Note 6 - Share-based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

Schedule of Employee Service Share Based Compensation Allocation of Recognized Period Costs, By Award Type [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Share-based compensation related to:	2021		2020		2021		2020
Common stock grants	$	100	$	100	$	300	$	300
Stock option grants		52		59		157		173
Restricted Stock Unit Awards ("RSUs")		498		80		1,314		865
Total share-based compensation	$	650	$	239	$	1,771	$	1,338

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

	Shares Under Options			Weighted Average Exercise Price (per share)		Weighted Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		94,513		$	30.22
Granted		10,716			57.34
Exercised		(6,558	)		24.77
Outstanding at September 30, 2021		98,671		$	33.53		6.06	$	2,769
Exercisable at September 30, 2021		87,955		$	30.63		5.62	$	2,723
Vested and expected to vest at September 30, 2021		98,671		$	33.53		6.06	$	2,769

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

Expected volatility	33.7	%
Expected dividends	None
Risk-free interest rate	0.8	%
Exercise price	$57.34
Expected term (years)	6.2
Weighted-average grant date fair value	19.60

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

	Restricted Stock Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		93,187		$	35.03
Awarded		51,046			50.07
Shares vested		(38,892	)		32.88
Forfeitures		(270	)		49.46
Outstanding at September 30, 2021		105,071		$	41.00