Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net loss	$ (45,381)	$ (9,597)
Adjustments for non-cash operating items:
Amortization of deferred revenue	(21,163)	(92,479)
Stock-based compensation	25,628	17,520
Amortization of debt discount and debt issuance costs	9,941	6,491
Depreciation on property and equipment	2,474	959
Accretion of discount on securities	(148)	(93)
Loss on disposal of equipment	35
Changes in operating assets and liabilities:
Receivable from collaboration partners	(32,126)	(4,537)
Prepaid expenses and other current assets	(6,567)	(1,981)
Other non-current assets	(1,468)	32
Accounts payable	3,378	(1,483)
Accrued expenses and other current liabilities	11,106	24,846
Interest payable	1,698
Other non-current liabilities	(239)	4,285
Net cash used in operating activities	(52,832)	(56,037)
Cash flows from investing activities:
Purchases of short-term investments	(144,926)	(374,784)
Maturities of short-term investments	285,000	225,000
Purchases of property and equipment	(6,321)	(13,549)
Change in restricted cash	(713)	(3,697)
Net cash provided by (used in) investing activities	133,040	(167,030)
Cash flows from financing activities:
Proceeds from issuance of Convertible Notes, net		250,987
Financing transaction costs		(614)
Proceeds from issuance of common stock under Medivation Equity Incentive Plan	6,459	18,115
Net cash provided by financing activities	6,459	268,488
Net increase in cash and cash equivalents	86,667	45,421
Cash and cash equivalents at beginning of period	71,301	70,136
Cash and cash equivalents at end of period	157,968	115,557
Non-cash investing activities:
Property and equipment expenditures incurred but not yet paid	23	265
Performance share units withheld to satisfy tax withholding obligations not yet paid		$ 1,608