Wayfair (W) 10-Q 12 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 31, 2015
Entity Registrant Name	Wayfair Inc.
Entity Central Index Key	1,616,707
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Amendment Flag	false
Class A common stock
Entity Common Stock, Shares Outstanding		44,505,054
Class B common stock
Entity Common Stock, Shares Outstanding		39,621,692

CONSOLIDATED AND CONDENSED BALA

CONSOLIDATED AND CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 278,690	$ 355,859
Short-term investments	46,654	60,000
Accounts receivable, net of allowance of $3,240 and $2,545 at September 30, 2015 and December 31, 2014, respectively	9,719	5,949
Inventories	22,552	19,798
Prepaid expenses and other current assets	75,486	45,262
Total current assets	433,101	486,868
Property and equipment, net	88,642	60,639
Goodwill and intangible assets, net	3,899	6,478
Long-term investments	74,460	0
Other noncurrent assets	1,242	1,538
Total assets	601,344	555,523
Current liabilities
Accounts payable	192,552	147,873
Accrued expenses	52,083	42,335
Deferred revenue	45,027	26,784
Other current liabilities	24,070	15,600
Total current liabilities	313,732	232,592
Other liabilities	32,916	17,392
Total liabilities	$ 346,648	$ 249,984
Commitments and contingencies
Convertible preferred stock, $0.001 par value per share: 10,000,000 shares authorized and none issued at September 30, 2015 and December 31, 2014	$ 0	$ 0
Stockholders’ equity:
Additional paid-in capital	374,794	363,944
Accumulated deficit	(120,070)	(58,122)
Accumulated other comprehensive loss	(112)	(366)
Total stockholders’ equity	254,696	305,539
Total liabilities and stockholders’ equity	601,344	555,523
Class A common stock
Stockholders’ equity:
Common stock	44	37
Class B common stock
Stockholders’ equity:
Common stock	$ 40	$ 46

CONSOLIDATED AND CONDENSED BAL3

CONSOLIDATED AND CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accounts receivable allowance for doubtful accounts	$ 3,240	$ 2,545
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Class A common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	44,145,083	37,002,874
Common stock, shares outstanding	44,145,083	37,002,874
Class B common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	164,000,000	164,000,000
Common stock, shares issued	39,894,391	46,179,192
Common stock, shares outstanding	39,894,391	46,179,192

CONSOLIDATED AND CONDENSED STAT

CONSOLIDATED AND CONDENSED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Net revenue	$ 593,972	$ 336,188	$ 1,510,095	$ 910,332
Cost of goods sold	452,586	257,161	1,145,073	697,644
Gross profit	141,386	79,027	365,022	212,688
Operating expenses:
Customer service and merchant fees	21,109	14,239	55,417	37,321
Advertising	70,711	49,763	190,249	136,478
Merchandising, marketing and sales	27,083	13,437	74,131	41,868
Operations, technology, general and administrative	40,912	25,203	109,887	71,558
Amortization of acquired intangible assets	208	249	694	748
Total operating expenses	160,023	102,891	430,378	287,973
Loss from operations	(18,637)	(23,864)	(65,356)	(75,285)
Interest income, net	325	89	897	222
Other income (expense), net	2,746	(309)	2,542	(405)
Loss before income taxes	(15,566)	(24,084)	(61,917)	(75,468)
(Benefit from) provision for income taxes	(88)	59	31	76
Net loss	(15,478)	(24,143)	(61,948)	(75,544)
Accretion of convertible redeemable preferred units	0	(4,748)	0	(16,503)
Net loss attributable to common stockholders	$ (15,478)	$ (28,891)	$ (61,948)	$ (92,047)
Net loss attributable to common stockholders per share, basic and diluted (in dollars per share)	$ (0.18)	$ (0.71)	$ (0.74)	$ (2.26)
Weighted average common shares outstanding, basic and diluted	83,886	40,513	83,569	40,722

CONSOLIDATED AND CONDENSED STA5

CONSOLIDATED AND CONDENSED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (15,478)	$ (24,143)	$ (61,948)	$ (75,544)
Other comprehensive loss:
Foreign currency translation adjustments	371	0	323	0
Net unrealized loss on available-for-sale investments	(67)	(67)	(69)	(59)
Comprehensive loss	$ (15,174)	$ (24,210)	$ (61,694)	$ (75,603)

CONSOLIDATED AND CONDENSED STA6

CONSOLIDATED AND CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities
Net loss	$ (61,948)	$ (75,544)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	23,351	14,438
Equity based compensation	21,741	5,528
Gain on sale of a business	(2,997)	0
Other non-cash adjustments	1,395	888
Changes in operating assets and liabilities:
Accounts receivable	(3,832)	2,376
Inventories	(2,778)	(6,155)
Prepaid expenses and other current assets	(28,419)	(12,721)
Accounts payable and accrued expenses	60,340	(1,108)
Deferred revenue and other liabilities	37,927	24,578
Other assets	(25)	(3,117)
Net cash provided by (used in) operating activities	44,755	(50,837)
Cash flows from investing activities
Purchase of short-term and long-term investments	(141,309)	(110,000)
Sale and maturities of short-term investments	78,715	59,964
Purchase of property and equipment	(36,695)	(31,168)
Site and software development costs	(13,107)	(10,643)
Cash received from the sale of a business (net of cash sold)	2,860	0
Other investing activities, net	302	(3,015)
Net cash used in investing activities	(109,234)	(94,862)
Cash flows from financing activities
Taxes paid related to net share settlement of equity awards	(12,899)	0
Net proceeds from exercise of stock options	374	0
Net proceeds from issuance of Series B convertible redeemable preferred units	0	154,774
Repurchase of common units	0	(23,500)
Dividends paid to Series A convertible redeemable preferred holders	0	(15,000)
Repurchase of employee equity	0	(5,528)
Net cash (used in) provided by financing activities	(12,525)	110,746
Effect of exchange rate changes on cash and cash equivalents	(165)	(29)
Net (decrease) in cash and cash equivalents	(77,169)	(34,982)
Cash and cash equivalents
Beginning of period	355,859	65,289
End of period	278,690	30,307
Supplemental disclosure of non-cash investing activities
Purchase of property and equipment included in accounts payable and accrued expenses and in other liabilities	2,636	2,079
Construction costs capitalized under finance lease obligations	8,687	0
Supplemental disclosure of non-cash financing activities
Accretion of preferred unit dividends	$ 0	$ 16,503

