Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:
Contract and grant revenue	$ 5,846	$ 6,176	$ 4,223
License and royalty revenue	1,872	11,343	25,795
Total revenues	7,718	17,519	30,018
Operating expenses:
Research and development	14,558	17,340	17,975
Manufacturing and production	12,698	13,055	10,267
General and administrative	11,814	10,557	9,598
Total operating expenses	39,070	40,952	37,840
Loss from operations	(31,352)	(23,433)	(7,822)
Other income (expense):
Investment and other income, net	114	534	539
Net loss	$ (31,238)	$ (22,899)	$ (7,283)
Basic and diluted net loss per share	$ (0.36)	$ (0.27)	$ (0.10)
Weighted average shares used in computing basic and diluted net loss per share	86,840	85,966	72,031