Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash Flows From Operating Activities:
Net loss	$ (17,617)	$ (24,449)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	762	478
Share-based compensation	3,225	5,356
Common shares issued for services	0	239
Product line exit expense	0	747
Gain on sale of assets	0	(27)
Warranty provision	210	10
Software impairment charge	0	170
Change in contingent liability	0	(23)
Non-cash lease expense	101	88
Provision for doubtful accounts	72	123
Changes in assets and liabilities:
Accounts receivable	957	(2,111)
Inventories	(2,410)	559
Prepaid expenses and other current assets	93	(109)
Accounts payable	(360)	546
Operating lease liability	(91)	(94)
Customer deposits	(43)	41
Accrued liabilities and other	611	(54)
Warranty settlement	(181)	38
Deferred revenue	68	249
Net cash used in operating activities	(14,603)	(18,223)
Cash Flows From Investing Activities:
Purchase of short-term investments	(30,466)	(55,014)
Proceeds from maturities of short-term investments	46,600	50,005
Capital expenditures for property and equipment	(256)	(995)
Proceeds from long-term deposits	(92)
Proceeds from long-term deposits		4
Net cash provided by (used in) investing activities	14,913	(6,937)
Cash Flows From Financing Activities:
Proceeds from exercise of warrants	0	12,047
Proceeds from exercise of stock options	83	1,678
Repayment of debt	0	(275)
Net cash provided by financing activities	83	13,450
Net (decrease) increase in cash and cash equivalents	393	(11,710)
Cash and cash equivalents, beginning of period	4,937	16,647
Cash and cash equivalents, end of period	5,330	4,937
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Change in unrealized gain on short-term investments	100	(21)
Right-of-use asset and liability recorded during period	234	0
Patents and Trademarks [Member]
Cash Flows From Investing Activities:
Investment in patents and trademarks	(173)	(187)
Intangibles Other than Patents and Trademarks [Member]
Cash Flows From Investing Activities:
Investment in patents and trademarks	$ (700)	$ (750)