Note 2 - Stock-based Compensation - Stock Option Activity (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) $ / shares shares
Options (in shares)		349,983
Weighted average exercise price (in dollars per share) | $ / shares		$ 10.97
Exercised (in shares)	0	(55,000)
Weighted average exercise price, exercised (in dollars per share) | $ / shares		$ 8
Options, end of period (in shares)	294,983	294,983
Weighted average exercise price, end of period (in dollars per share) | $ / shares	$ 11.53	$ 11.53
Weighted average remaining contractual term		1 year 299 days
Aggregate intrinsic value | $	$ 146,598	$ 146,598