Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss	$ (9,502)	$ (9,062)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	793	2,115
Depreciation and amortization	35	169
Accretion on marketable securities	133	155
Changes in operating assets and liabilities:
Prepaid and other current assets	(110)	84
Other assets	181	158
Accounts payable, accrued liabilities and other liabilities	(1,735)	(4,424)
Net cash used in operating activities	(10,205)	(12,184)
Cash flows from investing activities:
Purchase of marketable securities	(25,969)	(38,321)
Sale of marketable securities	36,721	36,482
Proceeds from Sale of Furniture and Fixtures	0	2,500
Acquisition of property and equipment	0	(11)
Net cash provided by investing activities	10,752	650
Cash flows from financing activities:
Proceeds from exercise of options	0	342
Tax withholding payments on net share settlement equity awards	(130)	(403)
Net proceeds from issuance of common stock	1,038	288
Repayment of notes payable	0	(136)
Net cash provided by financing activities	908	91
Net increase (decrease) in cash, cash equivalents and restricted cash	1,455	(11,443)
Cash, cash equivalents and restricted cash at beginning of period	10,299	34,168
Cash and cash equivalents at end of period	11,754	22,725
Cash paid during the period for:
Interest	0	5
Gain (Loss) on Disposition of Assets	$ 0	$ (1,379)