XML 51 R41.htm IDEA: XBRL DOCUMENT v3.20.2

NanoTx License Agreement - Additional Information (Details) - USD ($)	May 07, 2020	Jun. 30, 2020	Dec. 31, 2019	Aug. 06, 2019	Aug. 05, 2019
Common stock, shares issued (in shares)		4,273,857	3,880,588	50,000,000	50,000,000
Common stock, $0.001 par value; 100,000,000 shares authorized; 4,273,857 and 3,880,588 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively		$ 4,000	$ 4,000
NanoTx License Agreement [Member]
License fee payment in cash	$ 400,000
Common stock, shares issued (in shares)	230,769
Common stock, $0.001 par value; 100,000,000 shares authorized; 4,273,857 and 3,880,588 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively	$ 781,000
NanoTx License Agreement [Member] | Development and Sales Milestone [Member]
Milestone payments	$ 136,500,000

X

- Definition

Milestone Payments.

+ References

No definition available.

+ Details

Name:	pstv_MilestonePayments
Namespace Prefix:	pstv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.

+ 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=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The amount of cash paid for royalties during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585

+ Details

Name:	us-gaap_PaymentsForRoyalties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

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

X

- Details

Name:	us-gaap_IncomeStatementLocationAxis=pstv_DevelopmentAndSalesMilestoneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: