Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2013
Summary of Significant Accounting Policies
Basis of Presentation	*Basis of Presentation* The accompanying unaudited interim consolidated financial statements and footnotes have been prepared in accordance with generally accepted accounting principles in the United States of America (“US GAAP”) and applicable rules and regulations of the Securities and Exchange Commissions (the “SEC”) regarding unaudited interim financial information. In the opinion of management, the accompanying unaudited interim consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the Company’s consolidated balance sheets, statements of operations, comprehensive loss, mandatorily redeemable convertible preferred stock and changes in stockholders’ equity (deficit) and cash flows for the interim periods presented. Operating results for the interim periods presented are not necessarily indicative of the results of operations to be expected for the full year due to seasonal and other factors. Certain information and footnote disclosures normally included in the consolidated financial statements in accordance with US GAAP have been omitted in accordance with the rules and regulations of the SEC. Accordingly, these unaudited interim consolidated financial statements and footnotes should be read in conjunction with the consolidated financial statements and accompanying notes thereto included in the Company’s prospectus dated June 26, 2013, filed with the SEC on June 27, 2013 pursuant to Rule 424(b)(4) under the Securities Act (“Prospectus”).
Principles of Consolidation	*Principles of Consolidation* The unaudited interim consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All inter-company balances and transactions have been eliminated in the accompanying unaudited interim consolidated financial statements.
Initial Public Offering	*Initial Public Offering* On July 2, 2013, the Company closed its initial public offering (“IPO”) of common stock in which the Company issued and sold 7,500,000 shares of common stock. Upon closing of the IPO, all of the Company’s outstanding mandatorily redeemable convertible preferred stock (“preferred stock”) automatically converted into 34,172,316 shares of common stock, which includes a one-time $15,849 non-cash preferred stock deemed dividend related to 1,584,863 of additional shares of common stock in connection with to the Series F preferred stock ratchet provision (refer to note 10), and all of the Company’s outstanding Series II common stock automatically converted into 1,052,464 shares of common stock. In addition, the outstanding warrants to purchase preferred stock automatically converted into warrants to purchase 142,534 shares of common stock, and the warrants to purchase preferred stock liability of $790, which includes a $136 adjustment for the change in fair value from July 1, 2013 through July 2, 2013, was reclassified to additional paid-in capital.
Recently Issued Accounting Pronouncements	*Recently Issued Accounting Pronouncements* FASB Accounting Standards Update No. 2013-02 — Comprehensive Income: Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income In February 2013, the Financial Accounting Standards Board (“FASB”) issued new authoritative guidance requiring new disclosures about reclassifications from accumulated other comprehensive income to net loss. This new guidance requires an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present, either on the face of the financial statements where net loss is presented or in the notes thereto, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net loss but only if the amount reclassified is required under US GAAP to be reclassified to net loss in its entirety in the same reporting period. For other amounts that are not required under US GAAP to be reclassified in their entirety to net loss, an entity is required to cross-reference to other disclosures required under US GAAP that provide additional detail about those amounts. The new guidance is effective prospectively for annual and interim periods beginning after December 15, 2012. The Company adopted this guidance in its interim period beginning April 1, 2013. The adoption of this new guidance did not have a material impact on its unaudited interim consolidated financial statements and the required disclosures are provided in note 11.
Revenue Recognition and Deferred Revenue	*Revenue Recognition and Deferred Revenue* The Company generates revenue primarily from the delivery of in-stream video advertisements for brand advertisers and agencies through the Tremor Video Network. The Company also generates revenue from selling licenses to advertisers, agencies and publishers. Revenue is recognized when the related services are delivered based on the specific terms of the contract, which are commonly based on the number of impressions delivered or by the actions of the viewers. The Company recognizes revenue when four basic criteria are met: (1) persuasive evidence exists of an arrangement with the client reflecting the terms and conditions under which the services will be provided; (2) services have been provided or delivery has occurred; (3) the fee is fixed or determinable; and (4) collection is reasonably assured. Collectability is assessed based on a number of factors, including the creditworthiness of a client and transaction history. Amounts billed or collected in excess of revenue recognized are included as deferred revenue. The Company recognizes revenue from the delivery of video ads in the period in which the video ads are delivered. Specifically, revenue is recognized for video ad delivery through the Tremor Video Network upon either the delivery of each impression served for CPM-priced ad campaigns, delivery