Medivation 10-Q 6 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Trading Symbol	MDVN
Entity Registrant Name	MEDIVATION, INC.
Entity Central Index Key	1,011,835
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		81,694,468

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 421,150	$ 502,677
Short-term investments	76,357
Receivable from collaboration partner	197,157	184,737
Deferred income tax assets	9,533	21,987
Prepaid expenses and other current assets	18,640	12,264
Restricted cash	616	203
Total current assets	723,453	721,868
Property and equipment, net	44,291	41,161
Intangible assets	101,000	101,000
Deferred income tax assets, non-current	32,868	15,176
Restricted cash, net of current	12,723	11,562
Goodwill	10,000	10,000
Other non-current assets	6,355	10,852
Total assets	930,690	911,619
Current liabilities:
Accounts payable, accrued expenses and other current liabilities	118,850	106,128
Contingent consideration	10,000	10,000
Deferred revenue	565	2,822
Current portion of build-to-suit lease obligation	196	698
Current portion of Convertible Notes, net of unamortized discount of $18,650 and $1 at June 30, 2015 and December 31, 2014, respectively	149,098	4
Total current liabilities	278,709	119,652
Convertible Notes, net of unamortized discount of $- and $36,598 at June 30, 2015 and December 31, 2014, respectively		222,140
Contingent consideration	101,013	96,000
Build-to-suit lease obligation, excluding current portion	16,920	18,711
Other non-current liabilities	6,525	5,817
Total liabilities	$ 403,167	$ 462,320
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, $0.01 par value per share; 1,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.01 par value per share; 340,000,000 and 170,000,000 shares authorized at June 30, 2015 and December 31, 2014, respectively; 79,860,733 and 78,117,227 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	$ 799	$ 781
Additional paid-in capital	561,759	506,227
Accumulated other comprehensive loss	(34)
Accumulated deficit	(35,001)	(57,709)
Total stockholders' equity	527,523	449,299
Total liabilities and stockholders' equity	$ 930,690	$ 911,619

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Convertible Notes current, discount	$ 18,650	$ 1
Convertible Notes, discount		$ 36,598
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	340,000,000	170,000,000
Common stock, shares issued	79,860,733	78,117,227
Common stock, shares outstanding	79,860,733	78,117,227

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Collaboration revenue	$ 175,657	$ 148,090	$ 304,845	$ 235,279
Operating expenses:
Research and development expenses	47,294	40,344	91,970	86,263
Selling, general and administrative expenses	74,708	52,795	158,647	102,530
Total operating expenses	122,002	93,139	250,617	188,793
Income from operations	53,655	54,951	54,228	46,486
Other income (expense), net:
Loss on extinguishment of Convertible Notes	(7,868)		(7,871)
Interest expense	(5,309)	(5,336)	(10,917)	(10,566)
Interest income	30	8	41	17
Other, net	(82)	(93)	47	(131)
Total other income (expense), net	(13,229)	(5,421)	(18,700)	(10,680)
Income before income tax expense	40,426	49,530	35,528	35,806
Income tax expense	(14,600)	(1,611)	(12,820)	(1,552)
Net income	$ 25,826	$ 47,919	$ 22,708	$ 34,254
Basic net income per common share	$ 0.33	$ 0.63	$ 0.29	$ 0.45
Diluted net income per common share	$ 0.31	$ 0.60	$ 0.28	$ 0.43
Weighted average common shares used in the calculation of basic net income per common share	79,252	76,577	78,788	76,411
Weighted average common shares used in the calculation of diluted net income per common share	84,345	80,491	81,498	80,487

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 25,826	$ 47,919	$ 22,708	$ 34,254
Other comprehensive loss:
Change in unrealized loss on available-for-sale securities, net	(34)		(34)
Other comprehensive loss, net	(34)		(34)
Comprehensive income	$ 25,792	$ 47,919	$ 22,674	$ 34,254

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 22,708	$ 34,254
Adjustments for non-cash operating items:
Stock-based compensation	27,450	20,842
Excess tax benefits from stock-based compensation	(13,572)
Loss on extinguishment of Convertible Notes	7,871
Amortization of debt discount and debt issuance costs	7,827	7,170
Change in fair value of contingent purchase consideration	5,013
Depreciation on property and equipment	3,085	2,193
Amortization of deferred revenue	(2,257)	(8,465)
Change in deferred income taxes	(773)
Net accretion of discount on investment securities	6
Other non-cash items	(66)
Changes in operating assets and liabilities:
Receivable from collaboration partner	(12,420)	7,272
Prepaid expenses and other current assets	(6,085)	1,768
Other non-current assets	2,689	(4,847)
Accounts payable, accrued expenses and other current liabilities	25,352	(3,647)
Interest payable	(305)
Other non-current liabilities	718	(1)
Net cash provided by operating activities	67,241	56,539
Cash flows from investing activities:
Purchases of short-term investments	(76,397)
Purchases of property and equipment	(6,478)	(4,506)
Change in restricted cash	(1,574)	(2,073)
Net cash used in investing activities	(84,449)	(6,579)
Cash flows from financing activities:
Principal repayment of Convertible Notes	(90,994)	(1)
Cash settlement of Convertible Notes conversion premium	(1,126)
Proceeds from issuance of common stock under equity incentive and stock purchase plans	14,699	11,289
Excess tax benefits from stock-based compensation	13,572
Reduction of build-to-suit lease obligation	(470)
Net cash (used in) provided by financing activities	(64,319)	11,288
Net (decrease) increase in cash and cash equivalents	(81,527)	61,248
Cash and cash equivalents at beginning of period	502,677	228,788
Cash and cash equivalents at end of period	421,150	290,036
Non-cash investing and financing activities:
Reacquisition of Convertible Note equity component upon conversion	135,988
Fair value of common stock issued for conversion of Convertible Notes	131,084
Derecognition of build-to-suit lease asset	3,241
Derecognition of build-to-suit lease obligation	3,176
Property and equipment expenditures incurred but not yet paid	1,650	3,082
Interest capitalized during construction period for build-to-suit lease transactions	1,070	450
Accrued interest payable forfeited upon conversion of Convertible Notes	292
Amounts capitalized under build-to-suit lease transactions	$ 283	$ 16,800

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	NOTE 1. DESCRIPTION OF BUSINESS Medivation, Inc. (the “Company” or “Medivation”) is a biopharmaceutical company focused on the development and commercialization of medically innovative therapies to treat serious diseases for which there are limited treatment options. Through the Company’s collaboration with Astellas Pharma, Inc., or Astellas, it has one commercial product, XTANDI ® The Company seeks to become a global fully-integrated biopharmaceutical company through the continued commercialization of XTANDI, the acquisition or in-license and development and commercialization of other product opportunities, and through the advancement of its own proprietary research and development programs. The Company expects that its future growth may come from both internal research efforts and third party business development activities. In the fourth quarter of 2014, the Company licensed exclusive worldwide rights to pidilizumab (which is referred to as MDV9300), an immune modulatory, anti-Programmed Death-1 (PD-1) monoclonal antibody for all potential indications from CureTech, Ltd., or CureTech. Under the license agreement, the Company is responsible for all development, regulatory, manufacturing, and commercialization activities for MDV9300. The Company currently anticipates that it may initiate a Phase 3 clinical trial evaluating MDV9300 in one or more hematologic malignancies as early as in 2015. The Company is also considering evaluating MDV9300 in other indications, including but not limited to in combination with enzalutamide in breast and prostate cancer. In addition, the Company has various other internal research and discovery efforts focused, among other areas, in oncology and neurology. The Company has funded its operations primarily through public offerings of its common stock, the issuance of 2.625% convertible senior notes due April 1, 2017, or the Convertible Notes, from upfront, milestone, and cost-sharing payments under collaboration agreements, and subsequent to September 13, 2012, from collaboration revenue related to XTANDI net sales. As of June 30, 2015, the Company may earn up to $245.0 million of remaining sales milestones under the Astellas Collaboration Agreement.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 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 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 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 of any interim period are not necessarily indicative of the results of operations for the full year or any other interim period. The unaudited consolidated financial statements and related disclosures have been prepared with the presumption that users of the interim unaudited consolidated financial statements have read or have access to the audited consolidated financial statements for the preceding year. Accordingly, these unaudited 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 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 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 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 (loss) 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. On July 31, 2015, the Company announced that its Board of Directors has declared a two-for-one stock split of Medivation’s common stock to be effected through a stock dividend. Shareholders of record as of August 13, 2015, will receive one additional share of Medivation common stock, par value $0.01, for each share they hold as of the record date. The share distribution is scheduled for September 15, 2015. On June 19, 2015, the Company issued a notice of redemption to redeem on July 24, 2015 all of its outstanding Convertible Notes. Pursuant to this notice of redemption, the Company completed the settlement of $167.8 million aggregate principal amount of the Convertible Notes for $167.8 million in cash and 1,769,609 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. (e) New Accounting Pronouncements In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 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 provides guidance to help companies evaluate the accounting for fees paid by a customer in a cloud computing arrangement. The new guidance clarifies that if a cloud computing arrangement includes a software license, the customer should account for the license consistent with its accounting for other software licenses. If the arrangement does not include a software license, the customer should account for the arrangement as a service contract. The revised guidance will not change a customer’s accounting for service contracts. The ASU may be adopted prospectively or retrospectively 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 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 currently does not expect that the adoption of ASU 2015-03 will have a material impact 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 July 2015, the FASB decided to delay the effective date of the new revenue standard 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.

