Summary of Option Activity Under Company's Equity Incentive Plans (Detail) - $ / shares	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Number of Shares Underlying Outstanding Options
Number of Shares Underlying Outstanding Options, Beginning Balance	2,603,630
Number of Shares Underlying Outstanding Options, Options granted	879,200
Number of Shares Underlying Outstanding Options, Options forfeited	(658,947)
Number of Shares Underlying Outstanding Options, Options expired	(46,173)
Number of Shares Underlying Outstanding Options, Ending Balance	2,777,710	2,603,630
Number of Shares Underlying Outstanding Options, Exercisable - March 31, 2022	1,305,020
Weighted- Average Exercise Price
Weighted- Average Exercise Price, Beginning Balance	$ 7.70
Weighted- Average Exercise Price, Options granted	0.52
Weighted- Average Exercise Price, Options forfeited	5.20
Weighted- Average Exercise Price, Options expired	9.81
Weighted- Average Exercise Price, Ending Balance	5.92	$ 7.70
Weighted- Average Exercise Price, Exercisable - March 31, 2022	$ 9.42
Weighted-Average Remaining Contractual Term (Years)
Weighted-Average Remaining Contractual Term (Years), Outstanding Balance	8 years	7 years 5 months 15 days

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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

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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 grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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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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