XML 45 R29.htm IDEA: XBRL DOCUMENT
v3.22.1

License Agreement - Additional Information (Details) - shares | Mar. 31, 2022 | Dec. 31, 2021 | May 07, 2020
--- | --- | --- | ---
Common stock, shares issued (in shares) | 22,197,635 | 15,510,025 |
NanoTx License Agreement [Member] |  |  |
Common stock, shares issued (in shares) |  |  | 230,769

X
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis=pstv_NanoTxLicensesAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |