Share Option Plan and ESPP - Schedule of Fair Value Assumptions Used Only for Equity Based Awards Estimated Using Black-Scholes Option Pricing Model (Details)	3 Months Ended	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	6 months	6 months	6 months
Expected volatility	4700.00%	6200.00%
Expected volatility, minimum			44.00%
Expected volatility, maximum			62.00%
Risk-free interest rate	157.00%	251.00%
Risk-free interest rate, minimum			2.10%
Risk-free interest rate, maximum			2.51%
Dividend yield	0.00%	0.00%	0.00%
Stock Option Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	6 years 3 months	6 years 2 months 23 days
Expected volatility	5400.00%	5500.00%
Expected volatility, minimum			55.00%
Expected volatility, maximum			61.00%
Risk-free interest rate	86.00%	240.00%
Risk-free interest rate, minimum			1.73%
Risk-free interest rate, maximum			2.40%
Dividend yield	0.00%	0.00%	0.00%
Stock Option Plans \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			5 years 6 months
Stock Option Plans \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			6 years 6 months

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.

+ References

+ Details

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The estimated measure of the maximum 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.

+ References

No definition available.

+ Details

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The estimated measure of the minimum 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.

+ References

No definition available.

+ Details

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- Definition

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

+ References

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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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

No definition available.

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- Definition

Expected term of share-based compensation awards, 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
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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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