CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net product sales	$ 12,349	$ 0
Collaboration revenue	1,335	1,249
Total revenues	13,684	1,249
Costs and expenses:
Cost of product sales (excluding amortization of intangible asset)	676	0
Research and development	30,969	33,240
Selling, general and administrative	31,272	21,318
Intangible asset amortization	1,971	0
Acquired in-process research and development costs	0	1,500
Change in fair value of contingent consideration	600	(7,900)
Total costs and expenses	65,488	48,158
Loss from operations	(51,804)	(46,909)
Interest income	308	1,088
Interest expense	(3,737)	0
Other (expense) income, net	(397)	20,021
Net loss	$ (55,630)	$ (25,800)
Net loss per share, basic and diluted
Net loss per share, basic and diluted (in dollars per share)	$ (1.00)	$ (0.54)
Weighted average number of shares used in the calculation of basic and diluted net loss per common share (in shares)	55,750	48,185