Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Product sales	$ 5,613	$ 5,317	$ 19,860	$ 12,384
Operating expenses:
Cost of goods sold	1,317		1,810
Research and development	11,439	8,090	36,911	25,547
Selling, general and administrative	11,473	7,075	35,267	21,341
Intangible impairment charge		23,200		23,200
Change in contingent consideration liability	(500)	(8,000)	1,316	(5,900)
Total operating expenses	23,729	30,365	75,304	64,188
Operating loss	(18,116)	(25,048)	(55,444)	(51,804)
Other (expense) income:
Interest (expense) income and other income, net	(726)	(762)	(1,833)	(2,698)
Total other (expense) income	(726)	(762)	(1,833)	(2,698)
Loss before income tax benefit	(18,842)	(25,810)	(57,277)	(54,502)
Income tax benefit		1,453		1,549
Net loss	$ (18,842)	$ (24,357)	$ (57,277)	$ (52,953)
Net loss per share - basic and diluted (in dollars per share)	$ (0.22)	$ (0.30)	$ (0.67)	$ (0.70)
Weighted-average shares - basic and diluted (in shares)	86,421	80,325	85,328	75,648
Product [Member]
Revenues:
Product sales	$ 570		$ 840
Royalty [Member]
Revenues:
Product sales	4,912	5,169	12,666	11,757
License and Other [Member]
Revenues:
Product sales	$ 131	$ 148	$ 6,354	$ 627