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Product Milestone Payments and Royalty Agreements | 9 Months Ended
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Sep. 30, 2013
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Product Milestone Payments and Royalty Agreements | 9. Product Milestone Payments and Royalty Agreements In connection with an Asset Purchase Agreement with Tolerance Therapeutics, Inc. (Tolerance) entered into during June 2005, the Company may be required to issue Tolerance additional consideration as follows: (i) $10,950,000 if certain milestones are met, including the initiation of Phase 3 trials and filing of various regulatory product license applications; (ii) 36,135 shares of common stock; and (iii) royalty payments between 1.75% and 4.0% of net sales of products acquired from or patented by Tolerance or other product fees earned by the Company. Any additional consideration required to be paid under the Asset Purchase Agreement will be recorded as research and development expense when incurred. No payments related to the additional consideration have occurred during the three and nine-month periods ended September 30, 2013 or 2012. Additionally, certain agreements require the Company to pay royalties. Currently, the Company is not obligated to pay royalties, as no other revenue from product sales is being generated by the Company.

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