Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net loss	$ (49)	$ (4,086)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of patent portfolio	531	$ 2,422
Change in fair value of warrant liabilities	(1,542)
Stock-based compensation	131	$ 87
Realized loss on marketable securities	66	53
Unrealized gain on marketable securities	(12)	(57)
Changes in assets and liabilities:
Prepaid expenses and other assets	38	36
Accounts payable and accrued expenses	(29)	(54)
Accrued salaries and benefits	(534)	$ 305
Deferred revenue	(71)
Accrued lease liabilities	(45)	$ (43)
Net cash used in operating activities	(1,516)	(1,337)
Cash flows from investing activities
Purchase of marketable securities	(3,456)	$ (3,769)
Purchase of property and equipment	(2)
Sale of marketable securities	5,326	$ 4,412
Net provided by investing activities	1,868	643
Net increase (decrease) in cash and cash equivalents	352	(694)
Cash and cash equivalents, beginning of period	142	805
Cash and cash equivalents, end of period	$ 494	$ 111
Cash paid for interest and taxes