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Equity - Additional Information (Detail) - USD ($) |  |  |  |  | 1 Months Ended | 6 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 01, 2020 | Sep. 15, 2020 | Sep. 09, 2020 | Mar. 05, 2020 | Feb. 28, 2021 | Jun. 30, 2021 | Dec. 31, 2021 | Dec. 31, 2020 | Mar. 11, 2021 | Nov. 13, 2020 | Dec. 11, 2018
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Preferred stock, shares authorized |  |  |  |  |  |  | 10,000,000 | 10,000,000 |  |  |
Issuance of common stock and preferred stock net of offering costs and issuance costs |  |  |  |  |  |  | $ 7,831,000 | $ 77,929,000 |  |  |
Proceeds from sale of common stock to related party |  |  |  |  |  |  | 7,831,000 | 13,166,000 |  |  |
Pfizer Inc [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  |  | 2,362,348 |  |  |  |  |  |
Issuance of common stock and preferred stock net of offering costs and issuance costs |  |  |  |  | $ 27,500 |  |  |  |  |  |
Pfizer Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of common stock and preferred stock net of offering costs and issuance costs |  |  |  |  | $ 12,500 |  |  |  |  |  |
Pfizer Purchase Agreement [Member] | Pfizer Inc [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  |  |  | 2,362,348 |  |  |  |  |
Share price |  |  |  |  |  | $ 16.93 |  |  |  |  |
Proceeds from sale of common stock to related party |  |  |  |  |  | $ 40,000.0 |  |  |  |  |
At-The-Market Offering Program [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of common stock to related party |  |  |  |  |  |  | 8,100 |  |  |  |
At-The-Market Offering Program [Member] | Cantor Fitzgerald & Co [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock available for issuance |  |  |  |  |  |  | 344,205 |  |  |  |
Proceeds from sale of common stock to related party |  |  |  |  |  |  | $ 3,700,000 |  |  |  |
At-The-Market Offering Program [Member] | Sales Agreement [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock available for issuance |  |  |  |  |  |  |  |  |  | $ 34,000,000.0 |
At-The-Market Offering Program [Member] | Sales Agreement [Member] | Cantor Fitzgerald & Co [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Gross proceeds from issuance of common stock |  |  | $ 15,400,000 |  |  |  |  |  |  |  |
Common stock value remaining available for issuance |  |  | $ 34,600,000 |  |  |  |  |  |  | $ 34,000,000.0 |
At-The-Market Offering Program [Member] | Sales Agreement [Member] | Cantor Fitzgerald & Co [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Authorized offering value |  |  |  |  |  |  |  |  | $ 300,000,000.0 |  | $ 200,000,000.0
Common stock available for issuance |  |  |  |  |  |  |  |  | $ 75,000,000.0 |  | $ 50,000,000.0
Underwritten Public Offering Member |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Gross proceeds from issuance of common and preferred stock |  | $ 80,000,000.0 |  |  |  |  |  |  |  |  |
Net proceeds from issuance of common and preferred stock |  | $ 74,700,000 |  |  |  |  |  |  |  |  |
Series A Convertible Preferred Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  |  |  |  | 2,220 |  |  |  |
Preferred stock, shares authorized |  |  |  |  |  |  | 10,000,000 |  |  |  |
Number of shares issuable upon conversion |  |  |  |  |  |  | 1,000 |  |  |  |
Maximum percentage of common stock holding upon conversion of preferred stock |  |  |  |  |  |  | 9.99% |  |  |  |
Preferred stock, liquidation per share |  |  |  |  |  |  | $ 0.001 |  |  |  |
Voting rights |  |  |  |  |  |  | no |  |  |  |
Share price |  |  |  | $ 8.98 |  |  |  |  |  |  |
Series B Convertible Preferred Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  |  |  |  | 1,000 |  |  |  |
Preferred stock, shares authorized |  |  |  |  |  |  | 10,000,000 |  |  |  |
Number of shares issuable upon conversion |  |  |  |  | 62,000 |  | 1,000 |  |  |  |
Maximum percentage of common stock holding upon conversion of preferred stock |  |  |  |  |  |  | 9.99% |  |  |  |
Preferred stock, liquidation per share |  |  |  |  |  |  | $ 0.001 |  |  |  |
Voting rights |  |  |  |  |  |  | no |  |  |  |
Preferred stock, conversion basis |  |  |  |  | 62 |  |  |  |  |  |
Series C Convertible Preferred Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  |  |  |  | 3,333 |  |  |  |
Preferred stock, shares authorized |  |  |  |  |  |  | 10,000,000 |  |  |  |
Number of shares issuable upon conversion |  |  |  |  | 73,000 |  | 1,000 |  |  |  |
Maximum percentage of common stock holding upon conversion of preferred stock |  |  |  |  |  |  | 9.99% |  |  |  |
Preferred stock, liquidation per share |  |  |  |  |  |  | $ 0.001 |  |  |  |
Voting rights |  |  |  |  |  |  | no |  |  |  |
Preferred stock, conversion basis |  |  |  |  | 73 |  |  |  |  |  |
Series D Preferred Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  |  |  |  | 3,215,000 |  |  |  |
Preferred stock, shares authorized |  |  |  |  |  |  | 10,000,000 |  |  |  |
Maximum percentage of common stock holding upon conversion of preferred stock |  |  |  |  |  |  | 9.99% |  |  |  |
Preferred stock, liquidation per share |  |  |  |  |  |  | $ 0.001 |  |  |  |
Voting rights |  |  |  |  |  |  | no |  |  |  |
Preferred stock, conversion basis |  |  |  |  |  |  | The shares of Series D Preferred Stock are convertible on a one-to-one basis into shares of common stock at any time at the option of the holder, provided that the holder will be prohibited from converting the Series D Preferred Stock into shares of common stock if, as a result of such conversion, the holder, together with its affiliates, would own more than 9.99% of the total number of shares of common stock then issued and outstanding, subject to certain exceptions. |  |  |  |
Issuance of common stock and preferred stock net of offering costs and issuance costs |  |  |  |  |  |  |  | $ 30,221,000 |  |  |
Series D Preferred Stock [Member] | Underwritten Public Offering Member |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  | 3,215,000 |  |  |  |  |  |  |  |  |
Share price |  | $ 10.00 |  |  |  |  |  |  |  |  |
Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  | 1,046,249 |  |  | 475,469 | 8,025,119 |  |  |
Issuance of common stock and preferred stock net of offering costs and issuance costs |  |  |  |  |  |  | $ 1,000 | $ 8,000 |  |  |
Common Stock [Member] | At-The-Market Offering Program [Member] |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares |  |  |  |  |  |  | 475,469 |  |  |  |
Share price |  |  |  |  |  |  | $ 16.98 |  |  |  |
Common Stock [Member] | Underwritten Public Offering Member |  |  |  |  |  |  |  |  |  |  |
Class Of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Issuance of stock, shares | 1,200,000 | 4,785,000 |  |  |  |  |  |  |  |  |
Share price | $ 10.00 | $ 10.00 |  |  |  |  |  |  |  |  |
Proceeds from sale of common stock to related party | $ 11,200,000 |  |  |  |  |  |  |  |  |  |

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