CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Net product sales	$ 17,523	$ 0	$ 29,871	$ 0
Collaboration revenue	1,266	1,032	2,601	2,281
Total revenues	18,789	1,032	32,472	2,281
Costs and expenses:
Cost of product sales (excluding amortization of intangible asset)	1,222	0	1,898	0
Research and development	36,644	34,373	67,613	67,613
Selling, general and administrative	33,883	24,431	65,154	45,749
Intangible asset amortization	1,971	0	3,942	0
Acquired in-process research and development costs	0	1,500	0	3,000
Change in fair value of contingent consideration	500	12,200	1,100	4,300
Total costs and expenses	74,220	72,504	139,707	120,662
Loss from operations	(55,431)	(71,472)	(107,235)	(118,381)
Other income (expense), net:
Interest income	186	880	494	1,968
Interest expense	(3,789)	0	(7,525)	0
Other, net	138	(157)	(260)	19,864
Total other (expense) income, net	(3,465)	723	(7,291)	21,832
Loss before income taxes	(58,896)	(70,749)	(114,526)	(96,549)
Income tax benefit	0	(17,425)	0	(17,425)
Net loss	$ (58,896)	$ (53,324)	$ (114,526)	$ (79,124)
Net loss per share, basic and diluted
Net loss per share, basic (in dollars per share)	$ (1.05)	$ (0.96)	$ (2.05)	$ (1.53)
Net loss per share, diluted (in dollars per share)	$ (1.05)	$ (0.96)	$ (2.05)	$ (1.53)
Weighted average number of shares used in the calculation of basic net loss per common share (in shares)	55,836	55,355	55,794	51,770
Weighted average number of shares used in the calculation of diluted net loss per common share (in shares)	55,836	55,355	55,794	51,770