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v3.22.1

Net Loss per Share - Additional Information (Detail) $ in Millions | 12 Months Ended
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Dec. 31, 2020 USD ($)
Series C Preferred Stock [Member] |
Earnings Per Share [Line Items] |
Accretion of beneficial conversion feature | $ 0.5

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- Definition Earnings per share. + References No definition available. + Details
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Namespace Prefix: | spro_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of accretion of the preferred stock redemption discount during the period. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |