Common stock capital shares reserved for future issuance increase on each calendar year.

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Share based compensation arrangement by share based payment award options fair value of stock price.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate number of common shares reserved for future issuance.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Description of service or performance condition required to be met for earning right to award under share-based payment arrangement. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

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

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No definition available.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

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No definition available.

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Number of shares issued under share-based payment arrangement.

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Percentage of vesting of award under share-based payment arrangement.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

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Stock-Based Compensation - Additional Information (Details) - USD ($)		1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 15, 2020	May 31, 2021	Dec. 31, 2018	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jul. 26, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted						566,500
Weighted average grant-date fair value of stock options granted				$ 18.49	$ 13.34	$ 21.89	$ 10.30
Unrecognized compensation expense				$ 14,300,000		$ 14,300,000
Weighted-average period over which unrecognized compensation expense is expected to be recognized						3 years 18 days
Fair value of stock price						$ 2.96
Stock-based compensation expense				1,473,000	$ 375,000	$ 2,976,000	$ 401,000
Performance Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense				$ 233,000		$ 233,000
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards granted				0		0
Weighted-average period over which unrecognized compensation expense is expected to be recognized						2 years 8 months 15 days
Shares vested				0		0
Unvested restricted stock units outstanding				15,000		15,000
Unrecognized stock-based compensation expense				$ 289,000		$ 289,000
2018 Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Service-based awards, vesting period			4 years
Stock options, expiration term			10 years
Service-based awards vesting description						vest over a four-year period, with the first 25% of such awards vesting following twelve months of continued employment or service with the remaining awards vesting monthly in equal installments over the following thirty-six months
2018 Incentive Plan \| Following Twelve Months of Service
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Service-based awards vesting percentage			25.00%
2017 Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted	26,968
2017 Incentive Plan \| Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards granted	61,406
2020 Inducement Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for future grant									500,000
Shares available for issuance				135,000		135,000
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Service-based awards, vesting period		4 years
Service-based awards vesting description						vested over a four-year period, with the first 25% of such awards vesting following twelve months of continued employment or service with the remaining awards vesting monthly in equal installments over the following thirty-six months
Shares available for issuance		1,000,000		915,455		915,455
2021 Equity Incentive Plan \| Board of Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Service-based awards, vesting period		3 years				12 months
Service-based awards vesting description						vesting occurs in thirty-six equal monthly installments over a three-year period for initial grants and in twelve equal monthly installments over a twelve-month period for subsequent grants
2021 Equity Incentive Plan \| Following Twelve Months of Service
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Service-based awards vesting percentage		25.00%
2017 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Eligible employees withhold percentage of earnings to purchase shares of common stock		15.00%
Shares available for future issuance				176,694		176,694
Shares reserved for issuance increase percentage of total number of shares of common stock outstanding		1.00%
Shares Issued under plan						0
Stock-based compensation expense				$ 20,000		$ 20,000		$ 0
2017 Employee Stock Purchase Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance increase on of each calendar year		300,000
2017 Employee Stock Purchase Plan \| On First Date of Offering \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair market value of share of common stock to purchase		85.00%
2017 Employee Stock Purchase Plan \| On Date of Purchase \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair market value of share of common stock to purchase		85.00%