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Note 10 - Stockholders' Equity (Details Textual) - USD ($)			12 Months Ended
	Dec. 09, 2016	Nov. 30, 2006	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 12, 2007
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.01	$ 0.01
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)			417,000	432,930
Share-based Payment Arrangement, Expense			$ 255,000	$ 572,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)			0	0
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			$ 12,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)			1 year
Selling, General and Administrative Expenses [Member]
Share-based Payment Arrangement, Expense			$ 255,000	$ 572,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value			113,000	140,000
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			$ 25,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)			1 year
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value			$ 91,000	$ 309,000
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)	7 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)	10 years
The 2001 Non-qualified Stock Option Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)		300,000
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.01
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)			7,000	22,930	22,930
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)
The 2007 Share Incentive Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)						750,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)			345,000	345,000	365,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)
The 2016 Share Incentive Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	750,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)			65,000	65,000	20,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)