Note 2 - Basic and Diluted Net Income per Share Computational Data (Details) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Net income		$ 3,260	$ 2,024
Basic shares outstanding:
Common stock (in shares)		40,805	40,418
Diluted shares outstanding:
Basic (in shares)		40,805	40,418
Dilutive securities (1) (in shares)	[1]	1,557	2,262
Total (in shares)		42,362	42,680

[1] For the three months ended March 31, 2015 and 2016, the Company's dilutive securities exclude options potentially exercisable in the future into 32,000 shares and 86,000 shares, respectively, because their inclusion would have been anti-dilutive.