Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Product, net	$ 380,833	$ 301,034	$ 154,584
Type of Revenue [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Total revenues	$ 380,833	$ 301,034	$ 154,584
Cost and expenses:
Cost of sales (excluding amortization of in-licensed rights)	56,586	34,193	7,353
Research and development	560,909	401,843	166,707
Selling, general and administrative	284,812	207,761	122,682
Acquired in-process research and development	173,240
Settlement and license charges	10,000		28,427
Amortization of in-licensed rights	849	865	1,053
Total cost and expenses	1,086,396	644,662	326,222
Operating loss	(705,563)	(343,628)	(171,638)
Other (loss) income:
Other expense, net	(8,317)	(18,982)	(1,990)
Gain from sale of Priority Review Voucher			125,000
Total other (loss) income	(8,317)	(18,982)	123,010
Loss before income tax expense (benefit)	(713,880)	(362,610)	(48,628)
Income tax expense (benefit)	1,195	(692)	2,060
Net loss	(715,075)	(361,918)	(50,688)
Other comprehensive loss:
Unrealized gains (losses) on investments	149	280	(259)
Total other comprehensive income (loss)	149	280	(259)
Comprehensive loss	$ (714,926)	$ (361,638)	$ (50,947)
Net loss per share — basic and diluted	$ (9.71)	$ (5.46)	$ (0.86)
Weighted average number of shares of common stock used in computing basic and diluted net loss per share	73,615,000	66,250,000	58,818,000