CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
REVENUE:
Product Development and Licensing Agreements	$ 377	$ 284	$ 1,053	$ 518
Contracts and Grants	649	817	2,636	1,591
Total Revenue	1,026	1,101	3,689	2,109
OPERATING EXPENSE:
Research and Development	24,656	26,185	76,271	77,355
General and Administrative	8,487	5,004	22,761	14,373
Amortization of Acquired Intangible Assets	254	254	760	760
Total Operating Expense	33,397	31,443	99,792	92,488
Operating Loss	(32,371)	(30,342)	(96,103)	(90,379)
Investment and Other Income, Net	391	2,260	1,590	4,121
Net Loss	$ (31,980)	$ (28,082)	$ (94,513)	$ (86,258)
Basic and Diluted Net Loss Per Common Share (Note 3) (in dollars per share)	$ (0.32)	$ (0.31)	$ (0.98)	$ (0.97)
Shares Used in Calculating Basic and Diluted Net Loss per Share (Note 3) (in shares)	98,568	89,404	96,518	89,346
COMPREHENSIVE LOSS:
Net Loss	$ (31,980)	$ (28,082)	$ (94,513)	$ (86,258)
Other Comprehensive (Loss) Income:
Foreign Currency Translation Adjustments		(3)	15	(4)
Unrealized Gain (Loss) on Marketable Securities	124	(121)	(45)	(40)
Comprehensive Loss	$ (31,856)	$ (28,206)	$ (94,543)	$ (86,302)