Closing stock price.

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- Definition

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

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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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- Definition

Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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- Definition

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

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Merger - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 15, 2020	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Common stock, shares outstanding		14,754,447	12,830,598
Tocagen, Inc.
Business Acquisition [Line Items]
Estimated fair value of total consideration	$ 32,981
Common stock, shares outstanding	1,594,670
Options to purchase shares of common stock outstanding	26,968
Closing stock price	$ 18.90
Merger transaction costs	$ 1,200
Tocagen, Inc. \| Restricted Stock Awards
Business Acquisition [Line Items]
Vested restricted stock awards outstanding	61,406