Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended		27 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022		May 31, 2022	Jan. 01, 2023	Dec. 31, 2021	May 31, 2017
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross		13,000	29,000	108,000
Weighted Average Number of Shares Outstanding, Diluted, Adjustment	152,782	203,625	182,192	197,285
Letters of Credit Outstanding, Amount	$ 300		$ 300
Restricted Cash and Cash Equivalents, Current	$ 1,134	$ 231	$ 1,134	$ 231	$ 1,454	[1]
Finite-Lived Intangible Assets, Remaining Amortization Period	1 year 4 months 24 days		1 year 4 months 24 days
Finite-Lived Intangible Assets, Net	$ 342		$ 342		422	[1]			$ 501
Amortization of Intangible Assets	40	$ 35	80	$ 71	150
Accounts Receivable, Allowance for Credit Loss, Current	303		303		334	[1]
Retained Earnings (Accumulated Deficit)	(13,111)		(13,111)		$ (11,826)	[1]
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Accounts Receivable, Allowance for Credit Loss, Current								$ 30
Retained Earnings (Accumulated Deficit)								$ 30
Patents Received [Member]
Finite-Lived Intangible Assets, Net	88		88
Patents In Process [Member]
Finite-Lived Intangible Assets, Net	$ 110		$ 110
Service-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross	29,000	13,000	29,000	66,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 5.66
Market Condition Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross	0	0	0	21,000
Share-Based Payment Arrangement, Option [Member]
Share-Based Payment Arrangement, Expense	$ 55	$ 64	$ 123	$ 106
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 632		$ 632
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition			3 years 8 months 12 days
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	40,550	45,878	33,034	48,895
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expense	$ 38	$ 29	$ 69	$ 35
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 195		$ 195
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition			1 month 12 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period			18,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 9.37
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	20,178	19,114	14,148	20,057
Stock Incentive Plan 2017 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized										350,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized							325,000
Stock Incentive Plan 2017 [Member] | Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 9.37
Stock Incentive Plan 2017 [Member] | Restricted Stock Units (RSUs) [Member] | Non-employee Directors [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period		3,000		18,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period				2 years

[1] The balance sheet at December 31, 2022 has been derived from the audited financial statements at that date