| **Restructuring (Tables)**        | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
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| **Restructuring [Abstract]**      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| Activity in restructuring accrual | Activity in the 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.  Severance and Related Benefits  Other Exit Costs  Contract Termination Costs  Total Restructuring Accrual Balance at December 31, 2012 $813  $-  $-  $813 Additions, net  1,477   -   -   1,477 Payments  (854)  -   -   (854)Balance at March 31, 2013  1,436   -   -   1,436 Additions, net  15   15   1,359   1,389 Payments  (914)  (15)  (1,359)  (2,288)Balance at June 30, 2013 $537  $-  $-  $537  |

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| - Definition
Tabular disclosure of an entity's restructuring reserve that occurred during the period associated with the exit from or disposal of business activities or restructurings for each major type of cost. This element may also include a description of any reversal and other adjustment made during the period to the amount of an accrued liability for restructuring activities. This element may be used to encapsulate the roll forward presentations of an entity's restructuring reserve by type of cost and in total, and explanation of changes that occurred in the period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4(b)(2)) -URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747
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