Organization and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Organization and Summary of Significant Accounting Policies
Principles of Consolidation	Principles of Consolidation The accompanying condensed consolidated financial statements include all the accounts of the Company and its wholly-owned subsidiaries. The Company had two wholly-owned subsidiaries at March 31, 2015: Genomic Health International Holdings, LLC, which was established in Delaware in 2010 and supports the Company’s international sales and marketing efforts; and Oncotype Laboratories, Inc., which was established in 2012, and is inactive. Genomic Health International Holdings, LLC has 10 wholly-owned subsidiaries. The functional currency for the Company’s wholly-owned subsidiaries incorporated outside the United States is the U.S. dollar. All significant intercompany balances and transactions have been eliminated.
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The accompanying interim period condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). The condensed consolidated balance sheet as of March 31, 2015, and the condensed consolidated statements of operations, comprehensive income (loss), and cash flows for the three months ended March 31, 2015 and 2014 are unaudited, but include all adjustments, consisting only of normal recurring adjustments, which the Company considers necessary for a fair presentation of its financial position, operating results and cash flows for the periods presented. The condensed consolidated balance sheet at December 31, 2014 has been derived from audited financial statements, but it does not include certain information and notes required by GAAP for complete consolidated financial statements. The preparation of financial statements in conformity with GAAP requires management to make judgments, assumptions and estimates that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosures in the Company’s condensed consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates. The accompanying interim period condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. Certain reclassifications have been made to prior period amounts to conform to the current period presentation. For the period ended March 31, 2014, a reclassification of certain expenses from research and development to selling and marketing was made in the condensed consolidated statements of operations to conform to the current period presentation.
Revenue Recognition	Revenue Recognition The Company derives its revenues from product sales and contract research arrangements. The majority of the Company’s historical product revenues have been derived from the sale of the Oncotype DX breast cancer test. The Company generally bills third‑party payors upon generation and delivery of a patient report to the physician. As such, the Company takes assignment of benefits and the risk of collection with the third‑party payor. The Company usually bills the patient directly for amounts owed after multiple requests for payment have been denied or only partially paid by the insurance carrier. The Company pursues case‑by‑case reimbursement where medical policies are not in place or payment history has not been established. The Company’s product revenues for tests performed are recognized when the following revenue recognition criteria are met: (1) persuasive evidence that an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured. Criterion (1) is satisfied when the Company has an arrangement to pay or a contract with the payor in place addressing reimbursement for the Oncotype DX test. In the absence of such arrangements, the Company considers that criterion (1) is satisfied when a third‑party payor pays the Company for the test performed. Criterion (2) is satisfied when the Company performs the test and generates and delivers to the physician, or makes available on its web portal, a patient report. When evaluating whether the fee is fixed or determinable and collectibility, we consider whether we have sufficient history to reliably estimate the total fee that will be received from a payor and a payor’s individual payment patterns. Determination of criteria (3) and (4) are based on management’s judgments regarding whether the fee charged for products or services delivered is fixed or determinable, and the collectability of those fees under any contract or arrangement. Based upon at least several months of payment history, the Company reviews the number of tests paid against the number of tests billed and the payor’s outstanding balance for unpaid tests to determine whether payments are being made at a consistently high percentage of tests billed and at appropriate amounts given the contracted payment amount. The estimated accrual amounts per test, recorded upon delivery of a patient report, are calculated for each accrual payor and are based on the contracted price adjusted for individual payment patterns resulting from co-payment amounts and excluded services in healthcare plans. The Company also reduces sales for an estimate of amounts that qualify as patient assistance and related deductions that do not qualify for revenue recognition. When a payment received for an individual test is either higher or lower than the estimated accrual amount, the Company recognizes the difference as either cash revenue, in the case of higher payments, or in the case of lower payments, against either the patient assistance program and related deductions reserve or the allowance for doubtful accounts, as applicable. To the extent all criteria set forth above are not met when test results are delivered, product revenues are recognized when cash is received from the payor. The Company has exclusive distribution agreements for one or more of its Oncotype DX tests with distributors covering more than 90 countries. The distributor generally provides certain marketing and administrative services to the Company within its territory. As a condition of these agreements, the distributor generally pays the Company an agreed upon fee per test and the Company processes the tests. The same revenue recognition criteria described above generally apply to tests received through distributors. To the extent all criteria set forth above are not met when test results are delivered, product revenues are generally recognized when cash is received from the distributor. From time to time, the Company receives requests for refunds of payments, generally due to overpayments made by third-party payors. Upon becoming aware of a refund request, the Company establishes an accrued liability for tests covered by the refund request until such time as the Company determines whether or not a refund is due. Accrued refunds were $1.1 million and $944,000 at March 31, 2015 and December 31, 2014, respectively, and included in accrued expenses and other current liabilities. Contract revenues are generally derived from studies conducted with biopharmaceutical and pharmaceutical companies. The specific methodology for revenue recognition is determined on a case‑by‑case basis according to the facts and circumstances applicable to a given contract. Under certain contracts, the Company’s input, measured in terms of full‑time equivalent level of effort or running a set of assays through its clinical reference laboratory under a contractual protocol, triggers payment obligations, and revenues are recognized as costs are incurred or assays are processed. Certain contracts have payments that are triggered as milestones are completed, such as completion of a successful set of experiments. Milestones are assessed on an individual basis and revenue is recognized when these milestones are achieved, as evidenced by acknowledgment from collaborators, provided that (1) the milestone event is substantive and its achievability was not reasonably assured at the inception of the agreement and (2) the milestone payment is non‑refundable. Where separate milestones do not meet these criteria, the Company typically defaults to a performance‑based model, such as revenue recognition following delivery of effort as compared to an estimate of total expected effort. There was no contract revenue for the three months ended March 31, 2015 and 2014. Advance payments received in excess of revenues recognized are classified as deferred revenue until such time as the revenue recognition criteria have been met.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company accrues an allowance for doubtful accounts against its accounts receivable based on estimates consistent with historical payment experience. Bad debt expense is included in general and administrative expense on the Company’s condensed consolidated statements of operations. Accounts receivable are written off against the allowance when the appeals process is exhausted, when an unfavorable coverage decision is received or when there is other substantive evidence that the account will not be paid. The Company’s allowance for doubtful accounts as of March 31, 2015 and December 31, 2014 was $3.6 million. Write-offs for doubtful accounts of $1.0 million and $1.5 million were recorded against the allowance during the three months ended March 31, 2015 and 2014, respectively. Bad debt expense was $1.0 million and $1.5 million for the three months ended March 31, 2015 and 2014, respectively
Investments in Equity Securities	Investments in Equity Securities Beginning in 2011, the Company made investments in various tranches of the preferred stock of a private company such that the carrying value of this investment was $13.9 million at December 31, 2014. On February 18, 2015, the investee completed an initial public offering of its common stock and the Company’s investment automatically converted into 2,207,793 shares of common stock. This investment is accounted for under the cost method as an available-for-sale marketable security and valued at $37.0 million at March 31, 2015. These securities are subject to a lock-up agreement that expires in August 2015.
Property and Equipment	Property and Equipment Property and equipment, including purchased and internally developed software are stated at cost. Depreciation is calculated using the straight‑line method over the estimated useful lives of the assets, which generally range from three to seven years. Leasehold improvements are amortized using the straight‑line method over the estimated useful lives of the assets or the remaining term of the lease, whichever is shorter.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2015-05, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement (“ASU 2015-05). This amendment provides guidance to help entities determine whether a cloud computing arrangement contains a software license that should be accounted for as internal-use software or as a service contract. ASU 2015-05 is effective for interim and annual reporting periods beginning after December 15, 2015, with early adoption permitted. Upon adoption, an entity has the option to apply the provisions of ASU 2015-05 either prospectively to all arrangements entered into or materially modified, or retrospectively. The Company is currently evaluating the effects, if any, the adoption of ASU 2015-05 will have upon our consolidated financial position, results of operations or cash flows. In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”) to provide guidance on revenue recognition. ASU 2014-09 requires a company to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under current guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 is effective in the first quarter of fiscal 2017. Early adoption is not permitted. Upon adoption, ASU 2014-09 can be applied retrospectively to all periods presented or only to the most current period presented with the cumulative effect of changes reflected in the opening balance of retained earnings in the most current period presented. The Company is currently evaluating the impact of adopting ASU 2014-09 on its consolidated financial statements.

