2018 was $0.1 million and $0.2 million, respectively. Estimated amortization of purchased intangible assets for future periods is as follows (in thousands): Year Ending December 31, Estimated Amortization of Purchased Intangible Assets 2019 (remainder thereof) $ 140 2020 219 2021 172 2022 136 2023 107 Thereafter $ 85 Total $ 859

Other Liabilities

Other Liabilities	6 Months Ended
	Jun. 30, 2019
Other Liabilities [Abstract]
Other Liabilities	Other Liabilities Other Liabilities includes the following: June 30, 2019 December 31, 2018 Loan trailing fee 3,249 3,118 Deferred revenue 352 396 Servicing liabilities 4 12 Deferred income tax liability 363 373 Deferred rent — 3,408 Restructuring liability — 2,106 Operating lease liability 19,187 — Other 1,052 1,216 Total Other Liabilities $ 24,207 $ 10,629 Additionally, disclosures around the operating lease liabilities are included in Note 17.

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	Debt PWIT Warehouse Line On January 19, 2018, through a wholly-owned subsidiary, Prosper Warehouse I Trust ("PWIT"), Prosper entered into an agreement (the "Warehouse Agreement") for a committed revolving line of credit (the "PWIT Warehouse Line"). PWIT was deemed a VIE that the Company consolidates because the Company is the primary beneficiary of the VIE. In connection with the Warehouse Agreement, PWIT entered into a security agreement with a bank as administrative agent and a national banking association as collateral trustee and paying agent. Proceeds under the PWIT Warehouse Line may only be used to purchase certain unsecured consumer loans and related rights and documents from the Company and to pay fees and expenses related to the PWIT Warehouse Line. Effective June 12, 2018 the Warehouse Agreement was amended. The amendments included increasing the committed line of credit from $100 million to $200 million, extending the term of the Warehouse line (including the final maturity date), amending the monthly unused commitment fee, and reducing the rate at which the PWIT Warehouse Line bears interest. Subsequently the Warehouse Agreement was amended in June 2019, to extend the facility, reduce the interest rate and unused commitment fee, and expand the eligibility criteria for unsecured consumer loans that can be financed through the PWIT Warehouse Line. Under the amended agreement, proceeds of loans made under the PWIT Warehouse Line may be borrowed, repaid, and reborrowed until the earlier of June 20, 2021 and the occurrence of any accelerated amortization event or event of default. Repayment of any outstanding proceeds will be made over the 24 month period ending June 20, 2023, excluding the occurrence of any accelerated amortization event or event of default. Under the amended agreement, the PWIT Warehouse Line bears interest at a rate of LIBOR plus 2.90% and has an advance rate of 89%. Additionally, the PWIT Warehouse Line bears a monthly unused commitment fee of 0.50% per annum on the undrawn portion available under the Warehouse Line. The Warehouse Agreement contains certain covenants applicable to PWIT, including restrictions on PWIT’s ability to incur indebtedness, pledge assets, merge or consolidate, and enter into certain affiliate transactions. The Warehouse Line also requires Prosper to maintain a minimum tangible net worth of $25 million, minimum net liquidity of $15 million and a maximum leverage ratio of 5:1. Tangible net worth is defined as the sum of (i) (A) convertible preferred stock, (B) total stockholders’ deficit and (C) convertible preferred stock warrant liability, less the sum of (ii) (A) goodwill and (B) intangible assets. Net liquidity is defined as the sum of cash, cash equivalents and available for sale investments. The leverage ratio is defined as the ratio of total consolidated indebtedness other than non-recourse securitization indebtedness, non-recourse or limited recourse warehouse indebtedness, and borrower payment dependent Notes, to tangible net worth. As of June 30, 2019, Prosper was in compliance with the covenants under the Warehouse Agreement. As of June 30, 2019, Prosper had $88.0 million in debt outstanding and accrued interest under the PWIT Warehouse Line. This debt is secured by an aggregate outstanding principal balance of $99.5 million included in Loans Held for Sale, at Fair Value on the condensed consolidated balance sheet. At June 30, 2019 the undrawn portion available under the PWIT Warehouse Line was $112.0 million. Prosper incurred $1.8 million of capitalized debt issuance costs, which will be recognized as interest expense through June 20, 2023. Prosper has also purchased swaptions to limit our exposure to increases in LIBOR. The swaptions are recorded on the condensed consolidated balance sheet at fair value in Prepaids and Other Assets. Any changes in the fair value are recorded in the Change in Fair Value of Financial Instruments, Net on the condensed consolidated statement of operations. The fair value of the swaptions was not material at June 30, 2019. PWIIT Warehouse Line On March 28, 2019, through a wholly-owned subsidiary, Prosper Warehouse II Trust ("PWIIT"), Prosper entered into an agreement (the "PWIIT Warehouse Agreement") for a $300 million committed revolving line of credit (the "PWIIT Warehouse Line" and, together with the PWIT Warehouse Line, the "Warehouse Lines"), with a different national banking association than PWIT. PWIIT was deemed a VIE that the Company consolidates because the Company is the primary beneficiary of the VIE. In connection with the PWIIT Warehouse Agreement, PWIIT entered into a security agreement with a bank as administrative agent and a national banking association as collateral trustee and paying agent. Proceeds under the PWIIT Warehouse Line may only be used to purchase certain unsecured consumer loans and related rights and documents from the Company and to pay fees and expenses related to the PWIIT Warehou se Line. Under the agreement, proceeds of loans made under the PWIIT Warehouse Line may be borrowed, repaid, and reborrowed until the earlier of March 28, 2021 and the occurrence of any accelerated amortization event or event of default. Repayment of any outstanding proceeds will be made over the 24 month period ending March 28, 2023, excluding the occurrence of any accelerated amortization event or event of default. Under the agreement, the PWIIT Warehouse Line bears interest at a rate of LIBOR or the lender's asset-backed commercial paper rate plus a spread of 2.90%. The spread increases by 0.375% during the first 12 months immediately following the termination of the revolving period with an additional increase of 0.375% one year later. The PWIIT Warehouse Line has an advance rate of 90%. Additionally, the PWIIT Warehouse Line bears a monthly unused commitment fee of 0.50% per annum on the undrawn portion available under the PWIIT Warehouse Line. The PWIIT Warehouse Agreement contains certain covenants applicable to PWIIT, including restrictions on PWIIT’s ability to incur indebtedness, pledge assets, merge or consolidate, and enter into certain affiliate transactions. The PWIIT Warehouse Line also requires Prosper to maintain a minimum tangible net worth of $25 million, minimum net liquidity of $15 million and a maximum leverage ratio of 5:1. Tangible net worth is defined as the sum of (i) (A) convertible preferred stock, (B) total stockholders’ deficit and (C) convertible preferred stock warrant liability, less the sum of (ii) (A) goodwill and (B) intangible assets. Net liquidity is defined as the sum of cash, cash equivalents and available for sale investments. The leverage ratio is defined as the ratio of total consolidated indebtedness other than non-recourse securitization indebtedness, non-recourse or limited recourse warehouse indebtedness, and borrower dependent notes, to tangible net worth. As of June 30, 2019, Prosper was in compliance with the covenants under the PWIIT Warehouse Agreement. As of June 30, 2019, Prosper had $13.4 million in debt outstanding and accrued interest under the PWIIT Warehouse Line. This debt is secured by an aggregate outstanding principal balance of $14.9 million included in Loans Held for Sale, at Fair Value on the condensed consolidated balance sheet. At June 30, 2019 the undrawn portion available under the PWIIT Warehouse Line was $286.6 million. Prosper incurred $2.1 million of capitalized debt issuance costs, which will be recognized as interest expense through March 28, 2023.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net loss available to common stockholders for basic and diluted EPS $ (569) $ (12,599) $ (23,283) $ (24,000) Denominator: Weighted average shares used in computing basic and diluted net loss per share 70,502,797 70,362,716 70,494,945 70,333,145 Basic and diluted net loss per share $ (0.01) $ (0.18) $ (0.33) $ (0.34) The following common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (shares) (shares) (shares) (shares) Excluded securities: Convertible preferred stock issued and outstanding 214,637,925 214,637,925 214,637,925 214,637,925 Stock options issued and outstanding 73,234,877 75,206,928 71,592,576 66,403,696 Unvested stock options exercised — 2,190 — 2,190 Warrants issued and outstanding 1,080,349 1,080,349 1,080,349 1,082,917 Series E-1 convertible preferred stock warrants 35,544,141 35,544,141 35,544,141 35,544,141 Series F convertible preferred stock warrants 177,720,704 177,720,704 177,720,704 177,720,704 Total common stock equivalents excluded from diluted net loss per common share computation 502,217,996 504,192,237 500,575,695 495,391,573

Convertible Preferred Stock, Wa

Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit	6 Months Ended
	Jun. 30, 2019
Stockholders' Equity Note [Abstract]
Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit	Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit Convertible Preferred Stock and Warrants Under PMI’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 June 30, 2019 are disclosed in the table below (amounts in thousands except share and per share amounts): Convertible Preferred Stock Par Value Authorized Shares Outstanding and Issued Shares Liquidation Preference (Outstanding Shares) Series A $ 0.01 68,558,220 68,558,220 $ 19,774 Series A-1 0.01 24,760,915 24,760,915 49,522 Series B 0.01 35,775,880 35,775,880 21,581 Series C 0.01 24,404,770 24,404,770 70,075 Series D 0.01 23,888,640 23,888,640 165,000 Series E-1 0.01 35,544,141 — — Series E-2 0.01 16,858,078 — — Series F 0.01 177,720,707 3 — Series G 0.01 37,249,497 37,249,497 50,000 444,760,848 214,637,925 $ 375,952 Dividends Dividends on shares of the Series A, Series B, Series C, Series D, Series E-1, Series E-2, Series F and Series G convertible preferred stock are payable only when, as, and if declared by the Board of Directors. No dividends will be paid with respect to the common stock until any declared dividends on the Series A, Series B, Series C, Series D, Series E-1, Series E-2, Series F, and Series G convertible preferred stock have been paid or set aside for payment to the Series A, Series B, Series C, Series D, Series E-1, Series E-2, Series F, and Series G convertible preferred stockholders. After payment of any such dividends, any additional dividends or distributions will be distributed among all holders of common stock and preferred stock in proportion to the number of shares of common stock that would be held by each such holder if all shares of preferred stock were converted to common stock at the then effective conversion rate. The Series A-1 convertible preferred shares have no dividend rights. To date, no dividends have been declared on any of the PMI’s preferred stock or common stock. Conversion Under the terms of PMI’s amended and restated certificate of incorporation, the holders of preferred stock have the right to convert such preferred stock into common stock at any time. In addition, all preferred stock automatically converts into common stock (i) immediately prior to the closing of an initial public offering that values Prosper at least at $2 billion and that results in aggregate proceeds to Prosper of at least $100 million or (ii) upon a written request from the holders of at least 60% of the voting power of the outstanding preferred stock (on an as-converted basis), provided that (i) the Series A-1 convertible preferred stock shall not be converted without at least 14% of the voting power of the outstanding Series A-1 convertible preferred stock; (ii) the Series D shall not be converted without at least 60% of the voting power of the outstanding Series D; (iii) the Series E-1 and Series E-2 shall not be converted without at least 60% of the voting power of the outstanding Series E-1 and Series E-2, voting together as a single class; (iv) the Series F shall not be converted without at least 60% of the voting power of the outstanding Series F, and (v) the shares of Series G Preferred Stock will not be automatically converted unless the holders of at least 60% of the outstanding shares of Series G Preferred Stock approve such conversion. In addition, if a holder of the Series A convertible preferred stock has converted any of the Series A convertible preferred stock, then all of such holder’s shares of Series A-1 convertible preferred stock also will be converted upon a liquidation event. In lieu of any fractional shares of common stock to which a holder would otherwise be entitled, PMI shall pay such holder cash in an amount equal to the fair market value of such fractional shares, as determined by its Board of Directors. At present, each of the Series A, Series B, Series C, Series D, Series E-1, Series E-2, and Series F convertible preferred stock converts into PMI common stock at a 1:1 ratio. The Series A-1 convertible preferred stock converts into common stock at a 1,000,000:1 ratio and the Series G convertible preferred stock converts into common stock at a 1:1.36 ratio. The Series G convertible preferred stock conversion ratio reflects the Series G true-up that occurred at end of the vesting period for the Series E-2 and Series F Preferred Stock warrants. Liquidation Rights PMI’s convertible preferred stock has been classified as temporary equity on the condensed consolidated balance sheets. The preferred stock is not redeemable; however, in the event of a voluntary or involuntary liquidation, dissolution, change in control or winding up of PMI, holders of the convertible preferred stock may have the right to receive its liquidation preference under the terms of PMI’s certificate of incorporation. Each holder of Series E-1, Series E-2, and Series F convertible preferred stock is entitled to receive prior and in preference to any distribution of proceeds from a liquidation event to the holders of Series A, Series B, Series C, Series D, Series G and Series A-1 convertible preferred stock or common stock, an amount per share for (i) each share of Series E-1 convertible preferred stock equal to the sum of the liquidation preference specified for such share and all declared but unpaid dividends, if any, on such share, (ii) each share of Series E-2 convertible preferred stock equal to the sum of two-thirds the liquidation preference specified for such share and all declared but unpaid dividends, if any, on such share, and (iii) each share of Series F convertible preferred stock equal to the sum of two-thirds of the liquidation preference specified for such share and all declared but unpaid dividends, if any, on such share. After the payment or setting aside for payment to the holders of Series E-1, Series E-2, and Series F convertible preferred stock, each holder of Series A, Series B, Series C and Series D, Series E-2, Series F, and Series G convertible preferred stock is entitled to receive, on a pari passu basis, prior to and in preference to any distribution of proceeds from a liquidation event to the holders of Series A-1 convertible preferred stock or common stock, (i) an amount per share for each share of Series E-2 and Series F convertible preferred stock equal to the sum of one-third of the liquidation preference specified for such share and all declared but unpaid dividends, if any, on such share, and (ii) an amount per share for each share of Series A, Series B, Series C, Series D and Series G convertible preferred stock equal to the sum of the liquidation preference specified for such share and all declared but unpaid dividends, if any, on such share. After the payment or setting aside for payment to the holders of Series A, Series B, Series C, Series D, Series E-1, Series E-2, Series F, and Series G convertible preferred stock, the holders of Series A-1 convertible preferred stock are entitled to receive, prior and in preference to any distribution of proceeds to the holders of common stock, an amount per share for each such share of Series A-1 convertible preferred stock equal to the sum of the liquidation preference specified for such share and all declared but unpaid dividends, if any, on such share. After the payment or setting aside for payment to the holders of Series A, Series B, Series C, Series D, Series E-1, Series E-2, Series F, Series G, and Series A-1 convertible preferred stock, the entire remaining proceeds legally available for distribution will be distributed pro rata to the holders of Series A convertible preferred stock and common stock in proportion to the number of shares of common stock held by them assuming the Series A convertible preferred stock has been converted into shares of common stock at the then effective conversion rate, provided that the maximum aggregate amount per share of Series A convertible preferred stock which the holders of Series A convertible preferred stock shall be entitled to receive is three times the original issue price for the Series A convertible preferred stock. At present, the liquidation preferences are equal to $0.29 per share for the Series A convertible preferred stock, $2.00 per share for the Series A-1 convertible preferred stock, $0.60 per share for the Series B convertible preferred stock, $2.87 per share for the Series C convertible preferred stock, $6.91 per share for the Series D convertible preferred stock, $0.84 per share for the Series E-1 convertible preferred stock, $0.84 per share for the Series E-2 convertible preferred stock, $0.84 per share for the Series F convertible preferred stock and $1.34 per share for the Series G convertible preferred stock. Voting Each holder of shares of convertible preferred stock is entitled to the number of votes equal to the number of shares of common stock into which such shares of convertible preferred stock could be converted and has voting rights and powers equal to the voting rights and powers of the common stock. The holders of convertible preferred stock and the holders of common stock vote together as a single class (except with respect to certain matters that require separate votes or as required by law), and are entitled to notice of any stockholders’ meeting in accordance with the Bylaws of PMI. Convertible Preferred Stock Warrant Liability Series E-1 Warrants In connection with the Settlement and Release Agreement dated November 17, 2016 among PMI, PFL and Colchis, on December 16, 2016, PMI issued the First Series E-1 Warrant. The Second Series E-1 Warrant for an additional 15,277,006 shares of Series E-1 convertible preferred stock was granted on the signing of the Consortium Purchase Agreement (as defined in Note 16) on February 27, 2017. The warrants expire ten years from the dat e of issuance. For the three months ended June 30, 2019, Prosper recognized $1.1 million of income from the re-measurement of the fair value of the warrants. For the six months ended June 30, 2019, Prosper recognized $1.0 million of expense from the re-measurement of the fair value of the warrants. The income is recorded through change in fair value of convertible preferred stock warrants in the condensed consolidated statement of operations. To determine the fair value of the Series E-1 Warrants, the Company first determined the value of a share of a Series E-1 convertible preferred stock. To determine the fair value of the convertible preferred stock, the Company first derived the business enterprise value (“BEV”) of the Company using valuation methods, including a combination of methods, as deemed appropriate under the circumstances applicable at the valuation date. Once the Company determined an estimated BEV, the option pricing method ("OPM") was used to allocate the BEV to the various classes of the Company’s equity, including the Company’s preferred stock. The concluded per share value for the Series E-1 convertible preferred stock was utilized as an input to the Black-Scholes option pricing model. The Company determined the fair value of the outstanding Series E-1 Warrants utilizing the following assumptions as of the following dates: June 30, 2019 December 31, 2018 Volatility 40% 40% Risk-free interest rate 1.89% 2.62% Remaining contractual term (in years) 7.55 years 8.04 years Dividend yield —% —% The above assumptions were determined as follows: Volatility . The volatility is derived from historical volatilities of several unrelated publicly listed peer companies over a period approximately equal to the term of the warrant because the Company has limited information on the volatility of the preferred stock since there is currently no trading history. When making the selections of industry peer companies to be used in the volatility calculation, the Company considered the size, operational, and economic similarities to the Company’s principal business operations. Risk-Free Interest Rate . The risk-free interest rate is based on the U.S. Treasury yield in effect as of the period end date and for zero coupon U.S. Treasury notes with maturities approximately equal to the term of the warrant. Remaining Contractual Term . The remaining contractual term represents the time from the date of the valuation to the expiration of the warrant. Dividend Yield . The expected dividend assumption is based on the Company’s current expectations about the Company’s anticipated dividend policy. Series F Warrants In connection with the Consortium Purchase Agreement (as described in Note 16), PMI issued warrants to purchase up to 177,720,706 shares of PMI's Series F convertible preferred stock at $0.01 per share. For the three months ended June 30, 2019, Prosper recognized $3.6 million of income from the re-measurement of the fair value of the warrants. For the six months ended June 30, 2019, Prosper recognized $4.3 million of expense from the re-measurement of the fair value of the warrants. The income is recorded through change in fair value of convertible preferred stock warrants in the condensed consolidated statement of operations. To determine the fair value of the Series F Warrants, the Company first determined the value of a share of a Series F convertible preferred stock. To determine the fair value of the convertible preferred stock, the Company first derived the BEV of the Company using valuation methods, including a combination of methods, as deemed appropriate under the circumstances applicable at the valuation date. Once the Company determined an estimated BEV, the OPM was used to allocate the BEV to the various classes of the Company’s equity, including the Company’s preferred stock. The concluded per share value for the Series F convertible preferred stock warrants utilized the Black-Scholes option pricing model. The Company determined the fair value of the outstanding Series F Warrants utilizing the following assumptions as of the following dates: June 30, 2019 December 31, 2018 Volatility 40% 40% Risk-free interest rate 1.90% 2.63% Remaining contractual term (in years) 7.66 years 8.16 years Dividend yield —% —% The above assumptions were determined as follows: Volatility . The volatility is derived from historical volatilities of several unrelated publicly listed peer companies over a period approximately equal to the term of the warrant because the Company has limited information on the volatility of the preferred stock since there is currently no trading history. When making the selections of industry peer companies to be used in the volatility calculation, the Company considered the size, operational, and economic similarities to the Company’s principal business operations. Risk-Free Interest Rate . The risk-free interest rate is based on the U.S. Treasury yield in effect as of the period end date and for zero coupon U.S. Treasury notes with maturities approximately equal to the term of the warrant. Remaining Contractual Term . The remaining contractual term represents the time from the date of the valuation to the expiration of the warrant. Dividend Yield . The expected dividend assumption is based on the Company’s current expectations about the Company’s anticipated dividend policy. The combined activity of the Convertible Preferred Stock Warrant Liability for the six months ended June 30, 2019 is as follows (in thousands): Warrant Activity Balance at January 1, 2019 $ 143,679 Warrants Vested 17,553 Change in Fair Value 5,327 Balance at June 30, 2019 $ 166,559 Common Stock PMI, through its Amended and Restated Certificate of Incorporation, is the sole issuer of common stock and related options, restricted stock units ("RSUs") and warrants. On February 16, 2016, PMI amended and restated its Certificate of Incorporation to, among other things, effect a 5-for-1 forward stock split. On September 20, 2017, PMI further amended its Amended and Restated Certificate of Incorporation to increase the number of shares of common stock authorized for issuance. The total number of shares of stock which PMI has the authority to issue is 1,069,760,848, consisting of 625,000,000 shares of common stock, $0.01 par value per share, and 444,760,848 shares of preferred stock, $0.01 par value per share. As of June 30, 2019, 71,502,461 shares of common stock were issued and 70,566,526 shares of common stock were outstanding. As of December 31, 2018, 71,411,145 shares of common stock were issued and 70,475,210 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 six months ended June 30, 2019, PMI issued 91,316 shares of common stock upon the exercise of vested options for cash proceeds of $11 thousand.