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Wayfair Inc. (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 five 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. The consolidated and condensed financial statements and other disclosures contained in this Quarterly Report on Form 10-Q are those of the Company. The Company was incorporated as a Delaware corporation on August 8, 2014. Prior to the effectiveness of the Company’s registration statement on Form S-1 related to its initial public offering (“IPO”) in October 2014, Wayfair LLC was the principal operating entity. In connection with the IPO of the Company, Wayfair LLC completed a corporate reorganization pursuant to which Wayfair LLC became a wholly-owned subsidiary of the Company, and the holders of equity interests in Wayfair LLC became stockholders of the Company. For additional information regarding the change in reporting entity, see Note 1, Basis of Presentation , in the Notes to Consolidated Financial Statements included in Part II, Item 8, Financial Statements and Supplementary Data , of the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 . The consolidated and condensed balance sheet data as of December 31, 2014 was derived from audited financial statements. The accompanying consolidated and condensed balance sheet as of September 30, 2015 , the consolidated statements of operations, consolidated statements of comprehensive loss, and consolidated statements of cash flows for the periods ended September 30, 2015 and 2014 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, 2015 and statements of operations, comprehensive loss, and cash flows for the periods ended September 30, 2015 and 2014 . The financial data and the other information disclosed in these notes to the consolidated and condensed financial statements related to these periods are unaudited. The consolidated and condensed statements of operations, comprehensive loss, and cash flows for the periods ended September 30, 2015 are not necessarily indicative of the results of operations and cash flows that may be expected for the year ending December 31, 2015 , or for any other period.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The Company has identified the significant accounting policies that are critical to understanding its business and results of operations. The Company believes that there have been no significant changes during the three and nine months ended September 30, 2015 to the items disclosed in Note 2, Summary of Significant Accounting Policies , in the Notes to the Consolidated Financial Statements included in Part II, Item 8, Financial Statements and Supplementary Data , of the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 other than those noted below. Marketable Securities The Company classifies its marketable securities as “available-for-sale” or “trading” securities. Available-for-sale securities are classified as short term investments and long-term investments on the consolidated and condensed balance sheets and are carried at fair value. Unrealized gains and losses on available-for-sale securities that are considered temporary are recorded, net of taxes, in the “Accumulated other comprehensive loss” caption of the Company’s consolidated and condensed balance sheets. Unrealized losses, excluding losses related to the credit rating of the security (credit losses), on available-for-sale securities that are considered other-than-temporary but relate to securities that the Company (i) does not intend to sell and (ii) will not be required to sell below cost are also recorded, net of taxes, in “Accumulated other comprehensive loss.” Further, the Company does not believe it will be required to sell such securities below cost. Therefore, the only other-than-temporary losses the Company records in “Other income, net” in its consolidated statements of operations are related to credit losses. As of September 30, 2015 , the Company’s available-for-sale securities consisted of investment securities. The maturities of the Company’s long-term marketable securities generally range from one to three years.

Marketable Securities and Fair

Marketable Securities and Fair Value Measurements	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Marketable Securities and Fair Value Measurements	Marketable Securities and Fair Value Measurements Marketable Securities As of September 30, 2015 , all of the Company’s marketable securities were classified as available-for-sale and their estimated fair values were $91.1 million The Company did not hold any available-for-sale securities at December 31, 2014 . The following table presents details of the Company’s marketable securities as of September 30, 2015 (in thousands): September 30, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Short-term: Investment securities $ 16,646 $ 9 $ (1 ) $ 16,654 Long-term: Investment securities 74,535 55 (130 ) 74,460 Total $ 91,181 $ 64 $ (131 ) $ 91,114 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, 2015 and December 31, 2014 based on the three-tier value hierarchy (in thousands): September 30, 2015 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 182,227 $ — $ — $ 182,227 Short-term investments: Certificates of deposit 30,000 — — 30,000 Investment securities — 16,654 — 16,654 Long-term: Investment securities — 74,460 — 74,460 Total $ 212,227 $ 91,114 $ — $ 303,341 December 31, 2014 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 302,595 $ — $ — $ 302,595 Short-term investments: Certificates of deposit 60,000 — — 60,000 Restricted cash: Money market funds 302 — — 302 Total $ 362,897 $ — $ — $ 362,897

Intangible Assets and Goodwill

Intangible Assets and Goodwill	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	Intangible Assets and Goodwill The following table summarizes intangible assets as of September 30, 2015 and December 31, 2014 (in thousands): Weighted-Average September 30, 2015 Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Book Value Trademarks 5 $ 1,900 $ (823 ) $ 1,077 Customer relationships 5 1,300 (563 ) 737 Non-compete agreements 3 - 5 100 (72 ) 28 Other intangibles 3 373 (242 ) 131 Domain names 5 2,687 (2,685 ) 2 Total $ 6,360 $ (4,385 ) $ 1,975 Weighted-Average December 31, 2014 Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Book Value Trademarks 5 $ 2,001 $ (604 ) $ 1,397 Customer relationships 5 1,300 (368 ) 932 Non-compete agreements 3 - 5 108 (52 ) 56 Technology 5 718 (467 ) 251 Other intangibles 3 373 (158 ) 215 Domain names 5 2,687 (2,684 ) 3 Total $ 7,187 $ (4,333 ) $ 2,854 Amortization expense related to intangible assets was $0.2 million for the three months ended September 30, 2015 and 2014 , and $0.7 million for the nine months ended September 30, 2015 and 2014 . The following table presents the changes in goodwill during the nine months ended September 30, 2015 (in thousands): Net Book Value Goodwill as of December 31, 2014 $ 3,624 Sale during the period (1,520 ) Foreign currency exchange rate effect (180 ) Goodwill as of September 30, 2015 $ 1,924 In July 2015 the Company sold its Australian-based business in order to strategically focus its resources on its North America and Europe markets. At the time of the sale, the net carrying amounts of the goodwill and intangible assets of the Australian business were $1.5 million and $0.2 million , respectively. The proceeds from the sale exceeded the carrying value of the Australian business, resulting in a $3.0 million gain, recorded in "Other income (expense), net" in the unaudited consolidated and condensed statements of operations.

