Research and License Agreements	12 Months Ended
Dec. 31, 2016
Revenue Recognition [Abstract]
Research and License Agreement	10. Research and License Agreements In February 2004, the Company entered into a research services agreement (the Research Agreement) with the University of Basel (the University) for biological evaluation of selectin antagonists. Certain patents covering the rivipansel compound are subject to provisions of the Research Agreement. Under the terms of the Research Agreement, the Company will owe a 10% payment to the University for all future milestone and royalty payments received from Pfizer with respect to rivipansel. A milestone license fee of $2.0 million was recorded in the year ended December 31, 2015 for the payment due to the University of Basel representing 10% of the $20.0 million non-refundable milestone payment that the Company received from Pfizer in August 2015. The accrued license and milestone fee of $2.0 million was paid in February 2016. There were no payments recorded for the year ended December 31, 2016. In October 2011, the Company and Pfizer entered into a licensing agreement (the Pfizer Agreement) that provides Pfizer an exclusive worldwide license to rivipansel for vaso-occlusive crisis associated with sickle cell disease and for other diseases for which the drug candidate may be developed. The Company was responsible for completion of the Phase 2 trial, after which Pfizer will assume all further development and commercialization responsibilities. Upon execution of the Pfizer Agreement, the Company received an up-front payment of $22.5 million. The Pfizer Agreement also provides for potential milestone payments of up to $115.0 million upon the achievement of specified development milestones, including the dosing of the first patients in Phase 3 clinical trials for up to two indications and the first commercial sale of a licensed product in the United States and selected European countries for up to two indications; potential milestone payments of up to $70.0 million upon the achievement of specified regulatory milestones, including the acceptance of the Company’s filings for regulatory approval by regulatory authorities in the United States and Europe for up to two indications; and potential milestone payments of up to $135.0 million upon the achievement of specified levels of annual net sales of licensed products. Pfizer has the right to terminate the Pfizer Agreement by giving prior written notice. The Company has determined that each potential future clinical, development and regulatory milestone is substantive. Although sales-based milestones are not considered substantive, they are still recognized upon achievement of the milestone (assuming all other revenue recognition criteria have been met) because there are no undelivered elements that would preclude revenue recognition at that time. The Company is also eligible to receive royalties on future sales contingent upon annual net sales thresholds. In addition, the Company and Pfizer have formed a joint steering committee that will oversee and coordinate activities as set forth in the research program. The $22.5 million up-front payment was recognized over a period of 1.5 years. In May 2014, the Company received a non-refundable payment of $15.0 million from Pfizer as a partial milestone payment owed to the Company upon the dosing of the first patient in the Phase 3 clinical trial. The dosing of the first patient in a Phase 3 clinical trial of rivipansel in August 2015 triggered the remaining $20.0 million of the scheduled milestone payment under the Pfizer Agreement. During the years ended December 31, 2015 and 2014, the Company recorded revenue of $20.0 million and $15.0 million, respectively, pursuant to the Pfizer Agreement in the Company’s statement of operations. There was no revenue recognized under the Pfizer Agreement for the year ended December 31, 2016. In November 2014, the Company executed a worldwide license agreement with UniQuest Pty Limited (UniQuest) to secure the exclusive rights to two method-of-use patent applications relating to the use of E-selectin antagonists to reduce the risk of deadly infections in patients undergoing chemotherapy. Under the terms of the agreement, UniQuest received an upfront fee of $20,000 in 2014, and is eligible for a milestone payment of $2.0 million from the Company upon the Company’s receipt of marketing authorization from the FDA for a drug incorporating the licensed patents, as well as low single-digit royalties on any net sales for this indication. There were no expenses for this arrangement in 2016 and 2015.

10. Research and License Agreements

In February 2004, the Company entered into a research services agreement (the Research Agreement) with the University of Basel (the University) for biological evaluation of selectin antagonists. Certain patents covering the rivipansel compound are subject to provisions of the Research Agreement. Under the terms of the Research Agreement, the Company will owe a 10% payment to the University for all future milestone and royalty payments received from Pfizer with respect to rivipansel. A milestone license fee of $2.0 million was recorded in the year ended December 31, 2015 for the payment due to the University of Basel representing 10% of the $20.0 million non-refundable milestone payment that the Company received from Pfizer in August 2015. The accrued license and milestone fee of $2.0 million was paid in February 2016. There were no payments recorded for the year ended December 31, 2016.

In October 2011, the Company and Pfizer entered into a licensing agreement (the Pfizer Agreement) that provides Pfizer an exclusive worldwide license to rivipansel for vaso-occlusive crisis associated with sickle cell disease and for other diseases for which the drug candidate may be developed. The Company was responsible for completion of the Phase 2 trial, after which Pfizer will assume all further development and commercialization responsibilities. Upon execution of the Pfizer Agreement, the Company received an up-front payment of $22.5 million. The Pfizer Agreement also provides for potential milestone payments of up to $115.0 million upon the achievement of specified development milestones, including the dosing of the first patients in Phase 3 clinical trials for up to two indications and the first commercial sale of a licensed product in the United States and selected European countries for up to two indications; potential milestone payments of up to $70.0 million upon the achievement of specified regulatory milestones, including the acceptance of the Company’s filings for regulatory approval by regulatory authorities in the United States and Europe for up to two indications; and potential milestone payments of up to $135.0 million upon the achievement of specified levels of annual net sales of licensed products. Pfizer has the right to terminate the Pfizer Agreement by giving prior written notice.

The Company has determined that each potential future clinical, development and regulatory milestone is substantive. Although sales-based milestones are not considered substantive, they are still recognized upon achievement of the milestone (assuming all other revenue recognition criteria have been met) because there are no undelivered elements that would preclude revenue recognition at that time. The Company is also eligible to receive royalties on future sales contingent upon annual net sales thresholds. In addition, the Company and Pfizer have formed a joint steering committee that will oversee and coordinate activities as set forth in the research program. The $22.5 million up-front payment was recognized over a period of 1.5 years. In May 2014, the Company received a non-refundable payment of $15.0 million from Pfizer as a partial milestone payment owed to the Company upon the dosing of the first patient in the Phase 3 clinical trial. The dosing of the first patient in a Phase 3 clinical trial of rivipansel in August 2015 triggered the remaining $20.0 million of the scheduled milestone payment under the Pfizer Agreement. During the years ended December 31, 2015 and 2014, the Company recorded revenue of $20.0 million and $15.0 million, respectively, pursuant to the Pfizer Agreement in the Company’s statement of operations. There was no revenue recognized under the Pfizer Agreement for the year ended December 31, 2016.

In November 2014, the Company executed a worldwide license agreement with UniQuest Pty Limited (UniQuest) to secure the exclusive rights to two method-of-use patent applications relating to the use of E-selectin antagonists to reduce the risk of deadly infections in patients undergoing chemotherapy. Under the terms of the agreement, UniQuest received an upfront fee of $20,000 in 2014, and is eligible for a milestone payment of $2.0 million from the Company upon the Company’s receipt of marketing authorization from the FDA for a drug incorporating the licensed patents, as well as low single-digit royalties on any net sales for this indication. There were no expenses for this arrangement in 2016 and 2015.