Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues (Note 1(b))	$ 0	$ 0
Operating costs and expenses:
Selling, general and administrative	14,794	15,952
Research and development	15,993	21,886
Total operating costs and expenses	30,787	37,838
Loss from continuing operations before other expense and income taxes	(30,787)	(37,838)
Other (expense) income:
Interest income, net	704	1,061
Other expense, net	(10,534)	(11,285)
Total other expense	(9,830)	(10,224)
Loss from continuing operations before income taxes	(40,617)	(48,062)
Benefit for income taxes from continuing operations	0	8,216
Loss from continuing operations	(40,617)	(39,846)
Income from discontinued operations, net of income taxes (Note 10)	45	20,587
Net loss	$ (40,572)	$ (19,259)
Basic and diluted loss per share:
Loss per common share from continuing operations ($ per share)	$ (0.36)	$ (0.36)
Income per common share from discontinued operations ($ per share)	0	0.19
Net loss per common share ($ per share)	$ (0.36)	$ (0.18)
Weighted average shares outstanding:
Basic (shares)	111,780,571	109,552,602
Diluted (shares)	111,780,571	109,552,602