Collaboration Agreement

Collaboration Agreement	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration Agreement	NOTE 3. COLLABORATION AGREEMENT (a) Collaboration Agreement with Astellas In October 2009, the Company entered into a collaboration agreement with Astellas, or the Astellas Collaboration Agreement, pursuant to which it is collaborating with Astellas to develop and commercialize XTANDI globally for all indications, dosages, and formulations of enzalutamide. Under the agreement, decision making and economic participation differs between the U.S. market and the ex-U.S. market. In the United States, decisions are generally made by consensus, pre-tax profits and losses are shared equally, and, subject to certain exceptions, development and commercialization costs (including cost of goods sold and the royalty on net sales payable to The Regents of the University of California (“UCLA” or “the Regents”) under the Company’s license agreement with UCLA) are also shared equally. The primary exceptions to equal cost sharing in the U.S. market are that each party is responsible for its own commercial full-time equivalent, or FTE, costs, and that development costs supporting marketing approvals in both the United States and either Europe or Japan are borne one-third by the Company and two-thirds by Astellas. The Company and Astellas are co-promoting XTANDI in the U.S. market, with each company providing half of the sales and medical affairs effort in support of the product. Both the Company and Astellas are entitled to receive a fee for each qualifying detail made by its respective sales representatives. Outside the United States, decisions are generally made by Astellas and all development and commercialization costs (including cost of goods sold and the royalty on net sales payable to UCLA) are borne by Astellas. Astellas retains all ex-U.S. profits and losses, and pays the Company a tiered royalty ranging from the low teens to the low twenties on the aggregate net sales of XTANDI outside the United States, or ex-U.S. XTANDI net sales. Astellas has sole responsibility for promoting XTANDI outside the United States and for recording all XTANDI net sales both inside and outside the United States. Both the Company and Astellas have agreed not to commercialize certain other products having a similar mechanism of action (as defined by the Astellas Collaboration Agreement) as XTANDI for the treatment of prostate cancer for a specified time period, subject to certain exceptions. Under the Astellas Collaboration Agreement, Astellas paid the Company a non-refundable, upfront cash payment of $110.0 million in the fourth quarter of 2009. The Company was also eligible to receive up to $335.0 million in development milestone payments and is eligible to receive up to $320.0 million in sales milestone payments. As of June 30, 2015, the Company had earned all of the $335.0 million in development milestone payments and $75.0 million of the sales milestone payments under the Astellas Collaboration Agreement. The Company expects that any of the remaining $245.0 million in sales milestone payments that the Company may earn in future periods will be recognized as revenue in their entirety in the period in which the underlying milestone event is achieved. The triggering events for the sales milestone payments are as follows: Annual Global Net Sales in a Calendar Year Milestone Payment (1) $400 million (2) $800 million (3) $1.2 billion $ 70 million $1.6 billion $ 175 million (1) Each milestone shall only be paid once during the term of the Astellas Collaboration Agreement. (2) This milestone totaling $25.0 million was earned and recognized as collaboration revenue during the fourth quarter of 2013 and payment was received in the first quarter of 2014. (3) This milestone totaling $50.0 million was earned and recognized as collaboration revenue during the fourth quarter of 2014 and is included in receivable from collaboration partner on the consolidated balance sheet at December 31, 2014. Payment was received during the first quarter of 2015. The Company and Astellas are each permitted to terminate the Astellas Collaboration Agreement for an uncured material breach by the other party or for the insolvency of the other party. Astellas has a right to terminate the Astellas Collaboration Agreement unilaterally by advance written notice to the Company. Following any termination of the Astellas Collaboration Agreement in its entirety, all rights to develop and commercialize XTANDI will revert to the Company, and Astellas will grant a license to the Company to enable it to continue such development and commercialization. In addition, except in the case of a termination by Astellas for the Company’s material breach, Astellas will supply XTANDI to the Company during a specified transition period. Unless terminated earlier by the Company or Astellas pursuant to the terms thereof, the Astellas Collaboration Agreement will remain in effect: (a) in the United States, until such time as Astellas notifies the Company that Astellas has permanently stopped selling products covered by the Astellas Collaboration Agreement in the United States; and (b) in each other country of the world, on a country-by-country basis, until such time as (i) products covered by the Astellas Collaboration Agreement cease to be protected by patents or regulatory exclusivity in such country and (ii) commercial sales of generic equivalent products have commenced in such country. (b) Collaboration Revenue Collaboration revenue consists of three components: (a) collaboration revenue related to U.S. XTANDI net sales; (b) collaboration revenue related to ex-U.S. XTANDI net sales; and (c) collaboration revenue related to upfront and milestone payments. Collaboration revenue was as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Collaboration revenue: Related to U.S. XTANDI net sales $ 149,220 $ 71,866 $ 261,230 $ 134,091 Related to ex-U.S. XTANDI net sales 25,591 9,992 41,358 15,723 Related to upfront and milestone payments 846 66,232 2,257 85,465 Total $ 175,657 $ 148,090 $ 304,845 $ 235,279 The Company is required to pay UCLA ten percent of all Sublicensing Income, as defined in its license agreement with UCLA. The Company is currently involved in litigation with UCLA regarding certain terms of the license agreement and other matters, which are discussed in Note 14, “Commitments and Contingencies.” Collaboration Revenue Related to U.S. XTANDI Net Sales Under the Astellas Collaboration Agreement, Astellas records all U.S. XTANDI net sales. The Company and Astellas share equally all pre-tax profits and losses from U.S. XTANDI net sales. Subject to certain exceptions, the Company and Astellas also share equally all XTANDI development and commercialization costs attributable to the U.S. market, including cost of goods sold and the royalty on net sales payable to UCLA under the Company’s license agreement with UCLA. The primary exceptions to 50/50 cost sharing are that each party is responsible for its own commercial FTE costs and that development costs supporting marketing approvals in both the United States and either Europe or Japan are borne one-third by the Company and two-thirds by Astellas. The Company recognizes collaboration revenue related to U.S. XTANDI net sales in the period in which such sales occur. Collaboration revenue related to U.S. XTANDI net sales consists of the Company’s share of pre-tax profits and losses from U.S. XTANDI net sales, plus reimbursement of the Company’s share of reimbursable U.S. development and commercialization costs. The Company’s collaboration revenue related to U.S. XTANDI net sales in any given period is equal to 50% of U.S. XTANDI net sales as reported by Astellas for the applicable period. Collaboration revenue related to U.S. XTANDI net sales was as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 U.S. XTANDI net sales (as reported by Astellas) $ 298,440 $ 143,732 $ 522,460 $ 268,183 Shared U.S. development and commercialization costs (84,947 ) (70,543 ) (195,260 ) (148,250 ) Pre-tax U.S. profit $ 213,493 $ 73,189 $ 327,200 $ 119,933 Medivation’s share of pre-tax U.S. profit $ 106,747 $ 36,594 $ 163,600 $ 59,966 Reimbursement of Medivation’s share of shared U.S. costs 42,473 35,272 97,630 74,125 Collaboration revenue related to U.S. XTANDI net sales $ 149,220 $ 71,866 $ 261,230 $ 134,091 Collaboration Revenue Related to Ex-U.S. XTANDI Net Sales Under the Astellas Collaboration Agreement, Astellas records all ex-U.S. XTANDI net sales. Astellas is responsible for all development and commercialization costs for XTANDI outside the United States, including cost of goods sold and the royalty on net sales payable to UCLA under the Company’s license agreement with UCLA, and pays the Company a tiered royalty ranging from the low teens to the low twenties on net ex-U.S. XTANDI net sales. The Company recognizes collaboration revenue related to ex-U.S. XTANDI net sales in the period in which such sales occur. Collaboration revenue related to ex-U.S. XTANDI net sales consists of royalties from Astellas on those sales. Collaboration revenue related to ex-U.S. XTANDI net sales was $25.6 million and $41.4 million for the three and six months ended June 30, 2015, respectively. Collaboration revenue related to ex-U.S. XTANDI net sales was $10.0 million and $15.7 million for the three and six months ended June 30, 2014, respectively. Collaboration Revenue Related to Upfront and Milestone Payments Collaboration revenue related to upfront and milestone payments from Astellas was as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Development milestones earned $ — $ 62,000 $ — $ 77,000 Amortization of deferred upfront and development milestones 846 4,232 2,257 8,465 Total $ 846 $ 66,232 $ 2,257 $ 85,465 Deferred revenue under the Astellas Collaboration Agreement was $0.6 million and $2.8 million at June 30, 2015, and December 31, 2014, respectively. (c) Cost-Sharing Payments Under the Astellas Collaboration Agreement, the Company and Astellas share certain development and commercialization costs (including cost of goods sold and the royalty on net sales payable to UCLA under the Company’s license agreement with UCLA) in the United States. For the three and six months ended June 30, 2015, development cost sharing payments from Astellas were $17.6 million and $31.4 million, respectively. For the three and six months ended June 30, 2014, development cost sharing payments from Astellas were $17.5 million and $33.4 million, respectively. For the three and six months ended June 30, 2015, commercialization cost-sharing payments to Astellas were $2.7 million and $22.8 million, respectively. For the three and six months ended June 30, 2014, commercialization cost-sharing payments to Astellas were $2.6 million and $10.2 million, respectively. Development cost sharing payments from Astellas are recorded as reductions in research and development, or R&D, expenses. Commercialization cost sharing payments to Astellas are recorded as increases in selling, general, and administrative, or SG&A, expenses

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	NOTE 4. GOODWILL AND INTANGIBLE ASSETS In the fourth quarter of 2014, the Company entered into a License Agreement with CureTech, pursuant to which it licensed exclusive worldwide rights to CureTech’s late-stage clinical molecule, MDV9300. The Company concluded that the in-license transaction is an acquisition of a business in accordance with FASB Accounting Standards Codification, or ASC, 805-10, “Business Combinations.” The transaction resulted in identifiable intangible assets of $101.0 million consisting entirely of in-process research and development, or IPR&D, and goodwill of $10.0 million. The Company accounts for IPR&D as indefinite-lived intangible assets until regulatory approval or discontinuation at which time the Company evaluates impairment, converts the carrying value into a definite-lived intangible asset and determines the economic life for amortization purposes. The Company assesses the impairment of intangible assets and goodwill on an annual basis or more frequently whenever events or changes in circumstances may indicate that the carrying value might not be recoverable. The Company applies the rules in ASU No. 2011-08, “Testing Goodwill for Impairment,” which amends the rules for testing goodwill for impairment by allowing an entity the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, an entity determines it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, then performing the two-step impairment test is unnecessary. The Company applies the rules in ASU No. 2012-02, “Testing Indefinite-Lived Intangibles Assets for Impairment,” which provides entities with an option to perform a qualitative assessment of indefinite-lived intangible assets other than goodwill for impairment to determine if additional impairment testing is necessary. The Company evaluated its goodwill and indefinite-lived intangible assets utilizing the simplified approach as of June 30, 2015. The Company determined that its goodwill and indefinite-lived intangible assets were not impaired at June 30, 2015. The Company was not required to perform the two-step quantitative impairment test.

Net Income Per Common Share

Net Income Per Common Share	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Net Income Per Common Share	NOTE 5. NET INCOME PER COMMON SHARE The computation of basic net income per common share is based on the weighted-average number of common shares outstanding during each period. The computation of diluted net income per common share is based on the weighted-average number of common shares outstanding during the period plus, when their effect is dilutive, incremental shares consisting of shares subject to stock options, restricted stock units, stock appreciation rights, ESPP shares, warrants, and shares issuable upon conversion of convertible debt. At June 30, 2015, the Company had $167.8 million aggregate principal amount of the Convertible Notes outstanding, for which the Company controls the settlement method. During the second quarter of 2015, the Company asserted its intent and ability to settle the outstanding Convertible Notes for a combination of cash and common stock. Under the “cash settlement” method, interest is not added back to the numerator, and only the contingently issuable shares related to the conversion spread are included in the denominator, if dilutive. Under such method, the settlement of the conversion spread has a dilutive effect when the average share price of the Company’s common stock during the period exceeds the conversion price of approximately $51.24 per share of common stock. The calculation of diluted net income per common share for the three months ended June 30, 2015 includes the effect of approximately 2.4 million common shares related to the conversion spread of the Convertible Notes. The Company used the “if-converted” method to compute the dilutive effect of the Convertible Notes for the calculation of diluted net income per common share for the three and six months ended June 30, 2014. Under the “if-converted” method, interest expense, net of tax, related to the Convertible Notes, is added back to net income, and the Convertible Notes are assumed to have been converted into common shares at the beginning of the period during periods in which there would have been a dilutive effect. For the three and six months ended June 30, 2014, the impact of the Convertible Notes has been excluded from the calculation of diluted net income per common share because the effect of their inclusion would have been anti-dilutive (approximately 5.1 million contingently issuable shares have been excluded). The computation of diluted net income per common share for the six months ended June 30, 2015 reflects the application of the “if converted” method for the first quarter of 2015 and the “cash settlement” method for the second quarter of 2015 given the demonstrated and asserted redemption for the outstanding debt. For the six months ended June 30, 2015, the impact of the Convertible Notes has been excluded from the calculation of diluted net income per common share because the effect of their inclusion would have been anti-dilutive (approximately 3.7 million contingently issuable shares have been excluded). The Company completed the settlement of $167.8 million aggregate principal amount of the Convertible Notes for $167.8 million in cash and 1,769,609 shares of its common stock during the third quarter of 2015 as discussed further in Note 15, “Subsequent Events.” The following table reconciles the numerator and denominator used to calculate diluted net income per common share: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Numerator: Net income $ 25,826 $ 47,919 $ 22,708 $ 34,254 Denominator: Weighted-average common shares, basic 79,252 76,577 78,788 76,411 Dilutive effect of common stock equivalents 5,093 3,914 2,710 4,076 Weighted-average common shares, diluted 84,345 80,491 81,498 80,487 Net income per common share: Basic net income per common share $ 0.33 $ 0.63 $ 0.29 $ 0.45 Diluted net income per common share $ 0.31 $ 0.60 $ 0.28 $ 0.43

Convertible Senior Notes Due 20

Convertible Senior Notes Due 2017	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Convertible Senior Notes Due 2017	NOTE 6. CONVERTIBLE SENIOR NOTES DUE 2017 On March 19, 2012, the Company issued $258.8 million aggregate principal amount of the Convertible Notes. The Company was required to pay interest semi-annually in arrears on April 1 and October 1 of each year. The Convertible Notes were convertible upon the occurrence of certain conditions into shares of the Company’s common stock at a conversion rate of 19.5172 shares of common stock per $1,000 principal amount of the Convertible Notes, equivalent to a conversion price of approximately $51.24 per share of common stock. During the first quarter of 2015, the Company received notification that $0.7 million aggregate principal amount of Convertible Notes were surrendered for conversion. The Company settled the principal and conversion premium for approximately $1.9 million in cash during the second quarter of 2015. During the second quarter of 2015, the Company received notification that $90.3 million aggregate principal amount of Convertible Notes were surrendered for conversion. The Company settled these conversion obligations through a combination of $90.3 million in cash and 1,049,679 shares of its common stock during the second quarter of 2015. The Company recorded a non-cash loss on extinguishment of the Convertible Notes of $7.9 million for the three and six months ended June 30, 2015, which is included in other income (expense), net, on the unaudited consolidated statements of operations. Forfeited accrued interest payable of $0.3 million was reclassified to additional paid-in capital upon conversion. On June 19, 2015, the Company issued a notice of redemption to redeem on July 24, 2015 all of its outstanding Convertible Notes. At June 30, 2015, $167.8 million aggregate principal amount of the Convertible Notes was outstanding and was classified as a current liability on the unaudited consolidated balance sheet. Pursuant to this notice of redemption, the Company completed the settlement of $167.8 million aggregate principal amount of the Convertible Notes for $167.8 million in cash and 1,769,609 shares of its common stock during 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. The Company expects to record a non-cash loss on extinguishment of Convertible Notes of approximately $13.0 million during the third quarter of 2015.

