Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net income (loss)	$ (124)	$ 187
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation and amortization	360	320
Deferred income taxes	(43)	(2)
Stock-based compensation expense	6	11
Interest accrued on treasury bills	(4)	(182)
Other	4	0
Change in:
Trade receivables	79	(140)
Inventories	123	(77)
Other current assets	(11)	(4)
Accounts payable	68	13
Accrued expenses	(101)	26
Income taxes receivable	(26)	0
Net cash from operating activities	331	152
Cash flows from investing activitiesCash flows from (used in) investing activities
Purchases of treasury bills	(13,745)	(7,662)
Proceeds from the maturity of treasury bills	5,750	15,500
Purchase of intangible asset	0	(150)
Purchase of property and equipment	(25)	(107)
Net cash from (used in) investing activities	(8,020)	7,581
Cash flows used in financing activities
Payments on financing lease	(6)	(5)
Repayment of Paycheck Protection Program loan	(645)	0
Proceeds from Paycheck Protection Program	645	0
Repayment of Paycheck Protection Program loan	645	0
Net cash used in financing activities	(6)	(5)
Net increase (decrease) in cash and cash equivalents	(7,695)	7,728
Cash and cash equivalents, beginning	8,785	1,057
Cash and cash equivalents, ending	1,090	8,785
Supplemental cash flow information
Cash paid during the year for income taxes	20	1
Cash paid during the year for interest	$ 3	$ 2