Subsequent Events	12 Months Ended
Dec. 31, 2011
Subsequent Events [Abstract]
Subsequent Events	14. SUBSEQUENT EVENTS (a) Termination of Pfizer Collaboration Agreement and Dimebon Program In January 2012, the Company reported negative top line results from its Phase 3 CONCERT trial of dimebon in patients with mild-to-moderate Alzheimer's disease. The Company previously had reported negative top line results from its Phase 3 CONNECTION trial of dimebon in patients with mild-to-moderate Alzheimer's disease and its Phase 3 HORIZON trial of dimebon in patients with Huntington disease. In January 2012, Pfizer exercised its right to terminate the collaboration agreement and the Company and Pfizer discontinued development of dimebon for all indications. During the ensuing 180 days, the Company and Pfizer will work together to wind down their remaining collaboration activities. The Company estimates that it and Pfizer will complete their collaboration wind down activities in the first half of 2012. Thus, during the first quarter of 2012 the Company revised its estimate of the remaining performance period under its former collaboration agreement with Pfizer. The Company expects the performance period to conclude in the first half of 2012. The remaining deferred revenue balance relating to the former collaboration agreement with Pfizer, which totaled $72.0 million at December 31, 2011, will be recognized as revenue over the remaining performance period. (b) Oakbrook Terrace Lease In February 2012, the Company entered into a lease agreement for 15,336 square feet of office space located in Oakbrook Terrace, Illinois, which is intended to serve as its commercial headquarters following construction and build-out. The term of the lease is seven years and seven months, with an anticipated commencement date of May 2012. The Company selected this location for its commercial headquarters based on its proximity to the Company's collaboration partner, Astellas. The annual non-cancelable rent payments are approximately $0.3 million per year. In connection with the execution of the lease, the Company delivered to the lessor a letter of credit collateralized by restricted cash totaling $0.8 million.

14. SUBSEQUENT EVENTS

(a) Termination of Pfizer Collaboration Agreement and Dimebon Program

In January 2012, the Company reported negative top line results from its Phase 3 CONCERT trial of dimebon in patients with mild-to-moderate Alzheimer's disease. The Company previously had reported negative top line results from its Phase 3 CONNECTION trial of dimebon in patients with mild-to-moderate Alzheimer's disease and its Phase 3 HORIZON trial of dimebon in patients with Huntington disease. In January 2012, Pfizer exercised its right to terminate the collaboration agreement and the Company and Pfizer discontinued development of dimebon for all indications. During the ensuing 180 days, the Company and Pfizer will work together to wind down their remaining collaboration activities.

The Company estimates that it and Pfizer will complete their collaboration wind down activities in the first half of 2012. Thus, during the first quarter of 2012 the Company revised its estimate of the remaining performance period under its former collaboration agreement with Pfizer. The Company expects the performance period to conclude in the first half of 2012. The remaining deferred revenue balance relating to the former collaboration agreement with Pfizer, which totaled $72.0 million at December 31, 2011, will be recognized as revenue over the remaining performance period.

(b) Oakbrook Terrace Lease

In February 2012, the Company entered into a lease agreement for 15,336 square feet of office space located in Oakbrook Terrace, Illinois, which is intended to serve as its commercial headquarters following construction and build-out. The term of the lease is seven years and seven months, with an anticipated commencement date of May 2012. The Company selected this location for its commercial headquarters based on its proximity to the Company's collaboration partner, Astellas. The annual non-cancelable rent payments are approximately $0.3 million per year. In connection with the execution of the lease, the Company delivered to the lessor a letter of credit collateralized by restricted cash totaling $0.8 million.