Cash, Cash Equivalents, and Sho

Cash, Cash Equivalents, and Short-Term Investments	6 Months Ended
	Jun. 30, 2015
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Short-Term Investments	NOTE 7. CASH, CASH EQUIVALENTS, AND SHORT-TERM INVESTMENTS The following table summarizes the Company’s cash, cash equivalents, and short-term investments at June 30, 2015 and December 31, 2014: Amortized Gross Unrealized Fair Cost Gains Losses Value June 30, 2015 Cash and cash equivalents: Cash $ 224,412 $ — $ — $ 224,412 Money market funds 189,041 — — 189,041 Commercial paper 7,697 — — 7,697 Total cash and cash equivalents 421,150 — — 421,150 Short-term investments: Corporate debt securities 42,830 1 (39 ) 42,792 Commercial paper 21,568 — — 21,568 Federal agency securities 9,993 4 — 9,997 Certificates of deposit 2,000 — — 2,000 Total short-term investments 76,391 5 (39 ) 76,357 Total cash, cash equivalents, and short-term investments $ 497,541 $ 5 $ (39 ) $ 497,507 Amortized Gross Unrealized Fair Cost Gains Losses Value December 31, 2014 Cash and cash equivalents: Cash $ 313,646 $ — $ — $ 313,646 Money market funds 189,031 — — 189,031 Total cash and cash equivalents $ 502,677 $ — $ — $ 502,677 Cash and cash equivalents consist of cash on deposit with banks, money market funds, and all highly liquid investments with a remaining maturity of three months or less at the time of purchase. The Company considers all highly liquid investments with a remaining maturity at the time of purchase of more than three months but no longer than 12 months to be short-term investments. The Company classifies its short-term investments as available-for-sale securities and reports them at fair value with related unrealized gains and losses included as a component of comprehensive income. The amortized cost of debt securities in this category is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in other income (expense), net, on the consolidated statements of operations. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income (expense), net. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in other income (expense), net. At June 30, 2015, the Company had 20 available for sale securities with a fair value of $36.8 million in a gross unrealized loss position, all of which had been in such a position for less than twelve months. The Company does not intend to sell the securities that are in an unrealized loss position, and it is unlikely that the Company will be required to sell the investments before recovery of their amortized cost basis, which may be at maturity. All of the Company’s investments have remaining contractual maturities of less than twelve months.

Build-to-Suit Lease Obligation

Build-to-Suit Lease Obligation	6 Months Ended
	Jun. 30, 2015
Leases [Abstract]
Build-to-Suit Lease Obligation	NOTE 8. BUILD-TO-SUIT LEASE OBLIGATION In the fourth quarter of 2013, the Company entered into a property lease for approximately 51,632 square feet of space located in San Francisco, California. In the second quarter of 2015, the Company entered into an amended lease agreement to reduce the amount of leased space at this property to approximately 43,625 square feet. The lease agreement expires in August 2024, and the Company has an option to extend the lease term for up to an additional five years. The Company is deemed, for accounting purposes only, to be the owner of the entire project including the building shell, even though it is not the legal owner. In connection with the Company’s accounting for this transaction, the Company capitalized $14.5 million as a build-to-suit property within property and equipment, net, and recognized a corresponding build-to-suit lease obligation for the same amount. The Company has also recognized, as an additional build-to-suit lease property and obligation, structural tenant improvements totaling $3.9 million for amounts paid by the landlord and $2.5 million for capitalized interest during the construction period through June 30, 2015. As a result of the amended agreement, the Company surrendered a portion of the property totaling approximately 8,007 square feet to the lessor. The Company has no continuing involvement with the portion of the property surrendered to the lessor. Accordingly, the Company derecognized a portion of the build-to-suit asset totaling $3.2 million and a portion of the build-to-suit lease obligation totaling $3.1 million during the second quarter of 2015 related to the portion of the property that was surrendered to the lessor. A portion of the monthly lease payment is allocated to land rent and recorded as an operating lease expense and the non-interest portion of the amortized lease payments to the landlord related to the rent of the building is applied to reduce the build-to-suit lease obligation. At June 30, 2015, $0.2 million of the build-to-suit lease obligation representing the expected reduction in the liability over the next twelve months was classified as a current liability and the remaining $16.9 million was classified as a non-current liability on the consolidated balance sheet. Expected reductions in the build-to-suit lease obligation are as follows: Years Ending December 31, Build-To-Suit Lease Obligation Remainder of 2015 $ 197 2016 10 2017 77 2018 149 2019 228 2020 and thereafter 16,455 Total $ 17,116 The amounts included in the table above represent the reductions in the build-to-suit lease obligation included on the Company’s consolidated balance sheet at June 30, 2015 in each of the periods presented. The amount in the terminal period includes the amount to derecognize the build-to-suit lease obligation at the end of the lease term. The expected reductions in the build-to-suit lease obligation presented in the table above are impacted by the timing of the completion of the construction project. Actual expected lease payments under the build-to-suit lease obligation are included in Note 14, “Commitments and Contingencies.”

Property and Equipment, Net

Property and Equipment, Net	6 Months Ended
	Jun. 30, 2015
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	NOTE 9. PROPERTY AND EQUIPMENT, NET Property and equipment, net, consisted of the following: June 30, 2015 December 31, 2014 Build-to-suit property $ 17,656 $ 19,544 Leasehold improvements 15,027 15,051 Computer equipment and software 11,012 9,499 Furniture and fixtures 4,576 4,667 Construction in progress 7,999 1,360 Laboratory equipment 735 735 57,005 50,856 Less: Accumulated depreciation (12,714 ) (9,695 ) Total $ 44,291 $ 41,161 The reduction of the build-to-suit property in the table above resulted from the surrender of a portion of the construction project to the lessor in connection with the lease amendment described in Note 8, “Build-To-Suit-Lease Obligation.”

Accounts Payable, Accrued Expen

Accounts Payable, Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2015
Payables and Accruals [Abstract]
Accounts Payable, Accrued Expenses and Other Current Liabilities	NOTE 10. ACCOUNTS PAYABLE, ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accounts payable, accrued expenses and other current liabilities consisted of the following: June 30, December 31, Clinical and preclinical $ 35,676 $ 31,069 Accrued professional services and other current liabilities 17,117 8,909 Payroll and payroll-related 19,285 33,272 Royalties payable 18,860 13,582 Accounts payable 12,754 10,492 Other payable to licensor 14,057 5,000 Interest payable 1,101 1,698 Taxes payable — 2,106 Total $ 118,850 $ 106,128 Accounts payable represents short-term liabilities for which the Company has received and processed a vendor invoice prior to the end of the reporting period. Accrued expenses and other current liabilities represent, among other things, compensation and related benefits to employees, royalties due to licensors of technologies, interest payable related to the Company’s Convertible Notes, estimated amounts due to third party vendors for services rendered prior to the end of the reporting period, invoices received from third party vendors that have not yet been processed, taxes payable, and other accrued items.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Stockholders' Equity	NOTE 11. STOCKHOLDERS’ EQUITY (a) Stock Purchase Rights All shares of the Company’s common stock, if issued prior to the termination by the Company of its rights agreement, dated as of December 4, 2006, include stock purchase rights. The rights are exercisable only if a person or group acquires twenty percent or more of the Company’s common stock or announces a tender or exchange offer which would result in ownership of twenty percent or more of the Company’s common stock. Following the acquisition of twenty percent or more of the Company’s common stock, the holders of the rights, other than the acquiring person or group, may purchase Medivation common stock at half of its fair market value. In the event of a merger or other acquisition of the Company, the holders of the rights, other than the acquiring person or group, may purchase shares of the acquiring entity at half of their fair market value. The rights were not exercisable at June 30, 2015. (b) Medivation Equity Incentive Plan The Medivation Equity Incentive Plan provides for the issuance of options and other stock-based awards, including restricted stock units, performance share awards and stock appreciation rights. The vesting of all outstanding awards under the Medivation Equity Incentive Plan will accelerate, and all such awards will become immediately exercisable, upon a “change of control” of Medivation, as defined in the Medivation Equity Incentive Plan. On June 16, 2015, the Company’s stockholders approved an amendment and restatement of the Medivation Equity Incentive Plan to increase the aggregate number of shares of common stock authorized for issuance under the Medivation Equity Incentive Plan from 21,150,000 to 23,850,000. As of June 30, 2015, approximately 4.6 million shares were available for issuance under the Medivation Equity Incentive Plan. Stock Options The following table summarizes stock option activity for the six months ended June 30, 2015: Number of Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) Outstanding at December 31, 2014 5,067,957 $ 33.52 Granted 581,083 $ 115.77 Exercised (519,560 ) $ 22.77 Forfeited (52,345 ) $ 84.17 Outstanding at June 30, 2015 5,077,135 $ 43.51 6.33 $ 361.6 Vested and exercisable at June 30, 2015 3,399,023 $ 24.62 5.18 $ 304.5 (1) The aggregate intrinsic value is calculated as the pre-tax difference between the weighted average exercise price of the underlying awards and the closing price per share of $114.20 of the Company’s common stock on June 30, 2015. The calculation excludes any awards with an exercise price higher than the closing price of the Company’s common stock on June 30, 2015. The amounts are presented in millions. The weighted-average grant-date fair value per share of options granted during the six months ended June 30, 2015 was $51.87. Restricted Stock Units The following table summarizes restricted stock unit activity for the six months ended June 30, 2015: Number of Shares Weighted- Average Grant-Date Fair Value Unvested at December 31, 2014 483,580 $ 76.20 Granted 230,812 $ 112.91 Vested (118,662 ) $ 75.91 Forfeited (23,039 ) $ 89.76 Unvested at June 30, 2015 572,691 $ 90.51 Stock Appreciation Rights The following table summarizes stock appreciation rights activity for the six months ended June 30, 2015: Number of Rights Weighted Weighted Aggregate Intrinsic (1) Outstanding at December 31, 2014 688,228 $ 24.05 Granted — — Exercised (26,912 ) $ 23.20 Forfeited (5,514 ) $ 23.20 Outstanding at June 30, 2015 655,802 $ 24.09 6.46 $ 59.1 Vested and exercisable at June 30, 2015 564,384 $ 24.11 6.46 $ 50.8 (1) The aggregate intrinsic value is calculated as the pre-tax difference between the weighted average exercise price of the underlying awards and the closing price per share of $114.20 of the Company’s common stock on June 30, 2015. The calculation excludes any awards with an exercise price higher than the closing price of the Company’s common stock on June 30, 2015. The amounts are presented in millions. (c) ESPP The ESPP permits eligible employees to purchase shares of the Company’s common stock through payroll deductions at the lower of 85% of the fair market value of the common stock at the beginning or end of a purchase period. Eligible employee contributions are limited on an annual basis to $25,000 in accordance with Section 423 of the Internal Revenue Code. As of June 30, 2015, a total of 3,000,000 shares of the Company’s common stock were authorized for issuance under the ESPP, and 123,680 shares have been issued. (d) Stock-Based Compensation The Company estimates the fair value of stock options, stock appreciation rights, and ESPP shares using the Black-Scholes valuation model. The Black-Scholes assumptions used to estimate the fair value of stock options granted were as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Risk-free interest rate 1.33-1.78% 1.65-1.77% 1.33-1.78% 1.57-1.77% Estimated term (in years) 4.99-5.50 5.09-5.50 4.98-5.50 5.09-5.50 Estimated volatility 50-57% 60-61% 50-57% 60-64% Estimated dividend yield — — — — The Black-Scholes assumptions used to estimate the fair value of shares issued under the ESPP on the commencement date of the offering period were as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Risk-free interest rate 0.12 % 0.06 % 0.12 % 0.06 % Estimated term (in years) 0.50 0.50 0.50 0.50 Estimated volatility 37 % 53 % 37 % 53 % Estimated dividend yield — — — — Stock-based compensation expense was as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Stock-based compensation expense recognized as: R&D expense $ 6,109 $ 4,503 $ 11,920 $ 8,625 SG&A expense 7,969 6,678 15,530 12,217 Total $ 14,078 $ 11,181 $ 27,450 $ 20,842 Unrecognized stock-based compensation expense totaled $99.0 million at June 30, 2015 and is expected to be recognized over a weighted-average period of 2.5 years.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 12. INCOME TAXES The Company calculates its quarterly income tax provision in accordance with the guidance provided by ASC 740-270, “Interim Income Tax Accounting,” whereby the Company forecasts its estimated annual effective tax rate and then applies that rate to its year-to-date pre-tax book income (loss). Income tax expense for the three and six months ended June 30, 2015 was $14.6 million and $12.8 million, respectively. A discrete tax benefit of $2.8 million related to the loss on extinguishment of Convertible Notes was included in the provision for income taxes for the three and six months ended June 30, 2015. The provision for income taxes was higher than the tax computed at the U.S. federal statutory rate due primarily to state income taxes and non-deductible stock-based compensation. Income tax expense for both the three and six months ended June 30, 2014 was $1.6 million. The effective tax rate was 36.1% for both the three and six months ended June 30, 2015. The effective tax rate was 3.3% and 4.3% for the three and six months ended June 30, 2014, respectively. The increase in the effective tax rate for the three and six months ended June 30, 2015 as compared to the prior year periods was due to the release of a portion of the valuation allowance during the fourth quarter of 2014. The Company reduced its current Federal and state taxes payable by $13.6 million related to excess tax benefits from stock-based compensation, increasing additional paid-in capital. In addition, the Company recorded a credit to additional paid-in capital of $4.4 million related to certain tax impacts of the extinguishment of Convertible Notes. The Company records a valuation allowance to reduce deferred tax assets to reflect the net amount that is more likely than not to be realized. Based upon the weight of available evidence at December 31, 2014, the Company determined that it was more likely than not that a portion of its deferred tax assets would be realizable and consequently released the valuation allowance against Federal and certain state net deferred tax assets and recorded a discrete tax benefit of $33.4 million during the fourth quarter of 2014. The decision to reverse a portion of the valuation allowance was made after management considered all available evidence, both positive and negative, including but not limited to the historical operating results, income or loss in recent periods, cumulative income in recent years, forecasted earnings, forecasted future taxable income, and significant risk and uncertainty related to forecasts. The release of the valuation allowance resulted in the recognition of certain deferred net tax assets and a decrease to income tax expense. The future effective tax rate is subject to volatility and may be materially impacted by various internal and external factors. These factors may include, but are not limited to, the amount of income tax benefits and charges from: interpretations of existing tax laws; changes in tax laws and rates; future levels of research and development expenditures; changes in the mix of earnings in countries with differing statutory tax rates in which the Company may conduct business; changes in the valuation of deferred tax assets and liabilities; state income taxes; the tax impact of stock-based compensation; accounting for uncertain tax positions; closure of statute of limitations or settlement of tax audits; changes in estimates of prior years’ items; tax costs for acquisition-related items; changes in accounting standards; non-deductible officers’ compensation; limitations on the utilization of net operating losses and tax credits due to changes in ownership; and overall levels of income before taxes.

