Note 13 - Stock Based Compensation - Stock Option Activity (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Granted, shares (in shares) | shares
Granted, weighted average exercise price per share (in dollars per share) | $ / shares
Forfeited, shares (in shares) | shares
Forfeited, weighted average exercise price per share (in dollars per share) | $ / shares
Expired, shares (in shares) | shares
Expired, weighted average exercise price per share (in dollars per share) | $ / shares
The 2010 Stock Option and Incentive Plan [Member]
Outstanding, shares (in shares) | shares	4,308,383
Outstanding, weighted average exercise price per share (in dollars per share) | $ / shares	$ 3.44
Outstanding, shares (in shares) | shares	4,308,383
Outstanding, weighted average exercise price per share (in dollars per share) | $ / shares	$ 3.44
Outstanding, weighted average contractual life remaining in years (Year)	8 years 292 days
Outstanding, aggreate instrinsic value | $
Exercisable, shares (in shares) | shares	3,832,000
Exercisable, Weighted average exercise price per share (in dollars per share) | $ / shares	$ 3.58
Exercisable, weighted average contractual life remaining in years (Year)	8 years 292 days
Exercisable, aggreate instrinsic value | $
Vested and expected to vest, shares (in shares) | shares	4,308,383
Vested and expected to vest, Weighted average exercise price per share (in dollars per share) | $ / shares	$ 3.44
Vested and expected to vest, weighted average contractual life remaining in years (Year)	8 years 292 days
Vested and expected to vest, aggreate instrinsic value | $