Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Income Taxes [Line Items]
Net (decrease) increase in total valuation allowance	$ (200,000)	$ 500,000
Research and development credits carryforwards	6,264,000	$ 5,570,000
Unrecognized tax benefits that will impact the company's effective tax rate	1,800,000
Accrued interest or penalties related to uncertain tax positions	0
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	16,000,000.0
Net operating losses that can be carried forward indefinitely	2,200,000
Net operating losses subject to expiration	13,800,000
Federal | Research and development credit
Income Taxes [Line Items]
Research and development credits carryforwards	3,200,000
Federal | Tax Year 2020
Income Taxes [Line Items]
Net operating loss carryforwards	0
State
Income Taxes [Line Items]
Net operating losses subject to expiration	28,100,000
State | Research and development credit | California
Income Taxes [Line Items]
Research and development credits carryforwards	$ 2,800,000