Note 7 - Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2022

Notes Tables

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

	Three Months Ended				Six Months Ended
	June 30,				June 30,
Share-based compensation related to:	2022		2021		2022		2021
Common stock grants	$	100	$	100	$	200	$	200
Stock option grants		60		53		113		105
Restricted Stock Unit Awards ("RSUs")		621		467		1,160		816
Total share-based compensation	$	781	$	620	$	1,473	$	1,121

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, 2021		98,671		$	33.53
Granted		9,876			77.28
Exercised		(1,295	)		16.32
Outstanding at June 30, 2022		107,252		$	37.77		5.81	$	4,483
Exercisable at June 30, 2022		97,376		$	33.76		5.39	$	4,461
Vested and expected to vest at June 30, 2022		107,252		$	37.77	$	5.81	$	4,483

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

Expected volatility	34.7%
Expected dividends	None
Risk-free interest rate	2.9%
Exercise price	$77.28
Expected term (in years)	6.2
Weighted-average grant date fair value	$30.37

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

	Restricted Stock Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2021		101,168		$	41.78
Awarded		51,981			74.94
Shares vested		(49,575	)		41.05
Shares forfeited		(21	)		74.75
Outstanding at June 30, 2022		103,553		$	53.59