Investments in Variable Interest Entities	12 Months Ended
Dec. 31, 2016
Investments in Variable Interest Entities [Abstract]
Investments in Variable Interest Entities	Investments in Variable Interest Entities Consolidated Variable Interest Entities Our consolidated financial statements include the financial results of variable interest entities in which we are the primary beneficiary. The following are our significant variable interest entities. Neurimmune SubOne AG In 2007 we entered into a collaboration agreement with Neurimmune SubOne AG (Neurimmune), a subsidiary of Neurimmune AG, for the development and commercialization of antibodies for the treatment of Alzheimer’s disease. Neurimmune conducts research to identify potential therapeutic antibodies and we are responsible for the development, manufacturing and commercialization of all products. Our anti-amyloid beta antibody, aducanumab, for the treatment of Alzheimer’s disease resulted from this collaboration. In September 2015 we announced that the first patient had been enrolled in a Phase 3 trial for aducanumab, which triggered a $60.0 million milestone payment due to Neurimmune. As we consolidate the financial results of Neurimmune, we recognized this payment as a charge to noncontrolling interest in the third quarter of 2015. Based upon our current development plans for aducanumab, we may pay Neurimmune up to $275.0 million in remaining milestone payments. We may also pay royalties in the low-to-mid-teens on sales of any resulting commercial products. We determined that we are the primary beneficiary of Neurimmune because we have the power through the collaboration to direct the activities that most significantly impact the entity’s economic performance and are required to fund 100% of the research and development costs incurred in support of the collaboration agreement. Accordingly, we consolidate the results of Neurimmune. We are required to reimburse Neurimmune for amounts that are incurred by Neurimmune for research and development expenses in support of the collaboration. Amounts reimbursed are reflected in research and development expense in our consolidated statements of income. During the years ending December 31, 2016, 2015 and 2014, these amounts were immaterial. Future milestone payments and royalties, if any, will be reflected in our consolidated statements of income as a charge to noncontrolling interest, net of tax, when such milestones are achieved. The assets and liabilities of Neurimmune are not significant to our financial position or results of operations as it is a research and development organization. We have provided no financing to Neurimmune other than previously contractually required amounts. Rodin Therapeutics, Inc. In December 2015 we paid $8.0 million for preferred stock in Rodin Therapeutics, Inc. (Rodin) and entered into an option and collaboration agreement which gave us the right to purchase all remaining outstanding shares of Rodin at any time until 35 days after acceptance of an Investigational New Drug (IND) application by the FDA. As we determined that we were the primary beneficiary of Rodin, we consolidated the results of Rodin and recorded an IPR&D intangible asset of approximately $8.7 million and assigned approximately $10.9 million to noncontrolling interest. During the fourth quarter of 2016 we terminated our collaboration agreement with Rodin. Upon termination of the collaboration agreement, we deconsolidated the results of Rodin and impaired the IPR&D asset, resulting in an impairment loss of $8.7 million related to the IPR&D asset recorded upon entering into the collaboration agreement. The assets and liabilities of Rodin were not significant to our financial position or results of operations as Rodin is a research and development organization. We had provided no financing to Rodin other than the contractually required amounts disclosed above. Ataxion Inc. In February 2014 we paid $1.6 million for preferred stock in Ataxion, Inc. (Ataxion) and entered into an option and collaboration agreement which gave us the right to purchase all outstanding shares of Ataxion at any time until 30 days after delivery of a Phase 1 clinical trial study report. As we determined that we were the primary beneficiary of Ataxion, we consolidated the results of Ataxion and recorded an IPR&D intangible asset of $3.5 million and assigned that amount to noncontrolling interest. During the fourth quarter of 2016 we terminated our option agreement with Ataxion. Upon termination of the collaboration agreement, we deconsolidated the results of Ataxion and impaired the IPR&D asset, resulting in an impairment loss of $3.5 million related to the IPR&D asset recorded upon entering into the collaboration agreement. The assets and liabilities of Ataxion were not significant to our financial position or results of operations as Ataxion is a research and development organization. We had provided no financing to Ataxion other than the contractually required amounts disclosed above. Unconsolidated Variable Interest Entities We have relationships with other variable interest entities that we do not consolidate as we lack the power to direct the activities that significantly impact the economic success of these entities. These relationships include investments in certain biotechnology companies and research collaboration agreements. As of December 31, 2016 and 2015, the total carrying value of our investments in biotechnology companies totaled $47.4 million and $29.2 million, respectively. Our maximum exposure to loss related to these variable interest entities is limited to the carrying value of our investments. We have also entered into research collaboration agreements with certain variable interest entities where we are required to fund certain development activities. These development activities are included in research and development expense in our consolidated statements of income, as they are incurred. We have provided no financing to these variable interest entities other than previously contractually required amounts.

