Note 9 - Share-based Compensation and Cash-based Incentive Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock [Member]	9 Months Ended
	Sep. 30, 2019 $ / shares shares
Nonvested, units (in shares) | shares	181,832
Nonvested, weighted average grant date fair value per unit (in dollars per share) | $ / shares	$ 3.08
Granted (in shares) | shares	46,360
Granted, weighted average grant date fair value per unit (in dollars per share) | $ / shares	$ 6.04
Vested (in shares) | shares	(105,012)
Vested, weighted average grant date fair value per share (in dollars per share) | $ / shares	$ 2.67
Nonvested, units (in shares) | shares	123,180
Nonvested, weighted average grant date fair value per unit (in dollars per share) | $ / shares	$ 4.55