Licenses	12 Months Ended
Dec. 31, 2018
Research and Development [Abstract]
Licenses	Licenses The Company acquired rights to develop and commercialize its product candidates through licenses granted by various parties. The following summarizes the Company's material rights and obligations under those licenses: Nationwide Children's Hospital — As discussed in "— Note 3. Acquisitions," Celenex has an exclusive license agreement with Nationwide Children’s Hospital (“NCH”). Under this license agreement, NCH is eligible to receive development and sales based milestones of up to $7.8 million for each product. University of Pennsylvania — For discussion of the royalties and milestone payments potentially due to University of Pennsylvania (“Penn”), see "— Note 16. Collaborative Agreements." GSK — For discussion of the royalties and milestone payments potentially due to GSK, see "— Note 16. Collaborative Agreements." Mt. Sinai School of Medicine of New York University ("MSSM") — The Company acquired exclusive worldwide patent rights to develop and commercialize Galafold^® and other pharmacological chaperones for the prevention or treatment of human diseases or clinical conditions by increasing the activity of wild-type and mutant enzymes pursuant to a license agreement with Mt. Sinai School of Medicine ("MSSM") of New York University. Under this agreement, to date, the Company has paid no upfront or annual license fees and there are no milestone or future payments other than royalties on net sales. This agreement expires upon expiration of the last of the licensed patent rights, which will be in 2019, subject to any patent term extension that may be granted, or 2024 if the Company develops a product for combination therapy (pharmacological chaperone plus/ERT) and a patent issues from the pending application covering the combination therapy, subject to any patent term extension that may be granted. Under its license agreements, if the Company owes royalties on net sales for one of its products to more than one of the above licensors, then the Company has the right to reduce the royalties owed to one licensor for royalties paid to another. The amount of royalties to be offset is generally limited in each license and can vary under each agreement. For the year ended December 31, 2018, under the MSSM and GSK license and collaboration agreements, we paid $7.6 million in royalties. The Company's rights with respect to these agreements to develop and commercialize Galafold^® may terminate, in whole or in part, if the Company fails to meet certain development or commercialization requirements or if the Company does not meet its obligations to make royalty payments.

Licenses

The Company acquired rights to develop and commercialize its product candidates through licenses granted by various parties. The following summarizes the Company's material rights and obligations under those licenses:

Nationwide Children's Hospital — As discussed in "— Note 3. Acquisitions," Celenex has an exclusive license agreement with Nationwide Children’s Hospital (“NCH”). Under this license agreement, NCH is eligible to receive development and sales based milestones of up to $7.8 million for each product.

University of Pennsylvania — For discussion of the royalties and milestone payments potentially due to University of Pennsylvania (“Penn”), see "— Note 16. Collaborative Agreements."

GSK — For discussion of the royalties and milestone payments potentially due to GSK, see "— Note 16. Collaborative Agreements."

Mt. Sinai School of Medicine of New York University ("MSSM") — The Company acquired exclusive worldwide patent rights to develop and commercialize Galafold^® and other pharmacological chaperones for the prevention or treatment of human diseases or clinical conditions by increasing the activity of wild-type and mutant enzymes pursuant to a license agreement with Mt. Sinai School of Medicine ("MSSM") of New York University. Under this agreement, to date, the Company has paid no upfront or annual license fees and there are no milestone or future payments other than royalties on net sales. This agreement expires upon expiration of the last of the licensed patent rights, which will be in 2019, subject to any patent term extension that may be granted, or 2024 if the Company develops a product for combination therapy (pharmacological chaperone plus/ERT) and a patent issues from the pending application covering the combination therapy, subject to any patent term extension that may be granted.

Under its license agreements, if the Company owes royalties on net sales for one of its products to more than one of the above licensors, then the Company has the right to reduce the royalties owed to one licensor for royalties paid to another. The amount of royalties to be offset is generally limited in each license and can vary under each agreement.

For the year ended December 31, 2018, under the MSSM and GSK license and collaboration agreements, we paid $7.6 million in royalties.

The Company's rights with respect to these agreements to develop and commercialize Galafold^® may terminate, in whole or in part, if the Company fails to meet certain development or commercialization requirements or if the Company does not meet its obligations to make royalty payments.