Note 4. Stock Options and Restricted Stock Units (Details)	3 Months Ended
Mar. 31, 2019 $ / shares shares
Option 1
Exercise price range	$0.01 - $7.00
Number of options outstanding	10,000
Weighted average remaining contractual life (in years)	6 years 7 months 20 days
Weighted average exercise price \| $ / shares	$ 6.80
Number of options exercisable	10,000
Option 2
Exercise price range	$7.01 - $8.00
Number of options outstanding	20,313
Weighted average remaining contractual life (in years)	4 years 5 months 26 days
Weighted average exercise price \| $ / shares	$ 7.76
Number of options exercisable	20,313
Option 3
Exercise price range	$8.01 - $12.00
Number of options outstanding	4,250
Weighted average remaining contractual life (in years)	5 years 8 months 27 days
Weighted average exercise price \| $ / shares	$ 9.26
Number of options exercisable	4,250
Option 4
Exercise price range	$12.01 - $15.00
Number of options outstanding	59,500
Weighted average remaining contractual life (in years)	8 years 1 month 24 days
Weighted average exercise price \| $ / shares	$ 13.10
Number of options exercisable	32,000
Option 5
Exercise price range	$15.01 - $17.40
Number of options outstanding	32,000
Weighted average remaining contractual life (in years)	9 years 2 months 1 day
Weighted average exercise price \| $ / shares	$ 17.40
Number of options exercisable	0
Total
Number of options outstanding	126,063
Weighted average remaining contractual life (in years)	8 years 1 month 2 days
Weighted average exercise price \| $ / shares	$ 12.70
Number of options exercisable	66,563

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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