Description of Business - Additional Information (Detail)	6 Months Ended
Jun. 30, 2014 Country
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of countries in which XTANDI is approved for the post-docetaxel indication	40

Number of countries in which XTANDI is approved for the post-docetaxel indication.

No definition available.

Name:	mdvn_NumberOfCountriesInWhichXtandiIsApprovedForPostdocetaxelIndication
Namespace Prefix:	mdvn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration