Note 5 - Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

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:	2018		2017		2018		2017
Common stock grants	$	205	$	205	$	305	$	305
Stock option grants		118		117		134		126
Restricted Stock Unit awards ("RSUs")		130		105		252		205
Total share-based compensation	$	453	$	427	$	691	$	636

Share-based Compensation, Stock Options, 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, 2017		202,379		$	18.23
Granted		10,344			31.20
Exercised		(65,030	)		30.67
Outstanding at June 30, 2018		147,693		$	20.64		4.58	$	1,512
Exercisable at June 30, 2018		135,193		$	19.95		4.62	$	1,477
Vested and expected to vest at June 30, 2018		147,693		$	20.64		4.58	$	1,512

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

Expected volatility		27.7	%
Expected dividends		None
Risk-free interest rate		2.70	%
Exercise price	$	31.20
Expected term (in years)		6.0
Weighted-average grant date fair value	$	10.15

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]

	Restricted Stock Units			Weighted Average Award Date Fair Value
Outstanding at December 31, 2017		57,395		$	21.03
Awarded		22,399			29.30
Shares vested		(16,050	)		23.55
Outstanding at June 30, 2018		63,744		$	22.72