Note 8. Stock Options and Restricted Stock Units (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of options outstanding, beginning	137,288	163,850
Number of options granted	32,000	32,000
Number of options exercised	(61,875)	(56,645)
Number of options forfeited/cancelled	(8,850)	(1,917)
Number of options outstanding, ending	98,563	137,288
Range of exercise price options outstanding, beginning	0.01 - 13.49	0.01 - 13.49
Range of exercise price options granted	17.40	13.00
Range of exercise price options exercised	7.76 - 13.49	0.01 - 9.26
Range of exercise price options forfeited/cancelled	0.01 - 9.26	9.26
Range of exercise price options outstanding, ending	6.80 - 17.40	0.01 - 13.49
Weighted average exercise price outstanding, beginning	$ 10.20	$ 8.30
Weighted average exercise price granted	17.40	13.00
Weighted average exercise price exercised	11.46	6.32
Weighted average exercise price forfeited/cancelled	2.76	9.26
Weighted average exercise price outstanding, ending	$ 12.56	$ 10.20
Aggregate intrinsic value outstanding, beginning	$ 1,119,562	$ 297,542
Aggregate intrinsic value granted	$ 0	$ 0
Aggregate intrinsic value exercised	$ 346,284	$ 393,729
Aggregate intrinsic value forfeited/cancelled	$ 134,009	$ 3,984
Aggregate intrinsic value outstanding, ending	$ 127,306	$ 1,119,562