CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue:
Revenue from termination of ADM collaboration				$ 38,885
Product revenue	265	70	1,876	457
Grant revenue	563	576	1,871	1,415
Research and development revenue			618
License fee and royalty revenue	27	28	139	162
Total revenue	855	674	4,504	40,919
Costs and expenses:
Cost of product revenue	459	316	2,212	808
Research and development	4,643	4,931	14,446	15,982
Selling, general, and administrative	2,995	3,170	9,728	11,006
Total costs and expenses	8,097	8,417	26,386	27,796
Income (loss) from operations	(7,242)	(7,743)	(21,882)	13,123
Other income (expense):
Interest income, net	10	27	43	102
Other expense, net	(19)	(29)	(40)	(78)
Total other income (expense), net	(9)	(2)	3	24
Net income (loss)	$ (7,251)	$ (7,745)	$ (21,879)	$ 13,147
Net income (loss) per share:
Basic (in dollars per share)	$ (0.21)	$ (0.23)	$ (0.64)	$ 0.38
Diluted (in dollars per share)	$ (0.21)	$ (0.23)	$ (0.64)	$ 0.38
Number of shares used in per share calculations:
Basic (in shares)	34,516,051	34,243,792	34,435,129	34,188,146
Diluted (in shares)	34,516,051	34,243,792	34,435,129	34,270,455