CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
REVENUE:
Product Development and Licensing Agreements	$ 604	$ 334	$ 1,057	$ 676
Contracts and Grants	785	1,844	1,635	1,988
Total Revenue	1,389	2,178	2,692	2,664
OPERATING EXPENSE:
Research and Development	25,711	26,490	53,158	51,615
General and Administrative	7,790	8,184	17,097	14,273
Amortization of Acquired Intangible Assets	254	254	507	507
Total Operating Expense	33,755	34,928	70,762	66,395
Operating Loss	(32,366)	(32,750)	(68,070)	(63,731)
Investment and Other Income, Net	414	391	1,445	1,198
Net Loss	$ (31,952)	$ (32,359)	$ (66,625)	$ (62,533)
Basic and Diluted Net Loss Per Common Share (in dollars per share)	$ (0.32)	$ (0.33)	$ (0.67)	$ (0.65)
Shares Used in Calculating Basic and Diluted Net Loss per Share (in shares)	98,817	98,482	98,753	95,477
COMPREHENSIVE LOSS:
Net Loss	$ (31,952)	$ (32,359)	$ (66,625)	$ (62,533)
Other Comprehensive (Loss) Income:
Foreign Currency Translation Adjustments				15
Unrealized Gain (Loss) on Marketable Securities	36	(180)	416	(169)
Comprehensive Loss	$ (31,916)	$ (32,539)	$ (66,209)	$ (62,687)