Collaboration Agreement - Schedule of Collaboration Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Related to U.S. XTANDI net sales	$ 156,501	$ 90,723	$ 417,731	$ 224,814
Related to ex-U.S. XTANDI net sales	33,599	15,522	74,957	31,245
Related to upfront and milestone payments	70,565	94,233	72,822	179,698
Collaboration revenue	$ 260,665	$ 200,478	$ 565,510	$ 435,757

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