License and Collaboration Agreements - Additional Information (Detail) - USD ($)					1 Months Ended								3 Months Ended								12 Months Ended				27 Months Ended
	Sep. 23, 2014	Nov. 25, 2013	May 05, 2011	Nov. 10, 2009	Dec. 31, 2016	Oct. 31, 2016	Jun. 30, 2016	Oct. 31, 2015	Aug. 31, 2015	Jul. 31, 2015	Jan. 31, 2015	Sep. 30, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2016
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenues, current					$ 36,226,000								$ 36,226,000				$ 50,137,000				$ 36,226,000	$ 50,137,000			$ 36,226,000
Other revenues													1,431,000	$ 1,161,000	$ 1,498,000						$ 4,090,000
Agreement termination scheduled date																					Dec. 17, 2014
License and collaboration revenues													44,057,000	12,417,000	19,332,000	$ 11,313,000	17,090,000	$ 16,440,000	$ 36,558,000	$ 14,842,000	$ 87,119,000	84,930,000	$ 102,756,000
Assets maintained related to Sanofi Agreement					81,483,000								81,483,000				234,880,000				81,483,000	234,880,000			81,483,000
Liabilities maintained related to Sanofi Agreement					334,142,000								334,142,000				418,569,000				334,142,000	418,569,000			334,142,000
Research and development expenses													54,961,000	$ 32,078,000	$ 40,996,000	$ 32,882,000	44,740,000	$ 37,763,000	42,806,000	$ 35,679,000	160,917,000	160,988,000	138,495,000
Deferred Revenue, Noncurrent					25,673,000								25,673,000				51,197,000				$ 25,673,000	51,197,000			25,673,000
Baxalta [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fee received												$ 100,000,000
Baxalta [Member] | Regulatory Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone license fee received																									60,000,000
Maximum amount of milestone payments that can be received	$ 520,000,000
Baxalta [Member] | Research and Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone license fee received																									62,500,000
Maximum amount of milestone payments that can be received	100,000,000
Baxalta [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] | Clinical Trials in Pancreatic Cancer [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration agreement costs	98,800,000
Baxalta [Member] | License and Collaboration Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
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						$ 30,000,000	$ 10,000,000	$ 47,500,000	$ 15,000,000	$ 20,000,000
Royalty revenue																					$ 200,000
Deferred revenues					56,779,000								56,779,000				97,365,000				56,779,000	97,365,000			56,779,000
Deferred revenues, current					36,200,000								36,200,000								36,200,000				36,200,000
License and collaboration revenues																					87,119,000	84,930,000	10,460,000
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																									60,000,000
Milestone license fee	$ 530,000,000
Baxalta [Member] | Commercial Supply Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other revenues																					3,600,000
Sanofi [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fee received				$ 60,000,000
Milestone license fee received																					25,000,000
Expected development period from the effective date of agreement				12 years
License and collaboration revenues																					0	0
Assets maintained related to Sanofi Agreement					0								0				0				0	0			0
Liabilities maintained related to Sanofi Agreement					0								0				0				0	0			0
Sanofi [Member] | License and Collaboration Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and collaboration revenues																							92,296,000
Recognized revenue related to excess spending																							5,800,000
Spending in excess of budget																								$ 10,100,000
PharmaEngine [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fees paid			$ 10,000,000
Milestone payment					25,500,000		$ 10,000,000			$ 11,000,000		$ 7,000,000							$ 5,000,000
Royalty expense																					100,000
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]
Research and development expenses																					35,600,000	11,400,000	$ 12,600,000
PharmaEngine [Member] | Commercial Supply Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other revenues																					$ 300,000	0
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																					$ 4,900,000
Aggregate milestone payments eligible to receive, decrease											$ 400,000
Percentage of net profits on global sales of product																					The Company will also receive a mid-twenties percentage of net profits on global sales of the Initial Product and any additional products.
Milestones achieved						$ 1,100,000
Agreement expiration term respect to each product																					10 years
Additional renewal term																					2 years
Deferred Revenue, Noncurrent					$ 5,100,000								$ 5,100,000				$ 4,000,000				$ 5,100,000	$ 4,000,000			$ 5,100,000
Expected revenue recognition period begins after first sale of applicable product																					10 years