Collaboration Agreements - Additional Information (Details) - USD ($)	1 Months Ended			3 Months Ended		9 Months Ended	11 Months Ended	17 Months Ended
	Jul. 31, 2015	Apr. 30, 2015	May. 31, 2014	Dec. 31, 2015	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue					$ 19,732,000	$ 19,732,000	$ 19,732,000	$ 19,732,000	$ 33,427,000
Novartis Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Novartis share of joint development costs						38.00%
Period after first commercial sale of product on which Novartis' royalty obligation run on a country to country basis						12 years
Estimated performance period of agreement	13 years 6 months
Revenue recognized					3,700,000	$ 3,700,000
Deferred revenue					196,300,000	$ 196,300,000	196,300,000	196,300,000
Novartis Agreement | United States, Specified European Countries and /or Japan
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative Agreement, Obligations						With respect to the United States, specified European countries and/or Japan, the Company may elect for such region to either reduce by 50% or to eliminate in full the Company’s development and commercialization cost sharing obligation. If the Company elects to reduce its cost sharing percentage by 50% in any such region, then its profit share in such region will also be reduced by 50%. If the Company elects to eliminate its development cost sharing obligation, then such region will be removed from the profit share, and instead Novartis will owe the Company royalties on any net sales of product for such region, as described above.
Reduction percentage of development cost share						50.00%
Reduction percentage of profit share						50.00%
Novartis Agreement | United States
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement profit share percentage						50.00%
Novartis Agreement | European Countries and Japan
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement profit share percentage						45.00%
Novartis Agreement | Novartis
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Novartis share of joint development costs						62.00%
Collaborative arrangement profit share percentage						50.00%
Novartis Agreement | Upfront Payment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement		$ 200,000,000
Novartis Agreement | Maximum | Development Milestone
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive						$ 250,000,000
Novartis Agreement | Maximum | Regulatory Approval Milestone
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive						250,000,000
Janssen ADU-741 Agreements | Upfront Payment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement								12,000,000
Janssen ADU-741 Agreements | Non Substantive And Substantive Milestone
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement								6,500,000
Janssen ADU-741 Agreements | Maximum | Nonrefundable Milestone Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive						1,000,000
Janssen ADU-741 Agreements | Maximum | Contingent Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive						345,500,000
Janssen GVAX Prostate Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized					2,700,000	9,200,000
Deferred revenue					500,000	500,000	500,000	500,000
Janssen GVAX Prostate Agreement | Upfront Payment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement			$ 500,000
Janssen GVAX Prostate Agreement | Specified Commercial Milestone
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive						2,000,000
Janssen ADU-741 and Janssen GVAX Prostate Agreement | Upfront Payment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement						12,500,000
Janssen ADU-214 Agreement | Upfront Payment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement							30,000,000
Janssen ADU-214 Agreement | Non Substantive And Substantive Milestone
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement							500,000
Janssen ADU-214 Agreement | Maximum | Nonrefundable Milestone Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive						10,500,000
Janssen ADU-214 Agreement | Maximum | Contingent Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive						776,000,000
Janssen ADU-741 Agreement and Janssen ADU-214 Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized					11,100,000	22,900,000
Deferred revenue					$ 4,400,000	$ 4,400,000	$ 4,400,000	$ 4,400,000
Janssen ADU-741 Agreement and Janssen ADU-214 Agreement | Nonrefundable Milestone Payments | Subsequent Event
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive				$ 10,000,000