Contract Revenue from Collaboration	6 Months Ended
Jun. 30, 2013
Contract Revenue from Collaboration
Contract Revenue from Collaboration	Note 5. Contract Revenue from Collaboration In May 1995, the Company entered into a research and development collaboration agreement with Warner-Lambert Company (formerly Parke Davis), now a subsidiary of Pfizer, Inc., or Pfizer, to discover and commercialize small molecule drugs that restore control of, or otherwise intervene in, the misregulated cell cycle in tumor cells. Under this agreement, the Company developed screening tests, or assays, for jointly selected targets, and transferred these assays to Pfizer for screening of its compound library. The discovery research term ended in August 2001. Because Pfizer is developing a compound identified through this collaboration, the Company is entitled to receive payments upon achievement of certain clinical development and regulatory milestones and is entitled to receive royalties on worldwide sales. As a result of the collaboration, Pfizer identified palbociclib (formerly known as PD-0332991), a selective inhibitor of cyclin-dependent kinase 4/6, or CDK 4/6. Pfizer began clinical testing with this drug candidate in late 2004. During the six months ended June 30, 2013, the Company earned $2.0 million in clinical development milestone fees from Pfizer and since the inception of this agreement, the Company has earned $5.0 million in clinical development milestone fees relating to this drug candidate. Milestone payments earned under this agreement are classified as “Contract revenue from collaboration” on the Consolidated Statements of Operations. Under this agreement, remaining additional potential milestones payable by Pfizer to Onyx are, in aggregate, up to approximately $9.5 million and royalty payments will be based on 8% of net sales, if any. The remaining milestone payments may only become payable based on the efforts of Pfizer and therefore do not meet the definition of a substantive milestone. Since the Company does not have any remaining performance obligations under this agreement, such milestone payments would be recognized as revenue if and when received. The milestone and royalty provisions of the May 1995 collaboration agreement with Pfizer will remain in effect during the terms of the patents that cover palbociclib and will continue until the expiration of all licenses granted pursuant to the agreement. The patents that cover palbociclib will expire in January 2023, in both the United States and Europe. However, in both regions the patents may be extended up to 5 years under the statutes that provide for patent term extensions. There can be, though, no assurance that such extensions will be secured. Either party may terminate the agreement for the uncured material breach of the other party.

Note 5. Contract Revenue from Collaboration

In May 1995, the Company entered into a research and development collaboration agreement with Warner-Lambert Company (formerly Parke Davis), now a subsidiary of Pfizer, Inc., or Pfizer, to discover and commercialize small molecule drugs that restore control of, or otherwise intervene in, the misregulated cell cycle in tumor cells. Under this agreement, the Company developed screening tests, or assays, for jointly selected targets, and transferred these assays to Pfizer for screening of its compound library. The discovery research term ended in August 2001. Because Pfizer is developing a compound identified through this collaboration, the Company is entitled to receive payments upon achievement of certain clinical development and regulatory milestones and is entitled to receive royalties on worldwide sales.

As a result of the collaboration, Pfizer identified palbociclib (formerly known as PD-0332991), a selective inhibitor of cyclin-dependent kinase 4/6, or CDK 4/6. Pfizer began clinical testing with this drug candidate in late 2004. During the six months ended June 30, 2013, the Company earned $2.0 million in clinical development milestone fees from Pfizer and since the inception of this agreement, the Company has earned $5.0 million in clinical development milestone fees relating to this drug candidate. Milestone payments earned under this agreement are classified as “Contract revenue from collaboration” on the Consolidated Statements of Operations. Under this agreement, remaining additional potential milestones payable by Pfizer to Onyx are, in aggregate, up to approximately $9.5 million and royalty payments will be based on 8% of net sales, if any. The remaining milestone payments may only become payable based on the efforts of Pfizer and therefore do not meet the definition of a substantive milestone. Since the Company does not have any remaining performance obligations under this agreement, such milestone payments would be recognized as revenue if and when received.

The milestone and royalty provisions of the May 1995 collaboration agreement with Pfizer will remain in effect during the terms of the patents that cover palbociclib and will continue until the expiration of all licenses granted pursuant to the agreement. The patents that cover palbociclib will expire in January 2023, in both the United States and Europe. However, in both regions the patents may be extended up to 5 years under the statutes that provide for patent term extensions. There can be, though, no assurance that such extensions will be secured. Either party may terminate the agreement for the uncured material breach of the other party.