Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 29, 2014
Accounting Policies [Abstract]
Principles of Consolidation	The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary, Zulily UK Ltd. All intercompany transactions and balances are eliminated in consolidation. Reclassifications—Certain reclassifications have been made to the condensed consolidated financial statements in the prior period to conform to the current period presentation.
Fiscal Year	In 2011, the Company adopted a retail calendar whereby the fiscal year ends on the Sunday closest to December 31. Each fiscal year consists of four 13-week quarters, with one extra week added in the fourth quarter every five to six years.
Accounting Estimates	The preparation of unaudited condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances, the result of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results could differ materially from those estimates.
Cash and Cash Equivalents	The Company maintains the majority of its cash and cash equivalents in accounts with major financial institutions within the United States, generally in the form of demand and money market accounts.
Risks and Concentrations	The Company is subject to certain risks and concentrations, including dependence on third-party technology providers and hosting services, exposure to risks associated with online commerce security, consumer credit risk, and credit card fraud, as well as the interpretation of state and local laws and regulations in regards to the collection and remittance of sales and use taxes and occupancy taxes. The Company also depends upon third-party service providers for processing customer orders.
Recent Accounting Pronouncements	In July 2013, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar tax Loss, or a Tax Credit Carryforward Exists ("ASU 2013-11"). The amendments in this update require an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows: To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The assessment of whether a deferred tax asset is available is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date and should be made presuming disallowance of the tax position at the reporting date. The amendments in this update do not require new recurring disclosures. For public entities, ASU 2013-11 is effective for annual and interim periods beginning after December 15, 2013. The Company adopted ASU 2013-11 in the first quarter of 2014 and it did not have a material impact on our consolidated financial statements or related disclosures. In May 2014, the Financial Accounting Standards Board (“FASB”) issued an Accounting Standard Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”) amending revenue recognition guidance and requiring more detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The guidance is effective for annual and interim reporting periods beginning after December 15, 2016, with early adoption prohibited. We are currently evaluating the impact this ASU will have on our consolidated financial statements.

Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value.

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Disclosure of accounting policy for credit risk.

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Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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- Definition

Disclosure of accounting policy for determining an entity's fiscal year or other fiscal period. This disclosure may include identification of the fiscal period end-date, the length of the fiscal period, any reporting period lag between the entity and its subsidiaries, or equity investees. If a reporting lag exists, the closing date of the entity having a different period end is generally noted, along with an explanation of the necessity for using different closing dates. Any intervening events that materially affect the entity's financial position or results of operations are generally also disclosed.

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