Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Income Taxes [Line Items]
Net increase (decrease) in total valuation allowance	$ 19,000	$ (200,000)
Research and development credits carryforwards	7,322,000	$ 6,264,000
Unrecognized tax benefits that will impact the company's effective tax rate	2,100,000
Accrued interest or penalties related to uncertain tax positions	0
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	14,900,000
Net operating losses that can be carried forward indefinitely	9,400,000
Net operating losses subject to expiration	5,600,000
Federal \| Research and development credit
Income Taxes [Line Items]
Research and development credits carryforwards	3,800,000
Federal \| Tax Year 2020
Income Taxes [Line Items]
Net operating loss carryforwards	0
State
Income Taxes [Line Items]
Net operating losses subject to expiration	28,000,000
State \| Research and development credit \| California
Income Taxes [Line Items]
Research and development credits carryforwards	$ 3,400,000

Income taxes.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are not subject to expiration dates.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible research tax credit carryforwards.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

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