Wayfair (W) 10-Q 14 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 07, 2014	Oct. 07, 2014
		Class A common stock	Class B common stock
Entity Registrant Name	'Wayfair Inc.	'	'
Entity Central Index Key	'0001616707	'	'
Document Type	'10-Q	'	'
Document Period End Date	30-Sep-14	'	'
Amendment Flag	'false	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Current Reporting Status	'No	'	'
Entity Filer Category	'Non-accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	12,650,000	70,265,213
Document Fiscal Period Focus	'Q3	'	'
Document Fiscal Year Focus	'2014	'	'

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets	'	'
Cash and cash equivalents	$30,307	$65,289
Short-term investments	100,054	50,019
Accounts receivable, net of allowance	5,314	7,689
Inventories	21,118	14,963
Prepaid expenses and other current assets	37,839	25,167
Total current assets	194,632	163,127
Property and equipment, net	50,027	22,088
Intangible assets, net	3,099	3,919
Goodwill	4,629	5,165
Restricted cash	3,849	826
Other noncurrent assets	4,292	1,175
Total assets	260,528	196,300
Current liabilities	'	'
Accounts payable	87,686	102,153
Accrued expenses	32,697	19,239
Deferred revenue	21,828	13,397
Due to related party	1,787	1,878
Other current liabilities	12,587	8,342
Total current liabilities	156,585	145,009
Other liabilities	12,850	944
Total liabilities	169,435	145,953
Commitments and contingencies (Note 7)	'	'
Members' deficit/Stockholders' equity:	'	'
Common members' (deficit)/Retained earnings	-305,983	-190,511
Accumulated other comprehensive loss	-387	-328
Total member's deficit/stockholders' equity	-306,370	-190,839
Total liabilities and stockholders' equity	260,528	196,300
Series A convertible redeemable preferred units	'	'
Current liabilities	'	'
Convertible redeemable preferred units	240,234	241,186
Series B convertible redeemable preferred units	'	'
Current liabilities	'	'
Convertible redeemable preferred units	157,229	'
ProForma	'	'
Current assets	'	'
Cash and cash equivalents	265,959	'
Short-term investments	100,054	'
Accounts receivable, net of allowance	5,314	'
Inventories	21,118	'
Prepaid expenses and other current assets	37,839	'
Total current assets	430,284	'
Property and equipment, net	50,027	'
Intangible assets, net	3,099	'
Goodwill	4,629	'
Restricted cash	3,849	'
Other noncurrent assets	4,292	'
Total assets	496,180	'
Current liabilities	'	'
Accounts payable	87,686	'
Accrued expenses	34,484	'
Deferred revenue	21,828	'
Other current liabilities	12,587	'
Total current liabilities	156,585	'
Other liabilities	13,185	'
Total liabilities	169,770	'
Commitments and contingencies (Note 7)	'	'
Members' deficit/Stockholders' equity:	'	'
Additional paid-in capital	361,217	'
Common members' (deficit)/Retained earnings	-34,503	'
Accumulated other comprehensive loss	-387	'
Total member's deficit/stockholders' equity	326,410	'
Total liabilities and stockholders' equity	496,180	'
ProForma | Class A common stock	'	'
Members' deficit/Stockholders' equity:	'	'
Common stock	13	'
ProForma | Class B common stock	'	'
Members' deficit/Stockholders' equity:	'	'
Common stock	$70	'

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Common units, par value (in dollars per unit)	0	0
Common units, shares authorized	81,365,954	74,328,124
Common units, shares issued	43,784,060	44,904,110
Common units, shares outstanding	43,784,060	44,904,110
Class A common stock	'	'
Common stock, shares authorized	0	0
Common stock, shares issued	0	0
Common stock, shares outstanding	0	0
Class B common stock	'	'
Common stock, shares authorized	0	0
Common stock, shares issued	0	0
Common stock, shares outstanding	0	'
Series A convertible redeemable preferred units	'	'
Convertible redeemable preferred units, par value (in dollars per unit)	0	0
Convertible redeemable preferred units, shares authorized	21,551,801	21,551,801
Convertible redeemable preferred units, shares issued	21,551,801	21,551,801
Convertible redeemable preferred units, shares outstanding	21,551,801	'
Convertible redeemable preferred units, liquidation preference (in dollars)	240.2	'
Series B convertible redeemable preferred units	'	'
Convertible redeemable preferred units, par value (in dollars per unit)	0	0
Convertible redeemable preferred units, shares authorized	5,995,133	0
Convertible redeemable preferred units, shares issued	5,995,133	0
Convertible redeemable preferred units, shares outstanding	5,995,133	'
Convertible redeemable preferred units, liquidation preference (in dollars)	157.2	'
ProForma	'	'
Common units, shares authorized	0	'
Common units, shares issued	0	'
Common units, shares outstanding	0	'
ProForma | Class A common stock	'	'
Common stock, par value (in dollars per unit)	0.001	'
Common stock, shares authorized	500,000,000	'
Common stock, shares issued	12,650,000	'
Common stock, shares outstanding	12,650,000	'
ProForma | Class B common stock	'	'
Common stock, par value (in dollars per unit)	0.001	'
Common stock, shares authorized	164,000,000	'
Common stock, shares issued	70,265,213	'
Common stock, shares outstanding	70,265,213	'
ProForma | Series A convertible redeemable preferred units	'	'
Convertible redeemable preferred units, shares authorized	0	'
Convertible redeemable preferred units, shares issued	0	'
Convertible redeemable preferred units, shares outstanding	0	'
ProForma | Series B convertible redeemable preferred units	'	'
Convertible redeemable preferred units, shares authorized	0	'
Convertible redeemable preferred units, shares issued	0	'
Convertible redeemable preferred units, shares outstanding	0	'

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Condensed Consolidated Statements of Operations	'	'	'	'
Net revenue	$336,188	$237,302	$910,332	$620,510
Cost of goods sold	257,161	178,656	697,644	466,993
Gross profit	79,027	58,646	212,688	153,517
Operating expenses:	'	'	'	'
Sales and marketing	77,439	46,602	215,667	119,316
General and administrative	25,218	15,530	71,573	45,544
Amortization of acquired intangible assets	249	184	748	290
Total operating expenses	102,906	62,316	287,988	165,150
Loss from operations	-23,879	-3,670	-75,300	-11,633
Interest income, net	89	61	222	185
Other (expense) income, net	-304	579	-400	75
Loss before income taxes	-24,094	-3,030	-75,478	-11,373
Provision for income taxes	-49	-1	-66	4
Net loss	-24,143	-3,031	-75,544	-11,369
Accretion of convertible redeemable preferred units	-4,748	-4,673	-16,503	-20,621
Net loss attributable to common unit holders	($28,891)	($7,704)	($92,047)	($31,990)
Net loss attributable to common unit holders per unit - basic and diluted (in dollars per unit)	($0.71)	($0.19)	($2.26)	($0.77)
Weighted average number of common units outstanding used in computing per share amounts - basic and diluted (in units)	40,512,544	41,367,115	40,721,540	41,304,048

