Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Collaboration and licensing revenue	$ 15,158	$ 873	$ 15,426	$ 18,007
Operating expenses:
Research and development	4,466	8,485	9,002	29,552
General and administrative	2,225	5,084	8,367	15,485
Restructuring and lease exit		1,403	4,358	10,426
Operating Expenses, Total	6,691	14,972	21,727	55,463
Income (loss) from operations	8,467	(14,099)	(6,301)	(37,456)
Other income and expense:
Other (expense) income, net	(22)	98	(245)	103
Interest expense	(533)	(439)	(1,880)	(1,522)
Interest income	2	4	14	30
Other expense, net	(553)	(337)	(2,111)	(1,389)
Net income (loss)	$ 7,914	$ (14,436)	$ (8,412)	$ (38,845)
Basic net income (loss) per share
Net income (loss) per share	$ 0.14	$ (0.28)	$ (0.15)	$ (0.75)
Weighted average number of common shares outstanding	56,794	51,771	54,880	51,690
Dilutive net income (loss) per share
Net income (loss) per share	$ 0.14	$ (0.28)	$ (0.15)	$ (0.75)
Weighted average number of common shares and dilutive common share equivalents outstanding	57,016	51,771	54,880	51,690