Business Combinations and Contingent Consideration - Change in Fair Value of Contingent Consideration Related to Acquisitions (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2017	Dec. 31, 2016
Change in Fair Value of Contingent Consideration [Roll Forward]
Beginning	$ 14,445	$ 21,352
Ending	16,977	14,445
Contingent Consideration [Member] \| Talon Therapeutics, Inc. [Member]
Change in Fair Value of Contingent Consideration [Roll Forward]
Beginning	1,253
Fair value adjustment for the nine months ended September 30, 2017	3,236
Ending	4,489	1,253
Contingent Consideration [Member] \| Ligand Pharmaceuticals Inc [Member]
Change in Fair Value of Contingent Consideration [Roll Forward]
Beginning	$ 0	5,227
Fair value adjustment for the nine months ended September 30, 2017		773
Payment to Ligand in April 2016 for FDA approval milestone achievement		(6,000)
Ending		$ 0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ 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 (c)(1)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ 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 (c)(2)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ 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 (c)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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