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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Disclosure of accounting policy for investments in financial assets, including marketable securities (debt and equity securities with readily determinable fair values), investments accounted for under the equity method and cost method, securities borrowed and loaned, and repurchase and resale agreements. For marketable securities, the disclosure may include the entity's accounting treatment for transfers between investment categories and how the fair values for such securities are determined. Also, for all investments, an entity may describe its policy for assessing, recognizing and measuring impairment of the investment.

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Disclosure of accounting policy for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, basis of assets, depreciation and depletion methods used, including composite deprecation, estimated useful lives, capitalization policy, accounting treatment for costs incurred for repairs and maintenance, capitalized interest and the method it is calculated, disposals and impairments.

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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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Disclosure of accounting policy for trade and other accounts receivables. This disclosure may include the basis at which such receivables are carried in the entity's statements of financial position (for example, net realizable value), how the entity determines the level of its allowance for doubtful accounts, when impairments, charge-offs or recoveries are recognized, and the entity's income recognition policies for such receivables, including its treatment of related fees and costs, its treatment of premiums, discounts or unearned income, when accrual of interest is discontinued, how the entity records payments received on nonaccrual receivables and its policy for resuming accrual of interest on such receivables. If the enterprise holds a large number of similar loans, disclosure may include the accounting policy for the anticipation of prepayments and significant assumptions underlying prepayment estimates for amortization of premiums, discounts, and nonrefundable fees and costs.

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