Investments in Variable Interest Entities

Consolidated Variable Interest Entities

Our consolidated financial statements include the financial results of variable interest entities in which we are the primary beneficiary. The following are our significant variable interest entities.

Neurimmune SubOne AG

In 2007 we entered into a collaboration agreement with Neurimmune SubOne AG (Neurimmune), a subsidiary of Neurimmune AG, for the development and commercialization of antibodies for the treatment of Alzheimer’s disease. Neurimmune conducts research to identify potential therapeutic antibodies and we are responsible for the development, manufacturing and commercialization of all products. Our anti-amyloid beta antibody, aducanumab, for the treatment of Alzheimer’s disease resulted from this collaboration. In September 2015 we announced that the first patient had been enrolled in a Phase 3 trial for aducanumab, which triggered a $60.0 million milestone payment due to Neurimmune. As we consolidate the financial results of Neurimmune, we recognized this payment as a charge to noncontrolling interest in the third quarter of 2015. Based upon our current development plans for aducanumab, we may pay Neurimmune up to $275.0 million in remaining milestone payments. We may also pay royalties in the low-to-mid-teens on sales of any resulting commercial products.

We determined that we are the primary beneficiary of Neurimmune because we have the power through the collaboration to direct the activities that most significantly impact the entity’s economic performance and are required to fund 100% of the research and development costs incurred in support of the collaboration agreement. Accordingly, we consolidate the results of Neurimmune.

We are required to reimburse Neurimmune for amounts that are incurred by Neurimmune for research and development expenses in support of the collaboration. Amounts reimbursed are reflected in research and development expense in our consolidated statements of income. During the years ending December 31, 2016, 2015 and 2014, these amounts were immaterial. Future milestone payments and royalties, if any, will be reflected in our consolidated statements of income as a charge to noncontrolling interest, net of tax, when such milestones are achieved.

The assets and liabilities of Neurimmune are not significant to our financial position or results of operations as it is a research and development organization. We have provided no financing to Neurimmune other than previously contractually required amounts.

Rodin Therapeutics, Inc.

In December 2015 we paid $8.0 million for preferred stock in Rodin Therapeutics, Inc. (Rodin) and entered into an option and collaboration agreement which gave us the right to purchase all remaining outstanding shares of Rodin at any time until 35 days after acceptance of an Investigational New Drug (IND) application by the FDA. As we determined that we were the primary beneficiary of Rodin, we consolidated the results of Rodin and recorded an IPR&D intangible asset of approximately $8.7 million and assigned approximately $10.9 million to noncontrolling interest.

During the fourth quarter of 2016 we terminated our collaboration agreement with Rodin. Upon termination of the collaboration agreement, we deconsolidated the results of Rodin and impaired the IPR&D asset, resulting in an impairment loss of $8.7 million related to the IPR&D asset recorded upon entering into the collaboration agreement.

The assets and liabilities of Rodin were not significant to our financial position or results of operations as Rodin is a research and development organization. We had provided no financing to Rodin other than the contractually required amounts disclosed above.

Ataxion Inc.

In February 2014 we paid $1.6 million for preferred stock in Ataxion, Inc. (Ataxion) and entered into an option and collaboration agreement which gave us the right to purchase all outstanding shares of Ataxion at any time until 30 days after delivery of a Phase 1 clinical trial study report. As we determined that we were the primary beneficiary of Ataxion, we consolidated the results of Ataxion and recorded an IPR&D intangible asset of $3.5 million and assigned that amount to noncontrolling interest.

During the fourth quarter of 2016 we terminated our option agreement with Ataxion. Upon termination of the collaboration agreement, we deconsolidated the results of Ataxion and impaired the IPR&D asset, resulting in an impairment loss of $3.5 million related to the IPR&D asset recorded upon entering into the collaboration agreement.

The assets and liabilities of Ataxion were not significant to our financial position or results of operations as Ataxion is a research and development organization. We had provided no financing to Ataxion other than the contractually required amounts disclosed above.

Unconsolidated Variable Interest Entities

We have relationships with other variable interest entities that we do not consolidate as we lack the power to direct the activities that significantly impact the economic success of these entities. These relationships include investments in certain biotechnology companies and research collaboration agreements.

As of December 31, 2016 and 2015, the total carrying value of our investments in biotechnology companies totaled $47.4 million and $29.2 million, respectively. Our maximum exposure to loss related to these variable interest entities is limited to the carrying value of our investments.

We have also entered into research collaboration agreements with certain variable interest entities where we are required to fund certain development activities. These development activities are included in research and development expense in our consolidated statements of income, as they are incurred. We have provided no financing to these variable interest entities other than previously contractually required amounts.