Name:	bpth_SharebasedCompensationArrangementBySharebasedPaymentAwardOtherThanOptionOutstandingWeightedAverageExercisePricePerShare
Namespace Prefix:	bpth_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Number of other than option exercisable.

No definition available.

Name:	bpth_SharebasedCompensationArrangementBySharebasedPaymentAwardOtherThanOptionsExercisableNumberOfShares
Namespace Prefix:	bpth_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Weighted Average Exercise Price Per Share of exercisable other than option

No definition available.

Name:	bpth_SharebasedCompensationArrangementBySharebasedPaymentAwardOtherThanOptionsExercisableWeightedAverageExercisePricePerShare
Namespace Prefix:	bpth_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

Name:	us-gaap_ClassOfWarrantOrRightLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of warrants or rights outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_ClassOfWarrantOrRightAxis=bpth_Warrants2014Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ClassOfWarrantOrRightAxis=bpth_Warrants2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ClassOfWarrantOrRightAxis=bpth_Warrants2008Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: