XML 67 R55.htm IDEA: XBRL DOCUMENT
v3.20.4

Term Loan Obligations - Face Value to Book Value Reconciliation (Details) $ in Thousands | Dec. 31, 2020 USD ($)
--- | ---
Reconciliation of Face Value to Book Value [Abstract] |
Total debt obligations, including final payment fee (Face Value) | $ 7,481
Less: Debt discount | (1,146)
Total obligation | $ 6,335

X
- Definition Reconciliation of Face Value to Book Value [Abstract] + References No definition available. + Details
Name: | pstv_DebtInstrumentReconciliationOfFaceValueToBookValueAbstract
Namespace Prefix: | pstv_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments. + References No definition available. + Details
Name: | us-gaap_ContractualObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, after accumulated amortization, of debt discount. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28541-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of long-term debt and lease obligation, including portion classified as current. + References No definition available. + Details
Name: | us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant