Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (a) Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States, or U.S. GAAP, for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual audited consolidated financial statements. In the opinion of management, all adjustments, consisting of normal recurring adjustments necessary for the fair statement of the Company’s financial condition, results of operations and cash flows for the periods presented, have been included. The results of operations for any interim period are not necessarily indicative of the results of operations for the full year or any other interim period. The unaudited condensed consolidated financial statements and related disclosures have been prepared with the presumption that users of the interim unaudited condensed consolidated financial statements have read or have access to the audited consolidated financial statements for the preceding year. Accordingly, these unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the fiscal year ended December 31, 2014, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014, or the Annual Report, filed with the U.S. Securities and Exchange Commission, or SEC, on February 25, 2015. The consolidated balance sheet at December 31, 2014 has been derived from the audited consolidated financial statements at that date. The unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. The Company operates in one business segment. All tabular disclosures of dollar and share amounts are presented in thousands unless otherwise indicated. All per share amounts are presented at their actual amounts. The number of shares issuable under the Amended and Restated 2004 Equity Incentive Award Plan, or the Medivation Equity Incentive Plan, and the Medivation, Inc. 2013 Employee Stock Purchase Plan, or ESPP, disclosed in Note 11, “Stockholders’ Equity,” are presented at their actual amounts unless otherwise indicated. Amounts presented herein may not calculate or sum precisely due to rounding. (b) Use of Estimates The preparation of unaudited condensed consolidated financial statements in accordance with U.S. GAAP requires that management make estimates and assumptions in certain circumstances that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Management bases its estimates on historical experience and on assumptions believed to be reasonable under the circumstances. Although management believes that these estimates are reasonable, actual future results could differ materially from those estimates. In addition, had different estimates and assumptions been used, the unaudited condensed consolidated financial statements could have differed materially from what is presented. Significant estimates and assumptions used by management principally relate to revenue recognition, including reliance on third party information, estimating the performance periods of the Company’s deliverables under collaboration agreements, and estimating the various deductions from gross sales to calculate net sales of XTANDI. Additionally, significant estimates and assumptions used by management include those related to contingent purchase consideration, intangible assets, goodwill, the Convertible Notes, determining whether the Company is the primary beneficiary of any variable interest entities, leases, taxes, research and development and other accruals, share-based compensation, and the calculation of diluted net income per common share. (c) Significant Accounting Policies Reference is made to Note 2, “Summary of Significant Accounting Policies,” included in the notes to the Company’s audited consolidated financial statements included in its Annual Report. As of the date of the filing of this Quarterly Report on Form 10-Q, or Quarterly Report, there were no significant changes to the significant accounting policies described in the Company’s Annual Report, except for the Company’s accounting policy with respect to diluted net income per common share beginning in the second quarter of 2015 as discussed in Note 5, “Net Income per Common Share.” (d) Capital Structure On June 15, 2015, the Company filed a Certificate of Amendment to its Amended and Restated Certificate of Incorporation, as amended, effecting an increase in the total number of authorized shares of capital stock of the Company from 171,000,000 to 341,000,000 and an increase in the total number of authorized shares of common stock of the Company from 170,000,000 to 340,000,000. During the second quarter of 2015, the Company settled a total of $91.0 million aggregate principal amount of its 2.625% convertible senior notes due April 1, 2017, or the Convertible Notes, through a combination of $92.1 million in cash and 2,099,358 shares of its common stock. On June 19, 2015, the Company issued a notice of redemption to redeem all of its outstanding Convertible Notes on July 24, 2015. Pursuant to this notice of redemption, the Company completed the settlement of $167.8 million aggregate principal amount of the Convertible Notes through a combination of $167.8 million in cash and 3,539,218 shares of its common stock in the third quarter of 2015. Upon settlement, the Convertible Notes were no longer deemed outstanding, interest ceased to accrue thereon, and all rights of the holders of the Convertible Notes ceased to exist. On September 15, 2015, the Company effected a two-for-one forward stock split of its common stock in the form of a stock dividend. Stockholders of record as of August 13, 2015 received one additional share of the Company’s common stock, par value $0.01, for each