CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 31,294	$ 20,751
Marketable securities	3,044	4,452
Trading securities	0	3,761
Prepaid expenses and other current assets	2,856	4,644
Total current assets	37,194	33,608
Property and equipment, net	1,435	1,513
Ownership interests in and advances to partner companies	132,277	134,691
Long-term restricted cash equivalents	0	6,336
Other assets	316	316
Total Assets	171,222	176,464
Current Liabilities:
Accounts payable	237	155
Accrued compensation and benefits	2,355	3,321
Accrued expenses and other current liabilities	2,889	1,851
Convertible senior debentures - current	40,829	40,485
Total current liabilities	46,310	45,812
Other long-term liabilities	3,341	3,535
Credit facility	45,736	45,321
Total Liabilities	95,387	94,668
Commitments and contingencies (Note 10)
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 shares issued at March 31, 2018 and December 31, 2017	2,157	2,157
Additional paid-in capital	812,796	812,536
Treasury stock, at cost; 1,012 and 999 shares at March 31, 2018 and December 31, 2017, respectively	(17,441)	(17,308)
Accumulated deficit	(721,646)	(715,476)
Accumulated other comprehensive loss	(31)	(113)
Total Equity	75,835	81,796
Total Liabilities and Equity	$ 171,222	$ 176,464