CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and Cash Equivalents	$ 40,288	$ 42,461
Marketable Securities	99,139	147,315
Accounts and Other Receivables	1,880	1,784
Prepaid and Other Current Assets	3,449	4,009
Total Current Assets	144,756	195,569
Property and Equipment, Net	10,372	13,192
Intangible Assets, Net	67,591	81,487
Other Assets	1,929	2,134
Goodwill	90,976	90,976
Total Assets	315,624	383,358
Current Liabilities:
Accounts Payable	1,715	1,740
Accrued Expenses	19,455	28,657
Current Portion of Long-Term Liabilities	6,566	4,826
Total Current Liabilities	27,736	35,223
Other Long-Term Liabilities	51,519	82,704
Total Liabilities	79,255	117,927
Commitments and Contingent Liabilities (Notes 13 and 15)
Stockholders' Equity:
Convertible Preferred Stock, $.01 Par Value; 3,000,000 Shares Authorized; No Shares Issued and Outstanding at December 31, 2017 and 2016
Common Stock, $.001 Par Value; 297,000,000 Shares Authorized; 138,520,404 and 120,516,654 Shares Issued and Outstanding at December 31, 2017 and 2016, respectively	139	121
Additional Paid-In Capital	1,046,183	982,255
Accumulated Other Comprehensive Income	2,564	2,541
Accumulated Deficit	(812,517)	(719,486)
Total Stockholders' Equity	236,369	265,431
Total Liabilities and Stockholders' Equity	$ 315,624	$ 383,358