CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:
Revenue from termination of ADM collaboration		$ 38,885
Product revenue	2,067	1,211
Grant revenue	2,490	1,971	918
Research and development revenue	618
License fee and royalty revenue	219	249	507
Total revenue	5,394	42,316	1,425
Costs and expenses:
Cost of product revenue	3,026	1,426
Research and development	19,127	23,177	24,445
Selling, general, and administrative	13,743	14,110	15,841
Total costs and expenses	35,896	38,713	40,286
Income (loss) from operations	(30,502)	3,603	(38,861)
Other income (net):
Interest income, net	51	124	156
Other expense, net	(55)	(97)	(80)
Total other income (expense), net	(4)	27	76
Net income (loss)	$ (30,506)	$ 3,630	$ (38,785)
Net income (loss) per share:
Basic (in dollars per share)	$ (0.88)	$ 0.11	$ (1.24)
Diluted (in dollars per share)	$ (0.88)	$ 0.11	$ (1.24)
Number of shares used in per share calculations:
Basic (in shares)	34,471,301	34,217,298	31,257,376
Diluted (in shares)	34,471,301	34,279,779	31,257,376