Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	May 31, 2022	Mar. 31, 2020	Mar. 31, 2023	Mar. 31, 2022	Dec. 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			0
Weighted Average Number of Shares Outstanding, Diluted, Adjustment			211,602	191,170
Letters of Credit Outstanding, Amount			$ 300
Restricted Cash and Cash Equivalents, Current			$ 1,366	$ 776	$ 1,454
Finite-Lived Intangible Assets, Remaining Amortization Period			1 year 7 months 6 days
Finite-Lived Intangible Assets, Net			$ 382		422		$ 501
Amortization of Intangible Assets			40	36	150
Accounts Receivable, Allowance for Credit Loss, Current					303		$ 334
Retained Earnings (Accumulated Deficit)			(12,477)		$ (11,826)
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			95
Patents In Process [Member]
Finite-Lived Intangible Assets, Net			$ 111
Service-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross			53,000
Market Condition Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross			21,000
Share-Based Payment Arrangement, Option [Member]
Share-Based Payment Arrangement, Expense			$ 68	43
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount			$ 694
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition			3 years 5 months 12 days
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			20,518
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expense			$ 31	$ 5
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount			$ 124
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition			12 months
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period			9,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			8,118
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	175,000	50,000
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				21,000