Share Based Incentive Plan and

Share Based Incentive Plan and Compensation	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Share Based Incentive Plan and Compensation	Share Based Incentive Plan and Compensation PMI grants equity awards primarily through its Amended and Restated 2005 Stock Option Plan (the “2005 Plan”), which was approved as amended and restated by its stockholders on December 1, 2010; and its 2015 Equity Incentive Plan, which was approved by its stockholders on April 7, 2015 and subsequently amended by an Amendment No. 1, Amendment No. 2 and Amendment No. 3, which were approved by PMI's stockholders effective as of February 15, 2016, May 31, 2016, and September 5, 2018 respectively (as amended, the "2015 Plan"). In March 2015, the 2005 Plan expired, except that any awards granted under the 2005 Plan prior to its expiration remain in effect pursuant to their terms. As of June 30, 2019, up to 95,236,266 shares of common stock are reserved for issuance under the 2015 Plan, and may be granted to employees, directors, and consultants by PMI’s board of directors and stockholders to promote the success of Prosper’s business. Options generally vest (i) 25% one year from the vesting commencement date and 1/48t h per month thereafter, (ii) 50% one year from the vesting date and 1/48t h per month thereafter, (iii) 50% two years from the vesting commencement date and 1/48t h per month thereafter, or (iv) 1/36t h per month from the vesting commencement date. In no event are options exercisable more than 10 years after the date of grant. At June 30, 2019, there were 20,560,436 shares available for grant under the 2015 Plan and zero shares available for grant under the 2005 Plan. Stock Option Reprice On May 3, 2016, the Compensation Committee of the Board of Directors of PMI approved a stock option repricing program (the “2016 Reprice”), authorizing PMI’s officers to reprice certain outstanding stock options held by employees and directors that have exercise prices above the current fair market value of PMI’s common stock. The repricing was effected on May 16, 2016 for eligible directors and employees located in the United States and on May 19, 2016 for eligible employees located in Israel. On March 17, 2017, the Compensation Committee of the Board of Directors of PMI approved a stock option repricing program (the “2017 Reprice” and together with the 2016 Reprice, the "Repricings"), authorizing PMI’s officers to reprice certain outstanding stock options held by employees and directors that have exercise prices above the current fair market value of PMI’s common stock. The repricing was effected on March 17, 2017 for eligible directors and employees. Prosper believes that the Repricings will encourage the continued service of valued employees and directors, and motivate such service providers to perform at high levels, both of which are critical to Prosper’s continued success. Prosper expects to incur additional stock based compensation charges as a result of the Repricings. The financial statement impact of the above Repricings was $0.1 million in the three months ended June 30, 2019 and $0.1 million (net of forfeitures) that will be recognized over the remaining weighted average vesting period of 0.6 years. Stock Option Activity Stock option activity under the 2005 Plan and 2015 Plan is summarized for the six months ended June 30, 2019 below: Options Issued and Outstanding Weighted- Average Exercise Price Balance as of January 1, 2019 71,021,698 $ 0.33 Options issued 6,682,948 0.30 Options exercised – vested (91,316) 0.12 Options forfeited (2,136,356) 0.46 Balance as of June 30, 2019 75,476,974 $ 0.32 Options vested and expected to vest as of June 30, 2019 62,463,510 0.32 Options vested and exercisable at June 30, 2019 46,213,667 0.27 Other Information Regarding Stock Options Additional information regarding common stock options outstanding as of June 30, 2019 is as follows: Options Outstanding Options Vested and Exercisable Range of Exercise Prices Number Outstanding Weighted – Avg. Remaining Life (In years) Weighted –Avg. Exercise Price Number Vested Weighted – Avg. Exercise Price $ 0.02 - 0.20 4,062,390 4.55 $ 0.11 4,062,390 $ 0.11 0.21 - 0.50 51,346,996 7.85 0.26 34,178,267 0.23 0.51 - 1.13 20,067,588 8.60 0.54 7,973,010 0.54 $ 0.02 - 1.13 75,476,974 7.87 $ 0.32 46,213,667 $ 0.27 The fair value of options granted to employees is estimated on the grant date using the Black-Scholes option valuation model. This valuation model for stock-based compensation expense requires Prosper to make assumptions and judgments about the variables used in the calculation, including the fair value of PMI’s common stock, the expected term (the period of time that the options granted are expected to be outstanding), the volatility of PMI’s common stock, a risk-free interest rate, and expected dividends. Given the absence of a publicly traded market, Prosper considered numerous objective and subjective factors to determine the fair value of PMI’s common stock at each grant date. These factors included, but were not limited to: (i) contemporaneous valuations of common stock performed by unrelated third-party specialists, (ii) the prices for PMI’s preferred stock sold to outside investors, (iii) the rights, preferences and privileges of PMI’s preferred stock relative to PMI’s common stock, (iv) the lack of marketability of PMI’s common stock, (v) developments in the business, (vi) secondary transactions of PMI’s common and preferred shares, and (vii) the likelihood of achieving a liquidity event, such as an initial public offering or a merger or acquisition of Prosper, given prevailing market conditions. As PMI’s stock is not publicly traded, volatility for stock options is based on an average of the historical volatilities of the common stock of several entities with characteristics similar to those of Prosper. The expected term assumptions were determined based on the vesting terms, exercise terms and contractual lives of the options using the simplified method. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. Prosper uses an expected dividend yield of zero as it does not anticipate paying any dividends in the foreseeable future. Prosper also estimates forfeitures of unvested stock options. Expected forfeitures are based on Prosper’s historical experience. To the extent actual forfeitures differ from the estimates, the difference will be recorded as a cumulative adjustment in the period estimates are revised. No compensation cost is recorded for options that do not vest. The fair value of PMI’s stock option awards granted during the three and six months ended June 30, 2019 and June 30, 2018 was estimated at the date of grant using the Black-Scholes model with the following average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Volatility of common stock 46.72 % 44.43 % 46.72 % 44.12 % Risk-free interest rate 2.28 % 2.85 % 2.28 % 2.75 % Expected life (in years) 5.9 years 6.0 years 5.9 years 6.0 years Dividend yield — % — % — % — % Restricted Stock Unit Activity During the six months ended June 30, 2019, PMI did not grant any RSUs to employees. In previous reporting periods, PMI granted certain employees RSUs that are subject to three-year or four-year vesting terms and the occurrence of a liquidity event. The following table summarizes the number of PMI’s outstanding RSUs and their weighted-average grant date fair value during the six months ended June 30, 2019: Number of Shares Weighted-Average Grant Date Fair Value Unvested - January 1, 2019 4,856,141 $ 0.96 Forfeited (15,500) 2.18 Unvested - June 30, 2019 4,840,641 $ 0.96 The following table presents the amount of stock-based compensation related to stock-based awards granted to employees recognized in Prosper’s condensed consolidated statements of operations during the three and six months ended June 30, 2019 and June 30, 2018 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Origination and servicing $ 108 $ 241 $ 304 $ 456 Sales and marketing 63 108 145 216 General and administrative 1,064 1,904 2,401 3,912 Total stock based compensation $ 1,235 $ 2,253 $ 2,850 $ 4,584 During the three months ended June 30, 2019 and June 30, 2018, Prosper capitalized $0.1 million and $0.1 million, respectively, of stock-based compensation as internal use software and website development costs. As of June 30, 2019, the unamortized stock-based compensation expense adjusted for forfeiture estimates related to Prosper’s employees’ unvested stock-based awards was approximately $5.1 million, which will be recognized over the remaining weighted-average vesting period of approximately 2.2 years.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Income Taxes	Income Taxes For the three months ended June 30, 2019 and June 30, 2018, Prosper recognized $29 thousand and $9 thousand of income tax expense, respectively. For the six months ended June 30, 2019 and June 30, 2018, Prosper recognized $58 thousand and $19 thousand of income tax expense, respectively. The income tax expense relates to state income tax expense and the amortization of tax deductible goodwill which gives rise to an indefinite-lived deferred tax liability. No other income tax expense or benefit was recorded for the three or six month periods ended June 30, 2019 and June 30, 2018 due to a full valuation allowance recorded against our deferred tax assets. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to utilize our existing deferred tax assets. On the basis of this evaluation, it is not more likely than not that our deferred tax assets will be realized and therefore a full valuation allowance has been recorded.
Prosper Funding LLC
Entity Information [Line Items]
Income Taxes	Income TaxesProsper Funding incurred no income tax provision for the six months ended June 30, 2019 and June 30, 2018. Prosper Funding is a US disregarded entity and its income and loss is included in the return of its parent, PMI. Since PMI is in a loss position, is not currently subject to income taxes, and has fully reserved its deferred tax asset, the net effective tax rate for Prosper Funding is 0%.

Consortium Purchase Agreement

Consortium Purchase Agreement	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Consortium Purchase Agreement	Consortium Purchase Agreement On February 27, 2017, Prosper entered into a series of agreements (the "Consortium Purchase Agreement") with a consortium of investors (the "Consortium"), pursuant to which the Consortium agreed to purchase borrower loans in an aggregate principal amount of up to $5.0 billion (including certain loans purchased by one of the investors prior to the date of the Consortium Purchase Agreement). PFL was obligated to offer for purchase minimum monthly volumes of eligible loans to the Consortium, for the Consortium to elect to purchase. The obligation to offer for purchase minimum monthly volumes of eligible loans and the related vesting ended in May 2019. In connection with the Consortium Purchase Agreement, PMI issued to the Consortium three warrants to purchase up to an aggregate 177,720,706 shares of PMI’s Series F Preferred Stock at an exercise price of $0.01 per share (the “Warrant Shares”). The Consortium’s right to exercise the Series F Warrants was subject to monthly vesting during the term of the Consortium Purchase Agreement based upon the volume of loans the Consortium elected to purchase (if any) in each month, subject to certain cure rights such as offering additional loans for sale in subsequent periods. Pursuant to these cure rights, if the Consortium failed to respond to offers for allocation, purchase or funding, the Consortium could take advantage of a designated period of time to cure such failure. There were no such failures by the Consortium during the term of the Consortium Purchase Agreement. On vesting of the Series F Warrants, Prosper recorded a liability as "Convertible Preferred Stock Warrant Liability" on the condensed consolidated balance sheets at fair value and a corresponding amount as "Fair Value of Warrants Vested on Sale of Borrower Loans" on the condensed consolidated statement of operations. Subsequent changes in the fair value of the vested warrants are recorded in "Change in Fair Value of Convertible Preferred Stock Warrants" on the condensed consolidated statement of operations. Additionally, in connection with the execution of the Consortium Purchase Agreement, certain previously issued rebates were settled by an issuance of vested Series F Convertible Preferred Stock Warrants. The difference in fair value of these warrants over the cash settlement price is recorded in "Change in Fair Value of Convertible Preferred Stock Warrants" on the condensed consolidated statement of operations. The following represents the loans purchased and warrants vested under the Consortium Purchase Agreement: Loans Acquired (in thousands) Warrants Vested Balance as of January 1, 2019 $ 3,067,332 154,912,980 Six Months Ended June 30, 2019 235,951 22,807,726 Balance as of June 30, 2019 $ 3,303,283 177,720,706 In addition to the $3.3 billion above, warrants vested on signing of the Consortium Purchase Agreement were issued to settle certain rebates on $0.3 billion of whole loan purchases by members of the Consortium prior to the signing of the Consortium Purchase Agreement. This $0.3 billion also reduced the up to $5.0 billion aggregate amount under the Consortium Purchase Agreement. The Consortium Purchase Agreement came to an end in May 2019 at its contractual termination date.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	LeasesProsper has operating leases for corporate offices and datacenters. Our leases have remaining lease terms of one year to eight years. Rental expense under operating lease arrangements was $1.4 million and $1.0 million for the three months ended June 30, 2019 and June 30, 2018, respectively. Rental expense under operating lease arrangements was $2.7 million and $2.1 million for the six months ended June 30, 2019 and June 30, 2018, respectively Additionally, Prosper subleases certain leased office space to third parties when it determines there is excess leased capacity. Sublease income from operating lease arrangements was $0.2 million and $0.5 million for the three and six months ended June 30, 2019, respectively. Operating lease right-of-use ("ROU") assets The following represents the operating lease right-of-use assets as of June 30, 2019: June 30, 2019 Gross Carrying Value Accumulated Amortization Net Carrying Value ROU Assets - Office buildings $ 15,846 $ 1,517 $ 14,329 ROU Assets - Other 292 114 $ 178 Total right-of-use assets subject to amortization $ 16,138 $ 1,631 $ 14,507 Lease Liabilities Future minimum lease payments under non-cancellable leases as of June 30, 2019 were as follows (in thousands): Minimum Lease Payments Remainder of 2019 2,268 2020 5,240 2021 5,134 2022 5,018 2023 1,567 Thereafter 2,546 Total future minimum lease payments $ 21,773 Less imputed interest (2,586) Total $ 19,187 The table below presents future minimum rental payments at December 31, 2018, net of minimum sublease rentals of $5.3 million, for the remaining terms of the operating leases (in thousands): 2019 4,536 2020 4,683 2021 4,456 2022 4,319 2023 847 Thereafter 387 Total future operating lease obligations $ 19,228 Because the rate implicit in each lease is not readily determinable, the Company uses its incremental borrowing rate to determine the present value of the lease payments. Other information related to leases was as follows ($ in thousands): June 30, 2019 Cash paid for operating leases year-to-date $ 3,026 Right of use assets obtained in exchange for new operating lease obligations (1) $ 21,630 Weighted Average Remaining Lease Term 4.54 years Weighted Average Discount Rate 5.53 % (1) Consists of $21.6 million for operating leases existing on January 1, 2019.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Commitments and Contingencies	Commitments and Contingencies Operating Commitments Prosper has entered into an agreement with WebBank, under which all Borrower Loans originated through the marketplace are made by WebBank under its bank charter. Pursuant to the agreement, the marketing fee that Prosper receives in connection with the origination of each loan is partially reduced by an amount (the “Designated Amount”) calculated as a percentage of the principal amount of such loan based on the aggregate principal amount of loans originated for the applicable month. To the extent the aggregate Designated Amount for all loans originated during any month is less than $143,500, Prosper is required to pay WebBank an amount equal to such deficiency. Accordingly, the minimum fee for the remaining six months of 2019 is $0.9 million. The minimum fee is $1.7 million for the years 2020 and 2021, and $0.1 million for the year 2022. Additionally, under the agreement with WebBank, Prosper is required to maintain minimum net liquidity of $15.0 million at all times during the term of the agreement. Net liquidity is defined as the sum of Cash, Cash Equivalents and Available for Sale Investments. Violation of this covenant can result in termination of the contract with WebBank. As of June 30, 2019, Prosper was in compliance with the covenant. Loan Purchase Commitments Prosper has entered into an agreement with WebBank to purchase $29.8 million of Borrower Loans that WebBank originated during the last two business days of the quarter ended June 30, 2019 and the first business day of the quarter ending September 30, 2019. Prosper will purchase these Borrower Loans within the first three business days of the quarter ending September 30, 2019. Repurchase and Indemnification Contingency Under the terms of the loan purchase agreements between Prosper and investors that participate in the Whole Loan Channel, Prosper may, in certain circumstances, become obligated to repurchase a Borrower Loan from an investor. Generally, these circumstances include the occurrence of verifiable identity theft, the failure to properly follow loan listing or bidding protocols, or a violation of the applicable federal, state, or local lending laws. The fair value of the indemnification and repurchase obligation is estimated based on historical experience. 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 June 30, 2019 is $3.3 billion. Prosper has accrued $1.0 million and $0.9 million as of June 30, 2019 and December 31, 2018, respectively, in regard to this obligation. Regulatory Contingencies Prosper accrues for contingencies when a loss from such contingencies is probable and the amount of loss can be reasonably estimated. In determining whether a loss is probable and if it is possible to quantify the amount of the estimated loss, Prosper reviews and evaluates its litigation and regulatory matters on at least a quarterly basis in light of potentially relevant factual and legal developments. If Prosper determines that an unfavorable outcome is not probable or that the amount of a loss cannot be reasonably estimated, Prosper does not accrue for a potential litigation loss. If an unfavorable outcome is probable and Prosper can estimate a range of outcomes, we record the amount we consider to be the best estimate within the range of potential losses that are both probable and estimable; however, if we cannot quantify the amount of the estimated loss, then we record the low end of the range of those potential losses. SEC Inquiry
Prosper Funding LLC
Entity Information [Line Items]
Commitments and Contingencies	Commitments and Contingencies Operating Commitments Prosper has entered into an agreement with WebBank, under which all Borrower Loans originated through the marketplace are made by WebBank under its bank charter. Pursuant to the agreement, the marketing fee that Prosper receives in connection with the origination of each loan is partially reduced by an amount (the “Designated Amount”) calculated as a percentage of the principal amount of such loan based on the aggregate principal amount of loans originated for the applicable month. To the extent the aggregate Designated Amount for all loans originated during any month is less than $143,500, Prosper is required to pay WebBank an amount equal to such deficiency. Accordingly, the minimum fee for the remaining six months of 2019 is $0.9 million. The minimum fee is $1.7 million for the years 2020 and 2021, and the minimum fee is $0.1 million for the year 2022. Additionally, under the agreement with WebBank, Prosper is required to maintain minimum net liquidity of $15 million at all times during the term of the agreement. Net liquidity is defined as the sum of Cash, Cash Equivalents and Available for Sale Investments. Violation of this covenant can result in termination of the contract with WebBank. As of June 30, 2019, the Company was in compliance with the covenant. Loan Purchase Commitments Under the terms of Prosper Funding’s agreement with WebBank, Prosper Funding is committed to purchase $29.8 million of Borrower Loans that WebBank originated during the last two business days of the quarter ended June 30, 2019 and first business day of the quarter ending September 30, 2019. Prosper Funding will purchase these Borrower Loans within the first three business days of the quarter ending September 30, 2019. Repurchase and Indemnification Contingency Under the terms of the loan purchase agreements between Prosper Funding and investors that participate in the Whole Loan Channel, Prosper Funding may, in certain circumstances, become obligated to repurchase a Borrower Loan from an investor. Generally, these circumstances include the occurrence of verifiable identity theft, the failure to properly follow loan listing or bidding protocols, or a violation of the applicable federal, state, or local lending laws. The fair value of the indemnification and repurchase obligation is estimated based on historical experience. 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 as of June 30, 2019 is $3.7 billion. Prosper Funding had accrued $1.0 million and $0.9 million as of June 30, 2019 and December 31, 2018, respectively, in regard to this obligation. Regulatory Contingencies Prosper accrues for contingencies when a loss from such contingencies is probable and the amount of loss can be reasonably estimated. In determining whether a loss is probable and if it is possible to quantify the amount of the estimated loss, Prosper reviews and evaluates its litigation and regulatory matters on at least a quarterly basis in light of potentially relevant factual and legal developments. If Prosper determines that an unfavorable outcome is not probable or that the amount of a loss cannot be reasonably estimated, Prosper does not accrue for a potential litigation loss. If an unfavorable outcome is probable and Prosper can estimate a range of outcomes, we record the amount we consider to be the best estimate within the range of potential losses that are both probable and estimable; however, if we cannot quantify the amount of the estimated loss, then we record the low end of the range of those potential losses. SEC Inquiry