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Condensed Consolidated Statements of Comprehensive Loss	'	'	'	'
Net loss	($24,143)	($3,031)	($75,544)	($11,369)
Other comprehensive loss:	'	'	'	'
Foreign currency translation adjustments	-67	-754	-59	-170
Comprehensive loss	($24,210)	($3,785)	($75,603)	($11,539)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities	'	'
Net loss	($75,544)	($11,369)
Adjustments to reconcile net loss to net cash provided by operating activities, net of acquisition:	'	'
Depreciation and amortization	14,438	9,352
Equity based compensation	5,528	'
Other non-cash adjustments	888	11
Changes in operating assets and liabilities:	'	'
Accounts receivable and customer refunds payable	2,376	-6,840
Inventories	-6,155	-8,115
Prepaid expenses and other current assets	-12,721	-8,070
Due to related party	-96	-241
Accounts payable and accrued expenses	-1,012	9,095
Deferred revenue and other liabilities	24,578	9,483
Other assets	-3,117	269
Net cash used in operating activities	-50,837	-6,425
Cash flows from investing activities	'	'
Purchase of short-term investments	-110,000	-40,000
Sale and maturities of short-term investments	59,964	22,963
Purchase of property and equipment	-31,168	-4,421
Site and software development costs	-10,643	-6,412
Cash paid for acquisition	'	-3,741
Other investing activities, net	-3,015	-86
Net cash used in investing activities	-94,862	-31,697
Cash flows from financing activities	'	'
Repurchase of common units	-23,500	'
Repurchase of employee equity	-5,528	'
Net cash provided by financing activities	110,746	'
Effect of exchange rate changes on cash and cash equivalents	-29	5
Net decrease in cash and cash equivalents	-34,982	-38,117
Cash and cash equivalents	'	'
Beginning of period	65,289	77,861
End of period	30,307	39,744
Supplemental disclosure of cash flow information	'	'
Income tax payments	27	19
Supplemental disclosure of non-cash investing activities	'	'
Issuance of common units in connection with acquisition	'	1,194
Purchase of property and equipment included in accounts payable and accrued expenses and in other liabilities	2,079	396
Supplemental disclosure of non-cash financing activities	'	'
Accretion of preferred unit dividends	16,503	20,621
Series A convertible redeemable preferred units	'	'
Cash flows from financing activities	'	'
Dividends paid to Series A convertible redeemable preferred	-15,000	'
Series B convertible redeemable preferred units	'	'
Cash flows from financing activities	'	'
Net proceeds from issuance of Series B convertible redeemable preferred units	$154,774	'

Summary_of_Business_Operations

Summary of Business Operations and Basis of Presentation	9 Months Ended
	Sep. 30, 2014
Summary of Business Operations and Basis of Presentation	'
Summary of Business Operations and Basis of Presentation	'
	1. Summary of Business Operations and Basis of Presentation
	Wayfair LLC is a Delaware limited liability company and a wholly-owned subsidiary of Wayfair Inc. (together with Wayfair LLC, the “Company”), which is the registrant filing this Quarterly Report on Form 10-Q. Prior to the effectiveness of Wayfair Inc.’s registration statement on Form S-1 related to its initial public offering in October 2014, Wayfair LLC was the principal operating entity. In connection with the initial public offering of the Company, Wayfair LLC completed an internal restructuring pursuant to which Wayfair LLC became a wholly-owned subsidiary of Wayfair Inc. and the holders of equity interests in Wayfair LLC became stockholders of Wayfair Inc. Because the internal restructuring was not completed as of September 30, 2014 and Wayfair Inc. had no substantial assets or activities (other than activities relating to its formation and initial public offering) as of such time, the consolidated financial statements and these accompanying notes refer primarily to Wayfair LLC, unless otherwise noted.  The Company is an e-commerce business offering visually inspiring browsing, compelling merchandising, easy product discovery and attractive prices for over seven million products from over 7,000 suppliers across distinct brands — Wayfair.com, Joss & Main, AllModern, DwellStudio, and Birch Lane. In addition to generating net revenue through Direct Retail sales, which includes all sales generated primarily through the Company’s websites, mobile-optimized websites, and mobile applications (“sites”), net revenue is also generated through sites operated by third parties and through third-party advertising distribution providers that pay the Company based on the number of advertisement related clicks, actions, or impressions for advertisements placed on the Company’s sites.
	Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s prospectus dated October 1, 2014 filed with the SEC pursuant to Rule 424(b) under the Securities Act of 1933, as amended, on October 2, 2014.
	The consolidated balance sheet data as of December 31, 2013 was derived from audited financial statements. The accompanying consolidated balance sheet as of September 30, 2014, the consolidated statements of operations, consolidated statements of comprehensive loss, and consolidated statements of cash flows for the periods ended September 30, 2014 and 2013 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited consolidated financial statements and in the opinion of management, reflect all adjustments, consisting of only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of September 30, 2014 and results of operations and cash flows for the periods ended September 30, 2014 and 2013. The financial data and the other information disclosed in these notes to the condensed consolidated financial statements related to these periods are unaudited. Operating results for the three and nine months ended September 30, 2014 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2014, or for any other period. The condensed consolidated results of operations and cash flows for the nine months ended September 30, 2014 are not necessarily indicative of the results of operations and cash flows that may be expected for the year ending December 31, 2014.
	Unaudited Pro Forma Balance Sheet as of September 30, 2014
	On October 7, 2014, the Company completed its initial public offering (the “IPO”) of 12,650,000 shares of its Class A common stock at a public offering price of $29.00  per share, of which 10,500,000 shares were sold by the Company and 2,150,000 shares were sold by selling stockholders, including 1,650,000 shares pursuant to the underwriters’ option to purchase additional shares, resulting in net proceeds to the Company of approximately $282.7 million, after deducting underwriting discounts and estimated offering expenses. The Company did not receive any proceeds from the sale of shares by the selling stockholders.
	On October 1, 2014, in anticipation of the IPO, the Company completed an internal restructuring (the “corporate reorganization”). Pursuant to the corporate reorganization, Wayfair LLC became a wholly-owned subsidiary of Wayfair Inc., and the holders of equity interests in Wayfair LLC became stockholders of Wayfair Inc.  Wayfair Inc. was incorporated as a Delaware corporation on August 8, 2014. As of September 30, 2014, Wayfair Inc. had not engaged in any business or other activities except in connection with its formation and in preparation for the IPO.
	The unaudited pro forma balance sheet as of September 30, 2014, reflects the following:
	(i) net proceeds from the IPO of $282.7 million after deducting the underwriting discount and estimated offering expenses, (ii) a net adjustment to deferred income tax liabilities of $0.3 million in connection with the Company’s corporate reorganization, (iii) an adjustment of $14.4 million to reduce the carrying value of the participating preferred units to reflect conversion value assuming the security was converted on the balance sheet date, (iv) a distribution of $24.5 million of cash to the Company’s Series A convertible preferred stockholders upon completion of the IPO equal to the members’ distribution payable balance, (v) an adjustment of $48.6 million to give effect to equity based compensation expense associated with common option units, deferred units and restricted common units that have satisfied the service condition and (vi) the net issuance of 1,129,095 shares of Class B common stock issuable upon the vesting of outstanding deferred units upon completion of the IPO, net of minimum tax withholding obligations and the associated payment of cash, which amount was approximately $22.6 million. All of the aforementioned adjustments have been reflected in the pro forma consolidated balance sheet as if these events all occurred on September 30, 2014 and (vii) the reclassification of $1.8 million from due to related party to accrued expenses to reflect the effect of consolidation of SK Retail, which was the majority member of Wayfair LLC prior to the corporate reorganization.
	Summary of Significant Accounting Policies
	Principles of Consolidation
	The accompanying consolidated financial statements include the accounts of Wayfair LLC and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the financial statements, and the reported amounts of revenue and expenses during the reported period. On an ongoing basis, management evaluates these estimates and judgments, including those related to revenue recognition, capitalization of site and software development costs, stock-based compensation, and inventory. Actual results could differ from those estimates.
	Concentrations of Credit Risk
	Financial instruments that subject the Company to credit risk consist of cash and cash equivalents, short-term investments, and accounts receivable. The risk with respect to cash and cash equivalents and short-term investments is minimized by the Company’s policy of investing in financial instruments (i.e., cash equivalents) with short-term maturities issued by highly-rated financial institutions. At times, these balances may exceed federally insured limits; however, to date, the Company has not incurred any losses on these investments. The risk with respect to accounts receivable is managed by the Company through its policy of monitoring the creditworthiness of its customers to which it grants credit terms in the normal course of business. As of September 30, 2014 and December 31, 2013, the Company had $1.4 million and $2.6 million, respectively, in banks located outside the United States.
	Leases
	The Company leases office space in several countries around the world under non-cancelable lease agreements. The Company generally leases its office facilities under operating lease agreements. Office facilities subject to an operating lease and the related lease payments are not recorded on the balance sheet. The terms of certain lease agreements provide for rental payments on a graduated basis, however, the Company recognizes rent expense on a straight-line basis over the lease period in accordance with authoritative accounting guidance. Any lease incentives are recognized as reductions of rental expense on a straight-line basis over the term of the lease. The lease term begins on the date the Company becomes legally obligated for the rent payments or when it takes possession of the office space, whichever is earlier.
	The Company establishes assets and liabilities for the estimated construction costs incurred under lease arrangements where the Company is considered the owner for accounting purposes only, or build-to-suit leases, to the extent the Company is involved in the construction of structural improvements or take construction risk prior to commencement of a lease. Upon occupancy of facilities under build-to-suit leases, the Company assesses whether these arrangements qualify for sales recognition under the sale-leaseback accounting guidance. If the Company continues to be the deemed owner, the facilities are accounted for as financing leases.
	Recent Accounting Pronouncements
	In July 2013, the Financial Accounting Standards Board (“FASB”) issued a new accounting standard update that requires the presentation of certain unrecognized tax benefits as reductions to deferred tax assets rather than as liabilities in the consolidated balance sheets when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The Company adopted this new standard on a prospective basis in the first quarter of fiscal 2014, and the adoption of this accounting standard update did not have a material impact on the Company’s condensed consolidated financial statements.
	In May 2014, the FASB issued new accounting guidance regarding revenue recognition under GAAP. This new guidance will supersede nearly all existing revenue recognition guidance, and is effective for public entities for annual and interim periods beginning after December 31, 2016. Early adoption is not permitted. The Company is currently evaluating the impact of this new guidance on the Company’s condensed consolidated financial statements.
	In August 2014, the FASB issued Accounting Standards Update No. 2014-15, “Presentation of Financial Statements - Going Concern”, which requires management to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures.  ASU 2014-15 is effective for annual periods ending after December 15, 2016 and interim periods thereafter.  Early application is permitted.  The adoption of ASU 2014-15 is not expected to have a material effect on the condensed consolidated financial statements.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Measurements	'
Fair Value Measurements	'
	2. Fair Value Measurements
	The Company’s financial assets and liabilities are measured at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The three levels of inputs used to measure fair value are as follows:
	·         Level 1 — Unadjusted quoted prices in active markets for identical assets or liabilities
	·         Level 2 — Unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs other than quoted prices that are observable or can be corroborated by observable market data for substantially the full-term of the asset or liability
	·         Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the asset or liability
	The following tables set forth the fair value of the Company’s financial assets measured at fair value on a recurring basis as of September 30, 2014 and December 31, 2013 based on the three-tier value hierarchy:
		September 30, 2014
		Total		Level 1		Level 2		Level 3
		(in thousands)
	Cash equivalents
	Money market funds	$	5,071	$	5,071	—		—
	Certificates of deposit	—				—		—
	Short-term investments:
	Certificates of deposit	100,054		100,054		—		—
	Restricted cash
	Money market funds	3,848		3,848		—		—
	Total	$	108,973	$	108,973	$	—	$	—
		December 31, 2013
		Total		Level 1		Level 2		Level 3
		(in thousands)
	Cash equivalents
	Money market funds	$	32,560	$	32,560	—		—
	Short-term investments:
	Certificates of deposit	50,019		50,019		—		—
	Restricted cash
	Money market funds	346		346		—		—
	Total	$	82,925	$	82,925	$	—	$	—

