Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net loss	$ (1,884)	$ (2,779)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of patent portfolio	681	681
Change in fair value of investment	(680)
Change in fair value of warrant liabilities	(465)	1,326
Stock-based compensation	286	11
Depreciation expense	17
Realized loss on marketable securities	275	129
Unrealized loss (gain) on marketable securities	17	(137)
Changes in assets and liabilities:
Prepaid expenses and other assets	4	40
Accounts payable and accrued expenses	150	(20)
Accrued salaries and benefits	(103)	(364)
Deferred revenue		(618)
Accrued lease liabilities	(48)	(87)
Net cash used in operating activities	(1,750)	(1,816)
Cash flows from investing activities
Purchase of marketable securities	(10,047)	(6,510)
Sale of marketable securities	9,119	9,624
Purchase of investment at fair value	(25)	(675)
Purchase of property and equipment	(16)
Net cash (used in) provided by investing activities	(969)	2,439
Cash flows from financing activities
Cash from issuance common stock, net of offering cost	2,700
Repurchase of restricted stock units to pay for employee withholding taxes		(24)
Net cash provided by (used in) financing activities	2,700	(24)
Net (decrease) increase in cash and cash equivalents	(19)	599
Cash and cash equivalents, beginning of period	197	134
Cash and cash equivalents, end of period	178	733
Cash paid for interest and taxes