Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Collaboration and licensing revenue	$ 1,203	$ 134
Operating expenses:
Research and development	5,972	2,695
General and administrative	2,463	3,255
Restructuring and lease exit		4,333
Operating Expenses, Total	8,435	10,283
Loss from operations	(7,232)	(10,149)
Other income and expense:
Other expense, net	(9)	(14)
Interest expense	(386)	(716)
Interest income	17	5
Other expense, net	(378)	(725)
Loss before provision for income taxes	(7,610)	(10,874)
Provision for income taxes	(100)
Net loss	$ (7,710)	$ (10,874)
Net loss per share ─ basic and diluted	$ (0.13)	$ (0.21)
Weighted average number of common shares outstanding	58,166	52,638