share they held as of the record date. The Company issued 81,711,522 shares of its common stock as a result of the stock dividend. The par value of the Company’s common stock remained unchanged at $0.01 per share. The information of shares of common stock (except par value per share), par, additional paid-in capital, and net income per common share as of September 30, 2015 and for all other comparable periods presented have been retroactively adjusted to reflect the effects of the stock split. The number of shares of the Company’s common stock issuable upon exercise of outstanding stock options and stock appreciation rights, and vesting of other stock-based awards was proportionally increased, and the exercise price per share thereof, as applicable, was proportionately decreased, in accordance with the terms of the Medivation Equity Incentive Plan, as amended, and the ESPP. (e) New Accounting Pronouncements In September 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments.” ASU 2015-16 requires that the acquirer recognize adjustments to provisional amounts recognized in a business combination that are identified during the measurement period in the reporting period in which the adjustment amounts are determined and record, in the same period’s financial statements, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. The amended guidance eliminates the requirement to retrospectively account for adjustments made to provisional amounts during the measurement period. The amended guidance is effective for fiscal years beginning after December 15, 2015, including interim periods within that reporting period, and should be applied prospectively to provisional amounts that occur after the effective date. The Company is currently assessing the impact that the amended guidance will have on its consolidated financial statements and related disclosures. In August 2015, the FASB issued ASU 2015-15, “Interest – Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line of Credit Arrangements.” The amended guidance, which became effective immediately upon issuance, clarifies that entities are permitted to defer and present such debt issuance costs as an asset to be amortized ratably over the term of the line of credit arrangement, regardless of whether there are any outstanding borrowings on the line of credit arrangement. The adoption of ASU 2015-15 did not have a material impact on the Company’s consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-03, “Interest – Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs,” which requires that debt issuance costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts. The ASU requires retrospective adoption and is effective for reporting periods beginning after December 15, 2015. Early adoption is permitted. The Company is currently assessing the impact that the amended guidance will have on its consolidated financial statements and related disclosures. In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 820): Amendments to the Consolidation Analysis.” The amended guidance provides a revised consolidation model for all reporting entities to use in evaluating whether they should consolidate certain legal entities. All legal entities will be subject to reevaluation under this revised consolidation model. The revised consolidation model, among other things, (i) modifies the evaluation of whether limited partnerships and similar legal entities are voting interest entities, (ii) eliminates the presumption that a general partner should consolidate a limited partnership, and (iii) modifies the consolidation analysis of reporting entities that are involved with voting interest entities through fee arrangements and related party relationships. The amended guidance is effective for fiscal years beginning after December 15, 2015, including interim periods within that reporting period. The Company currently does not expect that the adoption of ASU 2015-02 will have a material impact on its consolidated financial statements and related disclosures. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (Topic 606), a comprehensive new revenue recognition standard that will supersede the existing revenue recognition guidance. The new accounting guidance creates a framework by which an entity will allocate the transaction price to separate performance obligations and recognize revenue when (or as) each performance obligation is satisfied. Under the new standard, entities will be required to use judgment and make estimates, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price, allocating the transaction price to each separate performance obligation and determining when an entity satisfies its performance obligations. The standard allows for either “full retrospective” adoption, meaning that the standard is applied to all of the periods presented with a cumulative catch-up as of the earliest period presented, or “modified retrospective” adoption, meaning the standard is applied only to the most current period presented in the financial statements with a cumulative catch-up as of the current period. In August 2015, the effective date of the new revenue standard was delayed by one year to December 15, 2017 for annual reporting periods beginning after that date. The FASB also agreed to permit early adoption of the standard, but not before the original effective date of December 15, 2016. The Company has not yet selected a transition method and is currently evaluating the effect that the updated standard will have on its consolidated financial statements and related disclosures.

NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

(a) Basis of Presentation and Principles of Consolidation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States, or U.S. GAAP, for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual audited consolidated financial statements. In the opinion of management, all adjustments, consisting of normal recurring adjustments necessary for the fair statement of the Company’s financial condition, results of operations and cash flows for the periods presented, have been included. The results of operations for any interim period are not necessarily indicative of the results of operations for the full year or any other interim period.

The unaudited condensed consolidated financial statements and related disclosures have been prepared with the presumption that users of the interim unaudited condensed consolidated financial statements have read or have access to the audited consolidated financial statements for the preceding year. Accordingly, these unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the fiscal year ended December 31, 2014, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014, or the Annual Report, filed with the U.S. Securities and Exchange Commission, or SEC, on February 25, 2015. The consolidated balance sheet at December 31, 2014 has been derived from the audited consolidated financial statements at that date.

The unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. The Company operates in one business segment.

All tabular disclosures of dollar and share amounts are presented in thousands unless otherwise indicated. All per share amounts are presented at their actual amounts. The number of shares issuable under the Amended and Restated 2004 Equity Incentive Award Plan, or the Medivation Equity Incentive Plan, and the Medivation, Inc. 2013 Employee Stock Purchase Plan, or ESPP, disclosed in Note 11, “Stockholders’ Equity,” are presented at their actual amounts unless otherwise indicated. Amounts presented herein may not calculate or sum precisely due to rounding.

(b) Use of Estimates

The preparation of unaudited condensed consolidated financial statements in accordance with U.S. GAAP requires that management make estimates and assumptions in certain circumstances that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Management bases its estimates on historical experience and on assumptions believed to be reasonable under the circumstances. Although management believes that these estimates are reasonable, actual future results could differ materially from those estimates. In addition, had different estimates and assumptions been used, the unaudited condensed consolidated financial statements could have differed materially from what is presented.

Significant estimates and assumptions used by management principally relate to revenue recognition, including reliance on third party information, estimating the performance periods of the Company’s deliverables under collaboration agreements, and estimating the various deductions from gross sales to calculate net sales of XTANDI. Additionally, significant estimates and assumptions used by management include those related to contingent purchase consideration, intangible assets, goodwill, the Convertible Notes, determining whether the Company is the primary beneficiary of any variable interest entities, leases, taxes, research and development and other accruals, share-based compensation, and the calculation of diluted net income per common share.

(c) Significant Accounting Policies

Reference is made to Note 2, “Summary of Significant Accounting Policies,” included in the notes to the Company’s audited consolidated financial statements included in its Annual Report. As of the date of the filing of this Quarterly Report on Form 10-Q, or Quarterly Report, there were no significant changes to the significant accounting policies described in the Company’s Annual Report, except for the Company’s accounting policy with respect to diluted net income per common share beginning in the second quarter of 2015 as discussed in Note 5, “Net Income per Common Share.”

(d) Capital Structure

On June 15, 2015, the Company filed a Certificate of Amendment to its Amended and Restated Certificate of Incorporation, as amended, effecting an increase in the total number of authorized shares of capital stock of the Company from 171,000,000 to 341,000,000 and an increase in the total number of authorized shares of common stock of the Company from 170,000,000 to 340,000,000.

During the second quarter of 2015, the Company settled a total of $91.0 million aggregate principal amount of its 2.625% convertible senior notes due April 1, 2017, or the Convertible Notes, through a combination of $92.1 million in cash and 2,099,358 shares of its common stock. On June 19, 2015, the Company issued a notice of redemption to redeem all of its outstanding Convertible Notes on July 24, 2015. Pursuant to this notice of redemption, the Company completed the settlement of $167.8 million aggregate principal amount of the Convertible Notes through a combination of $167.8 million in cash and 3,539,218 shares of its common stock in the third quarter of 2015. Upon settlement, the Convertible Notes were no longer deemed outstanding, interest ceased to accrue thereon, and all rights of the holders of the Convertible Notes ceased to exist.

