Note 1 - Description of Business and Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2020

Notes Tables

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Stock options		1,796,478		1,534,817		1,769,556		1,560,546
Restricted stock units		35,123		59,130		46,851		78,430