Inventory - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Inventory amounts written down	$ 8,500	$ 2,900	$ 18,608	$ 5,968
Keryx Biopharmaceuticals, Inc.
Business Acquisition [Line Items]
Inventory step-up charges	$ 1,400	$ 8,100	$ 7,400	$ 10,900