Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Operating Activities
Net loss	$ (1,458)	$ (1,354)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	154	182
Amortization	30	50
Non-cash interest income on held-to-maturity securities	(203)	0
Provision for credit losses, net of recoveries	0	43
Stock-based compensation, net of forfeitures	187	46
Changes in operating assets and liabilities:
Accounts receivable	966	(3,245)
Inventories	(135)	(58)
Prepaid expenses, other current assets and other non-current assets	114	205
Accounts payable	383	812
Accrued liabilities and other non-current liabilities	(21)	(2)
Net cash provided by (used in) operating activities	17	(3,321)
Investing Activities
Purchases of equipment and patents	(103)	(138)
Purchases of debt securities	(9,685)	0
Maturities of debt securities	1,500	0
Net cash used in investing activities	(8,288)	(138)
Financing Activities
Proceeds from exercise of stock options	42	0
Taxes paid on behalf of equity award participants	0	(17)
Net cash provided by (used in) financing activities	42	(17)
Effect of exchange rate fluctuations on cash	35	(280)
Net decrease in cash, cash equivalents and restricted cash	(8,194)	(3,756)
Cash, cash equivalents, and restricted cash and cash equivalents at beginning of period (Note 2)	23,328	37,054
Cash, cash equivalents and restricted cash at end of period (Note 2)	$ 15,134	$ 33,298