Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash Flows From Operating Activities:
Net loss	$ (9,035)	$ (10,217)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	403	380
Share-based compensation	1,849	1,756
Warranty provision	(44)	45
Non-cash lease expense	53	49
Provision for doubtful accounts	(4)	8
Changes in assets and liabilities:
Accounts receivable	884	2,446
Inventories	(2,545)	(467)
Prepaid expenses and other current assets	53	168
Accounts payable	508	(417)
Operating lease liability	(52)	(41)
Customer deposits	3	(39)
Accrued liabilities and other	7,149	106
Warranty settlement	(6)	(63)
Deferred revenue	8	79
Net cash used in operating activities	(776)	(6,207)
Cash Flows From Investing Activities:
Purchase of short-term investments	(2,645)	(14,890)
Proceeds from maturities of short-term investments	10,000	20,000
Capital expenditures for property and equipment	(66)	(168)
Investment in long-term deposits	0	(2)
Proceeds from long-term deposits	31	0
Net cash provided by investing activities	7,134	4,838
Cash Flows From Financing Activities:
Proceeds from exercise of stock options	0	75
Net cash provided by financing activities	0	75
Net decrease in cash and cash equivalents	6,358	(1,294)
Cash and cash equivalents, beginning of period	5,330	4,937
Cash and cash equivalents, end of period	11,688	3,643
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Change in unrealized gain on short-term investments	(94)	(11)
Right-of-use asset and liability recorded during period	0	335
Patents and Trademarks [Member]
Cash Flows From Investing Activities:
Purchase of intangible assets	(176)	(102)
Intangibles Other than Patents and Trademarks [Member]
Cash Flows From Investing Activities:
Purchase of intangible assets	$ (10)	$ 0