Related Parties

Related Parties	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Related Parties	Related Parties Since Prosper’s inception, it has engaged in various transactions with its directors, executive officers, and holders of more than 10% of its voting securities, and immediate family members and other affiliates of its directors, executive officers, and 10% stockholders. Prosper believes that all of the transactions described below were made on terms no less favorable to Prosper than could have been obtained from unaffiliated third parties. Prosper’s executive officers, directors who are not executive officers, and certain affiliates participate in its marketplace by placing bids and purchasing Notes and Borrower Loans. The aggregate amount of the Notes and Borrower Loans purchased and the income earned by parties deemed to be affiliates and related parties of Prosper for the three and six months ended June 30, 2019 and June 30, 2018, as well as the Notes and Borrower Loans outstanding as of June 30, 2019 and December 31, 2018 are summarized below (in thousands): Aggregate Amount of Notes and Borrower Loans Purchased Six Months Ended June 30, Interest Earned on Notes and Borrower Loans Six Months Ended June 30, Related Party 2019 2018 2019 2018 Executive officers and management $ 11 $ 9 $ 2 $ 1 Directors (excluding executive officers and management) 208 208 24 22 Total $ 219 $ 217 $ 26 $ 23 Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30, Interest Earned on Notes and Borrower Loans Three Months Ended June 30, Related Party 2019 2018 2019 2018 Executive officers and management $ 5 $ 3 $ 1 $ — Directors (excluding executive officers and management) 99 107 12 11 Total $ 104 $ 110 $ 13 $ 11 Notes balance as of Related Party June 30, 2019 December 31, 2018 Executive officers and management $ 34 $ 32 Directors (excluding executive officers and management) 589 569 $ 623 $ 601

Significant Concentrations

Significant Concentrations	6 Months Ended
	Jun. 30, 2019
Risks and Uncertainties [Abstract]
Significant Concentrations	Significant ConcentrationsProsper is dependent on third party funding sources such as banks, asset managers, and investment funds to provide the funds to allow WebBank to originate Borrower Loans that the third party funding sources will later purchase. Of all Borrower Loans originated in the six months ended June 30, 2019, two parties purchased 17% and 10% of such loans, respectively. This compares to 52% for the largest purchasing party for the six months ended June 30, 2018. Further, a significant portion of our business is dependent on funding through the Whole Loan Channel, through which 93% and 93% of Borrower Loans were originated in the six months ended June 30, 2019 and June 30, 2018, respectively.  Prosper receives all of its Borrower Loan transaction fee revenue from WebBank. Prosper earns a transaction fee from WebBank for our services in facilitating originations of Borrower Loans issued by WebBank. The rate of the transaction fee for each individual Borrower Loan is based on the term and credit grade of the Borrower Loan. No individual borrower or investor accounted for 10% or more of consolidated net revenue for any of the periods presented.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Marketplace, Inc. (“PMI”) was incorporated in the state of Delaware on March 22, 2005. Except as the context requires otherwise, as used in these notes to the condensed consolidated financial statements of PMI, “Prosper,” “we,” “us,” and “our” refer to PMI and its wholly-owned subsidiaries, on a consolidated basis. The unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2018. The balance sheet at December 31, 2018 has been derived from the audited financial statements at that date. Management believes these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. The preparation of Prosper’s condensed consolidated financial statements and related disclosures in conformity with US GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in Prosper’s financial statements and accompanying notes. Management bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions. The accompanying interim condensed consolidated financial statements include the accounts of PMI, its wholly-owned subsidiaries and consolidated variable interest entities ("VIEs"). All intercompany balances have been eliminated in consolidation. Securitization Notes are notes held by certain third party investors pursuant to Prosper’s securitization transactions, and are distinguishable from the borrower payment dependent Notes available to investors through our Note Channel.
Fair Value Measurements	Fair Value Measurements Financial instruments consist principally of Cash and Cash Equivalents, Restricted Cash, Available for Sale Investments at Fair Value, Borrower Loans, Loans Held for Sale, Accounts Receivable, Accounts Payable and Accrued Liabilities, Payable to Investors, Convertible Preferred Stock Warrant Liability, Certificates Issued by Securitization Trust 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.
Restricted Cash	Restricted Cash Restricted Cash consists primarily of cash deposits and short term certificate of deposit accounts held as collateral as required for long term leases, loan funding and servicing activities, and cash that investors or Prosper have on our marketplace that has not yet been invested in Borrower Loans or disbursed to the investor.
Borrower Loans, Loans Held for Sale and Notes	Borrower Loans, Loans Held for Sale and NotesThrough the Note Channel, Prosper purchases Borrower Loans from WebBank, then issues Notes and holds the Borrower Loans until maturity. The obligation to repay a series of Notes issued through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans funded and Notes issued through the Note Channel are carried on Prosper’s condensed consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes.
Leases	Leases We determine if an arrangement is a lease at inception. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are included on our consolidated balance sheets in the Property and Equipment, Net and the Other Liabilities sections, respectively.
Consolidation of Variable Interest Entities	Consolidation of Variable Interest Entities The determination of whether to consolidate a variable interest entity (“VIE”) in which we have a variable interest requires a significant amount of analysis and judgment regarding whether we are the primary beneficiary of a VIE due to our holding a controlling financial interest in the VIE. A controlling financial interest in a VIE exists if we have both the power to direct the VIE’s activities that most significantly affect the VIE’s economic performance and a potentially significant economic interest in the VIE. The determination of whether an entity is a VIE considers factors, such as (i) whether the entity’s equity investment at risk is insufficient to allow the entity to finance its activities without additional subordinated financial support and (ii) whether a holder’s equity investment at risk lacks any of the following characteristics of a controlling financial interest: the direct or indirect ability through voting rights or similar rights to make decisions about a legal entity’s activities that have a significant effect on the entity’s success, the obligation to absorb the expected losses of the entity or the right to receive the expected residual returns of the legal entity. Management regularly reviews and reconsiders its previous conclusions regarding the status of an entity as a VIE and whether we are required to consolidate such VIE in the consolidated financial statements.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Standards Adopted In The Current Period In June 2018, the FASB issued ASU No. 2018-07, "Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting." The ASU is intended to reduce the cost and complexity and to improve financial reporting for nonemployee share-based payments. The ASU expands the scope of Topic 718, Compensation-Stock Compensation, which currently only includes share-based payments to employees, to include share-based payments issued to nonemployees for goods or services. Consequently, the accounting for share-based payments to nonemployees and employees will be substantially aligned. Prosper adopted the standard effective January 1, 2019. The adoption of this standard did not have a material impact on Prosper’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)," which requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases, along with additional qualitative and quantitative disclosures. Prosper adopted the standard effective January 1, 2019. In accordance with ASU 2018-11, "Leases (Topic 842), Target Improvements", Prosper has elected not to restate prior periods and has presented the cumulative effect of applying the new standard as an adjustment to the opening balance of retained earnings on January 1, 2019. The standard had a material impact on our consolidated balance sheets, but did not materially impact our consolidated statement of operations. The most significant impact is the recognition of ROU assets and lease obligation liabilities for operating leases. Additionally, Prosper recorded an impairment charge to its ROU asset upon adoption due to existing sublease arrangements that were entered into at a loss. The impairment charge did not have a material impact as it will be offset by a reduction of the existing restructuring liability for those leases. Prosper has elected the package of practical expedients, which allows the Company not to reassess (1) whether any expired or existing contracts as of the adoption date are or contain a lease, (2) lease classification for any expired or existing leases as of the adoption date and (3) initial direct costs for any existing leases as of the adoption date. The Company did not elect to apply the hindsight practical expedient when determining lease term and assessing impairment of right-of-use assets. The Company also elected a practical expedient that allowed it to not separate non-lease components from lease components and instead to account for each lease and non-lease component as a single lease component. The adoption of ASU 2016-02 on January 1, 2019 resulted in the recognition of ROU assets of approximately $16.1 million, lease liabilities for operating leases of approximately $21.6 million, a reduction in existing other liabilities of $5.1 million related to deferred rent and restructuring liabilities, and no cumulative-effect adjustment on retained earnings on Prosper's Consolidated Balance Sheets, with no material impact to its Consolidated Statements of Operations. Accounting Standards Issued, To Be Adopted By The Company In Future Periods In June 2016, the FASB amended guidance related to impairment of financial instruments as part of ASU 2016-13, "Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments", which will be effective for interim and annual periods beginning after December 15, 2019. The guidance replaces the incurred loss impairment methodology with an expected credit loss model for which a company recognizes an allowance based on the estimate of expected credit loss. Prosper accounts for its Borrower Loans at fair value through net income, which is outside the scope of Topic 326. For certain available for sale investments, the guidance will require recognition of expected credit losses through recording an allowance for credit losses. The recognition of this allowance is limited to the difference between the security’s amortized cost basis and fair value. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment." The standard eliminates Step 2 from the goodwill impairment test, which requires a hypothetical purchase price allocation. Prosper will continue to have the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The standard is effective for interim and annual periods beginning after December 15, 2019 and early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The standard should be applied on a prospective basis. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, "Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement." Entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, but public companies will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. ASU No. 2018-13 is effective for all entities for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, but entities are permitted to early adopt either the entire standard or only the provisions that eliminate or modify the requirements. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, "Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract." This ASU aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within that fiscal year and early adoption is permitted. Prosper is currently evaluating the impact of this accounting standard update on its consolidated financial statements.
Prosper Funding LLC
Entity Information [Line Items]
Basis of Presentation	Basis of Presentation Prosper Funding LLC (“PFL”) was formed in the state of Delaware on February 17, 2012 as a limited liability company with the sole equity member being Prosper Marketplace, Inc. (“PMI”). Except as the context otherwise requires, as used in these Notes to the condensed consolidated financial statements of Prosper Funding LLC, “Prosper Funding,” “we,” “us,” and “our” refers to PFL and its wholly owned subsidiaries, Prosper Asset Holdings LLC (“PAH”), a Delaware limited liability company, and Prosper Depositor LLC, a Delaware limited liability company, on a consolidated basis. PAH was dissolved on November 28, 2018. As a result, references to Prosper Funding do not include PAH for periods subsequent to the year ended December 31, 2018. The unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) and disclosure requirements for interim financial information and the requirements of Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by US GAAP for complete financial statements. The unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2018. The balance sheet at December 31, 2018 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 six months ended June 30, 2019 and June 30, 2018. The preparation of Prosper Funding's condensed consolidated financial statements and related disclosures in conformity with US GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in its condensed consolidated financial statements and accompanying notes. Management bases its estimates on historical experience and on various other factors it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of certain assets and liabilities. These judgments, estimates and assumptions are inherently subjective in nature and actual results may differ from these estimates and assumptions, and the differences could be material.
Fair Value Measurements	Fair Value MeasurementsFinancial 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.
Restricted Cash	Restricted Cash Restricted cash consists primarily of cash deposits and short term certificate of deposit accounts held as collateral as required for long term leases, loan funding and servicing activities, and cash that investors or Prosper has on our marketplace that has not yet been invested in Borrower Loans or disbursed to the investor.
Borrower Loans, Loans Held for Sale and Notes	Borrower Loans, Loans Held for Sale and NotesThrough the Note Channel, Prosper Funding purchases Borrower Loans from WebBank, then issues Notes and holds the Borrower Loans until maturity. The obligation to repay a series of Notes funded through the Note Channel is dependent upon the repayment of the associated Borrower Loan. Borrower Loans and Notes funded through the Note Channel are carried on Prosper Funding’s condensed consolidated balance sheets as assets and liabilities, respectively. We choose to measure certain financial instruments and certain other items at fair value on an instrument-by-instrument basis with unrealized gains and losses on items for which the fair value option has been elected reported in earnings. Management believes that the fair value option is more meaningful for the readers of the financial statements and it allows both the Borrower Loans and Notes to be valued using the same methodology. The fair value election, with respect to an item, may not be revoked once an election is made. Prosper Funding estimates the fair value of such Borrower Loans and Notes using discounted cash flow methodologies that take into account expected prepayments, losses, recoveries and default rates. The Borrower Loans are not derecognized when a corresponding Note is issued as Prosper Funding maintains the ability to sell the Borrower Loans without the approval of the holders of the corresponding Notes.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Standards Adopted In The Current Period No accounting standards were adopted in the current period for Prosper Funding LLC. Accounting Standards Issued, To Be Adopted By The Company In Future Periods In August 2018, the FASB issued ASU No. 2018-13, " Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement ." Entities will no longer be required to disclose the amount of and reasons for transfers between level 1 and level 2 of the fair value hierarchy, but public companies will be required to disclose the range and weighted average used to develop significant unobservable inputs for level 3 fair value measurements. ASU No. 2018-13 is effective for all entities for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, but entities are permitted to early adopt either the entire standard or only the provisions that eliminate or modify the requirements. Prosper Funding is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of Cash, Cash Equivalents, and Restricted Cash reported within the condensed consolidated balance sheets that sum to the total of the same such amount shown in the condensed consolidated statements of cash flows: June 30, 2019 December 31, 2018 June 30, 2018 December 31, 2017 Cash and Cash Equivalents $ 68,124 57,945 $ 58,652 $ 45,795 Restricted Cash 160,990 149,114 134,552 152,668 Total Cash, Cash Equivalents and Restricted Cash shown in the consolidated statements of cash flows $ 229,114 $ 207,059 $ 193,204 $ 198,463
Prosper Funding LLC
Entity Information [Line Items]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amount shown in the consolidated statements of cash flows: June 30, 2019 December 31, 2018 June 30, 2018 December 31, 2017 Cash and Cash Equivalents $ 12,269 11,163 $ 10,892 $ 8,223 Restricted Cash 123,380 136,018 120,152 140,092 Total Cash, Cash Equivalents and Restricted Cash show in the consolidated statements of cash flows $ 135,649 $ 147,181 $ 131,044 $ 148,315

