CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current Assets:
Cash and cash equivalents	$ 108,694	$ 66,029
Cash held in escrow	0	6,434
Marketable securities	54,132	110,957
Restricted marketable securities	5	10
Prepaid expenses and other current assets	1,275	2,408
Total current assets	164,106	185,838
Property and equipment, net	160	193
Ownership interests in and advances to partner companies and funds (of which $14,560 and $20,972 are measured at fair value at September 30, 2013 and December 31, 2012, respectively)	143,048	148,639
Loan participations receivable	8,279	7,085
Available-for-sale securities	32	58
Long-term marketable securities	3,292	29,059
Other assets	2,826	3,272
Total Assets	321,743	374,144
Current Liabilities:
Convertible senior debentures—current	470	0
Accounts payable	374	610
Accrued compensation and benefits	3,552	4,050
Accrued expenses and other current liabilities	3,540	2,601
Total current liabilities	7,936	7,261
Other long-term liabilities	3,814	3,921
Convertible senior debentures—non-current	49,221	48,991
Total Liabilities	60,971	60,173
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; 21,519 and 20,968 shares issued and outstanding at September 30, 2013 and December 31, 2012, respectively	2,152	2,097
Additional paid-in capital	822,170	815,946
Accumulated deficit	(563,564)	(504,072)
Accumulated Other Comprehensive Income (Loss), Net of Tax	14	0
Total Equity	260,772	313,971
Total Liabilities and Equity	$ 321,743	$ 374,144