License, Collaboration and Other Significant Agreements - Revenues Recognized From License, Collaboration and Other Significant Agreements (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
License, Collaboration and Other Revenue:
Total revenues	$ 59,988,000	$ 91,977,000	$ 238,608,000	$ 265,446,000
Mitsubishi Tanabe Pharma Corporation
License, Collaboration and Other Revenue:
Total revenues	400,000	0
License, collaboration and other revenue
License, Collaboration and Other Revenue:
Total revenues	25,596,000	61,973,000	144,311,000	183,242,000
License, collaboration and other revenue | Mitsubishi Tanabe Pharma Corporation
License, Collaboration and Other Revenue:
Total revenues	373,000	0	15,373,000	10,000,000
License, collaboration and other revenue | Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement
License, Collaboration and Other Revenue:
Total revenues	16,256,000	39,718,000	80,721,000	103,461,000
License, collaboration and other revenue | Otsuka Pharmaceutical Company. Ltd. | Otsuka International Agreement
License, Collaboration and Other Revenue:
Total revenues	7,243,000	20,220,000	39,445,000	64,643,000
License, collaboration and other revenue | Total Proportional Performance Revenue
License, Collaboration and Other Revenue:
Total revenues	23,872,000	59,938,000	135,539,000	178,104,000
License, collaboration and other revenue | JT and Torii
License, Collaboration and Other Revenue:
Total revenues	1,183,000	1,549,000	4,049,000	4,266,000
License, collaboration and other revenue | MTPC Other Revenue | Mitsubishi Tanabe Pharma Corporation
License, Collaboration and Other Revenue:
Total revenues	$ 541,000	$ 486,000	$ 4,723,000	$ 872,000