Fair Value Disclosures

Fair Value Disclosures	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Disclosures	NOTE 13. FAIR VALUE DISCLOSURES The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis: Fair value measurements using: Fair Value Level 1 Level 2 Level 3 June 30, 2015: Cash equivalents: Money market funds $ 189,041 $ 189,041 — — Commercial paper $ 7,697 — $ 7,697 — Short-term investments Corporate debt securities $ 42,792 — $ 42,792 — Commercial paper $ 21,568 — $ 21,568 — Federal agency securities $ 9,997 — $ 9,997 — Certificates of deposit $ 2,000 — $ 2,000 — Current liabilities: Contingent consideration $ 10,000 — — $ 10,000 Long-term liabilities Contingent consideration $ 101,013 — — $ 101,013 December 31, 2014: Cash equivalents: Money market funds $ 189,031 $ 189,031 — — Current liabilities: Contingent consideration $ 10,000 — — $ 10,000 Long-term liabilities Contingent consideration $ 96,000 — — $ 96,000 The Company classifies money market funds, which are based on quoted market prices in active markets with no valuation adjustments, as Level 1 assets within the valuation hierarchy. The Company estimates the fair values of Level 2 marketable securities by taking into consideration valuations obtained from third-party pricing sources. These pricing sources utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly, or indirectly, to estimate fair value. These inputs include market pricing based on real-time trade data for the same or similar securities, issuer credit spreads, benchmark yields, and other observable inputs. The Company validates the prices provided by its third-party pricing sources by understanding the models used, obtaining market values from other pricing sources, and/or analyzing pricing data in certain instances. In connection with the CureTech license transaction, the Company recorded contingent consideration liabilities pertaining to amounts potentially payable to CureTech. The fair value of contingent consideration was estimated utilizing a model with key assumptions that included estimated revenues or completion of certain development and sales milestone targets during the earn-out period, volatility, and estimated discount rates corresponding to the periods of expected payments. The estimated fair value of the contingent consideration liability is measured at each reporting date based on significant inputs not observable in the market. The Company assesses these estimates on an ongoing basis as additional data impacting the assumptions is obtained. Changes in the estimated fair value of contingent consideration are reflected as non-cash adjustments to operating expenses in the consolidated statements of operations. During the three months ended June 30, 2015, the Company recorded a non-cash fair value adjustment of $0.1 million to reduce R&D expenses and a non-cash fair value adjustment of $1.1 million to increase SG&A expenses. During the six months ended June 30, 2015, the Company recorded non-cash fair value adjustments of $0.9 million and $4.1 million to increase R&D expenses and SG&A expenses, respectively. Contingent consideration may change significantly as development progresses and additional data is obtained that will affect the Company’s assumptions regarding probabilities of successful achievement of related milestones used to estimate the fair value of the liability and the timing in which they are expected to be achieved. Considerable judgment is required to interpret the market data used to develop the assumptions. The estimates of fair value may not be indicative of amounts that could be realized in a current market exchange. Accordingly, the use of different market assumptions and/or different valuation techniques could result in materially different fair value estimates. The $1.0 million and $5.0 million increases in the fair value of the contingent consideration liability during the three and six months ended June 30, 2015, respectively, are primarily due to the time value of money. The aggregate remaining, undiscounted amount of contingent consideration that the Company could potentially be required to pay to CureTech under the License Agreement is included in the table below: Potential sales milestones $ 245,000 Potential development and regulatory milestones $ 85,000 Potential payment upon completion of Manufacturing Technology Transfer $ 5,000 Potential future tiered royalties on annual worldwide net sales 5% to 11 % There were no transfers between Level 1 and Level 2 financial instruments during the three and six months ended June 30, 2015. The following table includes a roll-forward of the fair value of Level 3 financial instruments for the three and six months ended June 30, 2015: Three Months Ended Six Months Ended Contingent Consideration (Current and Long-Term): Balance at beginning of period $ 110,000 $ 106,000 Amounts acquired or issued — — Net change in fair value 1,013 5,013 Settlements — — Transfers in and/or out of Level 3 — — Balance at end of period $ 111,013 $ 111,013 The following table presents the total balance of the Company’s other financial instruments that are not measured at fair value on a recurring basis: Fair value measurements using: Total Balance Level 1 Level 2 Level 3 June 30, 2015: Assets: Bank deposits (included in “Cash and cash equivalents”) $ 224,412 $ 224,412 — — Liabilities: Convertible Notes $ 269,434 — $ 269,434 — December 31, 2014: Assets: Bank deposits (included in “Cash and cash equivalents”) $ 313,646 $ 313,646 — — Liabilities: Convertible Notes $ 359,219 — $ 359,219 — Due to their short-term maturities, the Company believes that the fair value of its bank deposits, receivable from collaboration partner, accounts payable and accrued expenses and other current assets and liabilities approximate their carrying value. The estimated fair value of the Company’s Convertible Notes, including the equity component, was $372.6 million and $496.8 million at June 30, 2015 and December 31, 2014, respectively, and was determined using recent trading prices of the Convertible Notes. The fair value of the Convertible Notes included in the table above represents only the liability component of the Convertible Notes, because the equity component is included in stockholders’ equity on the consolidated balance sheets. In the third quarter of 2015, the Company completed the settlement of $167.8 million aggregate principal amount of its Convertible Notes in exchange for $167.8 million in cash and 1,769,609 shares of its common stock. Additional information is included in Note 15, “Subsequent Events.”

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 14. COMMITMENTS AND CONTINGENCIES (a) Lease Obligations In the first quarter of 2015, the Company entered into the Sixth Amendment to its corporate headquarters lease agreement in San Francisco, California, pursuant to which it leased approximately 16,000 additional square feet of office space. The Company is entitled to approximately $0.3 million of tenant improvement allowances pursuant to the Sixth Amendment. In connection with the execution of the Sixth Amendment, the Company delivered to the lessor a letter of credit collateralized by restricted cash totaling $1.6 million. In total, at June 30, 2015, the Company leased approximately 143,000 square feet of office space pursuant to the lease agreement, as amended, which expires in June 2019. Lease commitments pursuant to the Sixth Amendment are approximately $6.1 million over the term of the lease. Future operating lease obligations as of June 30, 2015 are as follows: Years Ending December 31, Operating Remainder of 2015 $ 4,569 2016 9,345 2017 9,544 2018 9,746 2019 5,065 2020 and thereafter — Total minimum lease payments $ 38,269 The Company is considered the “accounting owner” for a build-to-suit property and has recorded a build-to-suit lease obligation on its consolidated balance sheets. Additional information regarding the build-to-suit lease obligation is included in Note 8, “Build-To-Suit Lease Obligation.” Expected future lease payments under the build-to-suit lease as of June 30, 2015 are as follows: Years Ending December 31, Expected Cash Remainder of 2015 $ 1,177 2016 2,168 2017 2,233 2018 2,300 2019 2,368 2020 and thereafter 12,028 Total minimum lease payments $ 22,274 (b) Restricted Cash The Company had outstanding letters of credit collateralized by restricted cash totaling $13.3 million and $11.8 million at June 30, 2015 and December 31, 2014, respectively, to secure various operating leases. At June 30, 2015, $0.6 million and $12.7 million of restricted cash associated with these letters of credit were classified as current and long-term assets, respectively, on the consolidated balance sheets. At December 31, 2014, $0.2 million and $11.6 million of restricted cash associated with these letters of credit were classified as current and long-term assets, respectively, on the consolidated balance sheets. (c) License Agreement with UCLA Under an August 2005 license agreement with UCLA, the Company’s subsidiary Medivation Prostate Therapeutics, Inc., or MPT, holds an exclusive worldwide license under several UCLA patents and patent applications covering XTANDI and related compounds. Under the Astellas Collaboration Agreement, the Company granted Astellas a sublicense under the patent rights licensed to it by UCLA. The Company is required to pay UCLA (a) an annual maintenance fee, (b) $2.8 million in aggregate milestone payments upon achievement of certain development and regulatory milestone events with respect to XTANDI (all of which has been paid as of June 30, 2015), (c) ten percent of all Sublicensing Income, as defined in the agreement, which the Company earns under the Astellas Collaboration Agreement, and (d) a four percent royalty on global net sales of XTANDI, as defined. Under the terms of the Astellas Collaboration Agreement, the Company shares this royalty obligation equally with Astellas with respect to sales in the United States, and Astellas is responsible for this entire royalty obligation with respect to sales outside of the United States. The Company is currently involved in litigation with UCLA, which is discussed in the section titled “Litigation” below. UCLA may terminate the agreement if the Company does not meet a general obligation to diligently proceed with the development, manufacturing and sale of licensed products, or if it commits any other uncured material breach of the agreement. The Company may terminate the agreement at any time upon advance written notice to UCLA. If neither party terminates the agreement early, the agreement will continue in force until the expiration of the last-to-expire patent on a country-by-country basis. (d) Clinical Manufacturing Agreements Manufacturing Services and Supply Agreements Contemporaneous with the execution of the License Agreement with CureTech, the Company entered into a Manufacturing Services and Supply Agreement, or MSA, with CureTech pursuant to which CureTech will provide clinical trial supply of MDV9300 over a three year period. In accordance with the terms of the MSA, as amended on June 29, 2015, the Company paid CureTech upfront and setup fees of $3.0 million during the fourth quarter of 2014 and $0.2 million during the second quarter of 2015. The Company is required to pay CureTech a one-time milestone payment of $5.0 million upon the completion of the Manufacturing Technology Transfer, as defined. In accordance with the terms of the MSA, the Company is also responsible for providing Manufacturing Funding totaling up to $19.3 million for clinical trial materials of MDV9300 over the three-year term of the MSA, of which $6.0 million has been paid through June 30, 2015. The Manufacturing Funding is contingent upon the successful achievement of the requirements set forth in the Manufacturing Plan, and any such amounts may be reduced or eliminated by the Company under the terms of the MSA. Development and Manufacturing Services Agreement During the fourth quarter of 2014, the Company entered into a Development and Manufacturing Services Agreement with a third party clinical manufacturing organization. The term of the agreement is for the longer of (i) a period of five (5) years or (ii) through the completion of the Services, as defined. Under the current statement of work under this agreement, the Company intends to transfer the current manufacturing process of MDV9300 from CureTech to this third party, further scale up and production of Phase 3 clinical trial material of MDV9300 from this entity’s manufacturing facility. The estimated total consideration under the current statement of work is approximately $14.5 million, of which approximately $1.0 million has been paid through June 30, 2015. (e) Research and License Agreement In March 2014, the Company entered into a Research and License Agreement with a third party. Under the terms of the agreement, the Company paid a $12.0 million license and research agreement fee which was recorded in R&D expense in the consolidated statement of operations for the three months ended March 31, 2014. The Company could also be required to pay potential future development and sales milestone payments, subject to the achievement of defined clinical and commercial events, and royalties based on sales. Such future milestone and royalty payments are contingent upon future events that may or may not materialize. (f) Litigation The Company is party to legal proceedings, investigations, and claims in the ordinary course of its business, including the matters described below. The Company records accruals for outstanding legal matters when it believes that it is both probable that a liability has been incurred and the amount of such liability can be reasonably estimated. The Company evaluates, on a quarterly basis, developments in significant legal matters that could affect the amount of any accrual and developments that would make a loss contingency both probable and reasonably estimable. To the extent new information is obtained and the Company’s views on the probable outcomes of claims, suits, assessments, investigations or legal proceedings change, changes in the Company’s accrued liabilities would be recorded in the period in which such determination is made. In addition, in accordance with the relevant authoritative guidance, for matters for which the likelihood of material loss is at least reasonably possible, the Company provides disclosure of the possible loss or range of loss; however, if a reasonable estimate cannot be made, the Company will provide disclosure to that effect. Gain contingencies, if any, are recorded as a reduction of expense when they are realized. In May 2011, the Company filed a lawsuit in San Francisco Superior Court against the Regents of the University of California, and one of its professors, alleging breach of contract and fraud claims, among others. The Company’s allegations in this lawsuit include that it has exclusive commercial rights to an investigational drug originally known as ARN-509, which is currently being developed by Aragon Pharmaceuticals, or Aragon. In August 2013, Johnson & Johnson and Aragon completed a transaction in which Johnson & Johnson acquired all ARN-509 assets owned by Aragon. Since its acquisition by Johnson & Johnson, ARN-509 is now known as JNJ-56021927, or JNJ-927. On April 11, 2014, the Regents filed a complaint against the Company in which UCLA alleges that the “Operating Profits” Medivation has received (and will continue to receive) from Astellas, as a result of the Astellas Collaboration Agreement, constitute Sublicensing Income under the license agreement between Medivation and the Regents and that Medivation and MPT have failed to pay the Regents ten percent of such Operating Profits. Although the Regents further alleged that Medivation breached its fiduciary duties to the Regents, as minority shareholder of MPT, the Regents dismissed this claim without prejudice on July 16, 2014. On March 23, 2015, based upon an application by both the Company and the Regents, the court designated the case complex and assigned a single judge in the complex division of San Francisco Superior Court. The Company denies the Regents’ allegations and intends to vigorously defend the litigation. While the Company believes it has meritorious positions with respect to the claims above and intends to advance its positions in these lawsuits vigorously, including on appeal, the process of resolving matters through litigation or other means is inherently uncertain, and it is not possible to predict the ultimate resolution of any such proceeding. The actual costs of defending the Company’s position may be significant, and the Company may not prevail.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	NOTE 15. SUBSEQUENT EVENTS (a) Convertible Notes On June 19, 2015, the Company issued a notice of redemption to redeem on July 24, 2015 all of its outstanding Convertible Notes. Pursuant to this notice of redemption, the Company completed the settlement of $167.8 million aggregate principal amount of the Convertible Notes for $167.8 million in cash and 1,769,609 shares of its common stock during 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. The Company expects to record a non-cash loss on extinguishment of Convertible Notes of approximately $13.0 million during the third quarter of 2015. (b) Stock Dividend On July 31, 2015, the Company announced that its Board of Directors has declared a two-for-one stock split of Medivation’s common stock to be effected through a stock dividend. Shareholders of record as of August 13, 2015, will receive one additional share of Medivation common stock, par value $0.01, for each share they hold as of the record date. The share distribution is scheduled for September 15, 2015.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Principles of Consolidation	(a) Basis of Presentation and Principles of Consolidation The accompanying unaudited 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 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 of any interim period are not necessarily indicative of the results of operations for the full year or any other interim period. The unaudited consolidated financial statements and related disclosures have been prepared with the presumption that users of the interim unaudited consolidated financial statements have read or have access to the audited consolidated financial statements for the preceding year. Accordingly, these unaudited 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 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.
Use of Estimates	(b) Use of Estimates The preparation of unaudited 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 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 (loss) per common share.
Significant Accounting Policies	(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”.
New Accounting Pronouncements	(e) New Accounting Pronouncements In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 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 provides guidance to help companies evaluate the accounting for fees paid by a customer in a cloud computing arrangement. The new guidance clarifies that if a cloud computing arrangement includes a software license, the customer should account for the license consistent with its accounting for other software licenses. If the arrangement does not include a software license, the customer should account for the arrangement as a service contract. The revised guidance will not change a customer’s accounting for service contracts. The ASU may be adopted prospectively or retrospectively 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 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 currently does not expect that the adoption of ASU 2015-03 will have a material impact 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 July 2015, the FASB decided to delay the effective date of the new revenue standard 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.
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS In the fourth quarter of 2014, the Company entered into a License Agreement with CureTech, pursuant to which it licensed exclusive worldwide rights to CureTech’s late-stage clinical molecule, MDV9300. The Company concluded that the in-license transaction is an acquisition of a business in accordance with FASB Accounting Standards Codification, or ASC, 805-10, “Business Combinations.” The transaction resulted in identifiable intangible assets of $101.0 million consisting entirely of in-process research and development, or IPR&D, and goodwill of $10.0 million. The Company accounts for IPR&D as indefinite-lived intangible assets until regulatory approval or discontinuation at which time the Company evaluates impairment, converts the carrying value into a definite-lived intangible asset and determines the economic life for amortization purposes. The Company assesses the impairment of intangible assets and goodwill on an annual basis or more frequently whenever events or changes in circumstances may indicate that the carrying value might not be recoverable. The Company applies the rules in ASU No. 2011-08, “Testing Goodwill for Impairment,” which amends the rules for testing goodwill for impairment by allowing an entity the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, an entity determines it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, then performing the two-step impairment test is unnecessary. The Company applies the rules in ASU No. 2012-02, “Testing Indefinite-Lived Intangibles Assets for Impairment,” which provides entities with an option to perform a qualitative assessment of indefinite-lived intangible assets other than goodwill for impairment to determine if additional impairment testing is necessary. The Company evaluated its goodwill and indefinite-lived intangible assets utilizing the simplified approach as of June 30, 2015. The Company determined that its goodwill and indefinite-lived intangible assets were not impaired at June 30, 2015. The Company was not required to perform the two-step quantitative impairment test.
Net Income (Loss) Per Common Share	The computation of basic net income per common share is based on the weighted-average number of common shares outstanding during each period. The computation of diluted net income per common share is based on the weighted-average number of common shares outstanding during the period plus, when their effect is dilutive, incremental shares consisting of shares subject to stock options, restricted stock units, stock appreciation rights, ESPP shares, warrants, and shares issuable upon conversion of convertible debt.
Income Taxes	INCOME TAXES The Company calculates its quarterly income tax provision in accordance with the guidance provided by ASC 740-270, “Interim Income Tax Accounting,” whereby the Company forecasts its estimated annual effective tax rate and then applies that rate to its year-to-date pre-tax book income (loss). Income tax expense for the three and six months ended June 30, 2015 was $14.6 million and $12.8 million, respectively. A discrete tax benefit of $2.8 million related to the loss on extinguishment of Convertible Notes was included in the provision for income taxes for the three and six months ended June 30, 2015. The provision for income taxes was higher than the tax computed at the U.S. federal statutory rate due primarily to state income taxes and non-deductible stock-based compensation. Income tax expense for both the three and six months ended June 30, 2014 was $1.6 million. The effective tax rate was 36.1% for both the three and six months ended June 30, 2015. The effective tax rate was 3.3% and 4.3% for the three and six months ended June 30, 2014, respectively. The increase in the effective tax rate for the three and six months ended June 30, 2015 as compared to the prior year periods was due to the release of a portion of the valuation allowance during the fourth quarter of 2014. The Company reduced its current Federal and state taxes payable by $13.6 million related to excess tax benefits from stock-based compensation, increasing additional paid-in capital. In addition, the Company recorded a credit to additional paid-in capital of $4.4 million related to certain tax impacts of the extinguishment of Convertible Notes. The Company records a valuation allowance to reduce deferred tax assets to reflect the net amount that is more likely than not to be realized. Based upon the weight of available evidence at December 31, 2014, the Company determined that it was more likely than not that a portion of its deferred tax assets would be realizable and consequently released the valuation allowance against Federal and certain state net deferred tax assets and recorded a discrete tax benefit of $33.4 million during the fourth quarter of 2014. The decision to reverse a portion of the valuation allowance was made after management considered all available evidence, both positive and negative, including but not limited to the historical operating results, income or loss in recent periods, cumulative income in recent years, forecasted earnings, forecasted future taxable income, and significant risk and uncertainty related to forecasts. The release of the valuation allowance resulted in the recognition of certain deferred net tax assets and a decrease to income tax expense. The future effective tax rate is subject to volatility and may be materially impacted by various internal and external factors. These factors may include, but are not limited to, the amount of income tax benefits and charges from: interpretations of existing tax laws; changes in tax laws and rates; future levels of research and development expenditures; changes in the mix of earnings in countries with differing statutory tax rates in which the Company may conduct business; changes in the valuation of deferred tax assets and liabilities; state income taxes; the tax impact of stock-based compensation; accounting for uncertain tax positions; closure of statute of limitations or settlement of tax audits; changes in estimates of prior years’ items; tax costs for acquisition-related items; changes in accounting standards; non-deductible officers’ compensation; limitations on the utilization of net operating losses and tax credits due to changes in ownership; and overall levels of income before taxes.
Litigation	(f) Litigation The Company is party to legal proceedings, investigations, and claims in the ordinary course of its business, including the matters described below. The Company records accruals for outstanding legal matters when it believes that it is both probable that a liability has been incurred and the amount of such liability can be reasonably estimated. The Company evaluates, on a quarterly basis, developments in significant legal matters that could affect the amount of any accrual and developments that would make a loss contingency both probable and reasonably estimable. To the extent new information is obtained and the Company’s views on the probable outcomes of claims, suits, assessments, investigations or legal proceedings change, changes in the Company’s accrued liabilities would be recorded in the period in which such determination is made. In addition, in accordance with the relevant authoritative guidance, for matters for which the likelihood of material loss is at least reasonably possible, the Company provides disclosure of the possible loss or range of loss; however, if a reasonable estimate cannot be made, the Company will provide disclosure to that effect. Gain contingencies, if any, are recorded as a reduction of expense when they are realized.

Collaboration Agreement (Tables

Collaboration Agreement (Tables)	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Potential Milestone Payments in Sales	The triggering events for the sales milestone payments are as follows: Annual Global Net Sales in a Calendar Year Milestone Payment (1) $400 million (2) $800 million (3) $1.2 billion $ 70 million $1.6 billion $ 175 million (1) Each milestone shall only be paid once during the term of the Astellas Collaboration Agreement. (2) This milestone totaling $25.0 million was earned and recognized as collaboration revenue during the fourth quarter of 2013 and payment was received in the first quarter of 2014. (3) This milestone totaling $50.0 million was earned and recognized as collaboration revenue during the fourth quarter of 2014 and is included in receivable from collaboration partner on the consolidated balance sheet at December 31, 2014. Payment was received during the first quarter of 2015.
Schedule of Collaboration Revenue	Collaboration revenue was as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Collaboration revenue: Related to U.S. XTANDI net sales $ 149,220 $ 71,866 $ 261,230 $ 134,091 Related to ex-U.S. XTANDI net sales 25,591 9,992 41,358 15,723 Related to upfront and milestone payments 846 66,232 2,257 85,465 Total $ 175,657 $ 148,090 $ 304,845 $ 235,279
Schedule of Collaboration Revenue Related to U.S. XTANDI Net Sales	Collaboration revenue related to U.S. XTANDI net sales was as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 U.S. XTANDI net sales (as reported by Astellas) $ 298,440 $ 143,732 $ 522,460 $ 268,183 Shared U.S. development and commercialization costs (84,947 ) (70,543 ) (195,260 ) (148,250 ) Pre-tax U.S. profit $ 213,493 $ 73,189 $ 327,200 $ 119,933 Medivation’s share of pre-tax U.S. profit $ 106,747 $ 36,594 $ 163,600 $ 59,966 Reimbursement of Medivation’s share of shared U.S. costs 42,473 35,272 97,630 74,125 Collaboration revenue related to U.S. XTANDI net sales $ 149,220 $ 71,866 $ 261,230 $ 134,091
Schedule of Collaboration Revenue Related to Upfront and Milestone Payments	Collaboration revenue related to upfront and milestone payments from Astellas was as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Development milestones earned $ — $ 62,000 $ — $ 77,000 Amortization of deferred upfront and development milestones 846 4,232 2,257 8,465 Total $ 846 $ 66,232 $ 2,257 $ 85,465

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Calculation of Diluted Net Income (Loss) Per Common Share	The following table reconciles the numerator and denominator used to calculate diluted net income per common share: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Numerator: Net income $ 25,826 $ 47,919 $ 22,708 $ 34,254 Denominator: Weighted-average common shares, basic 79,252 76,577 78,788 76,411 Dilutive effect of common stock equivalents 5,093 3,914 2,710 4,076 Weighted-average common shares, diluted 84,345 80,491 81,498 80,487 Net income per common share: Basic net income per common share $ 0.33 $ 0.63 $ 0.29 $ 0.45 Diluted net income per common share $ 0.31 $ 0.60 $ 0.28 $ 0.43

Cash, Cash Equivalents, and S25

Cash, Cash Equivalents, and Short-Term Investments (Tables)	6 Months Ended
	Jun. 30, 2015
Cash and Cash Equivalents [Abstract]
Summary of Cash, Cash Equivalents, and Short-Term Investments	The following table summarizes the Company’s cash, cash equivalents, and short-term investments at June 30, 2015 and December 31, 2014: Amortized Gross Unrealized Fair Cost Gains Losses Value June 30, 2015 Cash and cash equivalents: Cash $ 224,412 $ — $ — $ 224,412 Money market funds 189,041 — — 189,041 Commercial paper 7,697 — — 7,697 Total cash and cash equivalents 421,150 — — 421,150 Short-term investments: Corporate debt securities 42,830 1 (39 ) 42,792 Commercial paper 21,568 — — 21,568 Federal agency securities 9,993 4 — 9,997 Certificates of deposit 2,000 — — 2,000 Total short-term investments 76,391 5 (39 ) 76,357 Total cash, cash equivalents, and short-term investments $ 497,541 $ 5 $ (39 ) $ 497,507 Amortized Gross Unrealized Fair Cost Gains Losses Value December 31, 2014 Cash and cash equivalents: Cash $ 313,646 $ — $ — $ 313,646 Money market funds 189,031 — — 189,031 Total cash and cash equivalents $ 502,677 $ — $ — $ 502,677

Build-to-Suit Lease Obligation

Build-to-Suit Lease Obligation (Tables)	6 Months Ended
	Jun. 30, 2015
Leases [Abstract]
Schedule of Expected Reductions in Build-to-Suit Lease Obligation	Expected reductions in the build-to-suit lease obligation are as follows: Years Ending December 31, Build-To-Suit Lease Obligation Remainder of 2015 $ 197 2016 10 2017 77 2018 149 2019 228 2020 and thereafter 16,455 Total $ 17,116

