STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
REVENUE:
Product Development and Licensing Agreements	$ 1,442	$ 838	$ 160
Contracts and Grants	4,038	2,748	1,617
Product Royalties			2,334
Total Revenue	5,480	3,586	4,111
OPERATING EXPENSE:
Research and Development	100,171	104,381	67,401
Royalty			2,334
General and Administrative	33,837	20,622	14,805
Amortization of Acquired Intangible Assets	1,013	1,013	1,013
Total Operating Expense	135,021	126,016	85,553
Operating Loss	(129,541)	(122,430)	(81,442)
Investment and Other Income, Net	2,344	4,350	819
Interest Expense			(927)
Net Loss	$ (127,197)	$ (118,080)	$ (81,550)
Basic and Diluted Net Loss Per Common Share (in dollars per share)	$ (1.31)	$ (1.32)	$ (1.02)
Shares Used in Calculating Basic and Diluted Net Loss per Share (in shares)	97,051	89,399	79,777
COMPREHENSIVE LOSS:
Net Loss	$ (127,197)	$ (118,080)	$ (81,550)
Other Comprehensive (Loss) Income:
Foreign Currency Translation Adjustments	15	(5)	(3)
Unrealized Loss on Marketable Securities	(298)	(73)	(74)
Comprehensive Loss	$ (127,480)	$ (118,158)	$ (81,627)