Equity Incentive Plans - Fair Value of Options Granted (Detail)	12 Months Ended
Dec. 31, 2020 $ / shares
Time Based Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend rate	0.00%
Risk-free interest rate, minimum	0.20%
Risk-free interest rate, maximum	2.44%
Volatility, minimum	29.06%
Volatility, maximum	135.74%
Performance-based Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend rate	0.00%
Risk-free interest rate, minimum	0.30%
Risk-free interest rate, maximum	0.32%
Volatility, minimum	106.31%
Volatility, maximum	140.02%
Weighted average grant date fair value	$ 1.02
Minimum [Member] \| Time Based Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option term	1 year 9 months 18 days
Maximum [Member] \| Time Based Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option term	5 years

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 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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- Definition

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

+ References

No definition available.

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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.

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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

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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

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