Note 12 - Stock Based Compensation - Stock Option Activity (Details) - The 2010 Stock Option and Incentive Plan [Member]	3 Months Ended
	Mar. 31, 2019 USD ($) $ / shares shares
Outstanding, shares (in shares) | shares	783,383
Outstanding, Weighted average exercise price per share (in dollars per share) | $ / shares	$ 12.14
Outstanding, shares (in shares) | shares	783,383
Outstanding, Weighted average exercise price per share (in dollars per share) | $ / shares	$ 12.14
Outstanding, weighted average contractual life remaining in years (Year)	8 years 335 days
Outstanding, aggreate instrinsic value | $	$ 695,400
Exercisable, shares (in shares) | shares	434,515
Exercisable, Weighted average exercise price per share (in dollars per share) | $ / shares	$ 19.38
Exercisable, weighted average contractual life remaining in years (Year)	8 years 306 days
Exercisable, aggreate instrinsic value | $	$ 374,063
Vested and expected to vest, shares (in shares) | shares	783,383
Vested and expected to vest, Weighted average exercise price per share (in dollars per share) | $ / shares	$ 12.14
Vested and expected to vest, weighted average contractual life remaining in years (Year)	8 years 335 days
Vested and expected to vest, aggreate instrinsic value | $	$ 695,400