Collaboration Agreement	9 Months Ended
Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreement	5. Collaboration Agreement In 2015, the Company entered into a collaboration agreement with Seattle Genetics, whereby the parties agreed to jointly develop two product candidates incorporating the Company’s ACTR platform and Seattle Genetics’ antibodies (the “Collaboration Agreement”). Under the terms of the Collaboration Agreement, the Company conducts preclinical research and clinical development activities related to the two specified product candidates through Phase 1 clinical development, and Seattle Genetics provides the funding for those activities. As a result of the Collaboration Agreement, the Company recognized revenue of $1.0 million and $2.0 million for the three months ended September 30, 2019 and 2018, respectively, and $7.2 million and $5.9 million for the nine months ended September 30, 2019 and 2018 related to research and clinical development activities performed. As of September 30, 2019, deferred revenue of $14.7 million was recorded related to this agreement. As of September 30, 2019, the aggregate amount of the transaction price allocated to the remaining performance obligation for preclinical research and clinical development activities related to the two specified product candidates through Phase 1 is estimated to be approximately $40.7 million, which is expected to be recognized as revenue through December 31, 2022. In November 2019, the Company and Seattle Genetics suspended further development under the Collaboration Agreement. The impact to the Collaboration Agreement is outlined further in Note 11, “Subsequent Events.”

Collaboration Agreement

9 Months Ended

Sep. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

5. Collaboration Agreement

In 2015, the Company entered into a collaboration agreement with Seattle Genetics, whereby the parties agreed to jointly develop two product candidates incorporating the Company’s ACTR platform and Seattle Genetics’ antibodies (the “Collaboration Agreement”). Under the terms of the Collaboration Agreement, the Company conducts preclinical research and clinical development activities related to the two specified product candidates through Phase 1 clinical development, and Seattle Genetics provides the funding for those activities. As a result of the Collaboration Agreement, the Company recognized revenue of $1.0 million and $2.0 million for the three months ended September 30, 2019 and 2018, respectively, and $7.2 million and $5.9 million for the nine months ended September 30, 2019 and 2018 related to research and clinical development activities performed. As of September 30, 2019, deferred revenue of $14.7 million was recorded related to this agreement. As of September 30, 2019, the aggregate amount of the transaction price allocated to the remaining performance obligation for preclinical research and clinical development activities related to the two specified product candidates through Phase 1 is estimated to be approximately $40.7 million, which is expected to be recognized as revenue through December 31, 2022.

In November 2019, the Company and Seattle Genetics suspended further development under the Collaboration Agreement. The impact to the Collaboration Agreement is outlined further in Note 11, “Subsequent Events.”