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Property and Equipment, Net	Property and equipment consist of the following (in thousands): June 30, 2019 December 31, 2018 Property and Equipment: Operating lease right-of-use assets $ 16,138 $ — Computer equipment 12,790 15,193 Internal-use software and website development costs 24,621 22,505 Office equipment and furniture 2,995 3,015 Leasehold improvements 7,158 7,157 Assets not yet placed in service 3,268 2,745 Property and equipment 66,970 50,615 Less accumulated depreciation and amortization (35,801) (35,342) Total Property and Equipment, Net $ 31,169 $ 15,273
Prosper Funding LLC
Entity Information [Line Items]
Property and Equipment, Net	Property and equipment consist of the following (in thousands): June 30, 2019 December 31, 2018 Property and equipment: Internal-use software and web site development costs $ 22,075 $ 22,505 Less accumulated depreciation and amortization (16,581) (16,079) Total property and equipment, net $ 5,494 $ 6,426

Borrower Loans, Loans Held fo_2

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value (Tables)	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale	The aggregate principal balances outstanding and fair values of Borrower Loans, Loans Held for Sale, and Notes as of June 30, 2019 and December 31, 2018, are presented in the following table (in thousands): Borrower Loans Notes Loans Held for Sale June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 Aggregate principal balance outstanding $ 614,678 $ 269,093 $ (259,954) $ (272,430) $ 115,098 $ 185,657 Fair value adjustments (7,879) (5,571) 6,529 8,427 (136) (1,869) Fair value $ 606,799 $ 263,522 $ (253,425) $ (264,003) $ 114,962 $ 183,788
Prosper Funding LLC
Entity Information [Line Items]
Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale	The aggregate principal balances outstanding and fair values of Borrower Loans and Notes as of June 30, 2019 and December 31, 2018, are presented in the following table (in thousands): Borrower Loans Notes June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 Aggregate principal balance outstanding $ 257,921 $ 269,093 $ (259,954) $ (272,430) Fair value adjustments (3,851) (5,571) 6,529 8,427 Fair value $ 254,070 $ 263,522 $ (253,425) $ (264,003)

Available for Sale Investment_2

Available for Sale Investments, at Fair Value (Tables)	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Securities Available for Sale	The amortized cost, gross unrealized gains and losses, and fair value of available for sale investments as of June 30, 2019 and December 31, 2018, are as follows (in thousands): June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Treasury Bills — — — — US Treasury securities 1,492 7 — 1,499 Total Available for Sale Investments $ 1,492 $ 7 $ — $ 1,499 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity securities: Treasury Bills $ 17,940 $ — $ (3) $ 17,937 US Treasury securities 4,246 — (10) 4,236 Total Available for Sale Investments $ 22,186 $ — $ (13) $ 22,173
Summary of Securities Available for Sale of Continuous Unrealized Loss	A summary of available for sale investments with unrealized losses as of December 31, 2018, aggregated by category and period of continuous unrealized loss, is as follows (in thousands): Less than 12 months 12 months or longer Total December 31, 2018 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturity securities: Treasury Bills $ 17,937 $ (3) $ — $ — $ 17,937 $ (3) US Treasury securities $ — $ — $ 4,236 $ (10) $ 4,236 $ (10) Total Investments with Unrealized Losses $ 17,937 $ (3) $ 4,236 $ (10) $ 22,173 $ (13)
Schedule of Maturities of Securities Available for Sale	The maturities of available for sale investments at June 30, 2019 and December 31, 2018 are as follows (in thousands): June 30, 2019 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Treasury Bills — — — — — US Treasury securities 1,499 — — — 1,499 Total Fair Value $ 1,499 $ — $ — $ — $ 1,499 Total Amortized Cost $ 1,492 $ — $ — $ — $ 1,492 December 31, 2018 Within 1 year After 1 year through 5 years After 5 years to 10 years After 10 years Total Treasury Bills 17,937 — — — 17,937 US Treasury securities 4,236 — — — 4,236 Total Fair Value $ 22,173 $ — $ — $ — $ 22,173 Total Amortized Cost $ 22,186 $ — $ — $ — $ 22,186

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value	The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands): June 30, 2019 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 606,799 $ 606,799 Loans Held for Sale — — 114,962 114,962 Available for Sale Investments, at Fair Value — 1,499 — 1,499 Servicing Assets — — 13,387 13,387 Total Assets $ — $ 1,499 $ 735,148 $ 736,647 Liabilities: Notes $ — $ — $ 253,425 $ 253,425 Servicing Liabilities — — 4 4 Certificates Issued by Securitization Trust, at Fair Value — — 44,090 44,090 Convertible Preferred Stock Warrant Liability — — 166,559 166,559 Loan Trailing Fee Liability — — 3,249 3,249 Total Liabilities $ — $ — $ 467,327 $ 467,327 December 31, 2018 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 263,522 $ 263,522 Loans Held for Sale — — 183,788 183,788 Available for Sale Investments, at Fair Value — 22,173 — 22,173 Servicing Assets — — 14,687 14,687 Total Assets $ — $ 22,173 $ 461,997 $ 484,170 Liabilities: Notes $ — $ — $ 264,003 $ 264,003 Servicing Liabilities — — 12 12 Convertible Preferred Stock Warrant Liability — — 143,679 143,679 Loan Trailing Fee Liability — — 3,118 3,118 Total Liabilities $ — $ — $ 410,812 $ 410,812
Quantitative Information About Significant Unobservable Inputs	Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 4.9% - 12.9% 4.7% - 13.8% Default rate 2.0% - 16.6% 2.0% - 15.8%
Significant Unobservable Inputs Fair Value	Servicing Rights: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1% Market servicing rate 0.625 % 0.625 % Loan Trailing Fee Liability: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1%
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present additional information about level 3 Borrower Loans, Loans Held for Sale and Notes measured at fair value on a recurring basis (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Certificates Issued by Securitization Trust Loans Held for Sale Total Balance at January 1, 2019 $ 263,522 $ (264,003) $ — $ 183,788 $ 183,307 Purchase of Borrower Loans/Issuance of Notes 348,629 (86,713) (51,595) 1,161,237 1,371,558 Transfers in (Transfers out) 147,773 — — (147,773) — Principal repayments (134,031) 85,728 4,272 (26,529) (70,560) Borrower Loans sold to third parties (1,886) — — (1,053,308) (1,055,194) Other changes 91 603 (603) 89 180 Change in fair value (17,299) 10,960 3,836 (2,542) (5,045) Balance at June 30, 2019 $ 606,799 $ (253,425) $ (44,090) $ 114,962 $ 424,246
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 June 30, 2019 for Borrower Loans, Loans Held for Sale and Notes funded through the Note Channel are presented in the following table (in thousands, except percentages): Borrower Loans and Loans Held for Sale Notes Fair Value as of June 30, 2019 $721,761 $253,425 Discount rate assumption: 7.44 % * 7.87 % * Resulting fair value from: 100 basis point increase $ 715,006 $ 251,050 200 basis point increase 708,411 248,730 Resulting fair value from: 100 basis point decrease $ 728,682 $ 255,859 200 basis point decrease 735,775 258,354 Default rate assumption: 12.19 % * 12.55 % * Resulting fair value from: 100 basis point increase $ 713,132 $ 250,379 200 basis point increase 704,794 247,437 Resulting fair value from: 100 basis point decrease $ 730,554 $ 256,527 200 basis point decrease 739,384 259,643 * Represents weighted average assumptions considering all credit grades.
Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities	The following table presents the estimated impact on Prosper’s estimated fair value of servicing assets and liabilities, calculated using different market servicing rates and different default rates as of June 30, 2019 (in thousands, except percentages). Servicing Assets Fair Value as of June 30, 2019 $13,387 Market servicing rate assumptions 0.625 % Resulting fair value from: Market servicing rate increase to 0.65% $ 12,560 Market servicing rate decrease to 0.60% $ 14,214 Weighted average prepayment assumptions 20.59 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate $ 13,220 Applying a 0.9 multiplier to prepayment rate $ 13,556 Weighted average default assumptions 11.72 % Resulting fair value from: Applying a 1.1 multiplier to default rate $ 13,237 Applying a 0.9 multiplier to default rate $ 13,541
Financial Instruments, Assets And Liabilities Not Recorded At Fair Value	The following tables present the fair value hierarchy for financial instruments, assets, and liabilities not recorded at fair value (in thousands): June 30, 2019 Carrying Amount Level 1 Inputs Level 2 Inputs Level 3 Inputs Balance at Fair Value Assets: Cash and Cash Equivalents $ 68,124 $ 68,124 $ — $ — $ 68,124 Restricted Cash 160,990 — 160,990 — 160,990 Accounts Receivable 1,270 — 1,270 — 1,270 Total Assets $ 230,384 $ 68,124 $ 162,260 $ — $ 230,384 Liabilities: Accounts Payable and Accrued Liabilities $ 20,349 $ — $ 20,349 $ — $ 20,349 Payable to Investors 114,811 — 114,811 — 114,811 Notes Issued by Securitization Trust 313,111 — $ 318,304 — 318,304 Warehouse Lines 101,406 — 101,406 — 101,406 Total Liabilities $ 549,677 $ — $ 554,870 $ — $ 554,870
Prosper Funding LLC
Entity Information [Line Items]
Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value	The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands): June 30, 2019 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 254,070 $ 254,070 Servicing Assets — — 15,461 15,461 Total Assets — — 269,531 269,531 Liabilities: Notes $ — $ — $ 253,425 $ 253,425 Servicing Liabilities — — 4 4 Loan Trailing Fee Liability — — 3,249 3,249 Total Liabilities $ — $ — $ 256,678 $ 256,678 December 31, 2018 Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Assets: Borrower Loans $ — $ — $ 263,522 $ 263,522 Servicing Assets — — 15,550 15,550 Total Assets — — 279,072 279,072 Liabilities: Notes $ — $ — $ 264,003 $ 264,003 Servicing Liabilities — — 12 12 Loan Trailing Fee Liability — — 3,118 3,118 Total Liabilities $ — $ — $ 267,133 $ 267,133
Quantitative Information About Significant Unobservable Inputs	The following tables present quantitative information about the significant unobservable inputs used for Prosper Funding’s level 3 fair value measurements at June 30, 2019 and December 31, 2018: Borrower Loans, Loans Held for Sale and Notes: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 4.9% - 12.9% 4.7% - 13.8% Default rate 2.0% - 16.6% 2.0% - 15.8%
Significant Unobservable Inputs Fair Value	Servicing Assets and Liabilities: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1% Market servicing rate 0.625 % 0.625 % Loan Trailing Fee Liability: Range Unobservable Input June 30, 2019 December 31, 2018 Discount rate 15.0% - 25.0% 15.0% - 25.0% Default rate 1.6% - 17.6% 1.6% - 16.7% Prepayment rate 16.3% - 26.1% 15.5% - 25.1%
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The changes in the Borrower Loans, Loans Held for Sale and Notes, which are level 3 assets and liabilities measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2019 $ 263,522 $ (264,003) $ — $ (481) Originations 86,062 (86,713) 1,161,237 1,160,586 Principal repayments (82,414) 85,728 — 3,314 Borrower Loans sold to third parties (1,723) — (1,161,237) (1,162,960) Other changes (200) 603 — 403 Change in fair value (11,177) 10,960 — (217) Balance at June 30, 2019 $ 254,070 $ (253,425) $ — $ 645 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at January 1, 2018 $ 293,005 $ (293,948) $ 49 $ (894) Originations 91,075 (90,693) 1,324,100 1,324,482 Principal repayments (88,947) 91,525 (14) 2,564 Borrower Loans sold to third parties (2,016) — (1,324,100) (1,326,116) Other changes (338) 633 — 295 Change in fair value (15,418) 15,058 (4) (364) Balance at June 30, 2018 $ 277,361 $ (277,425) $ 31 $ (33) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at April 1, 2019 $ 259,899 $ (258,722) $ — $ 1,177 Originations 41,839 (41,774) 670,382 670,447 Principal repayments (41,215) 41,611 — 396 Borrower Loans sold to third parties (749) — (670,382) (671,131) Other changes (115) 2 — (113) Change in fair value (5,589) 5,458 — (131) Balance at June 30, 2019 $ 254,070 $ (253,425) $ — $ 645 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Borrower Loans Notes Loans Held for Sale Total Balance at April 1, 2018 $ 285,584 $ (285,095) $ 41 $ 530 Originations 44,799 (44,468) 728,901 729,232 Principal repayments (43,990) 44,423 (6) 427 Borrower Loans sold to third parties (950) — (728,901) (729,851) Other changes (202) 86 — (116) Change in fair value (7,880) 7,629 (4) (255) Balance at June 30, 2018 $ 277,361 $ (277,425) $ 31 $ (33)
Schedule of Servicing Assets and Liabilities Measured at Fair Value	The following table presents additional information about level 3 servicing assets recorded at fair value (in thousands): Servicing Assets Fair Value at January 1, 2019 15,550 Additions 6,796 Less: Changes in fair value (6,885) Fair Value at June 30, 2019 15,461 Servicing Assets Fair Value at January 1, 2018 14,598 Additions 8,147 Less: Changes in fair value (6,583) Fair Value at June 30, 2018 16,162 Servicing Assets Fair Value at April 1, 2019 15,174 Additions 3,830 Less: Changes in fair value (3,543) Fair Value at June 30, 2019 15,461 Servicing Assets Fair Value at April 1, 2018 15,023 Additions 4,452 Less: Changes in fair value (3,313) Fair Value at June 30, 2018 16,162 Loan Trailing Fee The fair value of the Loan Trailing Fee represents the present value of the expected monthly Loan Trailing Fee payments, which takes into consideration certain assumptions related to expected prepayment rates and defaults rates using a discounted cash flow model. The following table presents additional information about level 3 Loan Trailing Fee Liability measured at fair value on a recurring basis (in thousands): Loan Trailing Fee Liability Fair Value at January 1, 2019 3,118 Issuances 1,297 Cash payment of Loan Trailing Fee (1,298) Change in fair value 132 Fair Value at June 30, 2019 3,249
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 June 30, 2019 for Borrower Loans, Loans Held for Sale and Notes funded are presented in the following table (in thousands, except percentages): Borrower Loans Notes Fair Value at June 30, 2019 $ 254,070 $ 253,425 Discount rate assumption: 7.87 % * 7.87 % * Resulting fair value from: 100 basis point increase $ 251,692 $ 251,050 200 basis point increase 249,371 248,730 Resulting fair value from: 100 basis point decrease $ 256,507 $ 255,859 200 basis point decrease 259,004 258,354 Default rate assumption: 12.55 % * 12.55 % * Resulting fair value from: 100 basis point increase $ 251,033 $ 250,379 200 basis point increase 248,098 247,437 Resulting fair value from: 100 basis point decrease $ 257,166 $ 256,527 200 basis point decrease 260,274 259,643 * Represents weighted average assumptions considering all credit grades.
Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities	The following table presents the estimated impact on Prosper Funding’s estimated fair value of servicing assets, calculated using different market servicing rates and different default rates as of June 30, 2019 (in thousands, except percentages). Servicing Assets Fair Value at June 30, 2019 $ 15,461 Market servicing rate assumptions 0.625 % Resulting fair value from: Market servicing rate increase to 0.65% 14,506 Market servicing rate decrease to 0.60% 16,415 Weighted average prepayment assumptions 20.59 % Resulting fair value from: Applying a 1.1 multiplier to prepayment rate 15,267 Applying a 0.9 multiplier to prepayment rate 15,655 Weighted average default assumptions 11.72 % Resulting fair value from: Applying a 1.1 multiplier to default rate 15,287 Applying a 0.9 multiplier to default rate 15,638

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Other Intangible Assets for the Period Presented	The following table presents the detail of other intangible assets for the period presented (dollars in thousands): June 30, 2019 Gross Carrying Value Accumulated Amortization Net Carrying Value Remaining Useful Life (In Years) Developed technology $ 3,060 $ (3,060) $ — — User base and customer relationships 5,050 (4,191) $ 859 5.8 Brand name 60 (60) — — Total Intangible Assets Subject to Amortization $ 8,170 $ (7,311) $ 859
Summary of Estimated Amortization of Purchased Intangible Assets	Estimated amortization of purchased intangible assets for future periods is as follows (in thousands): Year Ending December 31, Estimated Amortization of Purchased Intangible Assets 2019 (remainder thereof) $ 140 2020 219 2021 172 2022 136 2023 107 Thereafter $ 85 Total $ 859

Other Liabilities (Tables)

Other Liabilities (Tables)	6 Months Ended
	Jun. 30, 2019
Other Liabilities [Abstract]
Schedule of Other Liabilities	Other Liabilities includes the following: June 30, 2019 December 31, 2018 Loan trailing fee 3,249 3,118 Deferred revenue 352 396 Servicing liabilities 4 12 Deferred income tax liability 363 373 Deferred rent — 3,408 Restructuring liability — 2,106 Operating lease liability 19,187 — Other 1,052 1,216 Total Other Liabilities $ 24,207 $ 10,629