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2015
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net, consisted of the following: June 30, 2015 December 31, 2014 Build-to-suit property $ 17,656 $ 19,544 Leasehold improvements 15,027 15,051 Computer equipment and software 11,012 9,499 Furniture and fixtures 4,576 4,667 Construction in progress 7,999 1,360 Laboratory equipment 735 735 57,005 50,856 Less: Accumulated depreciation (12,714 ) (9,695 ) Total $ 44,291 $ 41,161

Accounts Payable, Accrued Exp28

Accounts Payable, Accrued Expenses and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2015
Payables and Accruals [Abstract]
Components of Accounts Payable, Accrued Expenses and Other Current Liabilities	Accounts payable, accrued expenses and other current liabilities consisted of the following: June 30, December 31, Clinical and preclinical $ 35,676 $ 31,069 Accrued professional services and other current liabilities 17,117 8,909 Payroll and payroll-related 19,285 33,272 Royalties payable 18,860 13,582 Accounts payable 12,754 10,492 Other payable to licensor 14,057 5,000 Interest payable 1,101 1,698 Taxes payable — 2,106 Total $ 118,850 $ 106,128

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Summary of Stock Option Activity	The following table summarizes stock option activity for the six months ended June 30, 2015: Number of Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) Outstanding at December 31, 2014 5,067,957 $ 33.52 Granted 581,083 $ 115.77 Exercised (519,560 ) $ 22.77 Forfeited (52,345 ) $ 84.17 Outstanding at June 30, 2015 5,077,135 $ 43.51 6.33 $ 361.6 Vested and exercisable at June 30, 2015 3,399,023 $ 24.62 5.18 $ 304.5 (1) The aggregate intrinsic value is calculated as the pre-tax difference between the weighted average exercise price of the underlying awards and the closing price per share of $114.20 of the Company’s common stock on June 30, 2015. The calculation excludes any awards with an exercise price higher than the closing price of the Company’s common stock on June 30, 2015. The amounts are presented in millions.
Summary of Restricted Stock Units	The following table summarizes restricted stock unit activity for the six months ended June 30, 2015: Number of Shares Weighted- Average Grant-Date Fair Value Unvested at December 31, 2014 483,580 $ 76.20 Granted 230,812 $ 112.91 Vested (118,662 ) $ 75.91 Forfeited (23,039 ) $ 89.76 Unvested at June 30, 2015 572,691 $ 90.51
Summary of Stock Appreciation Rights Activity	The following table summarizes stock appreciation rights activity for the six months ended June 30, 2015: Number of Rights Weighted Weighted Aggregate Intrinsic (1) Outstanding at December 31, 2014 688,228 $ 24.05 Granted — — Exercised (26,912 ) $ 23.20 Forfeited (5,514 ) $ 23.20 Outstanding at June 30, 2015 655,802 $ 24.09 6.46 $ 59.1 Vested and exercisable at June 30, 2015 564,384 $ 24.11 6.46 $ 50.8 (1) The aggregate intrinsic value is calculated as the pre-tax difference between the weighted average exercise price of the underlying awards and the closing price per share of $114.20 of the Company’s common stock on June 30, 2015. The calculation excludes any awards with an exercise price higher than the closing price of the Company’s common stock on June 30, 2015. The amounts are presented in millions.
Schedule of Black-Scholes Assumptions Used for Stock Options	The Black-Scholes assumptions used to estimate the fair value of stock options granted were as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Risk-free interest rate 1.33-1.78% 1.65-1.77% 1.33-1.78% 1.57-1.77% Estimated term (in years) 4.99-5.50 5.09-5.50 4.98-5.50 5.09-5.50 Estimated volatility 50-57% 60-61% 50-57% 60-64% Estimated dividend yield — — — —
Schedule of Black-Scholes Assumptions Used to Estimate Fair Value of Shares Issued under ESPP	The Black-Scholes assumptions used to estimate the fair value of shares issued under the ESPP on the commencement date of the offering period were as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Risk-free interest rate 0.12 % 0.06 % 0.12 % 0.06 % Estimated term (in years) 0.50 0.50 0.50 0.50 Estimated volatility 37 % 53 % 37 % 53 % Estimated dividend yield — — — —
Schedule of Stock-Based Compensation Expense	Stock-based compensation expense was as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Stock-based compensation expense recognized as: R&D expense $ 6,109 $ 4,503 $ 11,920 $ 8,625 SG&A expense 7,969 6,678 15,530 12,217 Total $ 14,078 $ 11,181 $ 27,450 $ 20,842

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis: Fair value measurements using: Fair Value Level 1 Level 2 Level 3 June 30, 2015: Cash equivalents: Money market funds $ 189,041 $ 189,041 — — Commercial paper $ 7,697 — $ 7,697 — Short-term investments Corporate debt securities $ 42,792 — $ 42,792 — Commercial paper $ 21,568 — $ 21,568 — Federal agency securities $ 9,997 — $ 9,997 — Certificates of deposit $ 2,000 — $ 2,000 — Current liabilities: Contingent consideration $ 10,000 — — $ 10,000 Long-term liabilities Contingent consideration $ 101,013 — — $ 101,013 December 31, 2014: Cash equivalents: Money market funds $ 189,031 $ 189,031 — — Current liabilities: Contingent consideration $ 10,000 — — $ 10,000 Long-term liabilities Contingent consideration $ 96,000 — — $ 96,000
Schedule of Undiscounted Amount of Contingent Consideration	The aggregate remaining, undiscounted amount of contingent consideration that the Company could potentially be required to pay to CureTech under the License Agreement is included in the table below: Potential sales milestones $ 245,000 Potential development and regulatory milestones $ 85,000 Potential payment upon completion of Manufacturing Technology Transfer $ 5,000 Potential future tiered royalties on annual worldwide net sales 5% to 11 %
Schedule of Roll-forward of Fair Value of Level 3 Instruments	The following table includes a roll-forward of the fair value of Level 3 financial instruments for the three and six months ended June 30, 2015: Three Months Ended Six Months Ended Contingent Consideration (Current and Long-Term): Balance at beginning of period $ 110,000 $ 106,000 Amounts acquired or issued — — Net change in fair value 1,013 5,013 Settlements — — Transfers in and/or out of Level 3 — — Balance at end of period $ 111,013 $ 111,013
Fair Value of Other Financial Instruments Not Measured on Recurring Basis	The following table presents the total balance of the Company’s other financial instruments that are not measured at fair value on a recurring basis: Fair value measurements using: Total Balance Level 1 Level 2 Level 3 June 30, 2015: Assets: Bank deposits (included in “Cash and cash equivalents”) $ 224,412 $ 224,412 — — Liabilities: Convertible Notes $ 269,434 — $ 269,434 — December 31, 2014: Assets: Bank deposits (included in “Cash and cash equivalents”) $ 313,646 $ 313,646 — — Liabilities: Convertible Notes $ 359,219 — $ 359,219 —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Operating Lease Obligations	Future operating lease obligations as of June 30, 2015 are as follows: Years Ending December 31, Operating Remainder of 2015 $ 4,569 2016 9,345 2017 9,544 2018 9,746 2019 5,065 2020 and thereafter — Total minimum lease payments $ 38,269
Schedule of Future Lease Cash Payments under Build to Suit Lease	Expected future lease payments under the build-to-suit lease as of June 30, 2015 are as follows: Years Ending December 31, Expected Cash Remainder of 2015 $ 1,177 2016 2,168 2017 2,233 2018 2,300 2019 2,368 2020 and thereafter 12,028 Total minimum lease payments $ 22,274

Description of Business - Addit

Description of Business - Additional Information (Detail) - Jun. 30, 2015 $ in Millions	USD ($)Product	USD ($)Product
Convertible Senior Notes Due 2017 [Member] | Senior Notes [Member]
Organization And Description Of Business [Line Items]
Debt instrument, interest rate	2.625%	2.625%
Convertible Notes, maturity date	Apr. 1, 2017
Astellas Pharma Inc. [Member] | Milestone and cost-sharing payments [Member]
Organization And Description Of Business [Line Items]
Remaining sales milestone payments may receive	$ 245
XTANDI [Member]
Organization And Description Of Business [Line Items]
Number of commercial products | Product	1	1
XTANDI [Member] | Astellas Pharma Inc. [Member]
Organization And Description Of Business [Line Items]
World wide net sales		$ 2,400
Collaborative agreement [Member] | Astellas Pharma Inc. [Member]
Organization And Description Of Business [Line Items]
Range of percentage rates for royalties received on ex-U.S. net sales, as defined by collaboration agreement	Low teens to the low twenties

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Thousands	Jul. 31, 2015$ / shares	Sep. 30, 2015USD ($)shares	Jun. 30, 2015USD ($)Segment$ / shares	Jun. 30, 2014USD ($)	Jun. 15, 2015shares	Dec. 31, 2014$ / shares
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Number of operating business segment | Segment			1
Common stock, par value | $ / shares			$ 0.01			$ 0.01
Aggregate principal amount of convertible notes settled | $			$ 167,800
Repayment of convertible notes in cash | $			$ 90,994	$ 1
Scenario, Forecast [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Aggregate principal amount of convertible notes settled | $		$ 167,800
Repayment of convertible notes in cash | $		$ 167,800
Common stock, shares issued on redemption of convertible notes		1,769,609
Capital stock [Member] | Pre-Amended and Restated Certificate of Incorporation [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Shares of capital stock authorized pre-split					171,000,000
Capital stock [Member] | After-Amended and Restated Certificate of Incorporation [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Shares of capital stock authorized post-split					341,000,000
Common Stock [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Common stock split, description			On July 31, 2015, the Company announced that its Board of Directors has declared a two-for-one stock split of Medivation's common stock to be effected through a stock dividend. Shareholders of record as of August 13, 2015, will receive one additional share of Medivation common stock, par value $0.01, for each share they hold as of the record date. The share distribution is scheduled for September 15, 2015.
Common stock split, record date			Aug. 13, 2015
Common Stock [Member] | Subsequent Event [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Stock split of common stock	2
Common stock, par value | $ / shares	$ 0.01
Common Stock [Member] | Pre-Amended and Restated Certificate of Incorporation [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Shares of common stock authorized pre-split					170,000,000
Common Stock [Member] | After-Amended and Restated Certificate of Incorporation [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]
Shares of common stock authorized post-split					340,000,000

Collaboration Agreement - Colla

Collaboration Agreement - Collaboration Agreements with Astellas - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Dec. 31, 2009	Jun. 30, 2015
Collaborative agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion of sales and medical affairs percentage		50.00%
Astellas Pharma Inc. [Member] | Collaborative agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Range of percentage rates for royalties received on ex-U.S. net sales, as defined by collaboration agreement		Low teens to the low twenties
Up-front cash payment arrangement [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable, upfront cash payment	$ 110
Development milestone payments [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible to receive milestone payments		$ 335
Milestone payments earned		335
Sales milestone payments [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible to receive milestone payments		320
Milestone payments earned		75
Remaining future milestone payments eligible to receive		$ 245

Collaboration Agreement - Sched

Collaboration Agreement - Schedule of Potential Milestone Payments in Sales (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone Payment	$ 50	$ 25
Milestone Payment Three [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Remaining future milestone payments eligible to receive			$ 70
Milestone Payment Four [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Remaining future milestone payments eligible to receive			175
Milestone Sales One [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual global net sales of XTANDI (calendar year), as reported by Astellas			400
Milestone Sales Two [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual global net sales of XTANDI (calendar year), as reported by Astellas			800
Milestone Sales Three [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual global net sales of XTANDI (calendar year), as reported by Astellas			1,200
Milestone Sales Four [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual global net sales of XTANDI (calendar year), as reported by Astellas			$ 1,600

Collaboration Agreement - Sch36

Collaboration Agreement - Schedule of Potential Milestone Payments in Sales (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Milestone payments earned	$ 50	$ 25

Collaboration Agreement - Sch37

Collaboration Agreement - Schedule of Collaboration Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Related to U.S. XTANDI net sales	$ 149,220	$ 71,866	$ 261,230	$ 134,091
Related to ex-U.S. XTANDI net sales	25,591	9,992	41,358	15,723
Related to upfront and milestone payments	846	66,232	2,257	85,465
Collaboration revenue	$ 175,657	$ 148,090	$ 304,845	$ 235,279

Collaboration Agreement - Col38

Collaboration Agreement - Collaboration Revenue and Collaboration Receivables - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of sublicensing income			10.00%
Collaboration revenue percentage compared to U.S. XTANDI net sales	50.00%	50.00%	50.00%	50.00%
Collaboration revenue related to ex-U.S. XTANDI net sales	$ 25,600	$ 10,000	$ 41,400	$ 15,700
Deferred revenue, Current	565		565		$ 2,822
Collaborative agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue, Current	600		$ 600		$ 2,800
Development cost-sharing payments [Member] | Collaborative agreement [Member] | Medivation Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Share of developing and commercializing XTANDI U.S.			50.00%
Share of developing and commercializing XTANDI ex-U.S.			33.33%
Development cost-sharing payments [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development cost-sharing payments	17,600	17,500	$ 31,400	33,400
Commercial cost sharing-payments [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Commercialization cost-sharing payments	$ 2,700	$ 2,600	$ 22,800	$ 10,200
Commercial cost sharing-payments [Member] | Astellas Pharma Inc. [Member] | Collaborative agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Share of developing and commercializing XTANDI U.S.			50.00%
Share of developing and commercializing XTANDI ex-U.S.			66.67%

