Fair Value Disclosures - Additional Information (Detail)	6 Months Ended
Jun. 30, 2016 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
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
MDV9300 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Milestone payment	$ 5,000,000
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] \| 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
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

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

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

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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=66048111&loc=d3e19207-110258

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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