Note 4 - Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Notes Tables

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block]

	# of Shares		Wgt Avg Exercise Price		Wgt Avg Remaining Contractual Life in Years		Aggregate Intrinsic Value
Outstanding at March 31, 2019		194,500	$	5.07		4.9	$	5,226,180
Vested and exercisable at March 31, 2019		146,000	$	1.83		3.4	$	4,395,480