Subsequent Event	6 Months Ended
Jun. 30, 2016
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event In July 2016, we entered into a collaboration agreement with Jounce Therapeutics, Inc. (Jounce) for the development and commercialization of immunotherapies for cancer, including Jounce’s lead product candidate, JTX-2011, targeting ICOS (the Inducible T cell CO-Stimulator), up to four early stage programs to be selected from a defined pool of B cell, T regulatory cell and tumor-associated macrophage targets emerging from Jounce’s research platform, and a Jounce checkpoint immuno-oncology program. Under the terms of the collaboration agreement and other agreements with Jounce, we agreed to pay $261.0 million to Jounce, which included an upfront collaboration fee and a purchase of Jounce equity securities. Jounce is also eligible to receive regulatory, development, and net sales milestone payments. We have the right to opt into the collaboration programs at defined stages of development. Following opt-in, the parties will share U.S. profits and losses on the collaboration programs as follows: (a) Jounce will retain a 60 percent U.S. profit share of JTX-2011, with 40 percent allocated to us; (b) Jounce will retain a 25 percent U.S. profit share on the first additional program, with 75 percent allocated to us; and (c) the parties will equally share U.S. profits on up to three additional programs. Also, following opt-in to each of the foregoing programs, we will receive exclusive ex-U.S. commercialization rights with respect to such program, Jounce will be eligible to receive tiered royalties on sales outside the United States, and development costs will be shared by the parties in a manner that is commensurate with their respective product rights under such program. The parties will equally share global profits from the checkpoint program. The collaboration agreement has an initial term of four years, which may be extended up to three additional years. If the parties enter into any pre-negotiated license or co-commercialization agreement during the initial term, the collaboration agreement will continue until all such license and co-commercialization agreements have expired. The collaboration agreement may be terminated at our discretion upon 120 days prior written notice to Jounce and by either party upon material breach of the other party, subject to cure periods.

Subsequent Event

In July 2016, we entered into a collaboration agreement with Jounce Therapeutics, Inc. (Jounce) for the development and commercialization of immunotherapies for cancer, including Jounce’s lead product candidate, JTX-2011, targeting ICOS (the Inducible T cell CO-Stimulator), up to four early stage programs to be selected from a defined pool of B cell, T regulatory cell and tumor-associated macrophage targets emerging from Jounce’s research platform, and a Jounce checkpoint immuno-oncology program. Under the terms of the collaboration agreement and other agreements with Jounce, we agreed to pay $261.0 million to Jounce, which included an upfront collaboration fee and a purchase of Jounce equity securities. Jounce is also eligible to receive regulatory, development, and net sales milestone payments.

We have the right to opt into the collaboration programs at defined stages of development. Following opt-in, the parties will share U.S. profits and losses on the collaboration programs as follows: (a) Jounce will retain a 60 percent U.S. profit share of JTX-2011, with 40 percent allocated to us; (b) Jounce will retain a 25 percent U.S. profit share on the first additional program, with 75 percent allocated to us; and (c) the parties will equally share U.S. profits on up to three additional programs. Also, following opt-in to each of the foregoing programs, we will receive exclusive ex-U.S. commercialization rights with respect to such program, Jounce will be eligible to receive tiered royalties on sales outside the United States, and development costs will be shared by the parties in a manner that is commensurate with their respective product rights under such program. The parties will equally share global profits from the checkpoint program.

The collaboration agreement has an initial term of four years, which may be extended up to three additional years. If the parties enter into any pre-negotiated license or co-commercialization agreement during the initial term, the collaboration agreement will continue until all such license and co-commercialization agreements have expired. The collaboration agreement may be terminated at our discretion upon 120 days prior written notice to Jounce and by either party upon material breach of the other party, subject to cure periods.