Condensed Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net income (loss)	$ 212	$ (73)
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation and amortization	181	181
Deferred income taxes	(28)	(18)
Stock-based compensation expense	3	4
Interest accrued on treasury bills	(2)	0
Loss on investments	0	3
Change in:
Trade receivables	(455)	(18)
Inventories	47	(40)
Other current assets	(6)	(4)
Accounts payable	137	15
Accrued expenses	293	201
Income tax receivable/payable	84	(11)
Net cash from operating activities	466	240
Cash flows used in investing activities
Purchases of treasury bills	(8,999)	(6,748)
Proceeds from the maturity of treasury bills	9,000	0
Purchase of property and equipment	(14)	(12)
Net cash used in investing activities	(13)	(6,760)
Cash flows used in financing activities
Payments on financing lease	(3)	(3)
Proceeds from Paycheck Protection Program	0	645
Repayment of Paycheck Protection Program loan	0	(645)
Net cash used in financing activities	(3)	(3)
Net increase (decrease) in cash and cash equivalents	450	(6,523)
Cash and cash equivalents, beginning	1,090	8,785
Cash and cash equivalents, ending	1,540	2,262
Supplemental cash flow information
Cash paid for income taxes	1	11
Cash paid for interest	$ 1	$ 1