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Note 10 - Stock-based Compensation Expense (Details Textual) - USD ($)				3 Months Ended	12 Months Ended
	Aug. 03, 2020	May 04, 2020	Jan. 04, 2017	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2017	Jun. 30, 2021	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					258,000
Share-based Payment Arrangement, Expense					$ 420,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)					$ 1.10	$ 0.78
Options Issued During Period, Cashless Stock Options Exercised (in shares)					5,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)					22,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value						$ 0
Proceeds from Stock Options Exercised					$ 5,000	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Using Cash (in shares)					2,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)					1,000,000
Stock Repurchased During Period, Shares (in shares)					0	0
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares)					72,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					165,000	144,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					168,000	134,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number, Ending Balance (in shares)					10,000	13,000			3,000
Restricted Stock Units (RSUs) [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					130,000
Share-based Payment Arrangement, Expense					$ 331,000
Restricted Stock Units (RSUs) [Member] \| Non Employee Directors and Corporate Secretary [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					2,000
Share-based Payment Arrangement, Expense					$ 12,000
Restricted Stock Units (RSUs) [Member] \| Non Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					121,000
Share-based Payment Arrangement, Expense					$ 75,000
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					5,000
Share-based Payment Arrangement, Expense					$ 2,000	$ 17,000
Share-based Payment Arrangement, Expense, Tax Benefit						0
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)					4 years
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount					$ 10,000
Incentive Compensation Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)								2,580,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)					1,453,000
Incentive Compensation Plan [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					621,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					123,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Vested And Expected To Vest, Outstanding, Number (in shares)					487,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number, Ending Balance (in shares)					10,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total					$ 20,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)					4 years
Incentive Compensation Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					20,000
Incentive Compensation Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					220,000
Incentive Compensation Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Non Employee Directors and Corporate Secretary [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					53,000
Share-based Payment Arrangement, Expense					$ 12,000
Share-based Payment Arrangement, Expense, Tax Benefit					$ 3,000
Incentive Compensation Plan [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 (in shares)					328,000
Share-based Payment Arrangement, Expense					$ 75,000
Executive Equity Awards [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expense					$ 331,000	$ 195,000
Executive Equity Awards [Member] \| Restricted Stock Units (RSUs) [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	10,000	50,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)					120,000	90,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Day)	30 days
Stock Issued During Period, Shares, Issued for Services (in shares)					120,000	100,000
Executive Equity Awards [Member] \| Restricted Stock Units (RSUs) [Member] \| Senior Vice President [Member]
Stock Issued During Period, Shares, Issued for Services (in shares)						10,000
Performance Share Award Agreement [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			161,766
Share-based Payment Arrangement, Expense							$ 108,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total				$ 421,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)				129,000