Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Products, net	$ 111,344	$ 94,668	$ 211,792	$ 181,679
Type of Revenue [Extensible List]			us-gaap:ProductMember	us-gaap:ProductMember
Collaboration	26,019		$ 39,245
Total revenues	137,363	94,668	251,037	$ 181,679
Cost and expenses:
Cost of sales (excluding amortization of in-licensed rights)	13,341	15,919	25,963	27,982
Research and development	188,522	113,266	324,666	203,819
Selling, general and administrative	73,688	67,393	156,456	127,959
Acquired in-process research and development		173,240		173,240
Amortization of in-licensed rights	165	217	331	433
Total cost and expenses	275,716	370,035	507,416	533,433
Operating loss	(138,353)	(275,367)	(256,379)	(351,754)
Other income (loss):
Gain from sale of Priority Review Voucher			108,069
Other expense, net	(12,447)	(862)	(19,867)	(1,034)
Total other (loss) income	(12,447)	(862)	88,202	(1,034)
Loss before income tax expense	(150,800)	(276,229)	(168,177)	(352,788)
Income tax expense	20	174	135	258
Net loss	(150,820)	(276,403)	(168,312)	(353,046)
Other comprehensive (loss) income:
Unrealized (losses) gains on investments, net of tax	(618)	63	(44)	181
Total other comprehensive (loss) income	(618)	63	(44)	181
Comprehensive loss	$ (151,438)	$ (276,340)	$ (168,356)	$ (352,865)
Net loss per share - basic and diluted	$ (1.93)	$ (3.74)	$ (2.18)	$ (4.85)
Weighted average number of shares of common stock used in computing basic and diluted net loss per share	77,968	73,958	77,200	72,850