Note 8 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Share Price (in dollars per share)		$ 3.88
Proceeds from Stock Options Exercised		$ 296	$ 0
Deferred Compensation Plan for Directors [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense		$ 0	$ 0
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)		605,630	562,777
The 2014 Long-term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)		5,600,676
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)	1,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)		2,533,639
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 100
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		1 year 73 days
The 2014 Long-term Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)		10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		0
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount		$ 0
The 2014 Long-term Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		50.00%
The 2014 Long-term Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
The 2014 Long-term Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
The 2014 Long-term Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)		605,630	562,777
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value		$ 658	$ 554
The 2014 Long-term Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		2 years
The 2014 Long-term Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		4 years