Note 9 - Stock-based Compensation Expense (Tables)

6 Months Ended

Jun. 30, 2021

Notes Tables

Share-based Payment Arrangement, Option, Activity [Table Text Block]

2001 Non-Qualified Stock Option Plan
	Beginning		Granted		Exercised		Canceled			Ending
	Balance		During		During		During			Balance
	Outstanding		Period		Period		Period			Outstanding		Exercisable
Number of shares		7,000		-		-		(7,000	)		-		-
Weighted average exercise price per share	$	7.90		-		-	$	7.90			-		-

2007 Share Incentive Plan
	Beginning		Granted		Exercised		Canceled		Ending
	Balance		During		During		During		Balance
	Outstanding		Period		Period		Period		Outstanding		Exercisable
Number of shares		345,000		-		-		-		345,000		325,000
Weighted average exercise price per share	$	12.33		-		-		-	$	12.33	$	12.46

2016 Share Incentive Plan
	Beginning		Granted		Exercised		Canceled		Ending
	Balance		During		During		During		Balance
	Outstanding		Period		Period		Period		Outstanding		Exercisable
Number of shares		65,000		150,000		-		-		215,000		65,000
Weighted average exercise price per share	$	5.94	$	4.26		-		-	$	4.76	$	5.94

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

Stock Price	$	4.26
Exercise Price	$	4.26
Dividend yield		0	%
Expected volatility		67	%
Risk-Free interest rate		1.35	%
Expected life (in years)		6.00

Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]

			Options Outstanding								Options Exercisable
					Weighted		Weighted						Weighted
					Average		Average						Average
Exercise			Number		Remaining		Exercise		Intrinsic		Number		Exercise		Intrinsic
Price Range			Outstanding		Contractual		Price		Value		Exercisable		Price		Value
$4.00	-	7.00		195,000		9.8	$	4.43	$	36,000		45,000	$	5.00	$	0
$7.01	-	10.00		20,000		7.0	$	8.07	$	0		20,000	$	8.07	$	0
$10.01	-	12.00		220,000		3.7	$	10.81	$	0		200,000	$	10.87	$	0
$12.01	-	15.00		125,000		1.0	$	15.00	$	0		125,000	$	15.00	$	0

Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

				Weighted
	Shares of			Average Grant
	Restricted			Date Fair
	Stock			Value
Unvested outstanding at December 31, 2020		0		$	0
Granted		42,800		$	4.65
Vested		0		$	0
Forfeited/Cancelled		(4,746	)	$	4.65
Unvested outstanding at June 30, 2021		38,054		$	4.65

				Weighted
	Shares of			Average Grant
	Restricted			Date Fair
	Stock Units			Value
Unvested outstanding at December 31, 2020		8,750		$	5.00
Granted		2,333		$	5.36
Vested		(5,583	)	$	5.32
Forfeited/Cancelled		(-	)	$	- -
Unvested outstanding at June 30, 2021		5,500		$	4.83