Consolidated Statements of Comprehensive Loss (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues:
Collaborative research	$ 627	$ 211	$ 799	$ 495
Subscription and license fees	49	3	154	79
Total revenues	676	214	953	574
Operating expenses:
Research and development, including stock-based compensation of $940, $1,022, $2,398 and $2,352, respectively	21,187	23,692	45,140	44,019
Increase in fair value of Symphony Icon, Inc. purchase liability	448	477	1,590	1,741
General and administrative, including stock-based compensation of $900, $847, $1,692 and $1,626, respectively	5,152	4,669	10,806	8,993
Total operating expenses	26,787	28,838	57,536	54,753
Loss from operations	(26,111)	(28,624)	(56,583)	(54,179)
Interest income	4	44	12	97
Interest expense	(455)	(496)	(912)	(1,002)
Other income (loss), net	534	(4)	620	30
Consolidated net loss	(26,028)	(29,080)	(56,863)	(55,054)
Consolidated net loss per common share, basic and diluted	$ (0.05)	$ (0.06)	$ (0.11)	$ (0.11)
Shares used in computing consolidated net loss per common share, basic and diluted	514,623	513,083	514,291	512,757
Unrealized gain (loss) on investments	(5)	(11)	3	8
Comprehensive loss	$ (26,033)	$ (29,091)	$ (56,860)	$ (55,046)