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Basic and Diluted Net Loss Per Share	Basic and diluted net loss per share was calculated as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net loss available to common stockholders for basic and diluted EPS $ (569) $ (12,599) $ (23,283) $ (24,000) Denominator: Weighted average shares used in computing basic and diluted net loss per share 70,502,797 70,362,716 70,494,945 70,333,145 Basic and diluted net loss per share $ (0.01) $ (0.18) $ (0.33) $ (0.34)
Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share	The following common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (shares) (shares) (shares) (shares) Excluded securities: Convertible preferred stock issued and outstanding 214,637,925 214,637,925 214,637,925 214,637,925 Stock options issued and outstanding 73,234,877 75,206,928 71,592,576 66,403,696 Unvested stock options exercised — 2,190 — 2,190 Warrants issued and outstanding 1,080,349 1,080,349 1,080,349 1,082,917 Series E-1 convertible preferred stock warrants 35,544,141 35,544,141 35,544,141 35,544,141 Series F convertible preferred stock warrants 177,720,704 177,720,704 177,720,704 177,720,704 Total common stock equivalents excluded from diluted net loss per common share computation 502,217,996 504,192,237 500,575,695 495,391,573

Convertible Preferred Stock, _2

Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit (Tables)	6 Months Ended
	Jun. 30, 2019
Class of Stock [Line Items]
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 June 30, 2019 are disclosed in the table below (amounts in thousands except share and per share amounts): Convertible Preferred Stock Par Value Authorized Shares Outstanding and Issued Shares Liquidation Preference (Outstanding Shares) Series A $ 0.01 68,558,220 68,558,220 $ 19,774 Series A-1 0.01 24,760,915 24,760,915 49,522 Series B 0.01 35,775,880 35,775,880 21,581 Series C 0.01 24,404,770 24,404,770 70,075 Series D 0.01 23,888,640 23,888,640 165,000 Series E-1 0.01 35,544,141 — — Series E-2 0.01 16,858,078 — — Series F 0.01 177,720,707 3 — Series G 0.01 37,249,497 37,249,497 50,000 444,760,848 214,637,925 $ 375,952
Schedule of Stockholders' Equity Note, Warrants or Rights	The combined activity of the Convertible Preferred Stock Warrant Liability for the six months ended June 30, 2019 is as follows (in thousands): Warrant Activity Balance at January 1, 2019 $ 143,679 Warrants Vested 17,553 Change in Fair Value 5,327 Balance at June 30, 2019 $ 166,559
Series E-1 Preferred Stock
Class of Stock [Line Items]
Schedule of Assumptions Used	The Company determined the fair value of the outstanding Series E-1 Warrants utilizing the following assumptions as of the following dates: June 30, 2019 December 31, 2018 Volatility 40% 40% Risk-free interest rate 1.89% 2.62% Remaining contractual term (in years) 7.55 years 8.04 years Dividend yield —% —%
Series F convertible preferred stock warrants (in shares)
Class of Stock [Line Items]
Schedule of Assumptions Used	The Company determined the fair value of the outstanding Series F Warrants utilizing the following assumptions as of the following dates: June 30, 2019 December 31, 2018 Volatility 40% 40% Risk-free interest rate 1.90% 2.63% Remaining contractual term (in years) 7.66 years 8.16 years Dividend yield —% —%

Share Based Incentive Plan an_2

Share Based Incentive Plan and Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Summarized Option Activity under Option Plan	Stock option activity under the 2005 Plan and 2015 Plan is summarized for the six months ended June 30, 2019 below: Options Issued and Outstanding Weighted- Average Exercise Price Balance as of January 1, 2019 71,021,698 $ 0.33 Options issued 6,682,948 0.30 Options exercised – vested (91,316) 0.12 Options forfeited (2,136,356) 0.46 Balance as of June 30, 2019 75,476,974 $ 0.32 Options vested and expected to vest as of June 30, 2019 62,463,510 0.32 Options vested and exercisable at June 30, 2019 46,213,667 0.27
Additional Information Regarding Common Stock Options Outstanding	Additional information regarding common stock options outstanding as of June 30, 2019 is as follows: Options Outstanding Options Vested and Exercisable Range of Exercise Prices Number Outstanding Weighted – Avg. Remaining Life (In years) Weighted –Avg. Exercise Price Number Vested Weighted – Avg. Exercise Price $ 0.02 - 0.20 4,062,390 4.55 $ 0.11 4,062,390 $ 0.11 0.21 - 0.50 51,346,996 7.85 0.26 34,178,267 0.23 0.51 - 1.13 20,067,588 8.60 0.54 7,973,010 0.54 $ 0.02 - 1.13 75,476,974 7.87 $ 0.32 46,213,667 $ 0.27
Fair Value of Stock Option Awards	The fair value of PMI’s stock option awards granted during the three and six months ended June 30, 2019 and June 30, 2018 was estimated at the date of grant using the Black-Scholes model with the following average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Volatility of common stock 46.72 % 44.43 % 46.72 % 44.12 % Risk-free interest rate 2.28 % 2.85 % 2.28 % 2.75 % Expected life (in years) 5.9 years 6.0 years 5.9 years 6.0 years Dividend yield — % — % — % — %
Summarized Activities for RSU's	The following table summarizes the number of PMI’s outstanding RSUs and their weighted-average grant date fair value during the six months ended June 30, 2019: Number of Shares Weighted-Average Grant Date Fair Value Unvested - January 1, 2019 4,856,141 $ 0.96 Forfeited (15,500) 2.18 Unvested - June 30, 2019 4,840,641 $ 0.96
Stock Based Compensation Included in Consolidated Statements of Operations	The following table presents the amount of stock-based compensation related to stock-based awards granted to employees recognized in Prosper’s condensed consolidated statements of operations during the three and six months ended June 30, 2019 and June 30, 2018 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Origination and servicing $ 108 $ 241 $ 304 $ 456 Sales and marketing 63 108 145 216 General and administrative 1,064 1,904 2,401 3,912 Total stock based compensation $ 1,235 $ 2,253 $ 2,850 $ 4,584

Consortium Purchase Agreement (

Consortium Purchase Agreement (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Consortium Purchase Agreement	The following represents the loans purchased and warrants vested under the Consortium Purchase Agreement: Loans Acquired (in thousands) Warrants Vested Balance as of January 1, 2019 $ 3,067,332 154,912,980 Six Months Ended June 30, 2019 235,951 22,807,726 Balance as of June 30, 2019 $ 3,303,283 177,720,706

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Operating Lease Right-of-Use Assets	The following represents the operating lease right-of-use assets as of June 30, 2019: June 30, 2019 Gross Carrying Value Accumulated Amortization Net Carrying Value ROU Assets - Office buildings $ 15,846 $ 1,517 $ 14,329 ROU Assets - Other 292 114 $ 178 Total right-of-use assets subject to amortization $ 16,138 $ 1,631 $ 14,507
Future Minimum Lease Payments Under Topic 842	Future minimum lease payments under non-cancellable leases as of June 30, 2019 were as follows (in thousands): Minimum Lease Payments Remainder of 2019 2,268 2020 5,240 2021 5,134 2022 5,018 2023 1,567 Thereafter 2,546 Total future minimum lease payments $ 21,773 Less imputed interest (2,586) Total $ 19,187
Future Minimum Lease Payments Under Topic 840	The table below presents future minimum rental payments at December 31, 2018, net of minimum sublease rentals of $5.3 million, for the remaining terms of the operating leases (in thousands): 2019 4,536 2020 4,683 2021 4,456 2022 4,319 2023 847 Thereafter 387 Total future operating lease obligations $ 19,228
Other Information Related to Leases	Other information related to leases was as follows ($ in thousands): June 30, 2019 Cash paid for operating leases year-to-date $ 3,026 Right of use assets obtained in exchange for new operating lease obligations (1) $ 21,630 Weighted Average Remaining Lease Term 4.54 years Weighted Average Discount Rate 5.53 %

Related Parties (Tables)

Related Parties (Tables)	6 Months Ended
	Jun. 30, 2019
Entity Information [Line Items]
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes and Borrower Loans purchased and the income earned by parties deemed to be affiliates and related parties of Prosper for the three and six months ended June 30, 2019 and June 30, 2018, as well as the Notes and Borrower Loans outstanding as of June 30, 2019 and December 31, 2018 are summarized below (in thousands): Aggregate Amount of Notes and Borrower Loans Purchased Six Months Ended June 30, Interest Earned on Notes and Borrower Loans Six Months Ended June 30, Related Party 2019 2018 2019 2018 Executive officers and management $ 11 $ 9 $ 2 $ 1 Directors (excluding executive officers and management) 208 208 24 22 Total $ 219 $ 217 $ 26 $ 23 Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30, Interest Earned on Notes and Borrower Loans Three Months Ended June 30, Related Party 2019 2018 2019 2018 Executive officers and management $ 5 $ 3 $ 1 $ — Directors (excluding executive officers and management) 99 107 12 11 Total $ 104 $ 110 $ 13 $ 11 Notes balance as of Related Party June 30, 2019 December 31, 2018 Executive officers and management $ 34 $ 32 Directors (excluding executive officers and management) 589 569 $ 623 $ 601
Prosper Funding LLC
Entity Information [Line Items]
Aggregate Amount of Notes Purchased and the Income Earned	The aggregate amount of the Notes and Borrower Loans purchased and the income earned by parties deemed to be related parties of Prosper Funding as of June 30, 2019 and December 31, 2018 are summarized below (in thousands): Aggregate Amount of Notes and Borrower Loans Purchased Interest Earned on Notes and Borrower Loans Six Months Ended June 30, Six Months Ended June 30, Related Party 2019 2018 2019 2018 Executive officers and management $ 11 $ 9 $ 2 $ 1 Directors (excluding executive officers and management) — — — — Total $ 11 $ 9 $ 2 $ 1 Aggregate Amount of Notes and Borrower Loans Purchased Interest Earned on Notes and Borrower Loans Three Months Ended June 30, Three Months Ended June 30, Related Party 2019 2018 2019 2018 Executive officers and management $ 5 $ 3 $ 1 $ — Directors (excluding executive officers and management) — — — — Total $ 5 $ 3 $ 1 $ — Note and Borrower Loan Balance as of Related Party June 30, 2019 December 31, 2018 Executive officers and management $ 34 $ 32 Directors (excluding executive officers and management) — — $ 34 $ 32

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2019		Dec. 31, 2018		Jun. 30, 2018	Dec. 31, 2017
Entity Information [Line Items]
Cash and Cash Equivalents	$ 68,124		$ 57,945		$ 58,652	$ 45,795
Restricted Cash (1)	160,990	[1]	149,114	[1]	134,552	152,668
Total Cash, Cash Equivalents and Restricted Cash shown in the consolidated statements of cash flows	229,114		207,059		193,204	198,463
Prosper Funding LLC
Entity Information [Line Items]
Cash and Cash Equivalents	12,269		11,163		10,892	8,223
Restricted Cash (1)	123,380		136,018		120,152	140,092
Total Cash, Cash Equivalents and Restricted Cash shown in the consolidated statements of cash flows	$ 135,649		$ 147,181		$ 131,044	$ 148,315
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2019		Jan. 01, 2019	Dec. 31, 2018		Jun. 30, 2018	Dec. 31, 2017
Entity Information [Line Items]
Restricted Cash (1)	$ 160,990	[1]		$ 149,114	[1]	$ 134,552	$ 152,668
Operating Leases, Future Minimum Payments Due	19,228
Gross Carrying Value	16,138
Operating lease liability	19,187
Reduction in other liabilities	(24,207)			(10,629)
Accounting Standards Update 2016-02
Entity Information [Line Items]
Gross Carrying Value			$ 16,100
Operating lease liability			21,600
Reduction in other liabilities			$ 5,100
Prosper Funding LLC
Entity Information [Line Items]
Restricted Cash (1)	123,380			136,018		$ 120,152	$ 140,092
Reduction in other liabilities	$ (4,617)			$ (4,528)
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment	$ 66,970		$ 66,970		$ 50,615
Less accumulated depreciation and amortization	(35,801)		(35,801)		(35,342)
Total Property and Equipment, Net	31,169		31,169		15,273
Depreciation expense			3,743	$ 5,334
Property Plant And Equipment
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	1,800	$ 2,400	3,600	5,100
Operating lease right-of-use assets
Property, Plant and Equipment [Line Items]
Property and equipment	16,138		16,138		0
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	12,790		12,790		15,193
Internal-use software and website development costs
Property, Plant and Equipment [Line Items]
Property and equipment	24,621		24,621		22,505
Capitalized internal-use software and website development costs	2,300	1,400	4,300	2,500
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Property and equipment	2,995		2,995		3,015
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	7,158		7,158		7,157
Assets not yet placed in service
Property, Plant and Equipment [Line Items]
Property and equipment	3,268		3,268		2,745
Prosper Funding LLC
Property, Plant and Equipment [Line Items]
Less accumulated depreciation and amortization	(16,581)		(16,581)		(16,079)
Total Property and Equipment, Net	5,494		5,494		6,426
Depreciation expense	1,100	$ 1,400	2,203	$ 2,991
Prosper Funding LLC | Internal-use software and website development costs
Property, Plant and Equipment [Line Items]
Property and equipment	$ 22,075		$ 22,075		$ 22,505

Borrower Loans, Loans Held fo_3

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Aggregate Principal Balances Outstanding and Fair Values of Borrower Loans, Notes and Loans Held for Sale (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended	12 Months Ended
		Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower Loans Receivable at Fair Value	[1]	$ 606,799		$ 606,799	$ 263,522
Notes, at Fair Value		(253,425)		(253,425)	(264,003)
Loans Held for Sale, at Fair Value (1)	[1]	114,962		114,962	183,788
Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrower Loans Receivable at Fair Value		254,070		254,070	263,522
Notes, at Fair Value		(253,425)		(253,425)	(264,003)
Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Notes		(259,954)		(259,954)	(272,430)
Fair value adjustments, Notes				6,529	8,427
Notes, at Fair Value		(253,425)		(253,425)	(264,003)
Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding, Notes		(259,954)		(259,954)	(272,430)
Fair value adjustments, Notes			$ 8,427	6,529
Notes, at Fair Value		(253,425)		(253,425)	(264,003)
Borrower Loans
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding		614,678		614,678	269,093
Fair value adjustments				(7,879)	(5,571)
Borrower Loans Receivable at Fair Value		606,799		606,799	263,522
Borrower Loans | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal balance outstanding		257,921		257,921	269,093
Fair value adjustments			$ (5,571)	(3,851)
Borrower Loans Receivable at Fair Value		254,070		254,070	263,522
Loans Held for Sale
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value adjustments		(136)		(100)	(1,869)
Aggregate principal balance outstanding, Loans Held for Sale		115,098		115,098	185,657
Loans Held for Sale, at Fair Value (1)		$ 114,962		$ 114,962	$ 183,788
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.

Borrower Loans, Loans Held fo_4

Borrower Loans, Loans Held for Sale, and Notes Held at Fair Value - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loss related to credit risks on borrower loans				$ 400	$ 600
Interest income	$ 7,898		$ 3,085	$ 13,207	4,716
Minimum number of days for which loans originated were delinquent				90 days		90 days
Aggregate principal amount of loans originated	4,100			$ 4,100		$ 2,500
Fair value of loans originated	1,600			$ 1,600		1,100
Non accrual status past due date				120 days
Borrower loans receivable	400			$ 400		300
Loans Held for Sale
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value adjustments	(136)			(100)		$ (1,869)
Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loss related to credit risks on borrower loans				200
Interest income	668		$ 730	$ 1,350	1,471
Minimum number of days for which loans originated were delinquent				90 days		90 days
Aggregate principal amount of loans originated	2,200			$ 2,200		$ 2,500
Fair value of loans originated	900			$ 900		1,100
Non accrual status past due date				120 days
Borrower loans receivable	400			$ 400		$ 300
Outstanding Borrower Loans and Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed interest rate, minimum				5.31%		5.31%
Fixed interest rate, maximum				31.92%		31.92%
Interest income				$ 7,500
Loans Held For Sale Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed interest rate, minimum				5.31%		5.31%
Fixed interest rate, maximum				31.82%		31.82%
Interest income					$ 5,100
Aggregate principal amount of loans originated	400			$ 400		$ 800
Fair value of loans originated	$ 100			$ 100		$ 300
Loans Held For Sale Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed interest rate, minimum				5.31%		5.31%
Fixed interest rate, maximum				31.92%		31.92%
Minimum | Loans Held For Sale Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		36 months		36 months
Minimum | Loans Held For Sale Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		36 months		36 months
Maximum | Loans Held For Sale Borrower Loans And Underlying Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		60 months		60 months
Maximum | Loans Held For Sale Borrower Loans And Underlying Notes | Prosper Funding LLC
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maturity, in months		60 months		60 months

Loan Servicing Assets and Lia_2

Loan Servicing Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Servicing Assets And Liabilities Fair Value [Line Items]
Gain (loss) on sale of borrower loans	$ 3,559		$ 4,200	$ 6,256	$ 7,512
Fair value of warrants vested on sale of borrower loans	7,805		20,633	17,553	35,912
Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Gain (loss) on sale of borrower loans	(4,053)		(16,181)	(10,879)	(27,754)
Borrower Loans
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	3,300,000			$ 3,300,000		$ 3,600,000
Fixed interest rate, minimum				5.31%		5.31%
Fixed interest rate, maximum				35.52%		35.52%
Contractually specified servicing fees, late charges and ancillary fees				$ 18,500	21,600
Borrower Loans | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Outstanding principle	3,700,000			$ 3,700,000		$ 3,700,000
Fixed interest rate, minimum				5.31%		5.31%
Fixed interest rate, maximum				35.52%		35.52%
Contractually specified servicing fees, late charges and ancillary fees	$ (10,200)		$ 11,200	$ 20,200	$ 21,800
Minimum | Borrower Loans
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months		36 months		36 months
Minimum | Borrower Loans | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months		36 months		36 months		36 months
Maximum | Borrower Loans
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months		60 months		60 months
Maximum | Borrower Loans | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Maturity, in months						60 months

Available for Sale Investment_3

Available for Sale Investments, at Fair Value - Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Available for Sale Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Fair Value	$ 1,499	$ 22,173
Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,492	22,186
Gross Unrealized Gains	7	0
Gross Unrealized Losses	0	(13)
Fair Value	1,499	22,173
Treasury Bills | Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	0	17,940
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(3)
Fair Value	0	17,937
US Treasury securities | Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,492	4,246
Gross Unrealized Gains	7	0
Gross Unrealized Losses	0	(10)
Fair Value	$ 1,499	$ 4,236

Available for Sale Investment_4

Available for Sale Investments, at Fair Value - Summary of Available for Sale Investments of Continuous Unrealized Loss (Details) - Fixed Maturity Securities $ in Thousands	Dec. 31, 2018USD ($)
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	$ 17,937
Unrealized losses, less than 12 months	(3)
Fair value, 12 months or longer	4,236
Unrealized losses, 12 months or longer	(10)
Fair Value	22,173
Unrealized Losses	(13)
Treasury Bills
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	17,937
Unrealized losses, less than 12 months	(3)
Fair value, 12 months or longer	0
Unrealized losses, 12 months or longer	0
Fair Value	17,937
Unrealized Losses	(3)
US Treasury securities
Schedule Of Available For Sale Securities [Line Items]
Fair value, less than 12 months	0
Unrealized losses, less than 12 months	0
Fair value, 12 months or longer	4,236
Unrealized losses, 12 months or longer	(10)
Fair Value	4,236
Unrealized Losses	$ (10)

Available for Sale Investment_5

Available for Sale Investments, at Fair Value - Additional Information (Details)	6 Months Ended
	Jun. 30, 2019USD ($)
Investments, Debt and Equity Securities [Abstract]
Impairment charges recognized during period	$ 0
Proceeds from investments	$ 0

Available for Sale Investment_6

Available for Sale Investments, at Fair Value - Schedule of Maturities of Available for Sale Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Total	$ 1,499	$ 22,173
Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Within 1 year	1,499	22,173
After 1 year through 5 years	0	0
After 5 years to 10 years	0	0
After 10 years	0	0
Total	1,499	22,173
Amortized cost within 1 year	1,492	22,186
Amortized cost after 1 year through 5 years	0	0
Amortized cost after 5 years to 10 years	0	0
Amortized cost after 10 years	0	0
Amortized Cost	1,492	22,186
Treasury Bills | Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Within 1 year	0	17,937
After 1 year through 5 years	0	0
After 5 years to 10 years	0	0
After 10 years	0	0
Total	0	17,937
Amortized Cost	0	17,940
US Treasury securities | Fixed Maturity Securities
Schedule Of Available For Sale Securities [Line Items]
Within 1 year	1,499	4,236
After 1 year through 5 years	0	0
After 5 years to 10 years	0	0
After 10 years	0	0
Total	1,499	4,236
Amortized Cost	$ 1,492	$ 4,246

Securitization - Additional Inf

Securitization - Additional Information (Details) - USD ($) $ in Thousands		May 23, 2019	Feb. 07, 2019	Jun. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Notes issued	[1]			$ 313,111	$ 0
Borrower Loans	[1]			606,799	263,522
Primary Beneficiary
Variable Interest Entity [Line Items]
Notes issued	[2]			313,111	0
Borrower Loans	[2]			$ 348,898	$ 0
Securtization Trust PMT2019-1 | Primary Beneficiary
Variable Interest Entity [Line Items]
Securitization amount			$ 205,100
Net proceeds on sale of notes to third party			171,700
Ownership percentage				65.50%
Debt issuance costs				$ 2,300
Unamortized debt issuance costs				140,000
Borrower Loans				$ 158,900
2019-1, Class A Notes | Primary Beneficiary
Variable Interest Entity [Line Items]
Notes issued			127,300
Interest rate				3.54%
2019-1, Class B Notes | Primary Beneficiary
Variable Interest Entity [Line Items]
Notes issued			25,000
Interest rate				4.03%
2019-1, Class C Notes | Primary Beneficiary
Variable Interest Entity [Line Items]
Notes issued			$ 19,300
Interest rate				5.27%
Securitization Trust 2019-2 | Primary Beneficiary
Variable Interest Entity [Line Items]
Securitization amount		$ 203,500
Net proceeds on sale of notes to third party		$ 174,200
Ownership percentage		16.40%
Debt issuance costs				$ 1,900
Unamortized debt issuance costs				173,100
Borrower Loans				$ 192,800
2019-2, Class A Notes | Primary Beneficiary
Variable Interest Entity [Line Items]
Notes issued		$ 110,100
Interest rate				3.20%
2019-2, Class B Notes | Primary Beneficiary
Variable Interest Entity [Line Items]
Notes issued		31,400
Interest rate				3.69%
2019-2, Class C Notes | Primary Beneficiary
Variable Interest Entity [Line Items]
Notes issued		$ 32,700
Interest rate				5.05%
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.
[2]	The following table presents the assets and liabilities of consolidated variable interest entities (VIEs), which are included in the condensed consolidated balance sheets above. The assets in the table below may only be used to settle obligations of consolidated VIEs and are in excess of those obligations. Additionally, the assets and liabilities in the table below include third-party assets and liabilities of consolidated VIEs only and exclude intercompany balances that eliminate in consolidation. See Note 7 - Securitizations and Note 11 - Debt, to our Notes to Condensed Consolidated Financial Statements for add itional information.

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities - Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Assets:
Borrower Loans	[1]	$ 606,799	$ 263,522
Loans Held for Sale, at Fair Value (1)	[1]	114,962	183,788
Available for Sale Investments, at Fair Value		1,499	22,173
Servicing Assets		13,387	14,687
Total Assets		736,647	484,170
Liabilities:
Notes		253,425	264,003
Servicing Liabilities		4	12
Certificates Issued by Securitization Trust, at Fair Value	[1]	44,090	0
Convertible Preferred Stock Warrant Liability		166,559	143,679
Loan Trailing Fee Liability		3,249	3,118
Total Liabilities		467,327	410,812
Prosper Funding LLC
Assets:
Borrower Loans		254,070	263,522
Servicing Assets		15,461	15,550
Total Assets		269,531	279,072
Liabilities:
Notes		253,425	264,003
Servicing Liabilities		4	12
Loan Trailing Fee Liability		3,249	3,118
Total Liabilities		256,678	267,133
Level 1 Inputs
Assets:
Borrower Loans		0	0
Loans Held for Sale, at Fair Value (1)		0	0
Available for Sale Investments, at Fair Value		0	0
Servicing Assets		0	0
Total Assets		0	0
Liabilities:
Notes		0	0
Servicing Liabilities		0	0
Certificates Issued by Securitization Trust, at Fair Value		0
Convertible Preferred Stock Warrant Liability		0	0
Loan Trailing Fee Liability		0	0
Total Liabilities		0	0
Level 1 Inputs | Prosper Funding LLC
Assets:
Borrower Loans		0	0
Servicing Assets		0	0
Total Assets		0	0
Liabilities:
Notes		0	0
Servicing Liabilities		0	0
Loan Trailing Fee Liability		0	0
Total Liabilities		0	0
Level 2 Inputs
Assets:
Borrower Loans		0	0
Loans Held for Sale, at Fair Value (1)		0	0
Available for Sale Investments, at Fair Value		1,499	22,173
Servicing Assets		0	0
Total Assets		1,499	22,173
Liabilities:
Notes		0	0
Servicing Liabilities		0	0
Certificates Issued by Securitization Trust, at Fair Value		0
Convertible Preferred Stock Warrant Liability		0	0
Loan Trailing Fee Liability		0	0
Total Liabilities		0	0
Level 2 Inputs | Prosper Funding LLC
Assets:
Borrower Loans		0	0
Servicing Assets		0	0
Total Assets		0	0
Liabilities:
Notes		0	0
Servicing Liabilities		0	0
Loan Trailing Fee Liability		0	0
Total Liabilities		0	0
Level 3 Inputs
Assets:
Borrower Loans		606,799	263,522
Loans Held for Sale, at Fair Value (1)		114,962	183,788
Available for Sale Investments, at Fair Value		0	0
Servicing Assets		13,387	14,687
Total Assets		735,148	461,997
Liabilities:
Notes		253,425	264,003
Servicing Liabilities		4	12
Certificates Issued by Securitization Trust, at Fair Value		44,090
Convertible Preferred Stock Warrant Liability		166,559	143,679
Loan Trailing Fee Liability		3,249	3,118
Total Liabilities		467,327	410,812
Level 3 Inputs | Prosper Funding LLC
Assets:
Borrower Loans		254,070	263,522
Servicing Assets		15,461	15,550
Total Assets		269,531	279,072
Liabilities:
Notes		253,425	264,003
Servicing Liabilities		4	12
Loan Trailing Fee Liability		3,249	3,118
Total Liabilities		$ 256,678	$ 267,133
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities - Borrower Loans, Loans Held For Sale and Notes - Quantitative Information about the Significant Unobservable Inputs (Details)	Jun. 30, 2019	Dec. 31, 2018
Discount rate | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.049	0.047
Discount rate | Minimum | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.15	0.15
Discount rate | Minimum | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.049	0.047
Discount rate | Minimum | Prosper Funding LLC | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.15	0.15
Discount rate | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.129	0.138
Discount rate | Maximum | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.25	0.25
Discount rate | Maximum | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.129	0.138
Discount rate | Maximum | Prosper Funding LLC | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.25	0.25
Default rate | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.020	0.020
Default rate | Minimum | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.016	0.016
Default rate | Minimum | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.020	0.020
Default rate | Minimum | Prosper Funding LLC | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.016	0.016
Default rate | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.166	0.158
Default rate | Maximum | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.176	0.167
Default rate | Maximum | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.166	0.158
Default rate | Maximum | Prosper Funding LLC | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.176	0.167
Prepayment rate | Minimum | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.163	0.155
Prepayment rate | Minimum | Prosper Funding LLC | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.163	0.155
Prepayment rate | Maximum | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.261	0.251
Prepayment rate | Maximum | Prosper Funding LLC | Obligations
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value measurement inputs	0.261	0.251

Fair Value of Assets and Liab_5

Fair Value of Assets and Liabilities - Servicing Rights - Quantitative Information about the Significant Unobservable Inputs (Details)	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Servicing Liabilities at Fair Value [Line Items]
Market servicing rate	0.625%	0.625%
Prosper Funding LLC
Servicing Liabilities at Fair Value [Line Items]
Market servicing rate		0.625%	0.625%
Minimum
Servicing Liabilities at Fair Value [Line Items]
Discount rate	15.00%	15.00%
Default rate	1.60%	1.60%
Prepayment rate	15.50%	16.30%
Minimum | Prosper Funding LLC
Servicing Liabilities at Fair Value [Line Items]
Discount rate		15.00%	15.00%
Default rate		1.60%	1.60%
Prepayment rate		16.30%	15.50%
Maximum
Servicing Liabilities at Fair Value [Line Items]
Discount rate	25.00%	25.00%
Default rate	16.70%	17.60%
Prepayment rate	25.10%	26.10%
Maximum | Prosper Funding LLC
Servicing Liabilities at Fair Value [Line Items]
Discount rate		25.00%	25.00%
Default rate		17.60%	16.70%
Prepayment rate		26.10%	25.10%

Fair Value of Assets and Liab_6

Fair Value of Assets and Liabilities - Loan Trailing Fee Liability (Details)	Jun. 30, 2019	Dec. 31, 2018
Discount rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.049	0.047
Discount rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.129	0.138
Discount rate | Prosper Funding LLC | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.049	0.047
Discount rate | Prosper Funding LLC | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.129	0.138
Discount rate | Obligations | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.15	0.15
Discount rate | Obligations | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.25	0.25
Discount rate | Obligations | Prosper Funding LLC | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.15	0.15
Discount rate | Obligations | Prosper Funding LLC | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.25	0.25
Default rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.020	0.020
Default rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.166	0.158
Default rate | Prosper Funding LLC | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.020	0.020
Default rate | Prosper Funding LLC | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.166	0.158
Default rate | Obligations | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.016	0.016
Default rate | Obligations | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.176	0.167
Default rate | Obligations | Prosper Funding LLC | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.016	0.016
Default rate | Obligations | Prosper Funding LLC | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.176	0.167
Prepayment rate | Obligations | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.163	0.155
Prepayment rate | Obligations | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.261	0.251
Prepayment rate | Obligations | Prosper Funding LLC | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.163	0.155
Prepayment rate | Obligations | Prosper Funding LLC | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement inputs	0.261	0.251

Fair Value of Assets and Liab_7

Fair Value of Assets and Liabilities - Summary of Level 3 Borrower Loans, Loans Held for Sale and Notes, Measured at Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Asset And Liability [Roll Forward]
Beginning balance, Total	$ 277,494	$ 83,292	$ 183,307	$ (894)
Purchase of Borrower Loans/Issuance of Notes	810,999	729,232	1,371,558	1,324,482
Transfers in (Transfers out)	0		0
Principal repayments	(44,442)	(9,983)	(70,560)	(11,687)
Borrower Loans sold to third parties	(616,747)	(684,497)	(1,055,194)	(1,195,667)
Other changes	(227)	139	180	1,091
Change in fair value	(2,831)	(1,430)	(5,045)	(572)
Ending balance, Total	424,246	116,753	424,246	116,753
Prosper Funding LLC
Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Asset And Liability [Roll Forward]
Beginning balance, Total	1,177	530	(481)	(894)
Originations	670,447	729,232	(1,160,586)	(1,324,482)
Principal repayments	396	427	3,314	2,564
Borrower Loans sold to third parties	(671,131)	(729,851)	(1,162,960)	(1,326,116)
Other changes	(113)	(116)	403	295
Change in fair value	(131)	(255)	(217)	(364)
Ending balance, Total	645	(33)	645	(33)
Notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, Liabilities	(258,722)	(285,095)	(264,003)	(293,948)
Purchase of Borrower Loans/Issuance of Notes	(41,774)	(44,468)	(86,713)	(90,693)
Transfers in (Transfers out)	0		0
Principal repayments	41,611	44,423	85,728	91,525
Borrower Loans sold to third parties	0	0	0	0
Other changes	2	86	603	633
Change in fair value	5,458	7,629	10,960	15,058
Ending balance, Liabilities	(253,425)	(277,425)	(253,425)	(277,425)
Notes | Prosper Funding LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, Liabilities	(258,722)	(285,095)	(264,003)	(293,948)
Originations	(41,774)	(44,468)	(86,713)	(90,693)
Principal repayments	41,611	44,423	85,728	91,525
Borrower Loans sold to third parties	0	0	0	0
Other changes	2	86	603	633
Change in fair value	5,458	7,629	10,960	15,058
Ending balance, Liabilities	(253,425)	(277,425)	(253,425)	(277,425)
Certificates Issued by Securitization Trust
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, Liabilities	(19,134)		0
Purchase of Borrower Loans/Issuance of Notes	(30,979)		(51,595)
Transfers in (Transfers out)	0		0
Principal repayments	3,139		4,272
Borrower Loans sold to third parties	0		0
Other changes	(436)		(603)
Change in fair value	3,320		3,836
Ending balance, Liabilities	(44,090)		(44,090)
Borrower Loans
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	448,710	285,584	263,522	293,005
Purchase of Borrower Loans/Issuance of Notes	213,370	44,799	348,629	91,075
Transfers in (Transfers out)	33,457		147,773
Principal repayments	(77,402)	(43,990)	(134,031)	(88,947)
Borrower Loans sold to third parties	(912)	(950)	(1,886)	(2,016)
Other changes	(48)	(202)	91	(338)
Change in fair value	(10,376)	(7,880)	(17,299)	(15,418)
Ending balance, Assets	606,799	277,361	606,799	277,361
Borrower Loans | Prosper Funding LLC
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	259,899	285,584	263,522	293,005
Originations	41,839	44,799	86,062	91,075
Principal repayments	(41,215)	(43,990)	(82,414)	(88,947)
Borrower Loans sold to third parties	(749)	(950)	(1,723)	(2,016)
Other changes	(115)	(202)	(200)	(338)
Change in fair value	(5,589)	(7,880)	(11,177)	(15,418)
Ending balance, Assets	254,070	277,361	254,070	277,361
Loans Held for Sale
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	106,640	82,803	183,788	49
Purchase of Borrower Loans/Issuance of Notes	670,382	728,901	1,161,237	1,324,100
Transfers in (Transfers out)	(33,457)		(147,773)
Principal repayments	(11,790)	(10,416)	(26,529)	(14,265)
Borrower Loans sold to third parties	(615,835)	(683,547)	(1,053,308)	(1,193,651)
Other changes	255	255	89	796
Change in fair value	(1,233)	(1,179)	(2,542)	(212)
Ending balance, Assets	114,962	116,817	114,962	116,817
Loans Held for Sale | Prosper Funding LLC
Changes in Level 3 assets measured at fair value on a recurring basis [Abstract]
Beginning balance, Assets	0	41	0	49
Originations	670,382	728,901	1,161,237	1,324,100
Principal repayments	0	(6)	0	(14)
Borrower Loans sold to third parties	(670,382)	(728,901)	(1,161,237)	(1,324,100)
Other changes	0	0	0	0
Change in fair value	0	(4)	0	(4)
Ending balance, Assets	$ 0	$ 31	$ 0	$ 31

