CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
REVENUES:
Total Revenues	$ 9,538	$ 12,743	$ 6,786
OPERATING EXPENSES:
Research and Development	66,449	96,171	102,726
General and Administrative	19,269	25,003	35,979
Goodwill Impairment	90,976
Intangible Asset Impairment	18,677	13,000
Gain on Fair Value Remeasurement of Contingent Consideration	(29,621)	(800)
Amortization of Acquired Intangible Assets	224	896	997
Total Operating Expenses	165,974	134,270	139,702
Operating Loss	(156,436)	(121,527)	(132,916)
Investment and Other Income, Net	4,487	4,214	4,386
Net Loss Before Income Tax Benefit	(151,949)	(117,313)	(128,530)
Income Tax Benefit	765	24,282
Net Loss	$ (151,184)	$ (93,031)	$ (128,530)
Basic and Diluted Net Loss Per Common Share (in dollars per share)	$ (14.48)	$ (10.86)	$ (18.99)
Shares Used in Calculating Basic and Diluted Net Loss Per Share (in shares)	10,442	8,570	6,769
COMPREHENSIVE LOSS:
Net Loss	$ (151,184)	$ (93,031)	$ (128,530)
Other Comprehensive Income (Loss):
Unrealized Gain (Loss) on Marketable Securities	19	23	234
Comprehensive Loss	(151,165)	(93,008)	(128,296)
Product Development and Licensing Agreements
REVENUES:
Total Revenues	3,341	3,153	2,174
Contracts and Grants
REVENUES:
Total Revenues	$ 6,197	$ 9,590	$ 4,612