STOCKHOLDERS' EQUITY - Stock grant agreements with non employees, Stock options (Details) - shares	1 Months Ended	12 Months Ended
Apr. 30, 2018	Dec. 31, 2019
Share-Based Compensation Awards
Granted (in shares)		648,000
Nonemployees
Share-Based Compensation Awards
Granted (in shares)		0
2015 Plan \| Nonemployees
Share-Based Compensation Awards
Granted (in shares)	72,373
Vesting period	4 years
Term of award	10 years
2015 Plan \| Nonemployees \| Tranche one
Share-Based Compensation Awards
Vesting period	12 months
Vesting (as a percent)	25.00%
2015 Plan \| Nonemployees \| Tranche two
Share-Based Compensation Awards
Vesting period	3 years

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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 (a)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Gross number of share options (or share units) granted during the period.

+ References

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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