XML 50 R42.htm IDEA: XBRL DOCUMENT
v3.25.3

Commitments and Contingencies - Additional Information (Details) - USD ($) | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2025 | Dec. 31, 2024 | Nov. 05, 2024
Recorded Unconditional Purchase Obligation [Line Items] |  |  |
Operating lease right-of-use assets | $ 20,000 | $ 73,000 |
Pre-clinical Research Study Obligations [Member] |  |  |
Recorded Unconditional Purchase Obligation [Line Items] |  |  |
Contractual obligation | $ 0 |  |
Manufacturing Agreement with SpectronRX |  |  |
Recorded Unconditional Purchase Obligation [Line Items] |  |  |
Initial commitment fee |  |  | $ 300,000
Charlottesville [Member] |  |  |
Recorded Unconditional Purchase Obligation [Line Items] |  |  |
Lessee, operating lease, option to extend | The Charlottesville Lease expires on |  |
Operating leases, expiration date | Mar. 31, 2026 |  |

X
- Definition Initial commitment fee. + References No definition available. + Details
Name: | pstv_InitialCommitmentFee
Namespace Prefix: | pstv_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of contractual obligation, including, but not limited to, long-term debt, lease obligation, purchase obligation, and other commitments. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-4 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3 + Details
Name: | us-gaap_ContractualObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Date which lease or group of leases is set to expire, in YYYY-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 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/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-3 + Details
Name: | us-gaap_LesseeOperatingLeaseOptionToExtend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479041/842-20-45-1 + Details
Name: | us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 440 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482648/440-10-50-6 + Details
Name: | us-gaap_RecordedUnconditionalPurchaseObligationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=pstv_PreClinicalResearchStudyObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=pstv_ManufacturingAgreementWithSpectronRXMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=pstv_CharlottesvilleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |