Note 8. Stock Options and Restricted Stock Units (Details 2) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of options outstanding	75,230	127,563	98,563
Weighted average remaining contractual life (in years)	6 years 5 months 16 days
Weighted average exercise price	$ 12.16	$ 12.63	$ 12.56
Number of options exercisable	60,730
Option 1
Exercise price range	$0.01 - $7.00
Number of options outstanding	10,000
Weighted average remaining contractual life (in years)	4 years 10 months 17 days
Weighted average exercise price	$ 6.80
Number of options exercisable	10,000
Option 2
Exercise price range	$7.01 - $8.00
Number of options outstanding	10,313
Weighted average remaining contractual life (in years)	2 years 8 months 27 days
Weighted average exercise price	$ 7.76
Number of options exercisable	10,313
Option 3
Exercise price range	$8.01 - $12.00
Number of options outstanding	7,167
Weighted average remaining contractual life (in years)	5 years 10 months 13 days
Weighted average exercise price	$ 9.88
Number of options exercisable	5,167
Option 4
Exercise price range	$12.01 - $15.00
Number of options outstanding	31,750
Weighted average remaining contractual life (in years)	7 years 9 months 18 days
Weighted average exercise price	$ 13.16
Number of options exercisable	19,250
Option 5
Exercise price range	$15.01 - $17.40
Number of options outstanding	16,000
Weighted average remaining contractual life (in years)	7 years 5 months 1 day
Weighted average exercise price	$ 17.40
Number of options exercisable	16,000