Acquisition_Intangible_assets_

Acquisition, Intangible assets and Goodwill	9 Months Ended
	Sep. 30, 2014
Acquisition, Intangible assets and Goodwill	'
Acquisition, Intangible assets and Goodwill	'
	3. Acquisition, Intangible assets and Goodwill
	Intangible assets consisted of the following as of September 30, 2014 and December 31, 2013 (in thousands):
		Weighted-	September 30, 2014							December 31, 2013
		Average
		Amortization	Gross		Accumulated			Net Book		Gross		Accumulated			Net Book
		Period	Carrying		Amortization			Value		Carrying		Amortization			Value
		(Years)	Value							Value
	Trademarks	5	$	2,008	$	(511	)	$	1,497	$	2,030	$	(219	)	$	1,811
	Customer relationships	5	1,300		(303		)	997		1,300		(108		)	1,192
	Non-compete agreements	5-Mar	109		(44		)	65		110		(19		)	91
	Technology	5	768		(473		)	295		920		(430		)	490
	Other intangibles	3	373		(131		)	242		373		(47		)	326
	Domain names	5	2,684		(2,681		)	3		2,695		(2,686		)	9
	Total		$	7,242	$	(4,143	)	$	3,099	$	7,428	$	(3,509	)	$	3,919

Property_and_Equipment_net

Property and Equipment, net	9 Months Ended
	Sep. 30, 2014
Property and Equipment, net	'
Property and Equipment, net	'
	4. Property and Equipment, net
	Property and equipment, net consists of the following:
		September 30,			December 31,
		2014			2013
		(in thousands)
	Furniture and computer equipment	$	43,087		$	26,218
	Site and software development costs	32,239			23,715
	Leasehold improvements	13,682			1,912
	Construction in progress	25			184
		89,033			52,029
	Less accumulated depreciation and amortization	(39,006		)	(29,941		)
	Property and equipment, net	$	50,027		$	22,088

Accrued_Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2014
Accrued Expenses	'
Accrued Expenses	'
	5. Accrued Expenses
	Accrued expenses consist of the following:
		September 30,		December 31,
		2014		2013
		(in thousands)
	Employee compensation and related benefits	$	11,675	$	7,470
	Marketing	6,979		5,329
	Credit card	4,522		2,173
	Audit, legal and professional fees	1,851		377
	Accrued property, plant and equipment	1,248		—
	Other accrued expenses	6,422		3,890
		$	32,697	$	19,239

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies	'
Commitments and Contingencies	'
	6. Commitments and Contingencies
	Operating Leases
	The Company leases office space under non-cancelable operating leases. These leases expire at various dates through 2024 and include discounted rental periods and fixed escalation clauses, which are amortized straight-line over the terms of the lease.
	In March 2014, the Company expanded the lease of office space in Boston, MA to a total of approximately 275,000 square feet in order to accommodate the expansion of the Company’s headquarters.  The Company began occupying this space in June 2014 and expects to begin occupying additional space with the expansion occurring in June 2015.  This space will result in additional operating lease obligations of $52.1 million payable through 2024. The Company has an option to extend the lease for two successive 5 year periods.
	In September 2014, the Company signed a lease to expand its warehouse space in Ogden, UT by an additional 180,000 square feet which it plans to occupy in 2015. This space will result in additional operating lease obligations of $9.1 million payable through 2022.
	Collection of Sales or Other Similar Taxes
	Based on the location of the Company’s current operations, it collects and remits sales tax in Kentucky, Massachusetts, New York and Utah. The Company does not currently collect sales or other similar taxes for the sale of goods in states where no obligation to collect these taxes is required under applicable law. Several states have presented the Company with assessments, alleging that it is required to collect and remit sales or other similar taxes. The aggregate amount of claims from these states is approximately $11.7 million. The Company does not believe that it was obligated to collect and remit such taxes, and intends to vigorously defend its position. At this time, the Company believes a loss is not probable hence a liability has not been recorded, however, no assurance can be given as to the outcome of this situation.
	Legal Matters
	The Company is subject to legal proceedings and claims in the ordinary course of business. However, the Company is not currently aware of any legal proceedings or claims that it believes will have, individually or in the aggregate, a material adverse effect on the Company’s financial position, results of operations or cash flows.

