Condensed Consolidated Statements of Operations and Comprehensive (Loss) Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Revenues	$ 378.2	$ 288.9	$ 688.8	$ 525.5
Operating expenses:
Cost of revenues	4.8	3.1	9.4	6.0
Research and development	135.9	74.8	238.1	148.0
Acquired in-process research and development	0.0	5.0	0.0	5.0
Selling, general and administrative	182.8	143.2	383.5	272.2
Total operating expenses	323.5	226.1	631.0	431.2
Operating income	54.7	62.8	57.8	94.3
Other (expense) income:
Interest expense	(2.2)	(6.2)	(4.8)	(12.6)
Unrealized (loss) gain on equity securities	(7.4)	0.0	12.5	0.7
Loss on extinguishment of convertible senior notes	(70.0)	0.0	(70.0)	0.0
Investment income and other, net	1.6	0.9	2.6	2.3
Total other expense, net	(78.0)	(5.3)	(59.7)	(9.6)
(Loss) income before (benefit from) provision for income taxes	(23.3)	57.5	(1.9)	84.7
(Benefit from) provision for income taxes	(6.4)	15.2	1.1	10.3
Net (loss) income	(16.9)	42.3	(3.0)	74.4
Unrealized loss on debt securities available-for-sale, net of tax	(2.9)	(0.3)	(10.5)	(1.1)
Comprehensive (loss) income	$ (19.8)	$ 42.0	$ (13.5)	$ 73.3
(Loss) earnings per share:
Basic (in USD per share)	$ (0.18)	$ 0.45	$ (0.03)	$ 0.79
Diluted (in USD per share)	$ (0.18)	$ 0.43	$ (0.03)	$ 0.76
Weighted-average shares outstanding:
Basic (in shares)	95.6	94.6	95.4	94.4
Diluted (in shares)	95.6	97.7	95.4	98.0
Net product sales
Revenues:
Revenues	$ 352.0	$ 266.8	$ 657.0	$ 497.8
Collaboration revenues
Revenues:
Revenues	$ 26.2	$ 22.1	$ 31.8	$ 27.7