Stock-Based Compensation - Schedule of Nonvested Restricted Stock Units Activity (Detail) - 2014 Stock Option Plan [Member] - Restricted Stock Units [Member]	3 Months Ended
Mar. 31, 2021 $ / shares shares
Share-Based Compensation
Number of Shares, Nonvested restricted shares at the beginning of the period \| shares	1,643,779
Number of Shares, Restricted shares granted \| shares	5,921,020
Number of Shares, Restricted shares vested \| shares	(370,073)
Number of Shares, Restricted shares forfeited \| shares	(336,830)
Number of Shares, Nonvested restricted shares at the end of the period \| shares	6,857,896
Weighted-Average Grant Date Fair Value, Nonvested restricted shares at the beginning of the period \| $ / shares	$ 1.91
Weighted-Average Grant Date Fair Value, Granted \| $ / shares	2.15
Weighted-Average Grant Date Fair Value, Vested \| $ / shares	1.30
Weighted-Average Grant Date Fair Value, Forfeited \| $ / shares	4.35
Weighted-Average Grant Date Fair Value, Nonvested restricted shares at the end of the period \| $ / shares	$ 2.03

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Topic 718
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-Paragraph 2
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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-Publisher FASB
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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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-Publisher FASB
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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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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.

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No definition available.

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