Note 8. Stock Options and Restricted Stock Units (Details 3) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of restricted stock units outstanding, beginning	65,165	126,500
Number of restricted stock units granted	9,000	17,500
Number of restricted stock units vested/issued	(34,996)	(69,170)
Number of restricted stock units forfeited	(2,500)	(9,665)
Number of restricted stock units outstanding, ending	36,669	65,165
Weighted average exercise price outstanding, beginning	$ 6.66	$ 6.35
Weighted average exercise price granted	17.43	10.75
Weighted average exercise price vested/issued	7.28	6.95
Weighted average exercise price forfeited	5.80	7.88
Weighted average exercise price outstanding, ending	$ 8.76	$ 6.66
Aggregate intrinsic value outstanding, beginning	$ 1,111,703	$ 1,138,500
Aggregate intrinsic value granted	156,850	104,000
Aggregate intrinsic value vested/issued	850,984	799,563
Aggregate intrinsic value forfeited	43,329	106,330
Aggregate intrinsic value outstanding, ending	$ 257,987	$ 1,111,703