EquityBased_Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2014
Equity-Based Compensation	'
Equity-Based Compensation	'
	7. Equity-Based Compensation
	In July 2010, the Company established the CSN Stores LLC 2010 Common Unit Plan (the “CSN Plan”). Effective July 1, 2011, the CSN Plan was amended and restated as the Wayfair LLC Amended and Restated 2010 Common Unit Plan (the “2010 Plan”). The 2010 Plan was administered by the board of directors of Wayfair LLC and provided for the issuance of option units, deferred units, and restricted units (all common units), which currently represent Class B common stock of the Company. As of September 30, 2014, the 2010 Plan authorized up to 12,405,879 units to be issued, of which 603,769 units and 1,206,547 units were available for issuance at September 30, 2014 and December 31, 2013, respectively.
	Under the 2010 Plan, the deferred units, common unit options, and restricted common units are subject to two vesting triggers: a service period (typically five years) and the occurrence of a liquidity event, which is defined in the 2010 Plan as either a change of control or an initial public offering. Employees are able to retain provisionally vested units (defined as service period completed) upon departure. The Company made a policy election to consider the liquidity event a performance condition. The Company has determined that the liquidity event performance condition was met upon the Company’s IPO in October 2014 and the Company will recognize approximately $48.6 million related to the provisionally vested units in the fourth quarter of 2014. The common unit options have a contractual life of ten years from the date of issuance, and deferred units have a seven-year life. The restricted common units have no contractual life. All outstanding equity incentive units of Wayfair LLC outstanding immediately prior to the reorganization automatically converted into (i) options to purchase Class B common stock, (ii) shares of our Class B common stock subject to vesting and repurchase provisions or (iii) restricted stock units for our Class B common stock.
	In connection with the reorganization and the IPO in October 2014, the board of directors of Wayfair Inc. took over administration of the 2010 Plan and adopted the 2014 Incentive Award Plan (“2014 Plan”) to grant cash and equity incentive awards to eligible service providers in order to attract, motivate and retain the talent for which the Company competes. The 2014 Plan is administered by the board of directors of Wayfair Inc. with respect to awards to non-employee directors and by the compensation committee with respect to other participants and provides for the issuance of stock options, SARs, restricted stock, RSUs, performance shares, stock payments, cash payments, dividend awards and other incentives.  The 2014 Plan authorizes up to 8,603,066 shares of Class A common stock to be issued, of which no shares had been issued as of September 30, 2014.
	A summary of the status and activity for awards of common option units under the 2010 Plan for the nine months ended September 30, 2014, is as follows:
		Common		Weighted-		Weighted-Average
		Option		Average		Remaining
		Units		Exercise Price		Contractual Term
						(Years)
	Outstanding at December 31, 2013	664,232		$	2.99	6.7
	Repurchased	(9,028	)	$	2.93
	Forfeited/cancelled	(12,201	)	$	3.22
	Outstanding at September 30, 2014	643,003		$	2.98	5.9
	Provisionally vested at September 30, 2014	578,868		$	2.98	5.9
	A summary of the status and activity for awards of restricted common units under the 2010 Plan for the nine months ended September 30, 2014, is as follows:
		Restricted		Weighted-
		Common		Average Grant
		Units		Date Fair Value
	Outstanding at December 31, 2013	3,490,968		$	4.75
	Repurchased	(202,757	)	$	4.75
	Forfeited/cancelled	(16,695	)	$	4.75
	Outstanding at September 30, 2014	3,271,516		$	4.75
	Provisionally vested at September 30, 2014	2,865,700		$	4.75
	A summary of the status and activity for awards of deferred units under the 2010 Plan for the nine months ended September 30, 2014, is as follows:
		Deferred		Weighted-		Weighted-Average
		Common		Average Grant		Remaining
		Units		Date Fair Value		Contractual Term
						(Years)
	Outstanding at December 31, 2013	5,255,113		$	7.95	6
	Granted	1,953,227		$	27.07
	Forfeited/cancelled	(278,856	)	$	12.29
	Outstanding at September 30, 2014	6,929,484		$	14.42	5.6
	Provisionally vested at September 30, 2014	1,749,626		$	5.95	4.8

Segment_and_Geographic_Informa

Segment and Geographic Information	9 Months Ended
	Sep. 30, 2014
Segment and Geographic Information	'
Segment and Geographic Information	'
	8. Segment and Geographic Information
	The Company considers operating segments to be components of the Company in which separate financial information is available that is evaluated regularly by our chief operating decision maker (“CODM”) in managing and accessing the business. The CODM for the Company is the Chief Executive Officer. The CODM reviews financial information presented on a consolidated basis for purposes of making operating decisions, allocating resources and evaluating financial performance. Accordingly, the Company has determined that it has one operating and reportable segment. No country outside of the United States provided greater than 10% of total revenue.
	The Company generates net revenue from Direct Retail sales derived through the Company’s sites and Other sales derived through sites operated by third parties and fees from third-party advertising distribution providers as set forth below:
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
		(in thousands)
	Net revenue
	Direct Retail	$	285,502	$	181,693	$	755,036	$	450,058
	Other	50,686		55,609		155,296		170,452
	Net revenue	$	336,188	$	237,302	$	910,332	$	620,510
	Revenue from external customers for each group of similar products and services are not reported to the CODM. Separate identification of this information for purposes of segment disclosure is impractical, as it is not readily available and the cost to develop it would be excessive.
	The following table sets forth revenue and long-lived assets by geographic area:
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
		(in thousands)
	Geographic net revenue:
	United States	$	314,754	$	221,421	$	851,585	$	581,073
	International	21,434		15,881		58,747		39,437
	Total	$	336,188	$	237,302	$	910,332	$	620,510
		September 30,		December 31,
		2014		2013
		(in thousands)
	Geographic long-lived assets:
	United States	$	48,920	$	21,451
	International	1,107		637
	Total	$	50,027	$	22,088

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Taxes	'
Income Taxes	'
	9. Income Taxes
	Wayfair LLC is organized as a limited liability company and taxed as a partnership under the Internal Revenue Code, and accordingly, no provision for federal or state and local income taxes is made on income since the members are individually liable for federal and state and local income taxes on their share of the Company’s earnings. However, the Company is responsible for distributing monies to pay tax liabilities to its members if due, including SK Retail, which was its majority member prior to the corporate reorganization. In addition, the Company is responsible for making distributions to SK Retail for corporate taxes imposed by the Commonwealth of Massachusetts. Due to the Company incurring a taxable loss during the periods ended September 30, 2014 and 2013, the Company would not have been subject to additional income tax had it paid federal income taxes at the corporate level.
	The Company’s foreign subsidiaries are subject to income tax in those jurisdictions.  The (provision) benefit amounted to $(49,000), $(1,000), $(66,000) and $4,000 in the three and nine months ended September 30, 2014 and 2013 respectively and related to various minimum foreign income tax assessments.
	Upon the completion of the corporate reorganization described in note 1, the Company, will be subject to corporate tax on income.  The Company prepared and provided the unaudited pro forma consolidated balance sheet as if the reorganization from a limited liability company to a corporation in connection with this offering occurred on September 30, 2014. Pro forma deferred income taxes reflect the net tax effects of temporary differences between the pro forma carrying amounts of our tax assets and liabilities calculated for financial reporting purposes and the amounts that would have been calculated for our income tax returns in accordance with tax regulations and the net pro forma tax effects of operating loss and tax credit carryforwards if we had been a taxable entity.
	The ultimate realization of deferred tax assets depends on the generation of sufficient taxable income of the appropriate character and in the appropriate taxing jurisdictions during the future periods in which the related temporary differences become deductible. The Company determined the valuation allowance on pro forma deferred tax assets is in accordance with the accounting standard for income taxes, which require weight of both positive and negative evidence in order to ascertain whether it is more likely than not that the pro forma deferred tax assets would be realized. The Company evaluated all significant available positive and negative evidence, including the existence of cumulative net income, benefits that could be realized from available tax strategies and forecasts of future taxable income, in determining the need for a valuation allowance on pro forma deferred tax assets. After applying the evaluation guidance of the accounting standard for income taxes the Company determined that it was more likely than not that $28.8 million of the pro forma deferred tax assets will not be realized, and as such, a valuation allowance of $28.8 million was required.
	As of September 30, 2014, pro forma tax effected deferred tax assets, net of valuation allowance, and deferred tax liabilities were $7.0 million and $7.3 million respectively. Accordingly the pro forma net deferred tax liability as of September 30, 2014 was determined to be $0.3 million.

