License and Collaboration Agreements - Additional Information (Detail) - USD ($)				1 Months Ended						3 Months Ended		6 Months Ended		21 Months Ended	31 Months Ended
	Sep. 23, 2014	Nov. 25, 2013	May 05, 2011	Jun. 30, 2016	Oct. 31, 2015	Aug. 31, 2015	Jul. 31, 2015	Jan. 31, 2015	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other revenues										$ 1,498,000		$ 1,498,000
Deferred revenues, current				$ 44,157,000						44,157,000		44,157,000		$ 44,157,000	$ 44,157,000	$ 50,137,000
Research and development expenses										40,996,000	$ 42,806,000	73,878,000	$ 78,485,000
Deferred Revenue, Noncurrent				39,900,000						39,900,000		$ 39,900,000		39,900,000	39,900,000	51,197,000
Baxalta [Member] | License and Collaboration Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fee received									$ 100,000,000
Royalty for improved products												The Company is also entitled to tiered, escalating royalties ranging from sub-teen double digits to low twenties percentages of net sales of ONIVYDE in the Licensed Territory
Notice period of termination												180 days
Revenue recognized related to a substantive milestone payment					$ 47,500,000	$ 15,000,000				10,000,000	20,000,000
Deferred revenues				80,064,000						80,064,000		$ 80,064,000		80,064,000	80,064,000	97,365,000
Deferred revenues, current				44,200,000						44,200,000		44,200,000		44,200,000	44,200,000
Baxalta [Member] | License and Collaboration Agreements [Member] | Regulatory Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone license fee received														30,000,000
Maximum amount of milestone payments that can be received	$ 520,000,000
Baxalta [Member] | License and Collaboration Agreements [Member] | Research and Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum amount of milestone payments that can be received	100,000,000
Baxalta [Member] | License and Collaboration Agreements [Member] | Sales Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum amount of milestone payments that can be received	250,000,000
Baxalta [Member] | License and Collaboration Agreements [Member] | Clinical Trials in Pancreatic Cancer [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone license fee received														62,500,000
Collaboration agreement costs	98,800,000
Baxalta [Member] | Commercial Supply Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other revenues										1,200,000		1,200,000
Baxalta [Member] | Non-Substantive Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone license fee received														62,500,000
Milestone license fee	90,000,000
Baxalta [Member] | Substantive Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone license fee received														30,000,000
Milestone license fee	$ 530,000,000
PharmaEngine [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fees paid			$ 10,000,000
PharmaEngine [Member] | Sales Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum milestone payment obligation			130,000,000
PharmaEngine [Member] | Development and Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum milestone payment obligation			$ 80,000,000
PharmaEngine [Member] | License and Collaboration Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment							$ 11,000,000		$ 7,000,000
Research and development expenses										10,000,000	11,100,000	10,100,000	$ 11,300,000
PharmaEngine [Member] | License and Collaboration Agreements [Member] | New Drug Application [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment				10,000,000							$ 5,000,000
PharmaEngine [Member] | Commercial Supply Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other revenues										300,000		$ 300,000
Actavis [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Notice period of termination												90 days
Maximum amount of milestone and development payments that can be received		$ 15,100,000
Collaborative arrangement gross payments received															4,000,000
Aggregate milestone payments eligible to receive, decrease								$ 400,000
Agreement expiration term respect to each product												10 years
Additional renewal term												2 years
Deferred Revenue, Noncurrent				$ 4,000,000						$ 4,000,000		$ 4,000,000		$ 4,000,000	$ 4,000,000	$ 4,000,000
Expected revenue recognition period begins after first sale of applicable product												10 years