Fair Value of Assets and Liab_8

Fair Value of Assets and Liabilities - Schedule of Servicing Assets and Liabilities, Warrant Liability and Loan Trailing (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance			$ 14,687
Derecognition	$ (1,049)
Servicing Asset at Fair Value, Ending Balance	13,387		13,387
Servicing Liability at Amortized Cost [Roll Forward]
Servicing Liability at Fair Value, Beginning Balance			12
Servicing Liability at Fair Value, Ending Balance	4		4
Prosper Funding LLC
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance			15,550
Servicing Asset at Fair Value, Ending Balance	15,461		15,461
Servicing Liability at Amortized Cost [Roll Forward]
Servicing Liability at Fair Value, Beginning Balance			12
Servicing Liability at Fair Value, Ending Balance	4		4
Servicing Assets
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance	13,814	$ 14,754	14,687	$ 14,711
Additions	3,636	4,163	6,378	7,502
Derecognition	(685)
Less: Changes in fair value	(3,378)	(3,273)	(6,629)	(6,569)
Servicing Asset at Fair Value, Ending Balance	13,387	15,644	13,387	15,644
Servicing Assets | Prosper Funding LLC
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance	15,174	15,023	15,550	14,598
Additions	3,830	4,452	6,796	8,147
Less: Changes in fair value	(3,543)	(3,313)	(6,885)	(6,583)
Servicing Asset at Fair Value, Ending Balance	15,461	16,162	15,461	16,162
Preferred Stock Warrant Liability
Servicing Liability at Amortized Cost [Roll Forward]
Beginning balance	163,483	127,041	143,679	116,366
Issuances	7,805	20,633	17,553	35,912
Change in fair value	(4,729)	(3,998)	5,327	(8,602)
Ending balance	166,559	$ 143,676	166,559	$ 143,676
Loan Trailing Fee Liability
Servicing Liability at Amortized Cost [Roll Forward]
Beginning balance			3,118
Issuances			1,297
Cash payment of Loan Trailing Fee			(1,298)
Change in fair value			132
Ending balance	3,249		3,249
Loan Trailing Fee Liability | Prosper Funding LLC
Servicing Liability at Amortized Cost [Roll Forward]
Beginning balance			3,118
Issuances			1,297
Cash payment of Loan Trailing Fee			1,298
Change in fair value			132
Ending balance	3,249		3,249
Level 3 Inputs
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance			14,687
Servicing Asset at Fair Value, Ending Balance	13,387		13,387
Servicing Liability at Amortized Cost [Roll Forward]
Servicing Liability at Fair Value, Beginning Balance			12
Servicing Liability at Fair Value, Ending Balance	4		4
Level 3 Inputs | Prosper Funding LLC
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Servicing Asset at Fair Value, Beginning Balance			15,550
Servicing Asset at Fair Value, Ending Balance	15,461		15,461
Servicing Liability at Amortized Cost [Roll Forward]
Servicing Liability at Fair Value, Beginning Balance			12
Servicing Liability at Fair Value, Ending Balance	$ 4		$ 4

Fair Value of Assets and Liab_9

Fair Value of Assets and Liabilities - Fair Value Assumptions for Borrower Loans, Loans Held for Sale and Notes (Details) $ in Thousands	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes, at Fair Value	$ 253,425	$ 264,003
Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes, at Fair Value	253,425	$ 264,003
Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes, at Fair Value	253,425
Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes, at Fair Value	253,425
Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes, at Fair Value	721,761
Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes, at Fair Value	254,070
Discount rate assumption | 100 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	251,050
Discount rate assumption | 100 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	251,050
Discount rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	715,006
Discount rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	251,692
Discount rate assumption | 200 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	248,730
Discount rate assumption | 200 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	248,730
Discount rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	708,411
Discount rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	249,371
Discount rate assumption | 100 basis point decrease | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	255,859
Discount rate assumption | 100 basis point decrease | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	255,859
Discount rate assumption | 100 basis point decrease | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	728,682
Discount rate assumption | 100 basis point decrease | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	256,507
Discount rate assumption | 200 basis point decrease | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	258,354
Discount rate assumption | 200 basis point decrease | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	258,354
Discount rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	735,775
Discount rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	259,004
Default rate assumption | 100 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	250,379
Default rate assumption | 100 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	250,379
Default rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	713,132
Default rate assumption | 100 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	251,033
Default rate assumption | 200 basis point increase | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	247,437
Default rate assumption | 200 basis point increase | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	247,437
Default rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	704,794
Default rate assumption | 200 basis point increase | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	248,098
Default rate assumption | 100 basis point decrease | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	256,527
Default rate assumption | 100 basis point decrease | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	256,527
Default rate assumption | 100 basis point decrease | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	730,554
Default rate assumption | 100 basis point decrease | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	257,166
Default rate assumption | 200 basis point decrease | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	259,643
Default rate assumption | 200 basis point decrease | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Notes	259,643
Default rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	739,384
Default rate assumption | 200 basis point decrease | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Borrower loans	$ 260,274
Discount rate | Discount rate assumption | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.0787
Discount rate | Discount rate assumption | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.0787
Discount rate | Discount rate assumption | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.0744
Discount rate | Discount rate assumption | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.0787
Default rate | Default rate assumption | Notes
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.1255
Default rate | Default rate assumption | Notes | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.1255
Default rate | Default rate assumption | Borrower Loans and Loans Held for Sale
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.1219
Default rate | Default rate assumption | Borrower Loans and Loans Held for Sale | Prosper Funding LLC
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value assumptions	0.1255

Fair Value of Assets and Lia_10

Fair Value of Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2019	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing Assets		$ 13,387	$ 14,687
Servicing Liabilities		$ 4	12
Market servicing rate assumptions	0.625%	0.625%
Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing Assets		$ 15,461	15,550
Servicing Liabilities		$ 4	$ 12
Market servicing rate assumptions		0.625%	0.625%
Servicing Assets
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing Assets	$ 13,814	$ 13,387	$ 14,687	$ 15,644	$ 14,754	$ 14,711
Market servicing rate assumptions		0.625%
Resulting fair value from:
Market servicing rate increase to 0.65%		$ 12,560
Market servicing rate decrease to 0.60%		$ 14,214
Weighted average prepayment assumptions		20.59%
Resulting fair value from:
Weighted average default assumptions		11.72%
Servicing Assets | Prosper Funding LLC
Servicing Assets And Liabilities Fair Value [Line Items]
Servicing Assets	$ 15,174	$ 15,461	$ 15,550	$ 16,162	$ 15,023	$ 14,598
Market servicing rate assumptions		0.625%
Resulting fair value from:
Market servicing rate increase to 0.65%		$ 14,506
Market servicing rate decrease to 0.60%		$ 16,415
Weighted average prepayment assumptions		20.59%
Resulting fair value from:
Weighted average default assumptions		11.72%
Prepayment rate assumption | Servicing Assets | Applying a 1.1 multiplier to prepayment rate
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to prepayment rate		$ 13,220
Prepayment rate assumption | Servicing Assets | Applying a 1.1 multiplier to prepayment rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 1.1 multiplier to prepayment rate		15,267
Prepayment rate assumption | Servicing Assets | Applying a 0.9 multiplier to prepayment rate
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to prepayment rate		13,556
Prepayment rate assumption | Servicing Assets | Applying a 0.9 multiplier to prepayment rate | Prosper Funding LLC
Resulting fair value from:
Servicing Asset, Applying a 0.9 multiplier to prepayment rate		15,655
Default rate assumption | Servicing Assets | Applying a 1.1 multiplier to default rate
Applying Multiplier, Default Rate [Abstract]
Servicing Asset, Applying a 1.1 multiplier to default rate		13,237
Default rate assumption | Servicing Assets | Applying a 1.1 multiplier to default rate | Prosper Funding LLC
Applying Multiplier, Default Rate [Abstract]
Servicing Asset, Applying a 1.1 multiplier to default rate		15,287
Default rate assumption | Servicing Assets | Applying a 0.9 multiplier to default rate
Applying Multiplier, Default Rate [Abstract]
Servicing Asset, Applying a 0.9 multiplier to default rate		13,541
Default rate assumption | Servicing Assets | Applying a 0.9 multiplier to default rate | Prosper Funding LLC
Applying Multiplier, Default Rate [Abstract]
Servicing Asset, Applying a 0.9 multiplier to default rate		$ 15,638

Fair Value of Assets and Lia_11

Fair Value of Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities Additional Info (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rate increase	0.65%
Servicing rate decrease	0.60%
Prepayment rate assumption
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Prepayment rate increase	1.10%
Prepayment rate decrease	0.90%
Default rate assumption
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Default rate increase	1.10%
Default rate decrease	0.90%
Prosper Funding LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rate increase		0.65%
Servicing rate decrease		0.60%
Prosper Funding LLC | Prepayment rate assumption
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Prepayment rate increase		1.10%
Prepayment rate decrease		0.90%
Prosper Funding LLC | Default rate assumption
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Default rate increase		1.10%
Default rate decrease		0.90%

Fair Value of Assets and Lia_12

Fair Value of Assets and Liabilities - Financial Instruments, Assets and Liabilities not Recorded at Fair Value (Details) - USD ($) $ in Thousands		Jun. 30, 2019		Dec. 31, 2018		Jun. 30, 2018	Dec. 31, 2017
Assets
Cash and Cash Equivalents		$ 68,124		$ 57,945		$ 58,652	$ 45,795
Restricted Cash (1)		160,990	[1]	149,114	[1]	$ 134,552	$ 152,668
Accounts Receivable (1)	[1]	1,270		5,119
Total Assets		1,043,066		753,631
Liabilities:
Accounts Payable and Accrued Liabilities		20,349		19,967
Payable to Investors		114,811		127,538
Notes Issued by Securitization Trust (1)	[1]	313,111		0
Warehouse Lines (1)	[1]	101,406		162,488
Total Liabilities		1,037,958		$ 728,304
Carrying Amount
Assets
Total Assets		230,384
Liabilities:
Total Liabilities		549,677
Balance at Fair Value
Assets
Cash and Cash Equivalents		68,124
Restricted Cash (1)		160,990
Accounts Receivable (1)		1,270
Total Assets		230,384
Liabilities:
Accounts Payable and Accrued Liabilities		20,349
Payable to Investors		114,811
Notes Issued by Securitization Trust (1)		318,304
Warehouse Lines (1)		101,406
Total Liabilities		554,870
Level 1 Inputs
Assets
Cash and Cash Equivalents		68,124
Restricted Cash (1)		0
Accounts Receivable (1)		0
Total Assets		68,124
Liabilities:
Accounts Payable and Accrued Liabilities		0
Payable to Investors		0
Notes Issued by Securitization Trust (1)		0
Warehouse Lines (1)		0
Total Liabilities		0
Level 2 Inputs
Assets
Cash and Cash Equivalents		0
Restricted Cash (1)		160,990
Accounts Receivable (1)		1,270
Total Assets		162,260
Liabilities:
Accounts Payable and Accrued Liabilities		20,349
Payable to Investors		114,811
Notes Issued by Securitization Trust (1)		318,304
Warehouse Lines (1)		101,406
Total Liabilities		554,870
Level 3 Inputs
Assets
Cash and Cash Equivalents		0
Restricted Cash (1)		0
Accounts Receivable (1)		0
Total Assets		0
Liabilities:
Accounts Payable and Accrued Liabilities		0
Payable to Investors		0
Notes Issued by Securitization Trust (1)		0
Warehouse Lines (1)		0
Total Liabilities		$ 0
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Goodwill And Other Intangible Assets [Line Items]
Goodwill	$ 36,368,000		$ 36,368,000		$ 36,368,000
Goodwill impairment expense			0
Intangible assets, net	859,000		859,000		$ 999,000
Amortization of intangible assets	100,000	$ 100,000	100,000	$ 200,000
User base and customer relationships
Goodwill And Other Intangible Assets [Line Items]
Intangible assets, net	$ 859,000		$ 859,000
Intangible assets amortized period			5 years 9 months 18 days
User base and customer relationships | Minimum
Goodwill And Other Intangible Assets [Line Items]
Intangible assets amortized period	3 years
User base and customer relationships | Maximum
Goodwill And Other Intangible Assets [Line Items]
Intangible assets amortized period	10 years

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Summary of Other Intangible Assets for the Period Presented (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 8,170
Accumulated Amortization	(7,311)
Net Carrying Value	859	$ 999
Developed technology
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	3,060
Accumulated Amortization	(3,060)
Net Carrying Value	0
User base and customer relationships
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	5,050
Accumulated Amortization	(4,191)
Net Carrying Value	$ 859
Remaining Useful Life (In Years)	5 years 9 months 18 days
Brand name
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 60
Accumulated Amortization	(60)
Net Carrying Value	$ 0

Goodwill And Other Intangible_5

Goodwill And Other Intangible Assets - Summary of Estimated Amortization of Purchased Intangible Assets (Details) $ in Thousands	Jun. 30, 2019USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2019 (remainder thereof)	$ 140
2020	219
2021	172
2022	136
2023	107
Thereafter	85
Total	$ 859

Other Liabilities (Details)

Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Other Liabilities [Abstract]
Loan trailing fee	$ 3,249	$ 3,118
Deferred revenue	352	396
Servicing liabilities	4	12
Deferred income tax liability	363	373
Deferred rent	0	3,408
Restructuring liability	0	2,106
Operating lease liability	19,187
Other	1,052	1,216
Total Other Liabilities	$ 24,207	$ 10,629

Debt (Details)

Debt (Details) - USD ($)		Mar. 28, 2019	Jun. 12, 2018	Jun. 30, 2019	Dec. 31, 2018	Jan. 19, 2018
Line of Credit Facility [Line Items]
Warehouse Lines (1)	[1]			$ 101,406,000	$ 162,488,000
Loans Held for Sale, at Fair Value (1)	[1]			114,962,000	$ 183,788,000
PWIT
Line of Credit Facility [Line Items]
Loans Held for Sale, at Fair Value (1)				99,500,000
PWIT | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 200,000,000			$ 100,000,000
Repayment period			24 months
Advance rate			89.00%
Minimum tangible net worth			$ 25,000,000
Minimum net liquidity			$ 15,000,000
Maximum leverage ratio			5
Undrawn portion				112,000,000
Capitalized debt issuance cost				1,800,000
PWIT | Secured Debt
Line of Credit Facility [Line Items]
Warehouse Line				88,000,000
PWIIT
Line of Credit Facility [Line Items]
Loans Held for Sale, at Fair Value (1)				0
PWIIT | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 300,000,000
Repayment period		24 months
Advance rate		90.00%
Commitment fee percent		0.50%
Minimum tangible net worth		$ 25,000,000
Minimum net liquidity		$ 15,000,000
Maximum leverage ratio		5
Warehouse Line				13,400,000
Loans Held for Sale, at Fair Value (1)				14,900,000
Undrawn portion				286,600,000
Capitalized debt issuance cost				$ 2,100,000
LIBOR | PWIT | Revolving Credit Facility
Line of Credit Facility [Line Items]
Interest rate				3.00%
LIBOR | PWIIT | Revolving Credit Facility
Line of Credit Facility [Line Items]
Interest rate				290.00%
Increase to basis spread				0.375%
Minimum | PWIT | Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee percent			0.50%
[1]	(1) Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net loss available to common stockholders for basic    and diluted EPS	$ (569)	$ (22,714)	$ (12,599)	$ (11,401)	$ (23,283)	$ (24,000)
Denominator:
Weighted average shares used in computing basic and diluted net loss per share (in shares)	70,502,797		70,362,716		70,494,945	70,333,145
Basic and diluted net loss per share (in dollars per share)	$ (0.01)		$ (0.18)		$ (0.33)	$ (0.34)

Net Loss Per Share - Common Sto

Net Loss Per Share - Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	502,217,996	504,192,237	500,575,695	495,391,573
Convertible preferred stock issued and outstanding (in shares)
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)	214,637,925	214,637,925	214,637,925	214,637,925
Stock options issued and outstanding (in shares)
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)	73,234,877	75,206,928	71,592,576	66,403,696
Unvested stock options exercised (in shares)
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)	0	2,190	0	2,190
Warrants issued and outstanding (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	1,080,349	1,080,349	1,080,349	1,082,917
Series E-1 convertible preferred stock warrants (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	35,544,141	35,544,141	35,544,141	35,544,141
Series F convertible preferred stock warrants (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total common stock equivalents excluded from diluted net loss per common share computation (in shares)	177,720,704	177,720,704	177,720,704	177,720,704

Convertible Preferred Stock, _3

Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit - Additional Information (Details) $ / shares in Units, $ in Thousands	Dec. 16, 2016	Feb. 16, 2016	Jun. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2019USD ($)time$ / sharesshares	Jun. 30, 2018USD ($)	Dec. 31, 2018$ / sharesshares	Sep. 20, 2017$ / sharesshares	Feb. 27, 2017$ / sharesshares
Class of Stock [Line Items]
Common and preferred stock, shares authorized (in shares)							1,069,760,848
Common stock, shares authorized (in shares)			625,000,000	625,000,000		625,000,000	625,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01		$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)			444,760,848	444,760,848		444,760,848	444,760,848
Preferred stock, par value (in dollars per share) | $ / shares							$ 0.01
Common stock, shares issued (in shares)			71,502,461	71,502,461		71,411,145
Common stock, shares outstanding (in shares)			70,566,526	70,566,526		70,475,210
Common Stock
Class of Stock [Line Items]
Stock split conversion ratio		5
Exercise of stock options (in shares)				91,316
Cash proceeds | $				$ 11
Series E-1
Class of Stock [Line Items]
Warrant to purchase (in of shares)								15,277,006
Liquidation preference (in dollars per share) | $ / shares			$ 0.84	$ 0.84
Warrant expiration period	10 years
Income (expense) amount | $				$ (1,100)	$ 1,000
Preferred stock, shares authorized (in shares)			35,544,141	35,544,141
Series E-2
Class of Stock [Line Items]
Preferred stock, liquidation preference, conversion basis				0.666666666666667
Preferred stock, liquidation preference, conversion basis, after payment				0.333333333333333
Liquidation preference (in dollars per share) | $ / shares			$ 0.84	$ 0.84
Preferred stock, shares authorized (in shares)			16,858,078	16,858,078
Series F
Class of Stock [Line Items]
Exercise price (in dollars per share) | $ / shares								$ 0.01
Preferred stock, liquidation preference, conversion basis				0.666666666666667
Preferred stock, liquidation preference, conversion basis, after payment				0.333333333333333
Liquidation preference (in dollars per share) | $ / shares			$ 0.84	$ 0.84
Income (expense) amount | $			$ 3,600	$ (4,300)
Preferred stock, shares authorized (in shares)			177,720,707	177,720,707
Series G
Class of Stock [Line Items]
Voting power (at least)				60.00%
Liquidation preference (in dollars per share) | $ / shares			$ 1.34	$ 1.34
Preferred stock, shares authorized (in shares)			37,249,497	37,249,497
Series B
Class of Stock [Line Items]
IPO value (at least) | $				$ 2,000,000
Aggregate proceeds (at least) | $				$ 100,000
Voting power (at least)				60.00%
Liquidation preference (in dollars per share) | $ / shares			$ 0.60	$ 0.60
Preferred stock, shares authorized (in shares)			35,775,880	35,775,880
Series A-1
Class of Stock [Line Items]
Voting power (at least)				14.00%
Conversion ratio			1,000,000	1,000,000
Liquidation preference (in dollars per share) | $ / shares			$ 2	$ 2
Series A
Class of Stock [Line Items]
Conversion ratio			1	1
Times the original issue | time				3
Liquidation preference (in dollars per share) | $ / shares			$ 0.29	$ 0.29
Preferred stock, shares authorized (in shares)			68,558,220	68,558,220
Series C
Class of Stock [Line Items]
Liquidation preference (in dollars per share) | $ / shares			$ 2.87	$ 2.87
Preferred stock, shares authorized (in shares)			24,404,770	24,404,770
Series D
Class of Stock [Line Items]
Liquidation preference (in dollars per share) | $ / shares			$ 6.91	$ 6.91
Consortium Purchase Agreement | Series F Warrant
Class of Stock [Line Items]
Warrant to purchase (in of shares)								177,720,706
Exercise price (in dollars per share) | $ / shares								$ 0.01

