Net (Loss) Income Per Common Share - Schedule of Potentially Dilutive Securities (Parenthetical) (Detail) (Stock appreciation rights [Member])	3 Months Ended
Mar. 31, 2013
Stock appreciation rights [Member]
Earnings Per Share [Line Items]
Issuance of outstanding stock appreciation rights	426,951
Outstanding stock appreciation rights	874,092

Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Number

No definition available.

Name:	mdvn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingNumber
Namespace Prefix:	mdvn_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant