Collaboration Agreement - Schedule of Collaboration Revenue (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Related to U.S. XTANDI sales	$ 90,723	$ 54,244	$ 224,814	$ 133,134
Related to ex-U.S. XTANDI sales	15,522	1,551	31,245	2,033
Related to upfront and milestone payments	94,233	4,232	179,698	41,163
Collaboration revenue	$ 200,478	$ 60,027	$ 435,757	$ 176,330

Revenue earned from the amortization of non refundable upfront cash payment received under collaboration agreements over the expected performance period and milestone payments earned.

No definition available.

Name:	mdvn_CollaborationRevenueRelatedToUpFrontAndMilestonePayments
Namespace Prefix:	mdvn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration