XML 18 R9.htm IDEA: XBRL DOCUMENT
v3.23.3

Use of Estimates | 9 Months Ended
--- | ---
Sep. 30, 2023
Use Of Estimates [Abstract] |
Use of Estimates | 2. Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions affecting the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period. The Company’s most significant estimates and critical accounting policies involve reviewing assets for impairment and determining the assumptions used in measuring stock-based compensation expense.

X
- Definition Use of Estimates [Abstract] + References No definition available. + Details
Name: | pstv_UseOfEstimatesAbstract
Namespace Prefix: | pstv_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Provides an entity's explanation that the preparation of financial statements in conformity with generally accepted accounting principles requires the use of management estimates. + References No definition available. + Details
Name: | pstv_UseOfEstimatesTextBlock
Namespace Prefix: | pstv_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration