Note 7 - Stock-based Compensation - Stock-based Compensation Expense and Related Income Tax Benefit (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Stock-based compensation expense, gross	$ 2,157	$ 1,337
Income tax benefit at our statutory rate associated with stock-based compensation	(548)	(521)
Stock-based compensation expense, net	$ 1,609	$ 816

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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