Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (3,706)	$ (3,716)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	56	124
Stock-based compensation expense	269	184
Loss on sale and disposal of property and equipment	2	1
Changes in operating assets and liabilities:
Accounts receivable	(111)	87
Prepaid expenses and other assets	14	(43)
Inventories	(38)	(6)
Accounts payable, accrued liabilities and other liabilities	13	261
Net cash used in operating activities	(3,501)	(3,108)
Cash flows from investing activities:
Purchase of property and equipment	(23)	(49)
Proceeds from sale of property and equipment		1
Net cash used in investing activities	(23)	(48)
Cash flows from financing activities:
Principal repayment of DECD loan	(48)	(47)
Proceeds from issuance of common stock from exercise of stock options	1	17
Net cash used in financing activities	(47)	(30)
Net decrease in cash and cash equivalents	(3,571)	(3,186)
Cash and cash equivalents, beginning of period	11,703	9,360
Cash and cash equivalents, end of period	8,132	6,174
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	9	11
Supplemental disclosure of noncash investing and financing activities:
Net increase in other assets/other liabilities for right of use assets	$ 1	$ 147