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Subsequent Events - Additional Information (Detail) - USD ($) | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Jan. 19, 2022 | Mar. 11, 2021 | Nov. 13, 2020 | Dec. 11, 2018 | Jul. 31, 2018
Subsequent Event [Line Items] |  |  |  |  |  |  |
Proceeds from sale of common stock to related party | $ 7,831,000 | $ 13,166,000 |  |  |  |  |
BARDA [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Potential amount additional funding awarded |  |  | $ 12,900,000 |  |  |  |
Overall potential award increased |  |  | 46,900,000 |  |  |  |
Potential contract amount awarded |  |  | 59,700,000 |  |  |  | $ 44,200,000
At-The-Market Offering Program [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Proceeds from sale of common stock to related party | 8,100 |  |  |  |  |  |
At-The-Market Offering Program [Member] | Cantor Fitzgerald & Co [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Common stock available for issuance | $ 344,205 |  |  |  |  |  |
Price per share | $ 10.86 |  |  |  |  |  |
Proceeds from sale of common stock to related party | $ 3,700,000 |  |  |  |  |  |
Sales Agreement [Member] | At-The-Market Offering Program [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Common stock available for issuance |  |  |  |  | $ 34,000,000.0 |  |
Sales Agreement [Member] | At-The-Market Offering Program [Member] | Cantor Fitzgerald & Co [Member] | Maximum [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Common stock available for issuance |  |  |  | $ 75,000,000.0 |  | $ 50,000,000.0 |
Subsequent Event [Member] | BARDA [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Potential amount additional funding awarded |  |  | 12,900,000 |  |  |  |
Potential contract amount awarded |  |  | 59,700,000 |  |  |  |
Subsequent Event [Member] | Maximum [Member] | BARDA [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Overall potential award increased |  |  | $ 46,900,000 |  |  |  |

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- Definition Authorized common stock value available for issuance. + References No definition available. + Details
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- Definition Increase in overall potential award. + References No definition available. + Details
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- Definition Potential amount additional funding awarded. + References No definition available. + Details
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- Definition Potential contract amount awarded. + References No definition available. + Details
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- Definition The cash inflow from the additional capital contribution to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3255-108585 + Details
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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
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