Collaboration Agreement - Sch39

Collaboration Agreement - Schedule of Collaboration Revenue Related to U.S. XTANDI Net Sales (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue related to U.S. XTANDI net sales	$ 149,220	$ 71,866	$ 261,230	$ 134,091
U.S. XTANDI sales [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue related to U.S. XTANDI net sales	149,220	71,866	261,230	134,091
U.S. XTANDI sales [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
U.S. XTANDI net sales (as reported by Astellas)	298,440	143,732	522,460	268,183
Shared U.S. development and commercialization costs	(84,947)	(70,543)	(195,260)	(148,250)
Pre-tax U.S. profit	213,493	73,189	327,200	119,933
U.S. XTANDI sales [Member] | Medivation [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Medivation's share of pre-tax U.S. profit	106,747	36,594	163,600	59,966
Reimbursement of Medivation's share of shared U.S. costs	$ 42,473	$ 35,272	$ 97,630	$ 74,125

Collaboration Agreement - Sch40

Collaboration Agreement - Schedule of Collaboration Revenue Related to Upfront and Milestone Payments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amortization of deferred upfront and development milestones			$ 2,257	$ 8,465
Total collaboration revenue attributable to upfront and milestone payments	$ 846	$ 66,232	2,257	85,465
Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaboration revenue attributable to upfront and milestone payments	846	66,232	2,257	85,465
Astellas Pharma Inc. [Member] | Development milestones earned [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones earned		62,000		77,000
Astellas Pharma Inc. [Member] | Amortization of deferred upfront and development milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amortization of deferred upfront and development milestones	$ 846	$ 4,232	$ 2,257	$ 8,465

Goodwill and Intangible Assets

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Business combination, goodwill	$ 10,000,000	$ 10,000,000
Impairment of indefinite-lived intangible assets	0
Impairment of goodwill	$ 0
CureTech Ltd [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business combination, identifiable intangible asset		101,000,000
Business combination, goodwill		$ 10,000,000

Net Income Per Common Share - A

Net Income Per Common Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net Income Per Share [Line Items]
Aggregate principal amount of convertible notes settled		$ 167,800		$ 167,800
Conversion price, per share of common stock		$ 51.24		$ 51.24
Calculation of diluted net income per common share includes, effect of shares related to conversion spread of Convertible Notes		2,400,000
Dilutive common shares excluded from net loss per common share computations			5,100,000	3,700,000	5,100,000
Repayment of convertible notes in cash				$ 90,994	$ 1
Scenario, Forecast [Member]
Net Income Per Share [Line Items]
Aggregate principal amount of convertible notes settled	$ 167,800
Repayment of convertible notes in cash	$ 167,800
Common stock, shares issued on redemption of convertible notes	1,769,609

Net Income Per Common Share - C

Net Income Per Common Share - Calculation of Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net income	$ 25,826	$ 47,919	$ 22,708	$ 34,254
Denominator:
Weighted-average common shares, basic	79,252	76,577	78,788	76,411
Dilutive effect of common stock equivalents	5,093	3,914	2,710	4,076
Weighted-average common shares, diluted	84,345	80,491	81,498	80,487
Basic net income per common share	$ 0.33	$ 0.63	$ 0.29	$ 0.45
Diluted net income per common share	$ 0.31	$ 0.60	$ 0.28	$ 0.43

Convertible Senior Notes Due 44

Convertible Senior Notes Due 2017 - Additional Information (Detail)	2 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2015USD ($)$ / shares	Sep. 30, 2015USD ($)shares	Jun. 30, 2015USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / shares	Jun. 30, 2014USD ($)	Mar. 31, 2015USD ($)
Debt Instrument [Line Items]
Conversion price, per share of common stock | $ / shares	$ 51.24		$ 51.24	$ 51.24
Principal settlement amount				$ 90,994,000	$ 1,000
Non-cash loss on extinguishment of Convertible Notes			$ (7,868,000)	(7,871,000)
Convertible Notes, aggregate principal amount	$ 167,800,000		167,800,000	$ 167,800,000
Scenario, Forecast [Member]
Debt Instrument [Line Items]
Principal settlement amount		$ 167,800,000
Common stock, shares issued on redemption of convertible notes | shares		1,769,609
Convertible Notes, aggregate principal amount		$ 167,800,000
Convertible Senior Notes Due 2017 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Convertible Notes, payment terms				The Company was required to pay interest semi-annually in arrears on April 1 and October 1 of each year.
Convertible Notes, aggregate principal amount	$ 258,800,000		$ 258,800,000	$ 258,800,000
Conversion rate of common stock, shares per principal amount				19.5172
Debt instrument convertible increment of principal amount of conversion				$ 1,000
Conversion price, per share of common stock | $ / shares	$ 51.24		$ 51.24	$ 51.24
Aggregate principal amount of convertible notes surrendered for conversion	$ 90,300,000		$ 90,300,000	$ 90,300,000		$ 700,000
Principal settlement amount	$ 90,300,000		$ 1,900,000
Common stock, shares issued on redemption of convertible notes | shares			1,049,679
Non-cash loss on extinguishment of Convertible Notes			$ 7,900,000	7,900,000
Forfeited accrued interest payable reclassified to additional paid-in capital				$ 300,000
Convertible Senior Notes Due 2017 [Member] | Senior Notes [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Principal settlement amount		$ 167,800,000
Common stock, shares issued on redemption of convertible notes | shares		1,769,609
Non-cash loss on extinguishment of Convertible Notes		$ 13,000,000
Convertible Notes, aggregate principal amount		$ 167,800,000

Cash, Cash Equivalents, and S45

Cash, Cash Equivalents, and Short-Term Investments - Summary of Cash, Cash Equivalents, and Short-Term Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Cash And Cash Equivalents And Short Term Investments [Line Items]
Total cash, cash equivalents, and short-term investments, Amortized Cost	$ 497,541
Total cash, cash equivalents, and short-term investments, Gross Unrealized Gains	5
Total cash, cash equivalents, and short-term investments, Gross Unrealized Losses	(39)
Total cash, cash equivalents, and short-term investments, Fair Value	497,507
Cash and cash equivalents [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Cash and cash equivalents, Amortized Cost	421,150	$ 502,677
Cash and cash equivalents, Fair Value	421,150	502,677
Cash and cash equivalents [Member] | Cash [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Cash and cash equivalents, Amortized Cost	224,412	313,646
Cash and cash equivalents, Fair Value	224,412	313,646
Cash and cash equivalents [Member] | Money market funds [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Cash and cash equivalents, Amortized Cost	189,041	189,031
Cash and cash equivalents, Fair Value	189,041	$ 189,031
Cash and cash equivalents [Member] | Commercial paper [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Cash and cash equivalents, Amortized Cost	7,697
Cash and cash equivalents, Fair Value	7,697
Short-term investments [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	76,391
Gross Unrealized Gains	5
Gross Unrealized Losses	(39)
Fair Value	76,357
Short-term investments [Member] | Commercial paper [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	21,568
Fair Value	21,568
Short-term investments [Member] | Corporate debt securities [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	42,830
Gross Unrealized Gains	1
Gross Unrealized Losses	(39)
Fair Value	42,792
Short-term investments [Member] | Federal agency securities [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	9,993
Gross Unrealized Gains	4
Fair Value	9,997
Short-term investments [Member] | Certificates of deposit [Member]
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	2,000
Fair Value	$ 2,000

Cash, Cash Equivalents, and S46

Cash, Cash Equivalents, and Short-Term Investments - Additional Information (Detail) - Jun. 30, 2015 $ in Millions	USD ($)Securities
Cash and Cash Equivalents [Abstract]
Number of positions, available-for-sale securities in a gross unrealized loss position for less than twelve months | Securities	20
Available-for-sale securities in a gross unrealized loss position for less than twelve months, fair value	$ 36.8

Build-to-Suit Lease Obligatio47

Build-to-Suit Lease Obligation - Additional Information (Detail) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2015USD ($)ft²	Jun. 30, 2015USD ($)ft²	Jun. 30, 2014USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013ft²
Build To Suit Lease Obligation [Line Items]
Build to suit lease | ft²	143,000	143,000
Amounts capitalized under build-to-suit transactions		$ 283	$ 16,800
Area of surrender property | ft²	8,007	8,007
Derecognized portion of build-to-suit asset	$ 3,200
Derecognized portion of build-to-suit lease obligation	3,100
Build-to-suit lease obligation current liability	196	$ 196		$ 698
Build-to-suit lease obligation non-current liability	$ 16,920	16,920		$ 18,711
Build-to-suit Lease Property and Equipment [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit transactions		14,500
Tenant Improvements [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit transactions		3,900
Capitalized Interest Cost [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit transactions		$ 2,500
Laboratory Space [Member]
Build To Suit Lease Obligation [Line Items]
Build to suit lease | ft²	43,625	43,625			51,632
Lease expiry period		August 2,024
Build to suit lease extension term	5 years

Build-to-Suit Lease Obligatio48

Build-to-Suit Lease Obligation - Schedule of Expected Reductions in Build-to-Suit Lease Obligation (Detail) $ in Thousands	Jun. 30, 2015USD ($)
Leases [Abstract]
Build-to-Suit Lease Obligation, Remainder of 2015	$ 197
Build-to-Suit Lease Obligation, 2016	10
Build-to-Suit Lease Obligation, 2017	77
Build-to-Suit Lease Obligation, 2018	149
Build-to-Suit Lease Obligation, 2019	228
Build-to-Suit Lease Obligation, 2020 and after	16,455
Total minimum payments	$ 17,116

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 57,005	$ 50,856
Less: Accumulated depreciation	(12,714)	(9,695)
Total	44,291	41,161
Build-to-suit property [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	17,656	19,544
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,027	15,051
Computer equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	11,012	9,499
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,576	4,667
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,999	1,360
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 735	$ 735

Accounts Payable, Accrued Exp50

Accounts Payable, Accrued Expenses and Other Current Liabilities - Components of Accounts Payable, Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Clinical and preclinical	$ 35,676	$ 31,069
Accrued professional services and other current liabilities	17,117	8,909
Payroll and payroll-related	19,285	33,272
Royalties payable	18,860	13,582
Accounts payable	12,754	10,492
Other payable to licensor	14,057	5,000
Interest payable	1,101	1,698
Taxes payable		2,106
Total	$ 118,850	$ 106,128

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	6 Months Ended	15 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 16, 2015	Mar. 31, 2015	Dec. 04, 2006
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage before exercise					20.00%
Employees share purchase plan, fair market value of common stock at beginning of offering period	85.00%
Employees share purchase plan, fair market value of common stock at end of purchase period	85.00%
Eligible employee contributions	$ 25,000
Shares issued in period		123,680
Unrecognized stock-based compensation expense	$ 99,000,000	$ 99,000,000
Unrecognized stock-based compensation expense, weighted-average period for recognition	2 years 6 months
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance	3,000,000	3,000,000
Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance			23,850,000	21,150,000
Number of shares available for issuance	4,600,000	4,600,000
Equity Incentive Plan [Member] | Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value per share	$ 51.87

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Detail) - Jun. 30, 2015 - Equity Incentive Plan [Member] - Stock options [Member] - USD ($) $ / shares in Units, $ in Millions	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding at December 31, 2014	5,067,957
Number of Options, Granted	581,083
Number of Options, Exercised	(519,560)
Number of Options, Forfeited	(52,345)
Number of Options, Outstanding at June 30, 2015	5,077,135
Number of Options, Vested and exercisable at June 30, 2015	3,399,023
Weighted Average Exercise Price, Outstanding at December 31, 2014	$ 33.52
Weighted Average Exercise Price, Granted	115.77
Weighted Average Exercise Price, Exercised	22.77
Weighted Average Exercise Price, Forfeited	84.17
Outstanding at June 30, 2015	43.51
Vested and exercisable at June 30, 2015	$ 24.62
Weighted Average Remaining Contractual Term (in years), Outstanding at June 30, 2015	6 years 3 months 29 days
Weighted Average Remaining Contractual Term (in years), Vested and exercisable at June 30, 2015	5 years 2 months 5 days
Aggregate Intrinsic Value, Outstanding at June 30, 2015	$ 361.6
Aggregate Intrinsic Value, Vested and exercisable at June 30, 2015	$ 304.5

Stockholders' Equity - Summar53

Stockholders' Equity - Summary of Stock Option Activity (Parenthetical) (Detail)	Jun. 30, 2015$ / shares
Equity Incentive Plan [Member] | Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing stock price of common stock	$ 114.20

Stockholders' Equity - Summar54

Stockholders' Equity - Summary of Restricted Stock Units (Detail) - 6 months ended Jun. 30, 2015 - Equity Incentive Plan [Member] - Restricted stock units [Member] - $ / shares	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Unvested at December 31, 2014	483,580
Number of Shares, Granted	230,812
Number of Shares, Vested	(118,662)
Number of Shares, Forfeited	(23,039)
Number of Shares, Unvested at June 30, 2015	572,691
Weighted-Average Grant-Date Fair Value, Unvested at December 31, 2014	$ 76.20
Weighted-Average Grant-Date Fair Value, Granted	112.91
Weighted-Average Grant-Date Fair Value, Vested	75.91
Weighted-Average Grant-Date Fair Value, Forfeited	89.76
Weighted-Average Grant-Date Fair Value, Unvested at June 30, 2015	$ 90.51

