Condensed Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net income (loss)	$ 229	$ (119)
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation and amortization	254	272
Deferred income taxes	(24)	(24)
Stock-based compensation expense	4	5
Interest accrued on treasury bills	(2)	(2)
Loss on investments	0	3
Loss on disposal of fixed assets	8	0
Change in:
Trade receivables	(368)	(3)
Inventories	95	36
Other current assets	(37)	(37)
Accounts payable	(22)	52
Accrued expenses	299	142
Income tax receivable/payable	111	(23)
Net cash from operating activities	547	302
Cash flows from (used in) investing activities
Purchases of treasury bills	(10,999)	(7,747)
Proceeds from the maturity of treasury bills	14,000	5,750
Purchase of property and equipment	(14)	(24)
Net cash from (used in) investing activities	2,987	(2,021)
Cash flows used in financing activities
Payments on financing lease	(4)	(4)
Proceeds from Paycheck Protection Program	0	645
Repayment of Paycheck Protection Program loan	0	(645)
Net cash used in financing activities	(4)	(4)
Net increase (decrease) in cash and cash equivalents	3,530	(1,723)
Cash and cash equivalents, beginning	1,090	8,785
Cash and cash equivalents, ending	4,620	7,062
Supplemental cash flow information
Cash paid for income taxes	1	20
Cash paid for interest	$ 1	$ 3