CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
REVENUE:
Product Development and Licensing Agreements	$ 694	$ 604	$ 1,250	$ 1,057
Contracts and Grants	3,135	785	4,113	1,635
Total Revenue	3,829	1,389	5,363	2,692
OPERATING EXPENSE:
Research and Development	24,999	25,711	50,792	53,158
General and Administrative	6,534	7,790	13,763	17,097
Loss on Fair Value Remeasurement of Contingent Consideration	1,000		4,400
Amortization of Acquired Intangible Assets	224	254	448	507
Total Operating Expense	32,757	33,755	69,403	70,762
Operating Loss	(28,928)	(32,366)	(64,040)	(68,070)
Investment and Other Income, Net	362	414	1,213	1,445
Net Loss	$ (28,566)	$ (31,952)	$ (62,827)	$ (66,625)
Basic and Diluted Net Loss Per Common Share (in dollars per share)	$ (0.23)	$ (0.32)	$ (0.51)	$ (0.67)
Shares Used in Calculating Basic and Diluted Net Loss per Share (in shares)	125,202	98,817	123,932	98,753
COMPREHENSIVE LOSS:
Net Loss	$ (28,566)	$ (31,952)	$ (62,827)	$ (66,625)
Other Comprehensive Income:
Unrealized Gain on Marketable Securities	15	36	36	416
Comprehensive Loss	$ (28,551)	$ (31,916)	$ (62,791)	$ (66,209)