CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 111,897	$ 139,318
Marketable securities	25,263	38,250
Prepaid expenses and other current assets	1,684	1,562
Total current assets	138,844	179,130
Property and equipment, net	123	138
Ownership interests in and advances to partner companies (of which $0 and $20,057 are measured at fair value at December 31, 2014 and 2013, respectively)	154,192	148,579
Loan participations receivable	3,855	8,135
Long-term marketable securities	19,365	6,088
Other assets	2,075	3,926
Total Assets	318,454	345,996
Current Liabilities:
Convertible senior debentures—current	0	470
Accounts payable	226	245
Accrued compensation and benefits	3,997	5,028
Accrued expenses and other current liabilities	2,334	2,431
Total current liabilities	6,557	8,174
Other long-term liabilities	3,507	3,683
Convertible senior debentures—non-current	50,563	49,478
Total Liabilities	60,627	61,335
Commitments and contingencies
Equity:
Preferred stock, $0.10 par value; 1,000 shares authorized	0	0
Common stock, $0.10 par value; 83,333 shares authorized; 21,573 and 21,553 shares issued at December 31, 2014 and 2013, respectively	2,157	2,155
Additional paid-in capital	819,757	822,103
Treasury stock, at cost; 921 and 4 shares at December 31, 2014 and 2013, respectively	(19,341)	0
Accumulated deficit	(544,746)	(539,597)
Total Equity	257,827	284,661
Total Liabilities and Equity	$ 318,454	$ 345,996