Note 2 - Summary of Significant Accounting Policies - Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income	$ 2,371	$ 2,059	$ 4,148	$ 3,846
Weighted average shares outstanding (in shares)	58,746	56,945	57,927	56,885
Basic (in dollars per share)	$ 0.04	$ 0.04	$ 0.07	$ 0.07
Weighted average shares outstanding (including dilutive CSEs) (in shares)	59,911	58,301	59,147	58,165
Diluted (in dollars per share)	$ 0.04	$ 0.04	$ 0.07	$ 0.07