Note 5 - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Employee Stock Option [Member]
Effect of dilutive securities:
Effect of dilutive securities (in shares)	18,495	28,231	18,975	28,993
Restricted Stock [Member]
Effect of dilutive securities:
Effect of dilutive securities (in shares)
Net income	$ 1,820,915	$ 1,507,896	$ 3,341,912	$ 2,952,303
Numerator for basic and diluted earnings per share	$ 1,820,915	$ 1,507,896	$ 3,341,912	$ 2,952,303
Weighted-average shares outstanding-basic (in shares)	9,209,446	10,212,933	9,418,645	10,212,137
Effect of dilutive securities (in shares)	18,495	28,231	18,975	28,993
Denominator for diluted earnings per share-weighted-average shares (in shares)	9,227,941	10,241,164	9,437,620	10,241,130
Basic earnings per share (in dollars per share)	$ 0.19	$ 0.15	$ 0.35	$ 0.29
Diluted earnings per share (in dollars per share)	$ 0.19	$ 0.15	$ 0.35	$ 0.29