Stockholders' Equity - Warrant Activity Including Activity Related To Pre-funded Warrants (Detail) - $ / shares	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Number of Option Shares
Outstanding, Beginning	2,171,477
Issued	1,475,875
Outstanding, Ending	2,929,472	2,171,477
Weighted Average Exercise Price
Outstanding, Beginning	$ 5.62
Issued	2.94
Outstanding, Ending	$ 4.51	$ 5.62
Weighted Average Contractual Term, Outstanding	7 years 7 months 6 days	7 years 6 months
Warrants [Member]
Number of Option Shares
Issued	23,228,313
Exercised	(2,626,069)
Outstanding, Ending	20,602,244
Weighted Average Exercise Price
Issued	$ 1.08
Exercised	0.001
Outstanding, Ending	$ 1.22
Weighted Average Contractual Term, Outstanding	4 years 6 months

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

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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