Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities
Net loss	$ (817)	$ (1,327)
Adjustments to reconcile net loss to net cash provided by operating activities:
Inventories allowances	117	112
Deferred tax expense (benefit)	101	(416)
Depreciation and amortization	1,005	896
Share-based compensation expense-stock options	94	110
Share-based compensation expense-restricted stock units	112	85
Loss (gain) on investment in securities	797	(186)
Changes in operating assets and liabilities:
Trade accounts receivable	(1,814)	2,850
Inventories	4,970	(3,096)
Prepaid expenses and other current assets	278	609
Other assets	75	(31)
Lease liability	222	0
Accounts payable	(2,182)	1,259
Accrued compensation and related taxes	157	(854)
Accrued warranty expense	(337)	(156)
Deferred revenue	566	924
Accrued other expenses and other current liabilities	181	220
Net cash provided by operating activities	3,525	999
Investing activities
Purchases of property, plant and equipment	(742)	(2,301)
Net cash used in investing activities	(742)	(2,301)
Financing activities
Proceeds from issuance of common stock	0	2
Cash dividends declared and paid	(752)	(765)
Repurchase of common stock	(269)	(803)
Proceeds from debt	2,196	425
Repayment of debt	(2,253)	0
Net cash used in financing activities	(1,078)	(1,141)
Net change in cash and cash equivalents	1,705	(2,443)
Cash and cash equivalents, beginning of period	4,676	11,268
Cash and cash equivalents, end of period	6,381	8,825
Supplemental disclosure
Cash paid for interest	$ 18	$ 2
Non-cash financing activity
Common stock issued under restricted stock units	128	168