On September 15, 2015, the Company effected a two-for-one forward stock split of its common stock in the form of a stock dividend. Stockholders of record as of August 13, 2015 received one additional share of the Company’s common stock, par value $0.01, for each share they held as of the record date. The Company issued 81,711,522 shares of its common stock as a result of the stock dividend. The par value of the Company’s common stock remained unchanged at $0.01 per share.

The information of shares of common stock (except par value per share), par, additional paid-in capital, and net income per common share as of September 30, 2015 and for all other comparable periods presented have been retroactively adjusted to reflect the effects of the stock split. The number of shares of the Company’s common stock issuable upon exercise of outstanding stock options and stock appreciation rights, and vesting of other stock-based awards was proportionally increased, and the exercise price per share thereof, as applicable, was proportionately decreased, in accordance with the terms of the Medivation Equity Incentive Plan, as amended, and the ESPP.

(e) New Accounting Pronouncements

In September 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments.” ASU 2015-16 requires that the acquirer recognize adjustments to provisional amounts recognized in a business combination that are identified during the measurement period in the reporting period in which the adjustment amounts are determined and record, in the same period’s financial statements, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. The amended guidance eliminates the requirement to retrospectively account for adjustments made to provisional amounts during the measurement period. The amended guidance is effective for fiscal years beginning after December 15, 2015, including interim periods within that reporting period, and should be applied prospectively to provisional amounts that occur after the effective date. The Company is currently assessing the impact that the amended guidance will have on its consolidated financial statements and related disclosures.

In August 2015, the FASB issued ASU 2015-15, “Interest – Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line of Credit Arrangements.” The amended guidance, which became effective immediately upon issuance, clarifies that entities are permitted to defer and present such debt issuance costs as an asset to be amortized ratably over the term of the line of credit arrangement, regardless of whether there are any outstanding borrowings on the line of credit arrangement. The adoption of ASU 2015-15 did not have a material impact on the Company’s consolidated financial statements and related disclosures.

In April 2015, the FASB issued ASU 2015-03, “Interest – Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs,” which requires that debt issuance costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts. The ASU requires retrospective adoption and is effective for reporting periods beginning after December 15, 2015. Early adoption is permitted. The Company is currently assessing the impact that the amended guidance will have on its consolidated financial statements and related disclosures.

In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 820): Amendments to the Consolidation Analysis.” The amended guidance provides a revised consolidation model for all reporting entities to use in evaluating whether they should consolidate certain legal entities. All legal entities will be subject to reevaluation under this revised consolidation model. The revised consolidation model, among other things, (i) modifies the evaluation of whether limited partnerships and similar legal entities are voting interest entities, (ii) eliminates the presumption that a general partner should consolidate a limited partnership, and (iii) modifies the consolidation analysis of reporting entities that are involved with voting interest entities through fee arrangements and related party relationships. The amended guidance is effective for fiscal years beginning after December 15, 2015, including interim periods within that reporting period. The Company currently does not expect that the adoption of ASU 2015-02 will have a material impact on its consolidated financial statements and related disclosures.

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (Topic 606), a comprehensive new revenue recognition standard that will supersede the existing revenue recognition guidance. The new accounting guidance creates a framework by which an entity will allocate the transaction price to separate performance obligations and recognize revenue when (or as) each performance obligation is satisfied. Under the new standard, entities will be required to use judgment and make estimates, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price, allocating the transaction price to each separate performance obligation and determining when an entity satisfies its performance obligations. The standard allows for either “full retrospective” adoption, meaning that the standard is applied to all of the periods presented with a cumulative catch-up as of the earliest period presented, or “modified retrospective” adoption, meaning the standard is applied only to the most current period presented in the financial statements with a cumulative catch-up as of the current period. In August 2015, the effective date of the new revenue standard was delayed by one year to December 15, 2017 for annual reporting periods beginning after that date. The FASB also agreed to permit early adoption of the standard, but not before the original effective date of December 15, 2016. The Company has not yet selected a transition method and is currently evaluating the effect that the updated standard will have on its consolidated financial statements and related disclosures.