This excerpt taken from the TPTX 10-K filed Mar 29, 2007.
In-Process Research and Development
In connection with the Merger, we determined that a portion of the amount paid in the transaction was consideration for in-process research and development. The in-process research and development acquired in the Merger consisted of two product candidates under development for the treatment of Alzheimers disease. In-process research and development was expensed upon acquisition because technological feasibility has not been established and no future alternative uses exist for the technologies. Our valuation of the in-process research and development involved estimates and judgments and if we make additional acquisitions in the future, we may be required to make similar estimates and judgments.