Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Product sales	$ 9,966	$ 3,878	$ 14,247	$ 7,067
Operating expenses:
Cost of goods sold	493		493
Research and development	13,080	9,347	25,472	17,457
Selling, general and administrative	14,570	7,569	23,794	14,266
Change in contingent consideration liability	916	1,300	1,816	2,100
Total operating expenses	29,059	18,216	51,575	33,823
Operating loss	(19,093)	(14,338)	(37,328)	(26,756)
Other (expense) income:
Interest (expense) income and other income, net	(607)	(930)	(1,107)	(1,936)
Total other (expense) income	(607)	(930)	(1,107)	(1,936)
Loss before income tax benefit	(19,700)	(15,268)	(38,435)	(28,692)
Income tax benefit		96		96
Net loss	$ (19,700)	$ (15,172)	$ (38,435)	$ (28,596)
Net loss per share - basic and diluted (in dollars per share)	$ (0.23)	$ (0.20)	$ (0.45)	$ (0.39)
Weighted-average shares - basic and diluted (in shares)	85,000	74,017	84,772	73,271
Product [Member]
Revenues:
Product sales	$ 270		$ 270
Royalty [Member]
Revenues:
Product sales	3,593	3,530	7,754	6,588
License and Other [Member]
Revenues:
Product sales	$ 6,103	$ 348	$ 6,223	$ 479