Convertible Preferred Stock, _4

Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit - Summary of Shares Authorized, Issued, Outstanding, Par Value and Liquidation Preference of Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Sep. 20, 2017
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)	444,760,848	444,760,848	444,760,848
Convertible preferred stock, shares outstanding (in shares)	214,637,925
Convertible preferred stock, shares issued (in shares)	214,637,925	214,637,925
Liquidation Preference (Outstanding Shares)	$ 375,952	$ 375,952
Series A
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	68,558,220
Convertible preferred stock, shares outstanding (in shares)	68,558,220
Convertible preferred stock, shares issued (in shares)	68,558,220
Liquidation Preference (Outstanding Shares)	$ 19,774
Series A-1
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	24,760,915
Convertible preferred stock, shares outstanding (in shares)	24,760,915
Convertible preferred stock, shares issued (in shares)	24,760,915
Liquidation Preference (Outstanding Shares)	$ 49,522
Series B
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	35,775,880
Convertible preferred stock, shares outstanding (in shares)	35,775,880
Convertible preferred stock, shares issued (in shares)	35,775,880
Liquidation Preference (Outstanding Shares)	$ 21,581
Series C
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	24,404,770
Convertible preferred stock, shares outstanding (in shares)	24,404,770
Convertible preferred stock, shares issued (in shares)	24,404,770
Liquidation Preference (Outstanding Shares)	$ 70,075
Series D
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	23,888,640
Convertible preferred stock, shares outstanding (in shares)	23,888,640
Convertible preferred stock, shares issued (in shares)	23,888,640
Liquidation Preference (Outstanding Shares)	$ 165,000
Series E-1
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	35,544,141
Convertible preferred stock, shares outstanding (in shares)	0
Convertible preferred stock, shares issued (in shares)	0
Liquidation Preference (Outstanding Shares)	$ 0
Series E-2
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	16,858,078
Convertible preferred stock, shares outstanding (in shares)	0
Convertible preferred stock, shares issued (in shares)	0
Liquidation Preference (Outstanding Shares)	$ 0
Series F
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	177,720,707
Convertible preferred stock, shares outstanding (in shares)	3
Convertible preferred stock, shares issued (in shares)	3
Liquidation Preference (Outstanding Shares)	$ 0
Series G
Class of Stock [Line Items]
Convertible preferred stock, par value (in dollars per share)	$ 0.01
Convertible preferred stock, shares authorized (in shares)	37,249,497
Convertible preferred stock, shares outstanding (in shares)	37,249,497
Convertible preferred stock, shares issued (in shares)	37,249,497
Liquidation Preference (Outstanding Shares)	$ 50,000

Convertible Preferred Stock, _5

Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit - Schedule of Assumptions Used (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Volatility | Series E-1
Class of Stock [Line Items]
Fair value assumptions	0.40	0.40
Volatility | Series F
Class of Stock [Line Items]
Fair value assumptions	0.40	0.40
Risk-free interest rate | Series E-1
Class of Stock [Line Items]
Fair value assumptions	0.0189	0.0262
Risk-free interest rate | Series F
Class of Stock [Line Items]
Fair value assumptions	0.0190	0.0263
Remaining contractual term (in years) | Series E-1
Class of Stock [Line Items]
Remaining contractual term (in years)	7 years 6 months 18 days	8 years 14 days
Remaining contractual term (in years) | Series F
Class of Stock [Line Items]
Remaining contractual term (in years)	7 years 7 months 28 days	8 years 1 month 28 days
Dividend yield | Series E-1
Class of Stock [Line Items]
Fair value assumptions	0	0
Dividend yield | Series F
Class of Stock [Line Items]
Fair value assumptions	0	0

Convertible Preferred Stock, _6

Convertible Preferred Stock, Warrant Liability and Stockholders’ Deficit - Warrant Liability (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Warrants or Rights [Roll Forward]
Change in Fair Value	$ 5,327	$ (8,602)
Convertible Preferred Stock Warrant
Warrants or Rights [Roll Forward]
Balance at January 1, 2019	143,679
Warrants Vested	17,553
Change in Fair Value	5,327
Balance at June 30, 2019	$ 166,559

Share Based Incentive Plan an_3

Share Based Incentive Plan and Compensation - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options exercisable, maximum period			10 years
Financial statement impact amount			$ 2,850,000	$ 4,584,000
Unamortized expense related to unvested stock-based awards	$ 5,100,000		$ 5,100,000
Dividend yield	0.00%	0.00%	0.00%	0.00%
Unrecognized cost of unvested share-based compensation awards.	$ 0		$ 0
Internal-use software and website development costs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation capitalized	100,000	$ 100,000
Stock option repricing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Financial statement impact amount			100,000
Unamortized expense related to unvested stock-based awards	$ 100,000		$ 100,000
Weighted average vesting period			7 months 6 days
Restricted stock units (in shares)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average vesting period			2 years 2 months 12 days
Vesting period one
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percent			25.00%
Vesting period of the options			1 year
Incremental vesting percent			208.00%
Vesting period two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percent			50.00%
Vesting period of the options			1 year
Incremental vesting percent			208.00%
Vesting period three
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percent			50.00%
Vesting period of the options			2 years
Incremental vesting percent			208.00%
Vesting period four
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental vesting percent			278.00%
2015 Stock Option Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options made available in pool (in shares)	95,236,266		95,236,266
Shares available for grant under the plan (in shares)	20,560,436		20,560,436
2005 Stock Plan | Stock options issued and outstanding (in shares)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant under the plan (in shares)	0		0

Share Based Incentive Plan an_4

Share Based Incentive Plan and Compensation - Summarized Option Activity under Option Plan (Details) - 2005 Stock Plan and 2015 Stock Option Plan - $ / shares	6 Months Ended
	Jun. 30, 2019
Options Issued and Outstanding
Options Issued and Outstanding, Beginning Balance (in shares)	71,021,698
Options Issued and Outstanding, Options issued (in shares)	6,682,948
Options Issued and Outstanding, Options exercised - vested (in shares)	(91,316)
Options Issued and Outstanding, Options forfeited (in shares)	(2,136,356)
Options Issued and Outstanding, Ending balance (in shares)	75,476,974
Options Issued and Outstanding, Options vested and expected to vest (in shares)	62,463,510
Options Issued and Outstanding, Options vested and/or exercisable (in shares)	46,213,667
Weighted- Average Exercise Price
Weighted-Average Exercise Price, Beginning balance (in dollars per share)	$ 0.33
Weighted-Average Exercise Price, Options issued (in dollars per share)	0.30
Weighted-Average Exercise Price, Options exercised - vested (in dollars per share)	0.12
Weighted-Average Exercise Price, Options forfeited (in dollars per share)	0.46
Weighted-Average Exercise Price, Ending balance (in dollars per share)	0.32
Weighted-Average Exercise Price, Options vested and expected to vest (in dollars per share)	0.32
Weighted-Average Exercise Price, Options vested and/or exercisable (in dollars per share)	$ 0.27

Share Based Incentive Plan an_5

Share Based Incentive Plan and Compensation - Additional Information Regarding Common Stock Options Outstanding (Details) - Stock options issued and outstanding (in shares)	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	$ 0.02
Range of Exercise Prices, Maximum (in dollars per share)	$ 1.13
Number Outstanding (in shares) | shares	75,476,974
Weighted – Avg. Remaining Life (In years)	7 years 10 months 13 days
Weighted Avg. Exercise Price (in dollars per share)	$ 0.32
Number Vested and Exercisable (in shares) | shares	46,213,667
Weighted-Avg. Exercise Price (in dollars per share)	$ 0.27
0.02 - 0.20
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	0.02
Range of Exercise Prices, Maximum (in dollars per share)	$ 0.20
Number Outstanding (in shares) | shares	4,062,390
Weighted – Avg. Remaining Life (In years)	4 years 6 months 18 days
Weighted Avg. Exercise Price (in dollars per share)	$ 0.11
Number Vested and Exercisable (in shares) | shares	4,062,390
Weighted-Avg. Exercise Price (in dollars per share)	$ 0.11
0.21 - 0.50
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	0.21
Range of Exercise Prices, Maximum (in dollars per share)	$ 0.50
Number Outstanding (in shares) | shares	51,346,996
Weighted – Avg. Remaining Life (In years)	7 years 10 months 6 days
Weighted Avg. Exercise Price (in dollars per share)	$ 0.26
Number Vested and Exercisable (in shares) | shares	34,178,267
Weighted-Avg. Exercise Price (in dollars per share)	$ 0.23
0.51 - 1.13
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum (in dollars per share)	0.51
Range of Exercise Prices, Maximum (in dollars per share)	$ 1.13
Number Outstanding (in shares) | shares	20,067,588
Weighted – Avg. Remaining Life (In years)	8 years 7 months 6 days
Weighted Avg. Exercise Price (in dollars per share)	$ 0.54
Number Vested and Exercisable (in shares) | shares	7,973,010
Weighted-Avg. Exercise Price (in dollars per share)	$ 0.54

Share Based Incentive Plan an_6

Share Based Incentive Plan and Compensation - Fair Value of Stock Option Awards (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair value of stock option awards [Abstract]
Volatility of common stock	46.72%	44.43%	46.72%	44.12%
Risk-free interest rate	2.28%	2.85%	2.28%	2.75%
Expected life (in years)	5 years 10 months 24 days	6 years	5 years 10 months 24 days	6 years
Dividend yield	0.00%	0.00%	0.00%	0.00%

Share Based Incentive Plan an_7

Share Based Incentive Plan and Compensation - Summarized Activities for the Company's RSU's (Details) - Restricted stock units (in shares)	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Number of Shares
Restricted stock unit, Unvested, Beginning Balance (in shares) | shares	4,856,141
Forfeited (in shares) | shares	(15,500)
Restricted stock unit, Unvested, Ending Balance (in shares) | shares	4,840,641
Weighted-Average Grant Date Fair Value
Restricted stock unit, Unvested, Beginning Balance (in dollars per share) | $ / shares	$ 0.96
Forfeited (in dollars per share) | $ / shares	2.18
Restricted stock unit, Unvested, Ending Balance (in dollars per share) | $ / shares	$ 0.96

Share Based Incentive Plan an_8

Share Based Incentive Plan and Compensation - Stock Based Compensation Included in Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock based compensation	$ 1,235	$ 2,253	$ 2,850	$ 4,584
Origination and servicing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock based compensation	108	241	304	456
Sales and marketing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock based compensation	63	108	145	216
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock based compensation	$ 1,064	$ 1,904	$ 2,401	$ 3,912

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Taxes [Line Items]
Income tax expense	$ 29,000	$ 9,000	$ 58,000	$ 19,000
Prosper Funding LLC
Income Taxes [Line Items]
Income tax expense			$ 0	0
Net effective tax rate			0.00%
Valuation ​Allowance of Deferred ​Tax ​Assets
Income Taxes [Line Items]
Income tax expense			$ 0	$ 0

Consortium Purchase Agreement -

Consortium Purchase Agreement - Narrative (Details) - Consortium Purchase Agreement - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Feb. 27, 2017
Other Commitments [Line Items]
Commitment to purchase borrower loans (up to)	$ 5,000,000		$ 5,000,000
Loans acquired	3,303,283	$ 3,067,332
Amount settled with rebates	$ 300,000
Series F Warrant
Other Commitments [Line Items]
Warrant to purchase up to (in shares)			3
Warrant to purchase (in of shares)			177,720,706
Exercise price (in dollars per share)			$ 0.01

Consortium Purchase Agreement_2

Consortium Purchase Agreement - Consortium Purchase Agreement Table (Details) - Consortium Purchase Agreement - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Other Commitments [Line Items]
Loans Acquired	$ 3,303,283	$ 3,067,332
Loans Purchased by the Consortium	$ 235,951
Series F Warrant
Other Commitments [Line Items]
Warrants Vested (in shares)	177,720,706	154,912,980
Warrants vested during the year (in shares)	22,807,726

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Lessee, Lease, Description [Line Items]
Rental expense under operating lease arrangements		$ 1,400	$ 1,000	$ 2,700	$ 2,100
Sublease income		200		$ 500
Minimum sublease rentals						$ 5,300
Right-of-use asset obtained in exchange for operating lease liability	$ 21,600	$ 21,630
Minimum
Lessee, Lease, Description [Line Items]
Operating lease contract term		1 year		1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease contract term		8 years		8 years

Leases - Operating Lease Right-

Leases - Operating Lease Right-of-Use Assets (Details) $ in Thousands	Jun. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Gross Carrying Value	$ 16,138
Accumulated Amortization	1,631
Net Carrying Value	14,507
ROU Assets - Office buildings
Lessee, Lease, Description [Line Items]
Gross Carrying Value	15,846
Accumulated Amortization	1,517
Net Carrying Value	14,329
ROU Assets - Other
Lessee, Lease, Description [Line Items]
Gross Carrying Value	292
Accumulated Amortization	114
Net Carrying Value	$ 178

Leases - Schedule of Lease Matu

Leases - Schedule of Lease Maturity (Details) $ in Thousands	Jun. 30, 2019USD ($)
Schedule of Lease Maturity
Remainder of 2019	$ 2,268
2020	5,240
2021	5,134
2022	5,018
2023	1,567
Thereafter	2,546
Total future minimum lease payments	21,773
Less imputed interest	(2,586)
Total	19,187
Future Minimum Lease Payments
2019	4,536
2020	4,683
2021	4,456
2022	4,319
2023	847
Thereafter	387
Total future operating lease obligations	$ 19,228

Leases - Other Information Rela

Leases - Other Information Related to Leases (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Jun. 30, 2019
Leases [Abstract]
Cash paid for operating leases year-to-date		$ 3,026
Right-of-use asset obtained in exchange for operating lease liability	$ 21,600	$ 21,630
Weighted Average Remaining Lease Term		4 years 6 months 14 days
Weighted Average Discount Rate		5.53%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	Apr. 19, 2019	Apr. 30, 2019	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Commitments And Contingencies [Line Items]
Designated Amount for loans (less than)			$ 143,500	$ 143,500
Minimum fee, remaining in current year			900,000	900,000
Minimum fee, year two			1,700,000	1,700,000
Minimum fee, year three			1,700,000
Minimum fee, year four			100,000
Minimum liquidity covenant			15,000,000	15,000,000
Purchase of borrower loans			29,800,000
Maximum potential future payments			3,300,000,000	3,300,000,000
Accrued repurchase and indemnification obligation			1,000,000	1,000,000	$ 900,000
Amount awarded to other party	$ 3,000,000
Accrued penalty		$ 3,000,000
Prosper Funding LLC
Commitments And Contingencies [Line Items]
Designated Amount for loans (less than)			143,500	143,500
Minimum fee, remaining in current year			900,000	900,000
Minimum fee, year two			1,700,000	1,700,000
Minimum fee, year three			1,700,000
Minimum fee, year four			100,000
Minimum liquidity covenant			15,000,000	15,000,000
Purchase of borrower loans				29,800,000
Maximum potential future payments			3,700,000,000	3,700,000,000
Accrued repurchase and indemnification obligation			1,000,000	$ 1,000,000	$ 900,000
Amount awarded to other party	$ 3,000,000
Accrued penalty			$ 3,000,000

Related Parties - Additional In

Related Parties - Additional Information (Details)	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Minimum percentage of voting securities considered for related parties	10.00%
Minimum percentage of stock holders considered for related parties	10.00%

Related Parties - Aggregate Amo

Related Parties - Aggregate Amount of Notes Purchased and the Income Earned (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30,	$ 104		$ 110		$ 219	$ 217
Interest Earned on Notes and Borrower Loans Three Months Ended June 30,	13		11		26	23
Notes balance	623				623		$ 601
Prosper Funding LLC
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30,	5		3		11	9
Interest Earned on Notes and Borrower Loans Three Months Ended June 30,	1	$ 2	0	$ 1	2	1
Notes balance	34				34		32
Executive officers and management
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30,	5		3		11	9
Interest Earned on Notes and Borrower Loans Three Months Ended June 30,	1		0		2	1
Notes balance	34				34		32
Executive officers and management | Prosper Funding LLC
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30,	5		3		11	9
Interest Earned on Notes and Borrower Loans Three Months Ended June 30,	1		0		2	1
Notes balance	34				34		32
Directors (excluding executive officers and management)
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30,	99		107		208	208
Interest Earned on Notes and Borrower Loans Three Months Ended June 30,	12		11		24	22
Notes balance	589				589		569
Directors (excluding executive officers and management) | Prosper Funding LLC
Related Party Transaction [Line Items]
Aggregate Amount of Notes and Borrower Loans Purchased Three Months Ended June 30,	0	$ 0	0	0	0	0
Interest Earned on Notes and Borrower Loans Three Months Ended June 30,	0		$ 0	$ 0	0	$ 0
Notes balance	$ 0				$ 0		$ 0

Significant Concentrations (Det

Significant Concentrations (Details)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Concentration Risk [Line Items]
Percentage of funds originating in channel	93.00%	93.00%
Party One
Concentration Risk [Line Items]
Percentage of loan purchased	17.00%	52.00%