Consolidated Statements of Comprehensive Loss (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Contract revenue	$ 6,098	$ 20,255	$ 17,712
Operating expenses:
Research and development	24,519	18,512	18,893
General and administrative	5,061	4,010	4,942
Total operating expenses	29,580	22,522	23,835
Loss from operations	(23,482)	(2,267)	(6,123)
Other income (expense):
Interest income (expense), net	(140)	43	108
Other income (expense), net	113	(8)	915
Net loss	(23,509)	(2,232)	(5,100)
Other comprehensive income (loss):
Net unrealized gains (losses) on marketable securities	5	2	(13)
Comprehensive loss	$ (23,504)	$ (2,230)	$ (5,113)
Basic and diluted net loss per common share	$ (11.22)	$ (1.15)	$ (3.02)
Weighted average common shares outstanding used to calculate basic and diluted net loss per common share	2,095,950	1,933,672	1,689,894