Fair Value Disclosures - Additional Information (Detail) - USD ($)	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Change in fair value of contingent consideration liability	$ 5,959,000	$ 4,000,000
Fair value of liabilities transferred from Level 1 to Level 2	0
Fair value of liabilities transferred from Level 2 to Level 1	0
Fair value of assets transferred from Level 1 to Level 2	0
Fair value of assets transferred from Level 2 to Level 1	0
MDV3800 [Member] \| Defined Regulatory and Sales-Based Milestones [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Business acquisition maximum contingent consideration	160,000,000
MDV3800 [Member] \| R&D expense [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Change in fair value of contingent consideration liability	500,000
MDV3800 [Member] \| SG&A expense [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Change in fair value of contingent consideration liability	2,500,000
MDV9300 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Milestone payment	5,000,000
MDV9300 [Member] \| Development Milestones [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Business acquisition maximum contingent consideration	85,000,000
MDV9300 [Member] \| Sales Milestones [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Business acquisition maximum contingent consideration	$ 245,000,000
MDV9300 [Member] \| Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Percentage of royalty	5.00%
MDV9300 [Member] \| Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Percentage of royalty	11.00%
MDV9300 [Member] \| R&D expense [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Change in fair value of contingent consideration liability	$ 600,000	1,000,000
MDV9300 [Member] \| SG&A expense [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Change in fair value of contingent consideration liability	$ 2,300,000	$ 3,000,000

Dollar amount of future milestone payment for technology transfer under manufacturing services agreement.

No definition available.

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

- Definition

Range of percentage rates for royalties paid annual worldwide net sales, as defined by license agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	mdvn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479

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- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

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- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

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