Property and Equipment, net

Property and Equipment, net	9 Months Ended
	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Property and Equipment, net	Property and Equipment, net The following table summarizes property and equipment, net as of September 30, 2015 and December 31, 2014 (in thousands): September 30, December 31, Furniture and computer equipment $ 60,881 $ 48,399 Site and software development costs 47,653 36,294 Leasehold improvements 27,351 14,290 Construction in progress 9,556 4,800 145,441 103,783 Less accumulated depreciation and amortization (56,799 ) (43,144 ) Property and equipment, net $ 88,642 $ 60,639 Property and equipment depreciation and amortization expense was $9.0 million and $5.3 million for the three months ended September 30, 2015 and 2014 , respectively, and $22.7 million and $13.6 million for the nine months ended September 30, 2015 and 2014 , respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases The Company leases office space under non-cancelable 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. Rent expense under operating leases was $3.8 million and $2.6 million in the three months ended September 30, 2015 and 2014 , respectively, and $12.3 million and $8.8 million in the nine months ended September 30, 2015 and 2014 , respectively. The Company has issued letters of credit for approximately $4.7 million as security for these lease agreements as of September 30, 2015 and December 31, 2014 . 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, not including taxes allegedly owed for periods subsequent to such assessments or interest and penalties after the date the Company last received such assessments, is approximately $12.9 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 and therefore has not recorded a liability; however, no assurance can be given as to the outcome of these assessments. Legal Matters On September 2, 2015, a putative class action complaint was filed against us in the U.S. District Court for the Southern District of New York (Dingee v. Wayfair Inc., et al., Case No. 1:15-cv-06941) by an individual on behalf of himself and on behalf of all other similarly situated individuals, or collectively, the Plaintiffs, under sections 10(b) and 20(a) of the Securities and Exchange Act related to a drop in stock price that had followed a report issued by Citron Research. On September 3, a second putative class action complaint was filed, asserting nearly identical claims (Jenkins v. Wayfair Inc., et al., Case No. 1:15-cv-06985). On November 2, 2015, the plaintiff in the Dingee action moved to consolidate the two lawsuits, and to designate himself as lead plaintiff in the class action and his attorney as lead counsel for the class. On November 3, plaintiff in the Jenkins action voluntarily dismissed his complaint. As a result, only the Dingee action remains pending. The Plaintiff’s complaint seeks class certification, damages in an unspecified amount, and attorney’s fees and costs. The company intends to defend the lawsuit vigorously. 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.

Equity-Based Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity-Based Compensation	Equity-Based Compensation In 2010, the Company established an equity incentive plan and, in 2011, the 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 common option units, restricted common units (all common units), and deferred units, which currently represent Class A or Class B common stock of the Company. In connection with the IPO and as described in Note 1, Basis of Presentation , the Company completed a corporate reorganization pursuant to which Wayfair LLC became a wholly-owned subsidiary of the Company, and the holders of equity interests in Wayfair LLC became stockholders of the Company. In addition, all of the outstanding common units and incentive units of Wayfair LLC were exchanged for shares of common stock or incentive units for common stock, and then were converted into shares of Class B common stock or incentive units for Class B common stock of the Company. Accordingly, common option units, restricted common units and deferred units were converted to stock options, restricted common stock and restricted stock units (“RSU”), respectively, and may be referred to as such in these notes to the consolidated and condensed financial statements. In connection with the IPO, the board of directors of the Company 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 the Company 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 RSUs for 1,840,624 shares had been issued as of September 30, 2015 . Shares or RSUs forfeited, withheld for minimum statutory tax obligations, and unexercised stock option lapses from the 2010 Plan are available for grants of awards under the 2014 Plan. All equity awards granted prior to the IPO were subject to two vesting triggers: a service period (typically five years) and a performance condition (a liquidity event in the form of either a change of control or an initial public offering, each as defined in the 2010 Plan). Employees were able to retain provisionally vested stock options and shares upon departure. The Company determined that a liquidity event was not probable until the closing of its IPO on October 7, 2014, and as such, no expense was recognized until that date. After the IPO, awards for employees still providing service will continue to vest over the remaining service period. Any future grants of awards are expected to vest over the service period. In April 2014, the Company completed a tender offer to repurchase provisionally vested (defined as service period completed) stock options and restricted common stock from certain employees at a price of $26.23 per share. A total of 202,757 shares of restricted common stock and 9,028 stock options were tendered for an aggregate of approximately $5.5 million in net cash after adjusting for the exercise prices associated with the stock options. This tender offer was accounted for as a modification resulting in a $5.5 million compensation charge when accepted by the employee. The Company recorded an expense of $5.5 million in the nine months ended September 30, 2014. The following table presents activity relating to stock options under the 2010 Plan during the nine months ended September 30, 2015 : Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Outstanding at December 31, 2014 449,046 $ 2.98 6.5 Options exercised (143,887 ) $ 2.96 Options forfeited/canceled (2,542 ) $ 3.24 Outstanding at September 30, 2015 302,617 $ 2.98 5.7 Exercisable at September 30, 2015 298,336 $ 2.98 5.7 Expected to vest as of September 30, 2015 2,676 $ 3.42 5.7 Intrinsic value of stock options exercised was $4.4 million for the nine months ended September 30, 2015 . Aggregate intrinsic value of stock options outstanding and currently exercisable is $9.7 million and $9.6 million , respectively. Unrecognized equity based compensation expense related to stock options expected to vest is less than $0.1 million with a weighted average remaining vesting term of 0.2 years as of September 30, 2015 . The following table presents activity relating to restricted common stock under the 2010 Plan during the nine months ended September 30, 2015 : Shares Weighted- Average Grant Date Fair Value Outstanding at December 31, 2014 161,476 $ 4.75 Restricted stock vested (155,475 ) $ 4.75 Unvested at September 30, 2015 6,001 $ 4.75 Expected to vest as of September 30, 2015 3,753 $ 4.75 The intrinsic value of restricted common stock vested was $4.1 million for the nine months ended September 30, 2015 . Aggregate intrinsic value of restricted common stock unvested is $0.2 million as of June 30, 2015. Unrecognized equity based compensation expense related to restricted common stock expected to vest is less than $0.1 million with a weighted average remaining vesting term of 0.2 years as of September 30, 2015 . The following table presents activity relating to RSUs under the 2010 and 2014 Plans during the nine months ended September 30, 2015 : Shares Weighted- Average Grant Date Fair Value Outstanding at December 31, 2014 4,542,231 $ 17.67 RSUs granted 1,840,624 $ 33.67 RSUs vested (1,114,485 ) $ 17.00 RSUs forfeited/canceled (353,032 ) $ 22.15 Outstanding at September 30, 2015 4,915,338 $ 23.62 Expected to vest as of September 30, 2015 3,629,795 $ 24.10 The intrinsic value of RSUs vested was $35.4 million for the nine months ended September 30, 2015 . Aggregate intrinsic value of RSUs outstanding is $172.3 million as of September 30, 2015 . Unrecognized equity based compensation expense related to RSUs expected to vest is $60.7 million with a weighted average remaining vesting term of 1.7 years as of September 30, 2015 .

Segment and Geographic Informat

Segment and Geographic Information	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment and Geographic Information	Segment and Geographic Information Operating segments are defined as components of an enterprise for which separate financial information is available that is evaluated on a regular basis by the Chief Operating Decision Maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its 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. As a result, the Company identified that it has one operating and reportable segment. The following table presents the activity related to the Company’s 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 (in thousands): Three months ended September 30, Nine months ended September 30, 2015 2014 2015 2014 Net revenue Direct Retail $ 544,971 $ 285,502 $ 1,354,665 $ 755,036 Other 49,001 50,686 155,430 155,296 Net revenue $ 593,972 $ 336,188 $ 1,510,095 $ 910,332 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. No individual country outside of the United States provided greater than 10% of total revenue. The following table presents revenue and long-lived assets by geographic area (in thousands): Three months ended September 30, Nine months ended September 30, 2015 2014 2015 2014 Geographic net revenue: United States $ 566,227 $ 314,754 $ 1,431,466 $ 851,585 International 27,745 21,434 78,629 58,747 Total $ 593,972 $ 336,188 $ 1,510,095 $ 910,332 September 30, December 31, Geographic long-lived assets: United States $ 86,426 $ 59,013 International 2,216 1,626 Total $ 88,642 $ 60,639

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three and nine months ended September 30, 2015 , income tax (benefit) expense of less than $(0.1) million and less than $0.1 million was recorded, respectively. The income tax benefit recorded in the three months ended September 30, 2015 is primarily related to the recognition of $0.2 million of previously unrecognized tax benefit upon expiration of applicable statute of limitations and partially offset by various foreign income tax assessments and to a lesser extent the amortization of goodwill for tax purposes for which there is no corresponding book deduction. The income tax expense recorded in the nine months ended September 30, 2015 is primarily related to various foreign income tax assessments and to a lesser extent the amortization of goodwill for tax purposes for which there is no corresponding book deduction, partially offset by $0.2 million of previously unrecognized tax benefit. During the three and nine months ended September 30, 2014 , the Company was operating as a limited liability company and was taxed as a partnership under the Internal Revenue Code, and accordingly, no provision for federal or state and local income taxes was made on income since the members were individually liable for federal and state and local income taxes on their share of the Company’s earnings. The Company recorded less than $0.1 million in the three and nine months ended September 30, 2014 associated with various foreign income tax assessments. Deferred income taxes reflect the impact of temporary differences between the amounts of assets and liabilities for financial reporting purposes and such amounts as measured by tax laws. The Company has deferred tax assets related to its net operating loss carryforwards accumulated since its corporate reorganization in the fourth quarter of 2014 and related to net operating loss carryforwards of certain of its foreign subsidiaries. A valuation allowance against net deferred tax assets is required if, based upon the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company reassesses the valuation allowance on a quarterly basis and has provided a valuation allowance for the full amount of its net deferred tax assets. The Company had no unrecognized tax benefits as of September 30, 2015 and was $0.2 million as of December 31, 2014 . The Company’s policy is to recognize interest and penalties related to unrecognized tax benefits as a component of income tax expense.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Corporate Reorganization On October 1, 2014, in anticipation of the IPO, the Company completed a corporate reorganization as described further in Note 1, Basis of Presentation . Pursuant to the corporate reorganization, Wayfair LLC became a wholly-owned subsidiary of the Company, and the holders of equity interests in Wayfair LLC became stockholders of the Company. The Company was incorporated as a Delaware corporation on August 8, 2014. In connection with this corporate reorganization, $306.2 million of accumulated deficit from Wayfair LLC was transferred to additional paid in capital of the Company. Series A and Series B Convertible Redeemable Preferred Units of Wayfair LLC In connection with the corporate reorganization all of the outstanding Series A and Series B preferred units of Wayfair LLC were exchanged for shares of Series A and Series B convertible preferred stock of the Company. Immediately prior to the completion of the IPO, all of the outstanding shares of Series A and Series B convertible preferred stock converted into 27,546,934 shares of Class B common stock of the Company. The Company recognized changes in the redemption value of the convertible redeemable preferred stock immediately as they occurred by adjusting the carrying amount of the redeemable security to what would be the redemption amount assuming the security was redeemable at the balance sheet date. Accordingly, the Company recorded accretion of the Series A convertible preferred stock of $14.4 million credit, $25.4 million , and $12.2 million for the years ended December 31, 2014 and 2013 and 2012 , respectively. At the time of the conversion of Series A and Series B redeemable convertible preferred stock an adjustment of $14.8 million was recorded as a reduction of accretion expense when the carrying value of the convertible redeemable preferred units was reduced to its conversion value. The Company recorded accretion on the Series B redeemable convertible preferred stock of $2.5 million for the year ended December 31, 2014 . Upon the issuance of Series B preferred units by Wayfair LLC in March 2014, the Company distributed $15.0 million in accrued dividends to Series A convertible preferred stock holders and, upon the completion of the IPO in October 2014, distributed the remaining accrued dividends of $24.5 million to Series A convertible preferred stock holders. Preferred Stock Upon the closing of the IPO in October 2014, the Company authorized 10,000,000 shares of undesignated preferred stock, $0.001 par value per share, for future issuance. As of September 30, 2015 , the Company had no shares of undesignated preferred stock issued or outstanding. Common Stock On October 7, 2014, the Company completed its 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 its 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 $282.9 million , after deducting underwriting discounts and offering expenses. The Company did not receive any proceeds from the sale of shares by the selling stockholders. The Company 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 44,145,083 and 37,002,874 shares of Class A common stock and 39,894,391 and 46,179,192 shares of Class B common stock were outstanding as of September 30, 2015 and December 31, 2014 , respectively. 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. The Class B common stock also has approval rights over certain corporate actions. 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 66 2/3% 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. Since the IPO through September 30, 2015 , 30,708,834 shares of Class B common stock were converted to Class A common stock.

Credit Agreement

Credit Agreement	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Credit Agreement	Credit Agreement The Company has a credit agreement with Bank of America, which was renewed on July 31, 2015. The credit agreement currently provides the Company with a line of credit and a credit card program with a maximum commitment of $35.0 million , $45.0 million and $35.0 million for the periods of July 31, 2015 through September 30, 2015, October 1, 2015 through February 28, 2016 and March 1, 2016 through July 31, 2016, respectively, with the committed amounts of $10.0 million to be used for a revolving line of credit and to support letters of credit and the remainder to be used to support the Company’s credit card program. The credit agreement is renewable on an annual basis and, if not renewed, will expire on July 31, 2016. The Company is required to maintain certain covenants, including tangible net worth and unencumbered liquid assets, with which the Company was compliant at September 30, 2015 and December 31, 2014 . The Company did not borrow any amounts under the credit agreement during the three and nine months ended September 30, 2015 and the year ended December 31, 2014 .

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share Basic and diluted net loss per share is presented using the two class method required for participating securities. Class A and Class B common stock have been the only outstanding equity in the Company since the IPO in October 2014. The rights of the holders of Class A and Class B common stock are identical, except with respect to voting and conversion as described in Note 10, Stockholder’s Equity . Basic net loss per share attributable to common stockholders is computed using the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share attributable to common stockholders is computed using the weighted-average number of shares of common stock and, if dilutive, common stock equivalents outstanding during the period. The Company’s common stock equivalents consist of shares issuable upon the release of RSUs, and to a lesser extent, the incremental shares of common stock issuable upon the exercise of stock options and unvested restricted stock. The dilutive effect of these common stock equivalents is reflected in diluted earnings per share by application of the treasury stock method. The Company’s basic and diluted net loss per share are the same because the Company has generated net loss to common stockholders and common stock equivalents are excluded from diluted net loss per share because they have an antidilutive impact. The Company allocates undistributed earnings between the classes on a one-to-one basis when computing net loss per share. As a result, basic and diluted net loss per share of Class A and Class B common stock are equivalent. Prior to the conversion of the Series A and Series B convertible preferred stock to Class B common stock, effective October 7, 2014, the Company applied the two class method for calculating and presenting earnings per share. Under the two class method, net loss attributable to common stockholders is determined by allocating undistributed earnings between common stock and participating securities. Undistributed earnings are calculated as net loss less distributed earnings and accretion of Series A and Series B convertible preferred stock. As holders of Series A and Series B convertible preferred stock did not have a contractual obligation to share in the losses of the Company, the net loss attributable to common stockholders for each periods prior to the IPO was not allocated between common stock and participating securities. Accordingly, Series A and Series B convertible preferred stock are excluded from the calculation of basic and diluted net loss per share. The Company’s basic and diluted net loss per share are the same because the Company has generated net loss to common stockholders and common stock 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 share (in thousands, except per share data): Three months ended September 30, Nine months ended September 30, 2015 2014 2015 2014 Net loss $ (15,478 ) $ (24,143 ) $ (61,948 ) $ (75,544 ) Accretion of convertible redeemable preferred units — (4,748 ) — (16,503 ) Net loss attributable to common stockholders $ (15,478 ) $ (28,891 ) $ (61,948 ) $ (92,047 ) Weighted average common shares used for basic and diluted net loss per share computation 83,886 40,513 83,569 40,722 Net loss unit attributable to common stockholders per share: Basic and Diluted $ (0.18 ) $ (0.71 ) $ (0.74 ) $ (2.26 ) 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 and nine months ended September 30, 2015 2014 Series A convertible redeemable preferred units — 21,551,801 Series B convertible redeemable preferred units — 5,995,133 Stock options 302,617 643,003 Restricted stock 6,001 3,271,516 Restricted stock units 4,915,338 6,929,484 Total 5,223,956 38,390,937

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU 2014-15”), Presentation of Financial Statements, Going Concern . ASU 2014-15 will explicitly require management to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosure in certain circumstances. The new standard will be effective for all entities in the first annual period ending after December 15, 2016 and earlier adoption is permitted. Management does not expect that the application of ASU 2014-15 will have an impact on the Company’s financial condition, results of operations or cash flows. In May 2014, the FASB issued ASU No. 2014-09 (“ASU 2014-09”), Revenue from Contracts with Customers . This ASU is a comprehensive new revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. This ASU is effective for annual reporting periods beginning after December 15, 2016 and early adoption is not permitted. Accordingly, the Company will adopt this ASU on January 1, 2017. Management is currently evaluating which transition approach to use and the impact of the adoption of this ASU on the Company’s financial condition, results of operations or cash flows.

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Recent Accounting Pronouncements	In August 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU 2014-15”), Presentation of Financial Statements, Going Concern . ASU 2014-15 will explicitly require management to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosure in certain circumstances. The new standard will be effective for all entities in the first annual period ending after December 15, 2016 and earlier adoption is permitted. Management does not expect that the application of ASU 2014-15 will have an impact on the Company’s financial condition, results of operations or cash flows. In May 2014, the FASB issued ASU No. 2014-09 (“ASU 2014-09”), Revenue from Contracts with Customers . This ASU is a comprehensive new revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. This ASU is effective for annual reporting periods beginning after December 15, 2016 and early adoption is not permitted. Accordingly, the Company will adopt this ASU on January 1, 2017. Management is currently evaluating which transition approach to use and the impact of the adoption of this ASU on the Company’s financial condition, results of operations or cash flows.

Marketable Securities and Fai21

Marketable Securities and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Schedule of Marketable Securities	The following table presents details of the Company’s marketable securities as of September 30, 2015 (in thousands): September 30, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Short-term: Investment securities $ 16,646 $ 9 $ (1 ) $ 16,654 Long-term: Investment securities 74,535 55 (130 ) 74,460 Total $ 91,181 $ 64 $ (131 ) $ 91,114
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	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, 2015 and December 31, 2014 based on the three-tier value hierarchy (in thousands): September 30, 2015 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 182,227 $ — $ — $ 182,227 Short-term investments: Certificates of deposit 30,000 — — 30,000 Investment securities — 16,654 — 16,654 Long-term: Investment securities — 74,460 — 74,460 Total $ 212,227 $ 91,114 $ — $ 303,341 December 31, 2014 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 302,595 $ — $ — $ 302,595 Short-term investments: Certificates of deposit 60,000 — — 60,000 Restricted cash: Money market funds 302 — — 302 Total $ 362,897 $ — $ — $ 362,897

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Tables)	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	The following table summarizes intangible assets as of September 30, 2015 and December 31, 2014 (in thousands): Weighted-Average September 30, 2015 Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Book Value Trademarks 5 $ 1,900 $ (823 ) $ 1,077 Customer relationships 5 1,300 (563 ) 737 Non-compete agreements 3 - 5 100 (72 ) 28 Other intangibles 3 373 (242 ) 131 Domain names 5 2,687 (2,685 ) 2 Total $ 6,360 $ (4,385 ) $ 1,975 Weighted-Average December 31, 2014 Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Book Value Trademarks 5 $ 2,001 $ (604 ) $ 1,397 Customer relationships 5 1,300 (368 ) 932 Non-compete agreements 3 - 5 108 (52 ) 56 Technology 5 718 (467 ) 251 Other intangibles 3 373 (158 ) 215 Domain names 5 2,687 (2,684 ) 3 Total $ 7,187 $ (4,333 ) $ 2,854
Changes in Goodwill	The following table presents the changes in goodwill during the nine months ended September 30, 2015 (in thousands): Net Book Value Goodwill as of December 31, 2014 $ 3,624 Sale during the period (1,520 ) Foreign currency exchange rate effect (180 ) Goodwill as of September 30, 2015 $ 1,924

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	9 Months Ended
	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	The following table summarizes property and equipment, net as of September 30, 2015 and December 31, 2014 (in thousands): September 30, December 31, Furniture and computer equipment $ 60,881 $ 48,399 Site and software development costs 47,653 36,294 Leasehold improvements 27,351 14,290 Construction in progress 9,556 4,800 145,441 103,783 Less accumulated depreciation and amortization (56,799 ) (43,144 ) Property and equipment, net $ 88,642 $ 60,639

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
Equity based compensation
Summary of Status and Activity for Awards of Stock Options	The following table presents activity relating to stock options under the 2010 Plan during the nine months ended September 30, 2015 : Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Outstanding at December 31, 2014 449,046 $ 2.98 6.5 Options exercised (143,887 ) $ 2.96 Options forfeited/canceled (2,542 ) $ 3.24 Outstanding at September 30, 2015 302,617 $ 2.98 5.7 Exercisable at September 30, 2015 298,336 $ 2.98 5.7 Expected to vest as of September 30, 2015 2,676 $ 3.42 5.7
Restricted common units
Equity based compensation
Summary of Status and Activity for Awards of Restricted Stock Units	The following table presents activity relating to restricted common stock under the 2010 Plan during the nine months ended September 30, 2015 : Shares Weighted- Average Grant Date Fair Value Outstanding at December 31, 2014 161,476 $ 4.75 Restricted stock vested (155,475 ) $ 4.75 Unvested at September 30, 2015 6,001 $ 4.75 Expected to vest as of September 30, 2015 3,753 $ 4.75
Restricted stock units
Equity based compensation
Summary of Status and Activity for Awards of Restricted Stock Units	The following table presents activity relating to RSUs under the 2010 and 2014 Plans during the nine months ended September 30, 2015 : Shares Weighted- Average Grant Date Fair Value Outstanding at December 31, 2014 4,542,231 $ 17.67 RSUs granted 1,840,624 $ 33.67 RSUs vested (1,114,485 ) $ 17.00 RSUs forfeited/canceled (353,032 ) $ 22.15 Outstanding at September 30, 2015 4,915,338 $ 23.62 Expected to vest as of September 30, 2015 3,629,795 $ 24.10

Segment and Geographic Inform25

Segment and Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Schedule of Operating Information by Segment	The following table presents the activity related to the Company’s 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 (in thousands): Three months ended September 30, Nine months ended September 30, 2015 2014 2015 2014 Net revenue Direct Retail $ 544,971 $ 285,502 $ 1,354,665 $ 755,036 Other 49,001 50,686 155,430 155,296 Net revenue $ 593,972 $ 336,188 $ 1,510,095 $ 910,332
Schedule of Revenue and Long-Lived Assets by Geographic Area	The following table presents revenue and long-lived assets by geographic area (in thousands): Three months ended September 30, Nine months ended September 30, 2015 2014 2015 2014 Geographic net revenue: United States $ 566,227 $ 314,754 $ 1,431,466 $ 851,585 International 27,745 21,434 78,629 58,747 Total $ 593,972 $ 336,188 $ 1,510,095 $ 910,332 September 30, December 31, Geographic long-lived assets: United States $ 86,426 $ 59,013 International 2,216 1,626 Total $ 88,642 $ 60,639

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Net Loss Per Share	The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Three months ended September 30, Nine months ended September 30, 2015 2014 2015 2014 Net loss $ (15,478 ) $ (24,143 ) $ (61,948 ) $ (75,544 ) Accretion of convertible redeemable preferred units — (4,748 ) — (16,503 ) Net loss attributable to common stockholders $ (15,478 ) $ (28,891 ) $ (61,948 ) $ (92,047 ) Weighted average common shares used for basic and diluted net loss per share computation 83,886 40,513 83,569 40,722 Net loss unit attributable to common stockholders per share: Basic and Diluted $ (0.18 ) $ (0.71 ) $ (0.74 ) $ (2.26 )
Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders as their Effect Would Have Been Antidilutive	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 and nine months ended September 30, 2015 2014 Series A convertible redeemable preferred units — 21,551,801 Series B convertible redeemable preferred units — 5,995,133 Stock options 302,617 643,003 Restricted stock 6,001 3,271,516 Restricted stock units 4,915,338 6,929,484 Total 5,223,956 38,390,937

Basis of Presentation (Details)

Basis of Presentation (Details) supplier in Thousands, product in Millions	9 Months Ended
	Sep. 30, 2015brandproductsupplier
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Minimum number of products offered | product	7
Minimum number of suppliers providing products offered	7
Number of distinct brands | brand	5

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Details)	9 Months Ended
	Sep. 30, 2015
Minimum
Marketable securities, maturity	1 year
Maximum
Marketable securities, maturity	3 years

Marketable Securities and Fai29

Marketable Securities and Fair Value Measurements (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Marketable securities and fair value measurements
Amortized Cost	$ 91,181,000
Gross Unrealized Gains	64,000
Gross Unrealized Losses	(131,000)
Estimated Fair Value	91,114,000	$ 0
Short-term
Marketable securities and fair value measurements
Amortized Cost	16,646,000
Gross Unrealized Gains	9,000
Gross Unrealized Losses	(1,000)
Estimated Fair Value	16,654,000
Long-term
Marketable securities and fair value measurements
Amortized Cost	74,535,000
Gross Unrealized Gains	55,000
Gross Unrealized Losses	(130,000)
Estimated Fair Value	$ 74,460,000

Marketable Securities and Fai30

Marketable Securities and Fair Value Measurements (Details 2) - Recurring - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Marketable securities and fair value measurements
Total	$ 303,341	$ 362,897
Level 1
Marketable securities and fair value measurements
Total	212,227	362,897
Level 2
Marketable securities and fair value measurements
Total	91,114
Cash equivalents
Marketable securities and fair value measurements
Money market funds	182,227	302,595
Cash equivalents | Level 1
Marketable securities and fair value measurements
Money market funds	182,227	302,595
Short-term
Marketable securities and fair value measurements
Certificates of deposit	30,000	60,000
Investment securities	16,654
Short-term | Level 1
Marketable securities and fair value measurements
Certificates of deposit	30,000	60,000
Short-term | Level 2
Marketable securities and fair value measurements
Investment securities	16,654
Long-term
Marketable securities and fair value measurements
Investment securities	74,460
Long-term | Level 2
Marketable securities and fair value measurements
Investment securities	$ 74,460
Restricted cash
Marketable securities and fair value measurements
Money market funds		302
Restricted cash | Level 1
Marketable securities and fair value measurements
Money market funds		$ 302

