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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- References

No definition available.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the expected term of a nonvested share or option award issued to other than an employee.

+ References

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- Definition

Period an equity-based award is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The estimated measure of the percentage amount by which a share price is expected to fluctuate during the expected term of a nonvested share or option award issued to other than an employee.

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- Definition

The risk-free interest rate assumption that is used in valuing a nonvested share or option award issued to other than an employee.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents 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
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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STOCK-BASED COMPENSATION - Stock Options Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Stock Option \| Share-based Payment Arrangement, Employee
Stock options granted to employees
Risk-free interest rate	2.10%	2.70%	1.70%
Expected volatility	73.60%	64.60%
Expected term (in years)	5 years 10 months 24 days	5 years 9 months 18 days
Expected dividends	0.00%	0.00%	0.00%
Non-Employee Stock Option \| Share-based Payment Arrangement, Nonemployee
Stock options granted to employees
Risk-free interest rate	2.50%	2.70%
Expected volatility	76.40%	68.40%
Expected term (in years)	6 years 4 months 24 days	10 years
Expected dividends	0.00%	0.00%
Stock options granted to nonemployees
Expected dividends			0.00%
Minimum \| Employee Stock Option \| Share-based Payment Arrangement, Employee
Stock options granted to employees
Expected volatility			72.70%
Expected term (in years)			6 years 2 months 12 days
Minimum \| Non-Employee Stock Option \| Share-based Payment Arrangement, Nonemployee
Stock options granted to nonemployees
Risk-free interest rate			1.70%
Expected volatility			70.80%
Expected term (in years)			6 years 6 months
Maximum \| Employee Stock Option \| Share-based Payment Arrangement, Employee
Stock options granted to employees
Expected volatility			78.50%
Expected term (in years)			6 years 3 months 18 days
Maximum \| Non-Employee Stock Option \| Share-based Payment Arrangement, Nonemployee
Stock options granted to nonemployees
Risk-free interest rate			2.20%
Expected volatility			73.10%
Expected term (in years)			8 years 10 months 24 days