CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE (LOSS) INCOME - 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]
License and related revenue	$ 2,234	$ 0	$ 6,544	$ 0
Operating expenses:
Research and development	7,228	4,562	13,306	13,429
General and administrative	6,805	3,318	12,098	6,766
Change in fair value of contingent consideration	13,600	18,480	61,760	(35,220)
Total operating expenses	27,633	26,360	87,164	(15,025)
(Loss) Income from Operations	(25,399)	(26,360)	(80,620)	15,025
Other (expense) income , net	(43)	16	(46)	195
Net (Loss) Income and Comprehensive (Loss) Income Before Taxes	(25,442)	(26,344)	(80,666)	15,220
Provision for income taxes	0	0	(288)	0
Net (Loss) Income and Comprehensive (Loss) Income After Taxes	(25,442)	(26,344)	(80,954)	15,220
Net (loss) income attributable to common stockholders - basic	(25,442)	(26,491)	(80,954)	14,751
Net (loss) income attributable to common stockholders - diluted	$ (25,442)	$ (26,491)	$ (80,954)	$ 12,600
Net (loss) per common share - basic (in dollars per share)	$ (0.15)	$ (0.24)	$ (0.49)	$ 0.13
Weighted-average common shares outstanding - basic (in shares)	175,393	112,569	166,264	111,189
Net (loss) income per common share - diluted (in dollars per share)	$ (0.15)	$ (0.24)	$ (0.49)	$ 0.11
Weighted-average common shares outstanding for diluted (in shares)	175,393	112,569	166,264	111,203