| **Restructuring**            | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
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| **Restructuring [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| Restructuring                | 7.  RestructuringAs part of the reorientation of our research and development focus on oncology, in the third quarter we reduced headcount resulting in a restructuring accrual of $1.1 million which will be paid during the period from October 2011 through August 2012. This accrual consists of:   For the Three and Nine Months Ended September 30, 2011 Severance and related benefits $1,064 Total $1,064 Activity in the third quarter restructuring accrual, which is included in accounts payable and accrued expenses in our Consolidated Balance Sheets and research and development and general and administrative expenses in the Consolidated Statements of Operations, is specified below. We expect to incur additional employee termination benefit expense accruals related to this restructuring upon completion of arrangements finalized after third-quarter end.   Severance and related benefits Initial expense accrual $1,064 Cash payments  - Balance at September 30, 2011 $1,064  |

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| - Definition
Description of restructuring activities including exit and disposal activities, which should include facts and circumstances leading to the plan, the expected plan completion date, the major types of costs associated with the plan activities, total expected costs, the accrual balance at the end of the period, and the periods over which the remaining accrual will be settled. This description does not include restructuring costs in connection with a business combination or discontinued operations and long-lived assets (disposal groups) sold or classified as held for sale. This element may be used as a single block of text to encapsulate the entire disclosure including data and tables.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 146 -Paragraph 20Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 5 -Section P -Subsection 3, 4
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