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Collaboration, License, Co-Promotion and Other Commercial Agreements - Japan (Details) $ in Thousands		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Aug. 01, 2019 USD ($)	Nov. 30, 2009 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($) payment	Dec. 31, 2016 USD ($)
Collaboration, License and Co-Promotion Agreements
Revenue			$ 89,432	$ 102,215	$ 169,375	$ 170,945
Astellas Pharma Inc. \| Japan
Collaboration, License and Co-Promotion Agreements
Up-front fee received		$ 30,000
Astellas Pharma Inc. \| Japan \| Additional development milestones
Collaboration, License and Co-Promotion Agreements
Number of milestone payments \| payment							3
Total milestone payments to be received							$ 45,000
Collaborative arrangements revenue
Collaboration, License and Co-Promotion Agreements
Revenue			89,423	77,322	163,868	143,474
Collaborative arrangements revenue \| Astellas Pharma Inc. \| Japan
Collaboration, License and Co-Promotion Agreements
Revenue				24,900		27,500
Collaborative arrangement, collaboration and license agreements \| Astellas Pharma Inc. \| Japan
Collaboration, License and Co-Promotion Agreements
Revenue			504		983
Revenue remaining performance obligation	$ 20,400
Non-refundable upfront payment	$ 10,000
Sale of active pharmaceutical ingredient
Collaboration, License and Co-Promotion Agreements
Revenue			9	24,893	5,507	27,471
Sale of active pharmaceutical ingredient \| Astellas Pharma Inc. \| Japan
Collaboration, License and Co-Promotion Agreements
Revenue				$ 24,893		$ 27,468
Revenue remaining performance obligation								$ 0
Royalty \| Astellas Pharma Inc. \| Japan
Collaboration, License and Co-Promotion Agreements
Revenue			$ 500		$ 900