Intangible Assets and Goodwil31

Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Intangible assets
Gross Carrying Amount	$ 6,360		$ 6,360		$ 7,187
Accumulated Amortization	(4,385)		(4,385)		(4,333)
Net Book Value	1,975		1,975		2,854
Amortization expense related to intangibles	208	$ 249	694	$ 748
Goodwill
Goodwill, beginning of period			3,624
Sale during the period			(1,520)
Foreign currency exchange rate effect			(180)
Goodwill, end of period	1,924		1,924		$ 3,624
Gain on sale of business			2,997	$ 0
Australian Business
Goodwill
Goodwill, end of period	1,500		1,500
Carrying amount of the intangible assets	200		$ 200
Trademarks
Intangible assets
Weighted-Average Amortization Period			5 years		5 years
Gross Carrying Amount	1,900		$ 1,900		$ 2,001
Accumulated Amortization	(823)		(823)		(604)
Net Book Value	1,077		$ 1,077		$ 1,397
Customer relationships
Intangible assets
Weighted-Average Amortization Period			5 years		5 years
Gross Carrying Amount	1,300		$ 1,300		$ 1,300
Accumulated Amortization	(563)		(563)		(368)
Net Book Value	737		737		932
Non-compete agreements
Intangible assets
Gross Carrying Amount	100		100		108
Accumulated Amortization	(72)		(72)		(52)
Net Book Value	28		$ 28		$ 56
Non-compete agreements | Minimum
Intangible assets
Weighted-Average Amortization Period			3 years		3 years
Non-compete agreements | Maximum
Intangible assets
Weighted-Average Amortization Period			5 years		5 years
Technology
Intangible assets
Weighted-Average Amortization Period					5 years
Gross Carrying Amount					$ 718
Accumulated Amortization					(467)
Net Book Value					$ 251
Other intangibles
Intangible assets
Weighted-Average Amortization Period			3 years		3 years
Gross Carrying Amount	373		$ 373		$ 373
Accumulated Amortization	(242)		(242)		(158)
Net Book Value	131		$ 131		$ 215
Domain names
Intangible assets
Weighted-Average Amortization Period			5 years		5 years
Gross Carrying Amount	2,687		$ 2,687		$ 2,687
Accumulated Amortization	(2,685)		(2,685)		(2,684)
Net Book Value	$ 2		2		$ 3
Other income (expense), net | Australian Business
Goodwill
Gain on sale of business			$ 3,000

Property and Equipment, net (De

Property and Equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Property and equipment, net
Property and equipment, gross	$ 145,441		$ 145,441		$ 103,783
Less accumulated depreciation and amortization	(56,799)		(56,799)		(43,144)
Property and equipment, net	88,642		88,642		60,639
Depreciation and amortization	9,000	$ 5,300	22,700	$ 13,600
Furniture and computer equipment
Property and equipment, net
Property and equipment, gross	60,881		60,881		48,399
Site and software development costs
Property and equipment, net
Property and equipment, gross	47,653		47,653		36,294
Leasehold improvements
Property and equipment, net
Property and equipment, gross	27,351		27,351		14,290
Construction in progress
Property and equipment, net
Property and equipment, gross	$ 9,556		$ 9,556		$ 4,800

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Rental expense under operating leases	$ 3.8	$ 2.6	$ 12.3	$ 8.8
Letter of credit issued as security for lease agreements	$ 4.7		$ 4.7		$ 3.3

Commitments and Contingencies34

Commitments and Contingencies (Details 2) $ in Millions	Sep. 30, 2015USD ($)
Sales and other similar tax assessments
Contingencies
Aggregate amount of claims	$ 12.9

Equity-Based Compensation (Deta

Equity-Based Compensation (Details) $ / shares in Units, $ in Millions	1 Months Ended	9 Months Ended		12 Months Ended
	Apr. 30, 2014USD ($)$ / sharesshares	Sep. 30, 2015USD ($)vesting_trigger$ / sharesshares	Sep. 30, 2014USD ($)	Dec. 31, 2014$ / sharesshares
Equity based compensation
Number of vesting triggers | vesting_trigger		2
Service period		5 years
2014 Plan
Equity based compensation
Number of shares authorized		8,603,066
Restricted stock units
Equity based compensation
Shares issued under plan		1,840,624
Restricted stock units | 2014 Plan
Equity based compensation
Shares issued under plan		1,840,624
Stock options
Equity based compensation
Number of shares tendered	9,028
Common stock options
Outstanding at the beginning of the period (in shares)		449,046
Options exercised (in shares)		(143,887)
Options forfeited/cancelled (in shares)		(2,542)
Outstanding at the end of the period (in shares)		302,617		449,046
Exercisable at the end of the period (in shares)		298,336
Expected to vest at the end of the period (in shares)		2,676
Weighted- Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares		$ 2.98
Exercised (in dollars per share) | $ / shares		2.96
Forfeited/canceled (in dollars per share) | $ / shares		3.24
Outstanding at the end of the period (in dollars per share) | $ / shares		2.98		$ 2.98
Exercisable at the end of the period (in dollars per share) | $ / shares		2.98
Expected to vest at the end of the period (in dollars per share) | $ / shares		$ 3.42
Weighted- Average Remaining Contractual Term (Years)
Outstanding at the beginning of the period		5 years 8 months 19 days		6 years 6 months
Outstanding at the end of the period		5 years 8 months 19 days		6 years 6 months
Exercisable at the end of the period		5 years 8 months 19 days
Expected to vest at the end of the period		5 years 8 months 19 days
Additional disclosures
Aggregate intrinsic value of stock options exercised | $		$ 4.4
Aggregate intrinsic value of stock options outstanding and repurchased | $		9.7
Aggregate intrinsic value of stock options exercisable | $		9.6
Unrecognized share-based compensation (less than) | $		$ 0.1
Weighted average remaining vesting term for options expected to vest		2 months 19 days
Restricted stock
Equity based compensation
Number of shares tendered	202,757
Common stock options and restricted common stocks
Equity based compensation
Tender offer price per unit | $ / shares	$ 26.23
Payments of repurchase of stock | $	$ 5.5
Compensation charge | $	$ 5.5
Share based compensation expenses | $			$ 5.5

Equity-Based Compensation (De36

Equity-Based Compensation (Details 2) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015
Restricted stock
Restricted stock and units
Outstanding at the beginning of the period (in shares)	161,476
Vested (in shares)	(155,475)
Unvested at the end of the period (in shares)	6,001
Expected to vest at the end of the period (in shares)	3,753
Weighted-Average Grant-Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 4.75
Vested (in dollars per share)	4.75
Unvested at the end of the period (in dollars per share)	4.75
Expected to vest at the end of the period (in dollars per share)	$ 4.75
Additional information
Intrinsic value of stock vested and repurchased	$ 4.1
Aggregate intrinsic value		$ 0.2
Unrecognized share-based compensation	$ 0.1
Weighted average remaining vesting term for options expected to vest	2 months 5 days
Restricted stock units
Restricted stock and units
Outstanding at the beginning of the period (in shares)	4,542,231
Granted (in shares)	1,840,624
Vested (in shares)	(1,114,485)
Forfeited/cancelled (in shares)	(353,032)
Unvested at the end of the period (in shares)	4,915,338
Expected to vest at the end of the period (in shares)	3,629,795
Weighted-Average Grant-Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 17.67
Granted (in dollars per share)	33.67
Vested (in dollars per share)	17
Forfeited/cancelled (in dollars per share)	22.15
Unvested at the end of the period (in dollars per share)	23.62
Expected to vest at the end of the period (in dollars per share)	$ 24.10
Additional information
Intrinsic value of stock vested	$ 35.4
Aggregate intrinsic value	172.3
Unrecognized share-based compensation	$ 60.7
Weighted average remaining vesting term for options expected to vest	1 year 7 months 24 days

