Note 4 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

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

	Number of stock award s (in thousands)			Weighted average grant date fair value
Unvested at December 31, 2014		642		$	6.60
Granted		63		$	28.10
Vested		(246	)	$	4.97
Forfeited		(129	)	$	5.38
Unvested at December 31, 2015		330		$	12.43
Granted		120		$	18.92
Vested		(169	)	$	5.28
Forfeited		(16	)	$	16.53
Unvested at December 31, 201 6		265		$	18.63
Granted		434		$	16.69
Vested		(96	)	$	12.78
Forfeited		(16	)	$	19.25
Unvested at December 31, 201 7		587		$	18.14

Share-based Compensation, Stock Options, Activity [Table Text Block]

	Number of options (in thousands)			Weighted average exercise price		Weighted average remaining contractual term (in years)		Aggregate intrinsic value (in thousands)
Outstanding at December 31, 2014		76			$14.73		0.5		$945
Options granted		-			-
Options exercised		(73	)		$14.79
Options forfeited		-			-
Outstanding at December 31, 2015		3			$12.79		0.4		$15
Options granted		-			-
Options exercised		(3	)		$12.79		-		-
Options forfeited		-			-
Outstanding at December 31, 201 6		-			-		-		-
Options granted		-			-
Options exercised		-			-
Options forfeited		-			-
Outs tanding at December 31, 2017		-			-		-		-
Exercisable at December 31, 201 7		-			-		-		-