CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net loss	$ (1,398,000)	$ (970,000)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Inventories allowances	572,000	142,000
Deferred tax expense	184,000	101,000
Depreciation and amortization	1,033,000	1,005,000
Share-based compensation expense-stock options	215,000	94,000
Share-based compensation expense-restricted stock units	162,000	112,000
(Gain) loss on investment in securities	(310,000)	797,000
Changes in operating assets and liabilities:
Trade accounts receivable	(1,180,000)	(1,814,000)
Inventories	(6,008,000)	5,098,000
Prepaid expenses and other current assets	(63,000)	278,000
Other assets	24,000	75,000
ROU asset and lease liability	(15,000)	222,000
Accounts payable	2,401,000	(2,182,000)
Accrued compensation and related taxes	(113,000)	157,000
Accrued warranty expense	(125,000)	(337,000)
Deferred revenue	473,000	566,000
Accrued other expenses and other current liabilities	529,000	181,000
Net cash (used in) provided by operating activities	(3,619,000)	3,525,000
Investing activities
Purchases of property, plant, and equipment	(1,921,000)	(742,000)
Net cash used in investing activities	(1,921,000)	(742,000)
Financing activities
Proceeds from common stock issuance, net of costs	11,559,000	0
Cash dividends paid	(836,000)	(752,000)
Repurchase of common stock	0	(269,000)
Proceeds from the credit facility and notes payable	3,543,000	2,196,000
Repayment of the credit facility and notes payable	(1,465,000)	(2,253,000)
Net cash provided by (used in) financing activities	12,801,000	(1,078,000)
Net change in cash and cash equivalents	7,261,000	1,705,000
Cash and cash equivalents, beginning of period	6,826,000	4,676,000
Cash and cash equivalents, end of period	14,087,000	6,381,000
Supplemental disclosure
Cash paid for interest	37,000	18,000
Non-cash financing activity
Common stock issued under restricted stock units	$ 184,000	$ 128,000