CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net loss	$ (88,572)	$ (22,262)	$ (59,524)
Adjustments to reconcile to net cash used in operating activities:
Depreciation	322	328	190
Amortization of debt discount	2,542	1,604	1,472
Equity (income) loss	66,358	(671)	39,599
Other (income) loss, net	339	1,682	(217)
Stock-based compensation expense	1,138	2,394	1,611
Changes in assets and liabilities:
Accounts receivable, net	(3,560)	(1,521)	(923)
Accounts payable, accrued expenses, and other	628	(215)	43
Net cash used in operating activities	(20,805)	(18,661)	(17,749)
Cash Flows from Investing Activities:
Acquisitions of ownership interests in companies	(15,101)	(52,431)	(70,186)
Proceeds from sales of and distributions from companies	16,604	73,965	25,058
Advances and loans to companies	(22,867)	(27,967)	(15,208)
Repayment of advances and loans to companies	0	1,741	1,318
Increase in marketable securities	0	(21,194)	(29,755)
Decrease in marketable securities	11,237	46,315	33,640
Capital expenditures	0	(432)	(1,856)
Other, net	0	64	0
Net cash provided by (used in) investing activities	(10,127)	20,061	(56,989)
Cash Flows from Financing Activities:
Proceeds from credit facility	50,000	0	0
Issuance costs of credit facility	(5,696)	0	0
Repurchase of convertible senior debentures	(14,455)	0	0
Tax withholdings related to equity-based awards	(223)	(460)	0
Issuance of Company common stock, net	(1)	5	676
Repurchase of Company common stock	0	(5,389)	(4,997)
Net cash provided by (used in) financing activities	29,625	(5,844)	(4,321)
Net change in cash, cash equivalents and restricted cash equivalents	(1,307)	(4,444)	(79,059)
Cash, cash equivalents and restricted cash equivalents at beginning of period	28,394	32,838	111,897
Cash, cash equivalents and restricted cash equivalents at end of period	$ 27,087	$ 28,394	$ 32,838