Stockholders' Equity - Summar55

Stockholders' Equity - Summary of Stock Appreciation Rights Activity (Detail) - Jun. 30, 2015 - Equity Incentive Plan [Member] - Stock appreciation rights [Member] - USD ($) $ / shares in Units, $ in Millions	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock appreciation rights, Outstanding at December 31, 2014	688,228
Number of stock appreciation rights, Granted	0
Number of stock appreciation rights, Exercised	(26,912)
Number of stock appreciation rights, Forfeited	(5,514)
Number of stock appreciation rights, Outstanding at June 30, 2015	655,802
Number of stock appreciation rights, Vested and exercisable at June 30, 2015	564,384
Weighted Average Exercise Price, Outstanding at December 31, 2014	$ 24.05
Weighted Average Exercise Price, Granted	0
Weighted Average Exercise Price, Exercised	23.20
Weighted Average Exercise Price, Forfeited	23.20
Weighted Average Exercise Price, Outstanding at June 30, 2015	24.09
Weighted Average Exercise Price, Vested and exercisable at June 30, 2015	$ 24.11
Weighted Average Remaining Contractual Term (in years), Outstanding at June 30, 2015	6 years 5 months 16 days
Weighted Average Remaining Contractual Term (in years), Vested and exercisable at June 30, 2015	6 years 5 months 16 days
Aggregate Intrinsic Value, Outstanding at June 30, 2015	$ 59.1
Aggregate Intrinsic Value, Vested and exercisable at June 30, 2015	$ 50.8

Stockholders' Equity - Summar56

Stockholders' Equity - Summary of Stock Appreciation Rights Activity (Parenthetical) (Detail)	Jun. 30, 2015$ / shares
Equity Incentive Plan [Member] | Stock appreciation rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing stock price of common stock	$ 114.20

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Black-Scholes Assumptions Used for Stock Options (Detail) - Equity Incentive Plan [Member] - Stock options [Member]	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.33%	1.65%	1.33%	1.57%
Estimated term (in years)	4 years 11 months 27 days	5 years 1 month 2 days	4 years 11 months 23 days	5 years 1 month 2 days
Estimated volatility	50.00%	60.00%	50.00%	60.00%
Estimated dividend yield	0.00%	0.00%	0.00%	0.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.78%	1.77%	1.78%	1.77%
Estimated term (in years)	5 years 6 months	5 years 6 months	5 years 6 months	5 years 6 months
Estimated volatility	57.00%	61.00%	57.00%	64.00%
Estimated dividend yield	0.00%	0.00%	0.00%	0.00%

Stockholders' Equity - Schedu58

Stockholders' Equity - Schedule of Black-Scholes Assumptions Used to Estimate Fair Value of Shares Issued under ESPP (Detail) - ESPP [Member]	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.12%	0.06%	0.12%	0.06%
Estimated term (in years)	6 months	6 months	6 months	6 months
Estimated volatility	37.00%	53.00%	37.00%	53.00%
Estimated dividend yield	0.00%	0.00%	0.00%	0.00%

Stockholders' Equity - Schedu59

Stockholders' Equity - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 14,078	$ 11,181	$ 27,450	$ 20,842
R&D expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	6,109	4,503	11,920	8,625
SG&A expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 7,969	$ 6,678	$ 15,530	$ 12,217

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Income tax expense	$ 14,600		$ 1,611	$ 12,820	$ 1,552
Loss on extinguishment of Convertible Notes, tax benefit				$ 2,800
Effective tax rate	36.10%		3.30%	36.10%	4.30%
Tax impacts of extinguishment of Convertible Notes to additional paid in capital				$ 4,400
Excess tax benefits from stock-based compensation				$ 13,572
Release of valuation allowance for deferred income taxes		$ 33,400

Fair Value Disclosures - Financ

Fair Value Disclosures - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	$ 10,000	$ 10,000
Contingent consideration	101,013	96,000
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	10,000	10,000
Contingent consideration	101,013	96,000
Money market funds [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	189,041	189,031
Commercial paper [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	7,697
Short-term investments	21,568
Corporate debt securities [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	42,792
Federal agency securities [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	9,997
Certificates of deposit [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	2,000
Level 1 [Member] | Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	189,041	189,031
Level 2 [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	7,697
Short-term investments	21,568
Level 2 [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	42,792
Level 2 [Member] | Federal agency securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	9,997
Level 2 [Member] | Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	2,000
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	10,000	10,000
Contingent consideration	$ 101,013	$ 96,000

Fair Value Disclosures - Additi

Fair Value Disclosures - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Increase (decrease) in fair value of contingent consideration liability		$ 1,000,000	$ 5,013,000
Fair value of liabilities transferred from Level 1 to Level 2		0	0
Fair value of liabilities transferred from Level 2 to Level 1		0	0
Fair value of assets transferred from Level 1 to Level 2		0	0
Fair value of assets transferred from Level 2 to Level 1		0	0
Convertible Notes, aggregate principal amount		167,800,000	167,800,000
Repayment of convertible notes in cash			90,994,000	$ 1,000
R&D expense [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Increase (decrease) in fair value of contingent consideration liability		(100,000)	900,000
SG&A expense [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Increase (decrease) in fair value of contingent consideration liability		1,100,000	4,100,000
Scenario, Forecast [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible Notes, aggregate principal amount	$ 167,800,000
Repayment of convertible notes in cash	$ 167,800,000
Common stock, shares issued on redemption of convertible notes	1,769,609
Fair value, measurements, nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated fair value of the debt		$ 372,600,000	$ 372,600,000		$ 496,800,000

Fair Value Disclosures - Schedu

Fair Value Disclosures - Schedule of Undiscounted Amount of Contingent Consideration (Detail) - Jun. 30, 2015 - CureTech Ltd [Member] - USD ($) $ in Thousands	Total
Business Acquisition, Contingent Consideration [Line Items]
Potential payment upon completion of Manufacturing Technology Transfer	$ 5,000
Minimum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Potential future tiered royalties on annual worldwide net sales	5.00%
Maximum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Potential future tiered royalties on annual worldwide net sales	11.00%
Sales milestones earned [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition maximum contingent consideration	$ 245,000
Development milestones earned [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition maximum contingent consideration	$ 85,000

Fair Value Disclosures - Sche64

Fair Value Disclosures - Schedule of Roll-forward of Fair Value of Level 3 Instruments (Detail) - Jun. 30, 2015 - Level 3 [Member] - USD ($) $ in Thousands	Total	Total
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 110,000	$ 106,000
Amounts acquired or issued	0	0
Net change in fair value	1,013	5,013
Settlements	0	0
Transfers in and/or out of Level 3	0	0
Balance at end of period	$ 111,013	$ 111,013

Fair Value Disclosures - Fair V

Fair Value Disclosures - Fair Value of Other Financial Instruments Not Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of Convertible Notes	$ 149,098	$ 4
Convertible Notes		222,140
Fair value, measurements, nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank deposits (included in "Cash and cash equivalents")	224,412	313,646
Fair value, measurements, nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of Convertible Notes	269,434
Convertible Notes		359,219
Fair value, measurements, nonrecurring [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank deposits (included in "Cash and cash equivalents")	224,412	313,646
Current portion of Convertible Notes	$ 269,434
Convertible Notes		$ 359,219

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	3 Months Ended			6 Months Ended
	Jun. 30, 2015USD ($)ft²	Dec. 31, 2014USD ($)	Mar. 31, 2014USD ($)	Jun. 30, 2015USD ($)ft²
Commitments And Contingencies [Line Items]
Operating lease office space, in square feet | ft²	143,000			143,000
Lease expiry period				June 2,019
Percentage of sublicensing income				10.00%
Upfront and setup fees			$ 12,000,000
Total consideration under current statement of work		$ 14,500,000
Partial payment consideration under current statement of work				$ 1,000,000
CureTech Ltd [Member]
Commitments And Contingencies [Line Items]
Milestone payment				5,000,000
CureTech Ltd [Member] | MDV 9300 [Member]
Commitments And Contingencies [Line Items]
Upfront and setup fees	$ 200,000	$ 3,000,000
Manufacturing services and supply agreement period		3 years
Milestone payment				5,000,000
Funding for clinical trial materials				19,300,000
Clinical trial materials amount paid				$ 6,000,000
Funding period for clinical materials				3 years
Collateralized letters of credit [Member]
Commitments And Contingencies [Line Items]
Outstanding letters of credit collateralized by restricted cash	13,300,000	$ 11,800,000		$ 13,300,000
Current asset [Member] | Collateralized letters of credit [Member]
Commitments And Contingencies [Line Items]
Outstanding letters of credit collateralized by restricted cash	600,000	200,000		600,000
Long-term assets [Member] | Collateralized letters of credit [Member]
Commitments And Contingencies [Line Items]
Outstanding letters of credit collateralized by restricted cash	$ 12,700,000	$ 11,600,000		$ 12,700,000
Sixth Amendment To Lease Agreement [Member]
Commitments And Contingencies [Line Items]
Operating lease office space, in square feet | ft²	16,000			16,000
Tenant improvement allowance				$ 300,000
Outstanding letters of credit collateralized by restricted cash	$ 1,600,000			1,600,000
Minimum lease payments over the lease term	6,100,000			6,100,000
Development milestone payments [Member]
Commitments And Contingencies [Line Items]
Aggregate milestone payments upon achievement of certain development and regulatory milestone events	$ 2,800,000			$ 2,800,000
Percentage of sublicensing income				10.00%
Royalty percentage on sales				4.00%
Sales milestone payments [Member] | Astellas Pharma Inc. [Member]
Commitments And Contingencies [Line Items]
Percentage of sublicensing income				10.00%
Eligible to receive milestone payments				$ 320,000,000
Sales milestone payments under collaborative agreement				75,000,000
Payment related to sales milestones				$ 7,500,000

Commitments and Contingencies67

Commitments and Contingencies - Schedule of Future Operating Lease Obligations (Detail) $ in Thousands	Jun. 30, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Remainder of 2015	$ 4,569
Operating Leases, 2016	9,345
Operating Leases, 2017	9,544
Operating Leases, 2018	9,746
Operating Leases, 2019	5,065
Operating Leases, 2020 and thereafter	0
Total minimum lease payments	$ 38,269

Commitments and Contingencies68

Commitments and Contingencies - Schedule of Future Lease Cash Payments under the Build to Suit Lease (Detail) $ in Thousands	Jun. 30, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
Build-To-Suit Lease, Remainder of 2015	$ 1,177
Build-To-Suit Lease, 2016	2,168
Build-To-Suit Lease, 2017	2,233
Build-To-Suit Lease, 2018	2,300
Build-To-Suit Lease, 2019	2,368
Build-To-Suit Lease, 2020 and after	12,028
Build-To-Suit Lease, Future Minimum Payments	$ 22,274

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) $ / shares in Units, $ in Thousands	Jul. 31, 2015$ / shares	Jun. 30, 2015USD ($)$ / shares	Sep. 30, 2015USD ($)shares	Jun. 30, 2015USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / shares	Jun. 30, 2014USD ($)	Dec. 31, 2014$ / shares
Subsequent Event [Line Items]
Convertible Notes, aggregate principal amount		$ 167,800		$ 167,800	$ 167,800
Repayment of convertible notes in cash					90,994	$ 1
Non-cash loss on extinguishment of Convertible Notes				$ (7,868)	$ (7,871)
Common stock, par value | $ / shares		$ 0.01		$ 0.01	$ 0.01		$ 0.01
Common Stock [Member]
Subsequent Event [Line Items]
Common stock split, description					On July 31, 2015, the Company announced that its Board of Directors has declared a two-for-one stock split of Medivation's common stock to be effected through a stock dividend. Shareholders of record as of August 13, 2015, will receive one additional share of Medivation common stock, par value $0.01, for each share they hold as of the record date. The share distribution is scheduled for September 15, 2015.
Common stock split, record date					Aug. 13, 2015
Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Stock split of common stock	2
Common stock, par value | $ / shares	$ 0.01
Convertible Senior Notes Due 2017 [Member] | Senior Notes [Member]
Subsequent Event [Line Items]
Repayment of convertible notes in cash		$ 90,300		$ 1,900
Common stock, shares issued on redemption of convertible notes | shares				1,049,679
Non-cash loss on extinguishment of Convertible Notes				$ 7,900	$ 7,900
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Convertible Notes, aggregate principal amount			$ 167,800
Repayment of convertible notes in cash			$ 167,800
Common stock, shares issued on redemption of convertible notes | shares			1,769,609
Scenario, Forecast [Member] | Convertible Senior Notes Due 2017 [Member] | Senior Notes [Member]
Subsequent Event [Line Items]
Convertible Notes, aggregate principal amount			$ 167,800
Repayment of convertible notes in cash			$ 167,800
Common stock, shares issued on redemption of convertible notes | shares			1,769,609
Non-cash loss on extinguishment of Convertible Notes			$ 13,000