Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss) including noncontrolling interests in operating subsidiaries	$ 21,684,000	$ (54,799,000)	$ (157,478,000)
Adjustments to reconcile net income (loss) including noncontrolling interests in operating subsidiaries to net cash provided by (used in) operating activities:
Gain on Conversion of Loan and Accrued Interest	(2,671,000)	0	0
Gain on exercise of Primary Warrant	(4,616,000)	0	0
Change in fair value of investment	(42,239,000)	0	0
Depreciation and amortization	22,243,000	34,355,000	53,289,000
Non-cash stock compensation	8,885,000	9,062,000	11,048,000
Impairment of Patent-Related Intangible Assets	2,248,000	42,340,000	74,731,000
Impairment of Goodwill	0	0	30,149,000
Other	(374,000)	(477,000)	(109,000)
Changes in assets and liabilities:
Increase (Decrease) in Restricted Cash	11,512,000	(787,000)	(10,725,000)
Accounts receivable	26,597,000	6,750,000	(13,332,000)
Prepaid expenses and other assets	(135,000)	1,593,000	(619,000)
Accounts payable and accrued expenses / costs	(6,349,000)	(3,006,000)	2,570,000
Royalties and contingent legal fees payable	(12,307,000)	(970,000)	527,000
Net cash provided by (used in) operating activities	24,478,000	34,061,000	(9,949,000)
Cash flows from investing activities:
Payments to Acquire Other Investments	(31,514,000)	0	0
Payments to Acquire Notes Receivable	(4,000,000)	(20,000,000)	0
Purchase of property and equipment	(2,000)	(4,000)	(8,000)
Purchase of available-for-sale investments	(448,388,000)	(62,633,000)	(23,296,000)
Sale of available-for-sale investments		43,232,000	82,115,000
Proceeds from Sale and Maturity of Marketable Securities		43,232,000	82,115,000
Patent acquisition costs	0	(1,225,000)	(19,504,000)
Net cash provided by (used in) investing activities	(16,114,000)	(40,630,000)	39,307,000
Cash flows from financing activities:
Payments of Dividends	0	0	(25,434,000)
Distributions to noncontrolling interests in operating subsidiary	0	(1,358,000)	(4,105,000)
Proceeds from the exercise of stock options	745,000	326,000	938,000
Repurchases of common stock	(45,000)	(82,000)	0
Net cash provided by (used in) financing activities	700,000	(1,114,000)	(28,601,000)
Increase in cash and cash equivalents	9,064,000	(7,683,000)	757,000
Cash and cash equivalents, beginning	127,540,000	135,223,000	134,466,000
Cash and cash equivalents, ending	136,604,000	127,540,000	135,223,000
Patent acquisition costs included in accrued expenses	$ 0	$ 0	$ 1,000,000