Income Taxes - Reconciliation of Statutory Federal Income Tax Rate to Effective Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income taxes computed at statutory rates	$ 7,296	$ 6,832
(Increases) decreases resulting from:
Change in valuation allowance	(8,634)	(7,830)
Federal and state research and experimentation credits	787	947
State income taxes, net of federal tax benefit	414	451
Other	121	(401)
Total tax benefit (provision)	$ (16)	$ (1)
Income taxes computed at statutory rates, Percentage	(21.00%)	(21.00%)
(Increases) decreases resulting from:
Change in valuation allowance, Percentage	24.00%	24.00%
Federal and state research and experimentation credits, Percentage	(2.00%)	(3.00%)
State income taxes, net of federal tax benefit, Percentage	(1.00%)	(1.00%)
Other, Percentage	0.00%	1.00%
Total, Percentage	0.00%	0.00%

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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-Publisher FASB
-Name Accounting Standards Codification
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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