Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net (loss) income	$ (16,168)	$ 22,228
Income from discontinued operations	0	(38,399)
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Equity-based compensation expense	2,453	1,963
Depreciation and amortization	225	372
(Gain) loss on disposal of assets	(1,429)	212
Income tax benefit	0	(11,526)
Deferred income taxes	0	(575)
Amortization/accretion on marketable securities	282	340
Changes in operating assets and liabilities:
Prepaid and other current assets	261	1,014
Other assets	291	148
Due to PCT	0	(1,682)
Accounts payable, accrued liabilities and other liabilities	(5,901)	5,667
Net cash used in operating activities - continuing operations	(19,986)	(20,238)
Net cash used in operating activities - discontinued operations	0	(638)
Net cash used in operating activities	(19,986)	(20,876)
Cash flows from investing activities:
Purchase of marketable securities	(69,690)	(60,158)
Sales of marketable securities	62,567	33,873
Proceeds from CFC device sale	2,550	0
Proceeds from PCT sale	0	74,607
Net cash sold in PCT sale	0	(6,727)
Acquisition of property and equipment	(134)	(135)
Net cash (used in) provided by investing activities - continuing operations	(4,707)	41,460
Net cash used in investing activities - discontinued operations	0	(189)
Net cash (used in) provided by investing activities	(4,707)	41,271
Cash flows from financing activities:
Proceeds from exercise of options	355	13
Tax withholding payments on net share settlement equity awards	(403)	(358)
Net proceeds from issuance of capital stock	1,031	5,702
Repayment of long-term debt	0	(5,651)
Proceeds from notes payable	0	401
Repayment of notes payable	(159)	(965)
Net cash provided by (used in) financing activities - continuing operations	824	(858)
Net cash used in financing activities - discontinued operations	0	(74)
Net cash provided by (used in) financing activities	824	(932)
Net (decrease) increase in cash, cash equivalents and restricted cash	(23,869)	19,463
Cash and cash equivalents at beginning of year - continuing operations	34,168	7,077
Cash and cash equivalents at beginning of year - discontinued operations	0	7,628
Cash, cash equivalents and restricted cash at end of year	10,299	34,168
Supplemental Disclosure of Cash Flow Information:
Interest	5	712
Taxes	$ 0	$ 0