Note 8. Stock Options and Restricted Stock Units (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Notes to Financial Statements
Number of options outstanding, beginning	163,850	246,000
Number of options granted	32,000	0
Number of options exercised	(56,645)	(20,900)
Number of options forfeited/cancelled	(1,917)	(61,250)
Number of options outstanding, ending	137,288	163,850
Range of exercise price options outstanding, beginning	0.01 - 13.49	0.01 - 13.49
Range of exercise price options granted	13.00	0.00
Range of exercise price options exercised	0.01 - 9.26	0.01 - 3.33
Range of exercise price options forfeited/cancelled	9.26	7.76 - 9.26
Range of exercise price options outstanding, ending	0.01 - 13.49	0.01 - 13.49
Weighted average exercise price outstanding, beginning	$ 8.30	$ 7.69
Weighted average exercise price granted	13.00	0.00
Weighted average exercise price exercised	6.32	1.67
Weighted average exercise price forfeited/cancelled	9.26	8.11
Weighted average exercise price outstanding, ending	$ 10.20	$ 8.30
Aggregate intrinsic value outstanding, beginning	$ 297,542	$ 187,798
Aggregate intrinsic value granted	$ 0	$ 0
Aggregate intrinsic value exercised	$ 393,729	$ 89,180
Aggregate intrinsic value forfeited/cancelled	$ 3,984	$ 0
Aggregate intrinsic value outstanding, ending	$ 1,119,562	$ 297,542