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Collaboration and License Agreements - Additional Information 2 (Detail) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2013 Molecule	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
License And Collaboration Agreements [Line Items]
License grant fees		$ 15,000,000		$ 15,000,000
Clinical milestone payments		5,000,000		5,000,000
Deferred revenue under agreement		20,684,000		20,684,000		20,267,000
Gilead [Member]
License And Collaboration Agreements [Line Items]
Collaboration agreement date				January 2013
Commercialization of molecules	4
License grant fees	7,500,000
Expected period of development						21 months
Recognized revenue under agreement		2,300,000	2,000,000	4,500,000	3,700,000
Deferred revenue under agreement		900,000		900,000		3,600,000
Gilead [Member] | Minimum [Member]
License And Collaboration Agreements [Line Items]
Regulatory and sales milestone	240,000,000
Gilead [Member] | Maximum [Member]
License And Collaboration Agreements [Line Items]
Regulatory and sales milestone	250,000,000
Gilead [Member] | Pre-Clinical Milestones [Member] | Minimum [Member]
License And Collaboration Agreements [Line Items]
Clinical milestone payments	20,000,000
Gilead [Member] | Pre-Clinical Milestones [Member] | Maximum [Member]
License And Collaboration Agreements [Line Items]
Clinical milestone payments	$ 25,000,000

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- Definition

Aggregate potential clinical milestone payments available to be earned under collaboration agreement.

+ References

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Additional clinical, regulatory and sales milestone payments under agreement.

+ References

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- Definition

Additional license grant fees under agreement.

+ References

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- Definition

Collaboration and license agreement entered date.

+ References

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- Definition

Number of molecules to be developed and commercialized as per collaborations.

+ References

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- Definition

Upfront payment recognition period.

+ References

No definition available.

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- Definition

The carrying amount of consideration received or receivable as of the balance sheet date on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 8

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6935-107765



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

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Revenue earned during the period relating to consideration received from another party for the right to use, but not own, certain of the entity's intangible assets. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark. Licensing fees are generally, but not always, fixed as to amount and not dependent upon the revenue generated by the licensing party. An entity may receive licensing fees for licenses that also generate royalty payments to the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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