Summary of Operations and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, these financial statements do not include all information and footnotes required by U.S. GAAP for complete financial statements.
Unaudited Interim Financial Statements	The interim consolidated balance sheet as of September 30, 2016, the consolidated statements of operations and comprehensive income for the three and nine months ended September 30, 2016 and 2015, and the consolidated statement of cash flows for the nine months ended September 30, 2016 and 2015 are unaudited. The consolidated balance sheet as of December 31, 2015, included herein, was derived from the audited financial statements as of that date, but does not include all disclosures required by U.S. GAAP. These unaudited interim financial statements have been prepared on a basis consistent with the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary to state fairly the Company’s financial position as of September 30, 2016 and its consolidated results of operations, comprehensive income and cash flows for the three and nine months ended September 30, 2016 and 2015. The financial data and the other financial information disclosed in the notes to the financial statements related to these periods are also unaudited. The results of operations for the three and nine months ended September 30, 2016 are not necessarily indicative of the results to be expected for the fiscal year ending December 31, 2016 or for any other future annual or interim period. There have been no material changes in the significant accounting policies from those that were disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2015 filed with the SEC on February 24, 2016. These financial statements should also be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2015. The unaudited consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Certain immaterial changes in presentation have been made to conform the prior period presentation to current period reporting.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires the Company’s management to make a number of estimates and assumptions relating to the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the period. The Company evaluates its significant estimates on an ongoing basis, including, but not limited to allowance for doubtful accounts, sales refund reserve, accruals related to self-insurance, the fair value of goodwill, intangible assets and other long-lived assets, non-cash equity-based compensation, the fair value of contingent consideration, the provision for income taxes and the amount of certain non-income tax accruals. The Company bases its estimates on historical experience and on various other assumptions that it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.
Restricted Cash	Restricted Cash The Company’s restricted cash relates to security deposits for its office leases. As of September 30, 2016 and December 31, 2015, the Company had restricted cash of approximately $2.6 million and $1.8 million, respectively, in other assets that related to the lease for its headquarters in New York City, which expires in 2029. In January 2016, this lease was amended to provide additional space and extend the lease term, which required an increased security deposit. The carrying value of restricted cash approximates fair value.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company’s accounts receivable consist of customer obligations due under normal trade terms, carried at their face value less an allowance for doubtful accounts, if required. The Company determines its allowance for doubtful accounts based on an evaluation of the aging of its accounts receivable and on a customer-by-customer basis where appropriate. The Company’s reserve analysis contemplates the Company’s historical loss rate on receivables, specific customer situations and the economic environments in which the Company operates.
Deferred Rent	Deferred Rent The Company records rent expense on a straight-line basis over the term of the related lease. The difference between the rent expense recognized and the actual payments made in accordance with the lease agreement is recognized as a deferred rent liability on the Company’s balance sheet.
Chargeback and Sales Refund Allowance	Chargeback and Sales Refund Allowance The majority of the Company’s customers purchase products by making an electronic payment with a credit card at the time of a transaction. The Company establishes a chargeback allowance and sales refund reserve allowance based on factors surrounding historical credit card chargeback trends, historical sales refund trends and other information.
Medical Self-insurance Costs	Medical Self-insurance Costs The Company is partially self-insured for claims relating to employee medical benefit programs. The medical self-insurance program is administered by a third party and contains stop-loss provisions on both an individual claim basis and in aggregate. The Company records claims incurred as an expense each period, including an estimate of claims incurred but not yet reported. The Company uses claims data and historical experience, as applicable, to estimate the liability for unreported claims and believes that the methodologies used to estimate insurance liabilities result in an accurate reflection of the liabilities as of the date of the balance sheet.
Contingent Consideration	Contingent Consideration The Company records a liability for contingent consideration at the date of a business combination and reassesses the fair value of the liability each period until it is settled. Upon settlement of these liabilities, the portion of the contingent consideration payment that is attributable to the initial amount recorded as part of the business combination is classified as a cash flow from financing activities and the portion of the settlement that is attributable to subsequent changes in the fair value of the contingent consideration is classified as a cash flow from operating activities in the consolidated statement of cash flows.
Income Taxes	Income Taxes The Company’s income tax expense includes U.S. (federal and state) and foreign income taxes. Significant management judgment is required in projecting ordinary income in order to determine the Company’s estimated effective tax rate. The Company has assessed the realizability of deferred tax assets and determined that based on the available evidence, including a history of taxable income and estimates of future taxable income, it is more likely than not that the deferred tax assets will be realized. Quarterly, the Company will continue to evaluate its ability to realize deferred tax assets. Significant management judgment is required in determining the provision for income taxes and deferred tax assets and liabilities. In the event that actual results differ from these estimates, the Company will adjust these estimates in future periods, which may result in a change in the effective tax rate in a future period.
Recently Issued Accounting Standard Updates	Recently Issued Accounting Standard Updates In August 2016, the Financial Accounting Standards Board (“FASB”) issued new guidance related to the statement of cash flows. The new guidance is intended to provide clarification and reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017 and should be applied retrospectively. Early adoption is permitted, provided that all of the amendments are adopted in the same period. The Company is evaluating the impact of adopting this new accounting standard on its financial statements. In June 2016, the FASB issued new guidance which replaces the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses. The update is intended to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. Adoption of this guidance is required, prospectively, for annual periods beginning after December 15, 2019, with early adoption permitted for annual periods beginning after December 15, 2018. The Company is evaluating the impact of adopting this new accounting standard on its financial statements. In March 2016, the FASB issued new guidance related to stock-based compensation. The new standard changes how companies account for certain aspects of share-based payment awards to employees, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as the classification of certain related items in the statement of cash flows. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. Early adoption is permitted. Amendments related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value should be applied using a modified retrospective approach; amendments related to the recognition of excess tax benefits and tax deficiencies in the income statement and the practical expedient for estimating expected term should be applied prospectively; and amendments related to the presentation of excess tax benefits on the statement of cash flows may be applied prospectively or retrospectively. The Company is evaluating the impact of adopting this new accounting standard on its financial statements. In February 2016, the FASB issued new guidance related to leases. The new standard requires that the rights and obligations created by leases with a duration greater than 12 months be recorded as assets and liabilities on the balance sheet of the lessee. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 and can be applied using a modified retrospective approach for all leases entered into before the effective date. Early adoption is permitted. The Company is evaluating the impact of adopting this new accounting standard on its financial statements. In November 2015, the FASB issued new guidance related to income taxes. The new standard requires that all deferred tax assets and liabilities, and any related valuation allowance, be classified as non-current on the balance sheet. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016, although early adoption is permitted and can be applied either prospectively or retrospectively to all periods presented. The Company is evaluating the impact of adopting this new accounting standard on its financial statements. In May 2014, the FASB issued new accounting guidance related to revenue recognition. This new standard will replace all current U.S. GAAP guidance on this topic and will eliminate all industry-specific guidance. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. On July 9, 2015, the FASB approved the deferral of the effective date of this guidance by one year. As a result, this new guidance will be effective for the fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. The Company may choose to adopt the standard as of the original effective date for annual reporting periods beginning after December 15, 2016; if it does so, the Company is required to apply the standard beginning in the first interim period within the year of adoption. The Company is evaluating the impact of adopting this new accounting standard on its financial statements.