Subsequent Event	3 Months Ended
Mar. 29, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENT	SUBSEQUENT EVENTS Lease Amendment On April 1, 2019, we entered into an amendment to the existing Lease Agreement (the Lease) relating to our corporate headquarters located at 1851, 1801, and 1751 Harbor Bay Parkway, Alameda, California (the Premises). The Lease Amendment provides, among other things, for the (i) expansion of the Premises by 37,544 square feet of office facilities located at 1601 Harbor Bay Parkway, Alameda, California (the 1601 Expansion Space) and (ii) surrender of 2,703 square feet of office facilities located at 1751 Harbor Bay Parkway, Alameda, California (the 1751 Space). We surrendered the 1751 Space on April 15, 2019 and the term for the 1601 Expansion Space will begin ninety days after the landlord’s delivery of the entire 1601 Expansion Space (the 1601 Expansion Space Commencement Date). The term for the 1601 Expansion Space is expected to commence on December 1, 2019, and will run coterminous with the term of the Lease for the existing space, which ends on January 31, 2028. We have been provided an allowance of $1.7 million for tenant improvements to the 1601 Expansion Space. Following April 15, 2019, the monthly base rent for the Premises, other than the 1601 Expansion Space, is $224,505 through January 31, 2020, increasing throughout the remainder of the term to $283,933 at the end of the term. Following the 1601 Expansion Space Commencement Date, the monthly base rent for the 1601 Expansion Space will be $71,334 through November 30, 2020, increasing throughout the remainder of the term to $90,481 at the end of the term. The aggregate contractual base rent for the entire 169,606 square feet of the Premises from April 15, 2019, through the remainder of the Lease term will be approximately $34.6 million. In addition, we are required to pay the landlord for certain operating expenses and taxes they incur related to the Premises. Amendment to Collaboration Agreement with Takeda On April 29, 2019, we executed an amendment to our January 2017 collaboration agreement with Takeda (the Amendment), which will become effective on May 7, 2019. The Amendment, among other things, reduces the amount of reimbursements we will receive from Takeda for costs associated with our required global pharmacovigilance activities and limits those reimbursements to $1.0 million per year. It also increases the total potential development, regulatory and first-sale milestone payments to be paid to us by Takeda for second-line renal cell carcinoma (RCC), first-line RCC and second-line hepatocellular carcinoma by an aggregate of $12.0 million to $102.0 million, including an increase from $10.0 million to $16.0 million for the milestone we expect to receive for the April 2019 submission of a regulatory application for cabozantinib as a treatment for patients with advanced RCC to the Japanese Ministry of Health, Labour and Welfare. We continue to be eligible to receive additional development, regulatory and first-sale milestone payments for other potential future indications. The Amendment also increases the amount of Takeda’s potential sales-based milestones by an aggregate of $3.0 million to $86.0 million. We continue to be eligible to receive royalties on net sales of cabozantinib in Japan.

SUBSEQUENT EVENTS

Lease Amendment

On April 1, 2019, we entered into an amendment to the existing Lease Agreement (the Lease) relating to our corporate headquarters located at 1851, 1801, and 1751 Harbor Bay Parkway, Alameda, California (the Premises). The Lease Amendment provides, among other things, for the (i) expansion of the Premises by 37,544 square feet of office facilities located at 1601 Harbor Bay Parkway, Alameda, California (the 1601 Expansion Space) and (ii) surrender of 2,703 square feet of office facilities located at 1751 Harbor Bay Parkway, Alameda, California (the 1751 Space). We surrendered the 1751 Space on April 15, 2019 and the term for the 1601 Expansion Space will begin ninety days after the landlord’s delivery of the entire 1601 Expansion Space (the 1601 Expansion Space Commencement Date). The term for the 1601 Expansion Space is expected to commence on December 1, 2019, and will run coterminous with the term of the Lease for the existing space, which ends on January 31, 2028. We have been provided an allowance of $1.7 million for tenant improvements to the 1601 Expansion Space.

Following April 15, 2019, the monthly base rent for the Premises, other than the 1601 Expansion Space, is $224,505 through January 31, 2020, increasing throughout the remainder of the term to $283,933 at the end of the term. Following the 1601 Expansion Space Commencement Date, the monthly base rent for the 1601 Expansion Space will be $71,334 through November 30, 2020, increasing throughout the remainder of the term to $90,481 at the end of the term. The aggregate contractual base rent for the entire 169,606 square feet of the Premises from April 15, 2019, through the remainder of the Lease term will be approximately $34.6 million. In addition, we are required to pay the landlord for certain operating expenses and taxes they incur related to the Premises.

Amendment to Collaboration Agreement with Takeda

On April 29, 2019, we executed an amendment to our January 2017 collaboration agreement with Takeda (the Amendment), which will become effective on May 7, 2019. The Amendment, among other things, reduces the amount of reimbursements we will receive from Takeda for costs associated with our required global pharmacovigilance activities and limits those reimbursements to $1.0 million per year. It also increases the total potential development, regulatory and first-sale milestone payments to be paid to us by Takeda for second-line renal cell carcinoma (RCC), first-line RCC and second-line hepatocellular carcinoma by an aggregate of $12.0 million to $102.0 million, including an increase from $10.0 million to $16.0 million for the milestone we expect to receive for the April 2019 submission of a regulatory application for cabozantinib as a treatment for patients with advanced RCC to the Japanese Ministry of Health, Labour and Welfare. We continue to be eligible to receive additional development, regulatory and first-sale milestone payments for other potential future indications. The Amendment also increases the amount of Takeda’s potential sales-based milestones by an aggregate of $3.0 million to $86.0 million. We continue to be eligible to receive royalties on net sales of cabozantinib in Japan.