CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues [Abstract]
Revenue from Contract with Customers		$ 231,201	$ 393,096	$ 336,597
Operating costs and expenses:
Cost of Goods and Services Sold	[1]	18,299	23,783	21,329
Cost of contract and other revenue		35,402	55,364	45,761
Research and development	[1]	158,339	149,135	129,844
Sales, general and administrative	[1]	103,911	110,940	95,145
Restructuring charges		2,217	0	0
Impairment of in-process research and development intangible asset		0	0	18,300
Change in contingent consideration liability		0	0	(6,845)
Gain from sale of intellectual property		0	(533)	0
Gain from settlement		0	0	(579)
Total operating costs and expenses		318,168	338,689	302,955
Operating income (loss)		(86,967)	54,407	33,642
Interest income (expense), net		32,621	1,384	1,740
Loss on Extinguishment of Debt		0	(1,082)	0
Interest expense		(16,282)	(13,720)	(12,745)
Interest and other income (expense), net		16,339	(13,418)	(11,005)
Income (loss) before income taxes		(70,628)	40,989	22,637
Provision for income taxes		87,329	63,851	15,817
Net income (loss)		$ (157,957)	$ (22,862)	$ 6,820
Net income (loss) per share:
Basic (in dollars per share)		$ (1.46)	$ (0.21)	$ 0.06
Diluted (in dollars per share)		$ (1.46)	$ (0.21)	$ 0.06
Weighted average shares used in per share calculations:
Basic (in shares)		108,450	110,198	110,162
Diluted (in shares)		108,450	110,198	113,140
Royalty [Member]
Revenues [Abstract]
Revenue from Contract with Customers		$ 130,452	$ 289,594	$ 264,614
Product Revenue [Member]
Revenues [Abstract]
Revenue from Contract with Customers		38,690	36,509	26,052
Contract and other Revenue [Member]
Revenues [Abstract]
Revenue from Contract with Customers		$ 62,059	$ 66,993	$ 45,931

[1] * Includes stock-based compensation: Cost of product revenue$8 $78 $56Research and development$12,582 $12,185 $9,165Sales, general and administrative$9,146 $15,140 $11,792