XML 96 R73.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Subsequent Events - Additional Information (Detail) - Office Space [Member] $ in Millions |  | 1 Months Ended | 3 Months Ended
--- | --- | --- | ---
Jan. 17, 2018 USD ($) ft² Option | Aug. 31, 2015 | Mar. 31, 2018
Subsequent Event [Line Items] |  |  |
Term of lease |  | 5 years |
Lease renewal term |  | 5 years |
Lease Agreements [Member] | Cambridge, Massachusetts [Member] | U.S. REIF Central Plaza Massachusetts, LLC [Memebr] |  |  |
Subsequent Event [Line Items] |  |  |
Area of office space | ft² | 7,800 |  |
Term of lease | 7 years |  |
Lease expiration date | Dec. 01, 2018 |  |
Lease renewal term | 5 years |  |
Number of renewal options | Option | 2 |  |
Operating lease, option to extend | the Company has two consecutive options to extend the Lease Term for an additional period of five years (the “Option Terms”), subject to certain conditions, upon notice to the Landlord. |  | the Company has two consecutive options to extend the Lease Term for an additional period of five years (the “Option Terms”), subject to certain conditions, upon notice to the Landlord.
Operating leases annual base rent initial | $ 0.5 |  |
Operating leases annual base rent final | $ 0.6 |  |
Operating lease percentage of annual base rent | 100.00% |  |

X
- Definition Number of renewal options. + References No definition available. + Details
Name: | spro_NumberOfRenewalOptions
Namespace Prefix: | spro_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating lease percentage of annual base rent. + References No definition available. + Details
Name: | spro_OperatingLeasePercentageOfAnnualBaseRent
Namespace Prefix: | spro_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating leases annual base rent final. + References No definition available. + Details
Name: | spro_OperatingLeasesAnnualBaseRentFinal
Namespace Prefix: | spro_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operating leases annual base rent initial. + References No definition available. + Details
Name: | spro_OperatingLeasesAnnualBaseRentInitial
Namespace Prefix: | spro_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Area of a real estate property. + References No definition available. + Details
Name: | us-gaap_AreaOfRealEstateProperty
Namespace Prefix: | us-gaap_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date which lease or group of leases is set to expire, in CCYY-MM-DD format. + References No definition available. + Details
Name: | us-gaap_LeaseExpirationDate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of terms and conditions of option to extend lessee's operating lease. Includes, but is not limited to, information about option recognized as part of right-of-use asset and lease liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseOptionToExtend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LeaseArrangementTypeAxis=spro_OfficeSpaceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_LeaseAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=spro_CambridgeMassachusettsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CounterpartyNameAxis=spro_USREIFCentralPlazaMassachusettsLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |