Note 9 - Net Income Per Share (Restated) - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net income used in the computation of basic and diluted net income per share (in thousands)	$ 6,377	$ 15,174	$ 16,855	$ 18,541
Weighted average shares outstanding - basic (in shares)	15,433,412	15,016,062	15,327,374	15,020,457
Dilutive common stock equivalents (in shares)	654,324	155,024	712,231	165,535
Weighted average shares outstanding - diluted (in shares)	16,087,736	15,171,086	16,039,605	15,185,992
Net income per basic share (in dollars per share)	$ 0.41	$ 1.01	$ 1.10	$ 1.23
Net income per diluted share (in dollars per share)	$ 0.40	$ 1.00	$ 1.05	$ 1.22