Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss Stock-based compensation	$ (40)	$ (997)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation	135	97
Depreciation and amortization	166	251
Changes in assets and liabilities:
Accounts receivable	1,420	(52)
Contract assets	(1,537)	(179)
Inventories	(262)	(513)
Income tax receivable	0	716
Other current assets	119	109
Accounts payable	(25)	17
Accrued expenses	(467)	61
Contract liabilities	(2,781)	(930)
Net cash used in operating activities	(3,272)	(1,420)
Cash flows from investing activities:
Capital expenditures	(146)	(177)
Capitalized patent costs	0	(28)
Net proceeds from sale of assets	0	10
Net cash used in investing activities	(146)	(195)
Cash flows from financing activities:
Repayments of long-term debt	(19)	(1,766)
Proceeds from exercise of stock options	73	0
Net cash used in financing activities	54	(1,766)
Net decrease in cash and cash equivalents	(3,364)	(3,381)
Cash and cash equivalents at beginning of period	14,365	16,652
Cash and cash equivalents at end of period	11,001	13,271
Supplemental disclosure of cash flow information:
Income taxes paid	8	0
Interest paid	$ 6	$ 9