Note 2 - Calculation of Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Numerator:
Net income	$ 3,797	$ 10,227
Denominator:
Denominator for basic earnings per share – weighted-average shares (in shares)	18,147	18,145
Effect of dilutive securities:
Equivalent shares issuable upon conversion of unvested restricted stock (in shares)	125	147
Equivalent shares issuable upon conversion of unvested employee stock options (in shares)		15
Denominator for diluted earnings per share – adjusted weighted-average shares and assumed conversions (in shares)	18,272	18,307
Basic and diluted income per share: (in dollars per share)	$ 0.21	$ 0.56