Members_Deficit

Members' Deficit	9 Months Ended
	Sep. 30, 2014
Members' Deficit	'
Members' Deficit	'
	10. Members’ Deficit
	Corporate Reorganization
	On October 1, 2014, in anticipation of the IPO, the Company completed a corporate reorganization. Pursuant to the reorganization, Wayfair LLC became a wholly-owned subsidiary of Wayfair Inc., and the holders of equity interests in Wayfair LLC became stockholders of Wayfair Inc.  Wayfair Inc. was incorporated as a Delaware corporation on August 8, 2014. As of September 30, 2014, Wayfair Inc. had not engaged in any business or other activities except in connection with its formation and in preparation for this IPO.
	Preferred Units
	As of September 30, 2014, Wayfair LLC had 21,551,801 Series A convertible redeemable preferred units (“Series A units”) and 5,995,133 million Series B convertible redeemable preferred units (“Series B units”) issued and outstanding. Each holder of Series A and Series B units was entitled to certain rights and privileges. Upon the reorganization and in connection with the IPO in October 2014, all of the outstanding shares of Series A units and Series B units were ultimately converted into 27,546,934 shares of Class B common stock in Wayfair Inc.
	Preferred Stock
	As of September 30, 2014, Wayfair Inc. had no shares of undesignated preferred stock issued or outstanding.  Upon the closing of the IPO in October 2014, Wayfair Inc. authorized 10,000,000 shares of preferred stock, $0.001 par value per share, for future issuance.
	Common Units
	As of September 30, 2014 the Company had 43,784,060 shares of common units outstanding. Upon the corporate reorganization, and in connection with the IPO, all of the outstanding common units were exchanged for shares of common stock and further reclassified into 43,784,060 shares of Class B common stock.  In addition, upon the closing of the IPO in October 2014, Wayfair Inc. issued 1,129,095 shares of Class B common stock upon the vesting of outstanding restricted stock units, net of minimum tax withholding obligations.
	Common Stock
	As of September 30, 2014, Wayfair Inc. had authorized 1,000 shares of common stock all of which were outstanding. Upon the closing of the IPO in October, 2014, Wayfair Inc. authorized 500,000,000 shares of Class A common stock, $0.001 par value per share, and 164,000,000 shares of Class B common stock, $0.001 par value per share, of which 12,650,000 shares of Class A common stock and 70,265,404 shares of Class B common stock were outstanding.  The rights of the holders of Class A common stock and Class B common stock are identical, except with respect to voting and conversion rights. Each share of Class A common stock is entitled to one vote per share. Each share of Class B common stock is entitled to ten votes per share and is convertible into one share of Class A common stock.  Each share of Class B common stock may be converted into one share of Class A common stock at the option of its holder and will be automatically converted into one share of Class A common stock upon transfer thereof, subject to certain exceptions. In addition, upon the date on which the outstanding shares of Class B common stock represent less than 10% of the aggregate number of shares of the then outstanding Class A common stock and Class B common stock, or in the event of the affirmative vote or written consent of holders of at least 662/3% of the outstanding shares of Class B common stock, all outstanding shares of Class B common stock shall convert automatically into Class A common stock.   Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of common stock are entitled to receive dividends out of funds legally available if the Board, in its discretion, determines to issue dividends and then only at the times and in the amounts that the Board may determine.

Net_Loss_per_Common_UnitShare

Net Loss per Common Unit/Share	9 Months Ended
	Sep. 30, 2014
Net Loss per Common Unit/Share	'
Net Loss per Common Unit/Share	'
	11. Net Loss per Common Unit/Share
	Basic and diluted net (loss) income per common unit is presented using the two class method required for participating securities. Holders of the Series A and Series B units are entitled to receive cumulative dividends payable prior and in preference to any dividends on any of the common units of Wayfair LLC. The Company considers its Series A and Series B units to be participating securities and, in accordance with the two class method, earnings allocated to Series A and Series B units and the related number of outstanding participating securities would be excluded from the computation of basic and diluted net income (loss) per common unit.
	Under the two class method, net (loss) income attributable to common unit holders is determined by allocating undistributed earnings between common units and participating securities. Undistributed earnings are calculated as net income (loss) less distributed earnings and accretion of Series A and Series B units. As holders of Series A and Series B units do not have a contractual obligation to share in the losses of Wayfair LLC, the net loss attributable to common unit holders for each period is not allocated between common units and participating securities. Accordingly, Series A and Series B units are excluded from the calculation of basic and diluted net loss per common unit. The Company’s basic and diluted net loss per common unit are the same because the Company has generated net loss to common unit holders and common unit equivalents are excluded from diluted net loss per share because they have an antidilutive impact.
	The following table presents the calculation of basic and diluted net loss per common unit:
		Three months ended September 30,						Nine months ended September 30,
		2014			2013			2014			2013
		(in thousands, except share amount)
	Numerator:
	Net loss	$	(24,143	)	$	(3,031	)	$	(75,544	)	$	(11,369	)
	Accretion of preferred units to redemption value	$	(4,748	)	$	(4,673	)	$	(16,503	)	$	(20,621	)
	Net loss attributable to common unit holders per unit - basic and diluted	$	(28,891	)	$	(7,704	)	$	(92,047	)	$	(31,990	)
	Denominator:
	Weighted average units used for basic and diluted net loss per unit computation	40,512,544			41,367,115			40,721,540			41,304,048
	Net loss per common unit attributable to common unit holders:
	Basic and Diluted	$	(0.71	)	$	(0.19	)	$	(2.26	)	$	(0.77	)
	The following have been excluded from the computation of basic and diluted net loss per share attributable to common stockholders as their effect would have been antidilutive:
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
	Series A convertible redeemable preferred units	21,551,801		21,551,801		21,551,801		21,551,801
	Series B convertible redeemable preferred units	5,995,133		—		5,995,133		—
	Common option units	643,003		665,377		643,003		665,377
	Restricted common units	3,271,516		3,495,010		3,271,516		3,495,010
	Deferred common units	6,929,484		3,959,773		6,929,484		3,959,773
		38,390,937		29,671,961		38,390,937		29,671,961

Summary_of_Business_Operations1

Summary of Business Operations and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2014
Summary of Business Operations and Basis of Presentation	'
Principles of Consolidation	'
	Principles of Consolidation
	The accompanying consolidated financial statements include the accounts of Wayfair LLC and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the financial statements, and the reported amounts of revenue and expenses during the reported period. On an ongoing basis, management evaluates these estimates and judgments, including those related to revenue recognition, capitalization of site and software development costs, stock-based compensation, and inventory. Actual results could differ from those estimates.
Concentrations of Credit Risk	'
	Concentrations of Credit Risk
	Financial instruments that subject the Company to credit risk consist of cash and cash equivalents, short-term investments, and accounts receivable. The risk with respect to cash and cash equivalents and short-term investments is minimized by the Company’s policy of investing in financial instruments (i.e., cash equivalents) with short-term maturities issued by highly-rated financial institutions. At times, these balances may exceed federally insured limits; however, to date, the Company has not incurred any losses on these investments. The risk with respect to accounts receivable is managed by the Company through its policy of monitoring the creditworthiness of its customers to which it grants credit terms in the normal course of business. As of September 30, 2014 and December 31, 2013, the Company had $1.4 million and $2.6 million, respectively, in banks located outside the United States.
Leases	'
	Leases
	The Company leases office space in several countries around the world under non-cancelable lease agreements. The Company generally leases its office facilities under operating lease agreements. Office facilities subject to an operating lease and the related lease payments are not recorded on the balance sheet. The terms of certain lease agreements provide for rental payments on a graduated basis, however, the Company recognizes rent expense on a straight-line basis over the lease period in accordance with authoritative accounting guidance. Any lease incentives are recognized as reductions of rental expense on a straight-line basis over the term of the lease. The lease term begins on the date the Company becomes legally obligated for the rent payments or when it takes possession of the office space, whichever is earlier.
	The Company establishes assets and liabilities for the estimated construction costs incurred under lease arrangements where the Company is considered the owner for accounting purposes only, or build-to-suit leases, to the extent the Company is involved in the construction of structural improvements or take construction risk prior to commencement of a lease. Upon occupancy of facilities under build-to-suit leases, the Company assesses whether these arrangements qualify for sales recognition under the sale-leaseback accounting guidance. If the Company continues to be the deemed owner, the facilities are accounted for as financing leases.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In July 2013, the Financial Accounting Standards Board (“FASB”) issued a new accounting standard update that requires the presentation of certain unrecognized tax benefits as reductions to deferred tax assets rather than as liabilities in the consolidated balance sheets when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The Company adopted this new standard on a prospective basis in the first quarter of fiscal 2014, and the adoption of this accounting standard update did not have a material impact on the Company’s condensed consolidated financial statements.
	In May 2014, the FASB issued new accounting guidance regarding revenue recognition under GAAP. This new guidance will supersede nearly all existing revenue recognition guidance, and is effective for public entities for annual and interim periods beginning after December 31, 2016. Early adoption is not permitted. The Company is currently evaluating the impact of this new guidance on the Company’s condensed consolidated financial statements.
	In August 2014, the FASB issued Accounting Standards Update No. 2014-15, “Presentation of Financial Statements - Going Concern”, which requires management to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures.  ASU 2014-15 is effective for annual periods ending after December 15, 2016 and interim periods thereafter.  Early application is permitted.  The adoption of ASU 2014-15 is not expected to have a material effect on the condensed consolidated financial statements.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Measurements	'
Schedule of the fair value of the Company's financial assets measured at fair value on a recurring basis based on the three-tier value hierarchy	'
		September 30, 2014
		Total		Level 1		Level 2		Level 3
		(in thousands)
	Cash equivalents
	Money market funds	$	5,071	$	5,071	—		—
	Certificates of deposit	—				—		—
	Short-term investments:
	Certificates of deposit	100,054		100,054		—		—
	Restricted cash
	Money market funds	3,848		3,848		—		—
	Total	$	108,973	$	108,973	$	—	$	—
		December 31, 2013
		Total		Level 1		Level 2		Level 3
		(in thousands)
	Cash equivalents
	Money market funds	$	32,560	$	32,560	—		—
	Short-term investments:
	Certificates of deposit	50,019		50,019		—		—
	Restricted cash
	Money market funds	346		346		—		—
	Total	$	82,925	$	82,925	$	—	$	—