of each impression served to a target demographic as validated by a third-party for ad campaigns priced on a CPM-basis with a guaranteed demographic reach, engagement by the viewer with a video ad for cost per engagement (“CPE”) priced ad campaigns, or the completion of a video ad by the viewer for cost per video completed (“CPVC”) priced ad campaigns. In the normal course of business, the Company acts as an intermediary in executing transactions with third parties. The determination of whether revenue should be reported on a gross or net basis is based on an assessment of whether the Company is acting as the principal or an agent in the Company’s transactions. In determining whether the Company acts as the principal or an agent, the Company follows the accounting guidance for principal-agent considerations. The determination of whether the Company is acting as a principal or an agent in a transaction involves judgment and is based on an evaluation of the terms of each arrangement. While none of the factors individually are considered presumptive or determinative, because the Company is the primary obligor and is responsible for (1) identifying and contracting with third-party advertisers, (2) establishing the selling prices of the video ads sold, (3) performing all billing and collection activities, including retaining credit risk, and (4) bearing sole responsibility for fulfillment of the advertising, the Company acts as the principal in these arrangements and therefore reports revenue earned and costs incurred related to these transactions on a gross basis. The license fees for VHA and the Company’s publisher solutions are based on the number of impressions being analyzed through these solutions. The Company recognizes revenue with respect to these solutions on a cost per impression basis based on the number of impressions being analyzed in a given month. Typically, the Company’s license terms are for one year periods. In limited cases, the Company charges a minimum monthly fee. Deferred revenue arises as a result of differences between the timing of revenue recognition and receipt of cash from the Company’s clients. As of September 30, 2013 and December 31, 2012 there were $194 and $210, respectively, of services for which cash payments were received in advance of the Company’s performance of the service under the arrangement and recorded as deferred revenue in the accompanying consolidated balance sheets.
Cost of Revenue	*Cost of Revenue* Cost of revenue primarily represents the video advertising inventory costs under the Company’s publisher contracts, third party hosting fees and third party serving fees incurred to deliver the video ads run through the Tremor Video Network. Cost of revenue also includes costs of licenses from third party data providers utilized in the Company’s VHA solution. Substantially all of the Company’s cost of revenue is attributable to video advertising inventory costs under its publisher contracts. Cost of revenue is recognized on a publisher-by-publisher basis at the same time that the associated advertising revenue is recognized. Substantially all of the Company’s exclusive publisher contracts contain minimum percentage fill rates on qualified video ad requests, which effectively means that the Company must purchase this inventory even if the Company lacks a video advertising campaign to deliver to these video ad impressions. The Company recognizes the difference between the contractually required fill rate and the number of video ads actually delivered on the publisher’s website, if any, as a cost of revenue as of the end of each applicable monthly period. Historically, the impact of the difference between the contractually required fill rate and the number of ads delivered has not been material. Costs owed to publishers but not yet paid are recorded in the consolidated balance sheets as accounts payable and accrued expenses.
Concentrations of Credit Risk	*Concentrations of Credit Risk* Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. All of the Company’s cash and cash equivalents are held at financial institutions that management believes to be of high credit quality. The Company’s cash and cash equivalent accounts exceed federally insured limits at times. The Company has not experienced any losses on cash and cash equivalents to date. To manage accounts receivable risk, the Company evaluates the creditworthiness of its clients and maintains an allowance for doubtful accounts. During the three and nine months ended September 30, 2013, there was one advertiser that accounted for approximately 10.5% and 10.7% of revenue, respectively. During the three and nine months ended September 30, 2012, there were no advertisers that accounted for more than 10% of revenue. As of September 30, 2013 and December 31, 2012, there were no advertisers that accounted for more than 10% of outstanding accounts receivables.

Disclosure of accounting policy for credit risk.

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- Definition

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 recognition of costs in the period which correspond to the sales and revenue categories presented in the statement of operations. The accounting policy may include the amount and nature of costs incurred, provisions associated with inventories, purchase discounts, freight and other costs included in cost of sales incurred and recorded in the period. This disclosure also includes the nature of costs of sales incurred and recorded in the statement of operations for the period relating to transactions with related parties.

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- Definition

Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.

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