Segment and Geographic Inform37

Segment and Geographic Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)segment	Sep. 30, 2014USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			1
Number of reportable segments | segment			1
Net revenue
Direct Retail	$ 544,971	$ 285,502	$ 1,354,665	$ 755,036
Other	49,001	50,686	155,430	155,296
Net revenue	$ 593,972	$ 336,188	$ 1,510,095	$ 910,332

Segment and Geographic Inform38

Segment and Geographic Information (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Geographic net revenue:
Geographic net revenue	$ 593,972	$ 336,188	$ 1,510,095	$ 910,332
Geographic long-lived assets:
Geographic long-lived assets	88,642		88,642		$ 60,639
United States
Geographic net revenue:
Geographic net revenue	566,227	314,754	1,431,466	851,585
Geographic long-lived assets:
Geographic long-lived assets	86,426		86,426		59,013
International
Geographic net revenue:
Geographic net revenue	27,745	$ 21,434	78,629	$ 58,747
Geographic long-lived assets:
Geographic long-lived assets	$ 2,216		$ 2,216		$ 1,626

Income Taxes (Detail)

Income Taxes (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Taxes
(Benefit from) provision for income taxes (less than)	$ (88,000)	$ 59,000	$ 31,000	$ 76,000
Recognition of previously unrecognized tax benefit	200,000		200,000
Current income tax expense (benefit)
Current federal income tax expense (benefit)		0		0
Current state income tax expense (benefit)		0		0
Components of deferred tax assets and liabilities
Gross unrecognized tax benefits	$ 0		$ 0		$ 200,000
Maximum | Foreign
Income Taxes
(Benefit from) provision for income taxes (less than)		$ 100,000		$ 100,000

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ / shares in Units, $ in Millions	Oct. 07, 2014USD ($)$ / sharesshares	Oct. 01, 2014USD ($)	Oct. 31, 2014USD ($)$ / sharesshares	Mar. 31, 2014USD ($)	Sep. 30, 2015USD ($)vote$ / sharesshares	Sep. 30, 2015$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Stockholders' Equity
Accumulated deficit transferred to additional paid in capital | $		$ 306.2
Preferred stock, shares authorized			10,000,000		10,000,000	10,000,000	10,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.001		$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares issued					0	0	0
Preferred stock, shares outstanding					0	0
Class A common stock
Common stock
Common stock, shares authorized					500,000,000	500,000,000	500,000,000
Common stock, par value (in dollars per share) | $ / shares					$ 0.001	$ 0.001	$ 0.001
Common stock, shares outstanding					44,145,083	44,145,083	37,002,874
Number of votes each holder is entitled | vote					1
Class A common stock | Initial Public Offering
Common stock
Initial public offering, aggregate number of shares of common stock sold	12,650,000
Share issue price (in dollars per share) | $ / shares	$ 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 | $	$ 282.9
Class B common stock
Common stock
Common stock, shares authorized					164,000,000	164,000,000	164,000,000
Common stock, par value (in dollars per share) | $ / shares					$ 0.001	$ 0.001	$ 0.001
Common stock, shares outstanding					39,894,391	39,894,391	46,179,192
Number of votes each holder is entitled | vote					10
Conversion ratio					1
Conversion ratio following the completion of the offering					1
Conversion ratio upon transfer					1
Number of shares converted into Class A shares						30,708,834
Class B common stock | Minimum
Common stock
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%
Class B common stock | Maximum
Common stock
Aggregate number of shares outstanding Class A common stock and Class B common stock that shall convert automatically (less than)					10.00%
Series A and Series B convertible redeemable preferred units | Class B common stock
Stockholders' Equity
Conversion of units to common stock (in shares)					27,546,934
Series A convertible redeemable preferred units
Stockholders' Equity
Accretion of convertible redeemable preferred units | $							$ 14.4	$ 25.4	$ 12.2
Reduction of accretion expenses | $					$ 14.8
Accrued dividend distribution | $			$ 24.5	$ 15
Series B convertible redeemable preferred units
Stockholders' Equity
Accretion of convertible redeemable preferred units | $							$ 2.5

Credit Agreement (Details)

Credit Agreement (Details) - USD ($)	Sep. 30, 2015	Jul. 31, 2015	Dec. 31, 2014
Credit agreement
Borrowings outstanding	$ 0		$ 0
Revolving line of credit
Credit agreement
Maximum borrowing capacity		$ 10,000,000
Wayfair, Inc. | July 31, 2015 through September 30, 2015 | Line of credit
Credit agreement
Maximum borrowing capacity		35,000,000
Wayfair, Inc. | October 1, 2015 through February 28, 2016 | Line of credit
Credit agreement
Maximum borrowing capacity		45,000,000
Wayfair, Inc. | March 1, 2016 through July 31, 2016 | Line of credit
Credit agreement
Maximum borrowing capacity		$ 35,000,000

Net Loss per Share (Details)

Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Anti-dilutive securities
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	5,223,956	38,390,937	5,223,956	38,390,937
Numerator:
Net loss	$ (15,478)	$ (24,143)	$ (61,948)	$ (75,544)
Accretion of convertible redeemable preferred units	0	(4,748)	0	(16,503)
Net loss attributable to common stockholders	$ (15,478)	$ (28,891)	$ (61,948)	$ (92,047)
Denominator:
Weighted average common shares used for basic and diluted net loss per share computation (in shares)	83,886,000	40,513,000	83,569,000	40,722,000
Net loss unit attributable to common stockholders per share:
Basic and Diluted (in dollars per share)	$ (0.18)	$ (0.71)	$ (0.74)	$ (2.26)
Series A convertible redeemable preferred units
Anti-dilutive securities
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	0	21,551,801	0	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	0	5,995,133	0	5,995,133
Stock options
Anti-dilutive securities
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	302,617	643,003	302,617	643,003
Restricted stock
Anti-dilutive securities
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	6,001	3,271,516	6,001	3,271,516
Restricted stock units
Anti-dilutive securities
Common stockholders outstanding that were excluded from the computation of diluted net loss per share	4,915,338	6,929,484	4,915,338	6,929,484
Class B common stock
Numerator:
Net loss	$ (15,478)	$ (24,143)	$ (61,948)	$ (75,544)
Accretion of convertible redeemable preferred units	0	(4,748)	0	(16,503)
Net loss attributable to common stockholders	$ (15,478)	$ (28,891)	$ (61,948)	$ (92,047)
Denominator:
Weighted average common shares used for basic and diluted net loss per share computation (in shares)	83,886,000		83,569,000
Net loss unit attributable to common stockholders per share:
Basic and Diluted (in dollars per share)	$ (0.18)	$ (0.71)	$ (0.74)	$ (2.26)