Acquisition_Intangible_assets_1

Acquisition, Intangible assets and Goodwill (Tables)	9 Months Ended
	Sep. 30, 2014
Acquisition, Intangible assets and Goodwill	'
Schedule of intangible assets	'
	Intangible assets consisted of the following as of September 30, 2014 and December 31, 2013 (in thousands):
		Weighted-	September 30, 2014							December 31, 2013
		Average
		Amortization	Gross		Accumulated			Net Book		Gross		Accumulated			Net Book
		Period	Carrying		Amortization			Value		Carrying		Amortization			Value
		(Years)	Value							Value
	Trademarks	5	$	2,008	$	(511	)	$	1,497	$	2,030	$	(219	)	$	1,811
	Customer relationships	5	1,300		(303		)	997		1,300		(108		)	1,192
	Non-compete agreements	5-Mar	109		(44		)	65		110		(19		)	91
	Technology	5	768		(473		)	295		920		(430		)	490
	Other intangibles	3	373		(131		)	242		373		(47		)	326
	Domain names	5	2,684		(2,681		)	3		2,695		(2,686		)	9
	Total		$	7,242	$	(4,143	)	$	3,099	$	7,428	$	(3,509	)	$	3,919

Property_and_Equipment_net_Tab

Property and Equipment, net (Tables)	9 Months Ended
	Sep. 30, 2014
Property and Equipment, net	'
Schedule of property and equipment, net	'
		September 30,			December 31,
		2014			2013
		(in thousands)
	Furniture and computer equipment	$	43,087		$	26,218
	Site and software development costs	32,239			23,715
	Leasehold improvements	13,682			1,912
	Construction in progress	25			184
		89,033			52,029
	Less accumulated depreciation and amortization	(39,006		)	(29,941		)
	Property and equipment, net	$	50,027		$	22,088

Accrued_Expenses_Tables

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2014
Accrued Expenses	'
Schedule of accrued expenses	'
		September 30,		December 31,
		2014		2013
		(in thousands)
	Employee compensation and related benefits	$	11,675	$	7,470
	Marketing	6,979		5,329
	Credit card	4,522		2,173
	Audit, legal and professional fees	1,851		377
	Accrued property, plant and equipment	1,248		—
	Other accrued expenses	6,422		3,890
		$	32,697	$	19,239

EquityBased_Compensation_Table

Equity-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2014
Equity-Based Compensation	'
Summary of status and activity for awards of common option units	'
		Common		Weighted-		Weighted-Average
		Option		Average		Remaining
		Units		Exercise Price		Contractual Term
						(Years)
	Outstanding at December 31, 2013	664,232		$	2.99	6.7
	Repurchased	(9,028	)	$	2.93
	Forfeited/cancelled	(12,201	)	$	3.22
	Outstanding at September 30, 2014	643,003		$	2.98	5.9
	Provisionally vested at September 30, 2014	578,868		$	2.98	5.9
Restricted common units	'
Equity based compensation	'
Summary of the status and activity for awards of units	'
		Restricted		Weighted-
		Common		Average Grant
		Units		Date Fair Value
	Outstanding at December 31, 2013	3,490,968		$	4.75
	Repurchased	(202,757	)	$	4.75
	Forfeited/cancelled	(16,695	)	$	4.75
	Outstanding at September 30, 2014	3,271,516		$	4.75
	Provisionally vested at September 30, 2014	2,865,700		$	4.75
Deferred units	'
Equity based compensation	'
Summary of the status and activity for awards of units	'
		Deferred		Weighted-		Weighted-Average
		Common		Average Grant		Remaining
		Units		Date Fair Value		Contractual Term
						(Years)
	Outstanding at December 31, 2013	5,255,113		$	7.95	6
	Granted	1,953,227		$	27.07
	Forfeited/cancelled	(278,856	)	$	12.29
	Outstanding at September 30, 2014	6,929,484		$	14.42	5.6
	Provisionally vested at September 30, 2014	1,749,626		$	5.95	4.8

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2014
Segment and Geographic Information	'
Schedule of operating information by segment	'
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
		(in thousands)
	Net revenue
	Direct Retail	$	285,502	$	181,693	$	755,036	$	450,058
	Other	50,686		55,609		155,296		170,452
	Net revenue	$	336,188	$	237,302	$	910,332	$	620,510
Schedule of revenue and long-lived assets by geographic area	'
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
		(in thousands)
	Geographic net revenue:
	United States	$	314,754	$	221,421	$	851,585	$	581,073
	International	21,434		15,881		58,747		39,437
	Total	$	336,188	$	237,302	$	910,332	$	620,510
		September 30,		December 31,
		2014		2013
		(in thousands)
	Geographic long-lived assets:
	United States	$	48,920	$	21,451
	International	1,107		637
	Total	$	50,027	$	22,088

Net_Loss_per_Common_UnitShare_

Net Loss per Common Unit/Share (Tables)	9 Months Ended
	Sep. 30, 2014
Net Loss per Common Unit/Share	'
Schedule of calculation of basic and diluted net loss per common unit	'
		Three months ended September 30,						Nine months ended September 30,
		2014			2013			2014			2013
		(in thousands, except share amount)
	Numerator:
	Net loss	$	(24,143	)	$	(3,031	)	$	(75,544	)	$	(11,369	)
	Accretion of preferred units to redemption value	$	(4,748	)	$	(4,673	)	$	(16,503	)	$	(20,621	)
	Net loss attributable to common unit holders per unit - basic and diluted	$	(28,891	)	$	(7,704	)	$	(92,047	)	$	(31,990	)
	Denominator:
	Weighted average units used for basic and diluted net loss per unit computation	40,512,544			41,367,115			40,721,540			41,304,048
	Net loss per common unit attributable to common unit holders:
	Basic and Diluted	$	(0.71	)	$	(0.19	)	$	(2.26	)	$	(0.77	)
Schedule of computation of basic and diluted net loss per share attributable to common stockholders as their effect would have been antidilutive	'
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
	Series A convertible redeemable preferred units	21,551,801		21,551,801		21,551,801		21,551,801
	Series B convertible redeemable preferred units	5,995,133		—		5,995,133		—
	Common option units	643,003		665,377		643,003		665,377
	Restricted common units	3,271,516		3,495,010		3,271,516		3,495,010
	Deferred common units	6,929,484		3,959,773		6,929,484		3,959,773
		38,390,937		29,671,961		38,390,937		29,671,961

