STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (1,664)	$ (2,735)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	5	6
Amortization of right-of-use asset - operating	16
Amortization of premiums and discounts on marketable securities		2
Share-based compensation	50	97
Change in operating assets and liabilities:
Other current assets	5	287
Accounts payable	(2)	(14)
Accrued compensation and employee benefits	56	(518)
Accrued expenses and other liabilities	(32)	(196)
Net cash used in operating activities	(1,566)	(3,071)
Cash flows from investing activities:
Purchases of property and equipment		(1)
Proceeds from maturities of marketable securities		3,050
Net cash provided by investing activities		3,049
Cash flows from financing activities:
Proceeds from the issuance of common stock	3,081	3,532
Common stock offering costs	(117)	(116)
Net cash provided by financing activities	2,964	3,416
Net increase in cash and cash equivalents	1,398	3,394
Cash and cash equivalents, beginning of period	6,608	8,702
Cash and cash equivalents, end of period	8,006	12,096
Supplemental cash flow information:
Income tax refund received	82
Supplemental disclosure of noncash investing and financing transactions:
Vendor finance agreement	349	311
Common stock offering costs accrued but not yet paid	64	1
Leased assets obtained in exchange for operating lease liabilities, upon adoption	$ 60
Change in unrealized loss on marketable securities		$ 2