CONDENSED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues:
License fees and royalties	$ 474	$ 765
Operating expenses:
Research and development	5,211	7,999
General and administrative	3,994	4,751
Total operating expenses	9,205	12,750
Loss from operations	(8,731)	(11,985)
Unrealized gain on derivatives	224	25
Interest and other income	83	81
Interest and other expense	(16)	(18)
Net loss	$ (8,440)	$ (11,897)
Basic and diluted net loss per share (in dollars per share)	$ (0.06)	$ (0.09)
Shares used in computing basic and diluted net loss per share (in shares)	143,465,818	127,982,931