Summary_of_Business_Operations2

Summary of Business Operations and Basis of Presentation (Details) (USD $)	9 Months Ended		0 Months Ended	1 Months Ended	0 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Oct. 07, 2014	Oct. 31, 2014	Jun. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014
	item		Subsequent event	Class B common stock	Pro Forma	Pro Forma	Pro Forma	Pro Forma	Pro Forma
							Series A convertible redeemable preferred units	Class B common stock	Class B common stock
									Minimum
Summary of Business Operations and Basis of Presentation	'	'	'	'	'	'	'	'	'
Minimum number of products offered	7,000,000	'	'	'	'	'	'	'	'
Minimum number of suppliers providing products offered	7,000	'	'	'	'	'	'	'	'
Summary of business operations	'	'	'	'	'	'	'	'	'
Initial public offering, aggregate number of shares of common stock sold	'	'	12,650,000	'	'	'	'	'	'
Share issue price (in dollars per share)	'	'	$29	'	'	'	'	'	'
Number of shares of common stock sold	'	'	10,500,000	'	'	'	'	'	'
Number of shares of stock sold by the selling shareholders	'	'	2,150,000	'	'	'	'	'	'
Number of shares of sold by the selling shareholders pursuant to an option granted to the underwriters to purchase additional shares	'	'	1,650,000	'	'	'	'	'	'
Net proceeds from initial public offering	'	'	$282.70	'	'	'	'	'	'
Deferred income tax liabilities in connection with reorganization	'	'	'	'	0.3	'	'	'	'
Adjustment to reduce carrying value of preferred units to reflect conversion value	'	'	'	'	'	14.4	'	'	'
Cash distribution paid to preferred stockholders	'	'	'	'	'	'	24.5	'	'
Equity based compensation expense	'	'	'	'	'	48.6	'	'	'
Share issued upon the vesting of outstanding deferred units	'	'	'	1,129,095	'	'	'	1,129,095	'
Tax withholding obligations	'	'	'	'	'	'	'	'	22.6
Reclassification from due to related party to accrued expenses	'	'	'	'	'	1.8	'	'	'
Concentrations of Credit Risk	'	'	'	'	'	'	'	'	'
Cash and cash equivalents and short-term investments held in banks located outside the U.S.	$1.40	$2.60	'	'	'	'	'	'	'

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (Recurring basis, USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair value measurements	'	'
Total assets	$108,973	$82,925
Cash equivalents	'	'
Fair value measurements	'	'
Money market funds	5,071	32,560
Short-term investments	'	'
Fair value measurements	'	'
Certificates of deposit	100,054	50,019
Restricted cash	'	'
Fair value measurements	'	'
Money market funds	3,848	346
Level 1	'	'
Fair value measurements	'	'
Total assets	108,973	82,925
Level 1 | Cash equivalents	'	'
Fair value measurements	'	'
Money market funds	5,071	32,560
Level 1 | Short-term investments	'	'
Fair value measurements	'	'
Certificates of deposit	100,054	50,019
Level 1 | Restricted cash	'	'
Fair value measurements	'	'
Money market funds	$3,848	$346

Acquisition_Intangible_assets_2

Acquisition, Intangible assets and Goodwill (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Intangible assets	'	'
Gross Carrying Value	$7,242	$7,428
Accumulated Amortization	-4,143	-3,509
Net Book Value	3,099	3,919
Trademarks	'	'
Intangible assets	'	'
Weighted-Average Amortization Period	'5 years	'
Gross Carrying Value	2,008	2,030
Accumulated Amortization	-511	-219
Net Book Value	1,497	1,811
Customer relationships	'	'
Intangible assets	'	'
Weighted-Average Amortization Period	'5 years	'
Gross Carrying Value	1,300	1,300
Accumulated Amortization	-303	-108
Net Book Value	997	1,192
Non-compete agreements	'	'
Intangible assets	'	'
Gross Carrying Value	109	110
Accumulated Amortization	-44	-19
Net Book Value	65	91
Non-compete agreements | Minimum	'	'
Intangible assets	'	'
Weighted-Average Amortization Period	'3 years	'
Non-compete agreements | Maximum	'	'
Intangible assets	'	'
Weighted-Average Amortization Period	'5 years	'
Technology	'	'
Intangible assets	'	'
Weighted-Average Amortization Period	'5 years	'
Gross Carrying Value	768	920
Accumulated Amortization	-473	-430
Net Book Value	295	490
Other intangibles	'	'
Intangible assets	'	'
Weighted-Average Amortization Period	'3 years	'
Gross Carrying Value	373	373
Accumulated Amortization	-131	-47
Net Book Value	242	326
Domain names	'	'
Intangible assets	'	'
Weighted-Average Amortization Period	'5 years	'
Gross Carrying Value	2,684	2,695
Accumulated Amortization	-2,681	-2,686
Net Book Value	$3	$9

Property_and_Equipment_net_Det

Property and Equipment, net (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property and equipment, net	'	'
Property and equipment, gross	$89,033	$52,029
Less accumulated depreciation and amortization	-39,006	-29,941
Property and equipment, net	50,027	22,088
Furniture and computer equipment	'	'
Property and equipment, net	'	'
Property and equipment, gross	43,087	26,218
Leasehold improvements	'	'
Property and equipment, net	'	'
Property and equipment, gross	13,682	1,912
Construction in progress	'	'
Property and equipment, net	'	'
Property and equipment, gross	25	184
Site and software development costs	'	'
Property and equipment, net	'	'
Property and equipment, gross	$32,239	$23,715

Accrued_Expenses_Details

Accrued Expenses (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accrued Expenses	'	'
Employee compensation and related benefits	$11,675	$7,470
Marketing	6,979	5,329
Credit card	4,522	2,173
Audit, legal and professional fees	1,851	377
Accrued property, plant and equipment	1,248	'
Other accrued expenses	6,422	3,890
Total accrued expenses	$32,697	$19,239

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (Office space, USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Mar. 31, 2014
	item	sqft
Boston, MA	'	'
Operating leases	'	'
Area of space (in square feet)	'	275,000
Additional operating lease obligations	$52.10	'
Number of successive periods	2	'
Period for extension for lease term	'5 years	'
Ogden, UT	'	'
Operating leases	'	'
Area of space (in square feet)	180,000	'
Additional operating lease obligations	$9.10	'

Commitments_and_Contingencies_1

Commitments and Contingencies (Details 2) (Sales and other similar tax assessments, USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Sales and other similar tax assessments	'
Contingencies	'
Aggregate amount of claims	$11.70

EquityBased_Compensation_Detai

Equity-Based Compensation (Details) (USD $)	9 Months Ended			3 Months Ended	9 Months Ended		12 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Jul. 01, 2011	Dec. 31, 2014	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014
	2010 Plan	2010 Plan	2010 Plan	2010 Plan	2014 Plan	Common unit options	Common unit options	Deferred units	Restricted common units
	item			Forecast
Equity based compensation	'	'	'	'	'	'	'	'	'
Number of units authorized	'	'	12,405,879	'	8,603,066	'	'	'	'
Number of units available for issuance	603,769	1,206,547	'	'	'	'	'	'	'
Number of vesting triggers	2	'	'	'	'	'	'	'	'
Service period	'5 years	'	'	'	'	'	'	'	'
Share based expenses	'	'	'	$48.60	'	'	'	'	'
Contractual life	'	'	'	'	'	'10 years	'	'7 years	'0 years
Common options, units	'	'	'	'	'	'	'	'	'
Outstanding at the beginning of the period (in units)	'	'	'	'	'	664,232	'	'	'
Repurchased (in units)	'	'	'	'	'	-9,028	'	'	'
Forfeited/canceled (in units)	'	'	'	'	'	-12,201	'	'	'
Outstanding at the end of the period (in units)	'	'	'	'	'	643,003	664,232	'	'
Provisionally vested at the end of the period (in units)	'	'	'	'	'	578,868	'	'	'
Weighted Average Grant Date Fair Value	'	'	'	'	'	'	'	'	'
Outstanding at the beginning of the period (in dollars per unit)	'	'	'	'	'	$2.99	'	'	'
Repurchased (in dollars per unit)	'	'	'	'	'	$2.93	'	'	'
Forfeited/canceled (in dollars per unit)	'	'	'	'	'	$3.22	'	'	'
Outstanding at the end of the period (in dollars per unit)	'	'	'	'	'	$2.98	$2.99	'	'
Provisionally vested at the end of the period (in dollars per unit)	'	'	'	'	'	$2.98	'	'	'
Weighted-Average Remaining Contractual Term (Years)	'	'	'	'	'	'	'	'	'
Outstanding at the end of the period	'	'	'	'	'	'5 years 10 months 24 days	'6 years 8 months 12 days	'	'
Provisionally vested at the end of the period	'	'	'	'	'	'5 years 10 months 24 days	'	'	'
Shares issued under plan	'	'	'	'	0	'	'	'	'

EquityBased_Compensation_Detai1

Equity-Based Compensation (Details 2) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Restricted common units	'	'
Common Units	'	'
Outstanding at the beginning of the period (in units)	3,490,968	'
Repurchased (in units)	-202,757	'
Forfeited/canceled (in units)	-16,695	'
Outstanding at the end of the period (in units)	3,271,516	'
Provisionally vested at the end of the period (in units)	2,865,700	'
Weighted-Average Grant-Date Fair Value	'	'
Outstanding at the beginning of the period (in dollars per unit)	$4.75	'
Repurchased (in dollars per unit)	$4.75	'
Forfeited/canceled (in dollars per unit)	$4.75	'
Outstanding at the end of the period (in dollars per unit)	$4.75	'
Provisionally vested at the end of the period (in dollars per unit)	$4.75	'
Deferred units	'	'
Common Units	'	'
Outstanding at the beginning of the period (in units)	5,255,113	'
Granted (in units)	1,953,227	'
Forfeited/canceled (in units)	-278,856	'
Outstanding at the end of the period (in units)	6,929,484	5,255,113
Provisionally vested at the end of the period (in units)	1,749,626	'
Weighted-Average Grant-Date Fair Value	'	'
Outstanding at the beginning of the period (in dollars per unit)	$7.95	'
Granted (in dollars per unit)	$27.07	'
Forfeited/canceled (in dollars per unit)	$12.29	'
Outstanding at the end of the period (in dollars per unit)	$14.42	$7.95
Provisionally vested at the end of the period (in dollars per unit)	$5.95	'
Weighted-Average Remaining Contractual Term (Years)	'	'
Outstanding at the end of the period	'5 years 7 months 6 days	'6 years
Provisionally vested at the end of the period	'4 years 9 months 18 days	'

Segment_and_Geographic_Informa2

Segment and Geographic Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
			item
Segment and Geographic Information	'	'	'	'
Number of operating segment	'	'	1	'
Number of reportable segment	'	'	1	'
Direct Retail	$285,502	$181,693	$755,036	$450,058
Other	50,686	55,609	155,296	170,452
Net revenue	$336,188	$237,302	$910,332	$620,510

Segment_and_Geographic_Informa3

Segment and Geographic Information (Details 2) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Geographic analysis, revenue and long-lived assets	'	'	'	'	'
Geographic net revenue	$336,188	$237,302	$910,332	$620,510	'
Geographic long-lived assets	50,027	'	50,027	'	22,088
United States	'	'	'	'	'
Geographic analysis, revenue and long-lived assets	'	'	'	'	'
Geographic net revenue	314,754	221,421	851,585	581,073	'
Geographic long-lived assets	48,920	'	48,920	'	21,451
International	'	'	'	'	'
Geographic analysis, revenue and long-lived assets	'	'	'	'	'
Geographic net revenue	21,434	15,881	58,747	39,437	'
Geographic long-lived assets	$1,107	'	$1,107	'	$637

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Taxes	'	'	'	'
Provision for federal income taxes	'	'	$0	'
Provision for state and local income taxes	'	'	0	'
(Provision) benefit for foreign income taxes	-49,000	-1,000	-66,000	4,000
ProForma	'	'	'	'
Pro Forma Income Tax Accounting Related to the Reorganization	'	'	'	'
Valuation allowance required	28,800,000	'	28,800,000	'
Deferred tax assets, net of valuation allowance	7,000,000	'	7,000,000	'
Deferred tax liabilities	7,300,000	'	7,300,000	'
Deferred tax liabilities	$300,000	'	$300,000	'

Members_Deficit_Details

Members' Deficit (Details) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Oct. 31, 2014

Sep. 30, 2014

Dec. 31, 2013

Oct. 31, 2014

Sep. 30, 2014

Dec. 31, 2013

Oct. 31, 2014

Oct. 31, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Wayfair, Inc.

Class A common stock

Class A common stock

Class A common stock

Class B common stock

Class B common stock

Class B common stock

Class B common stock

Class B common stock

Common units

Series A convertible redeemable preferred units

Series A convertible redeemable preferred units

Series A and Series B convertible redeemable preferred units

Series B convertible redeemable preferred units

Series B convertible redeemable preferred units

item

item

Minimum

Maximum

Class B common stock

Class B common stock

Members' deficit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible redeemable preferred units, shares issued

'

'

'

'

'

'

'

'

'

'

'

'

21,551,801

21,551,801

'

5,995,133

0

Convertible redeemable preferred units, shares outstanding

'

'

'

'

'

'

'

'

'

'

'

'

21,551,801

'

'

5,995,133

'

Conversion of units to common stock (in shares)

'

'

'

'

'

'

'

'

'

'

'

43,784,060

'

'

27,546,934

'

'

Preferred stock, shares issued

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock, shares outstanding

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock, shares authorized

10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock, par value (in dollars per unit)

$0.00

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common units, shares outstanding

43,784,060

44,904,110

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares issued for vesting of deferred units

'

'

'

'

'

'

1,129,095

'

'

'

'

'

'

'

'

'

'

Common stock, shares authorized

'

'

1,000

500,000,000

0

0

164,000,000

0

0

'

'

'

'

'

'

'

'

Common stock, par value (in dollars per unit)

'

'

'

$0.00

'

'

$0.00

'

'

'

'

'

'

'

'

'

'

Common stock, shares outstanding

'

'

'

12,650,000

0

0

70,265,404

0

'

'

'

'

'

'

'

'

'

Number of votes each holder is entitled

'

'

'

1

'

'

10

'

'

'

'

'

'

'

'

'

'

Conversion ratio

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

Conversion ratio following the completion of the offering

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

Conversion ratio upon transfer

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

Aggregate number of shares outstanding Class A common stock and Class B common stock that shall convert automatically (as a percent)

'

'

'

'

'

'

'

'

'

'

10.00%

'

'

'

'

'

'

Percentage of outstanding shares of Class B common stock that shall convert automatically in the event of the affirmative vote or written consent of holders

'

'

'

'

'

'

'

'

'

66.67%

'

'

'

'

'

'

'

Net_Loss_per_Common_UnitShare_1

Net Loss per Common Unit/Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator:	'	'	'	'
Net loss	($24,143)	($3,031)	($75,544)	($11,369)
Accretion of preferred units to redemption value	-4,748	-4,673	-16,503	-20,621
Net loss attributable to common unit holders	($28,891)	($7,704)	($92,047)	($31,990)
Denominator:	'	'	'	'
Weighted average units used for basic and diluted net loss per unit computation (in units)	40,512,544	41,367,115	40,721,540	41,304,048
Net loss per common unit attributable to common unit holders:	'	'	'	'
Basic and Diluted (in dollars per unit)	($0.71)	($0.19)	($2.26)	($0.77)
Anti-dilutive securities	'	'	'	'
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	38,390,937	29,671,961	38,390,937	29,671,961
Series A convertible redeemable preferred units	'	'	'	'
Anti-dilutive securities	'	'	'	'
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	21,551,801	21,551,801	21,551,801	21,551,801
Series B convertible redeemable preferred units	'	'	'	'
Anti-dilutive securities	'	'	'	'
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	5,995,133	'	5,995,133	'
Common unit options	'	'	'	'
Anti-dilutive securities	'	'	'	'
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	643,003	665,377	643,003	665,377
Restricted common units	'	'	'	'
Anti-dilutive securities	'	'	'	'
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	3,271,516	3,495,010	3,271,516	3,495,010
Deferred common units	'	'	'	'
Anti-dilutive securities	'	'	'	'
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	6,929,484	3,959,773	6,929,484	3,959,773