Quarterly Results of Operations (Detail) (USD $)	3 Months Ended	12 Months Ended
Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Total Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues	$ 0us-gaap_Revenues
Expenses	1,603,127us-gaap_OperatingExpenses	1,154,108us-gaap_OperatingExpenses	1,274,801us-gaap_OperatingExpenses	510,210us-gaap_OperatingExpenses	790,956us-gaap_OperatingExpenses	1,393,728us-gaap_OperatingExpenses	428,646us-gaap_OperatingExpenses	655,910us-gaap_OperatingExpenses	4,542,246us-gaap_OperatingExpenses	3,269,240us-gaap_OperatingExpenses	2,582,679us-gaap_OperatingExpenses
Loss From Operations	(1,603,127)us-gaap_OperatingIncomeLoss	(1,154,108)us-gaap_OperatingIncomeLoss	(1,274,801)us-gaap_OperatingIncomeLoss	(510,210)us-gaap_OperatingIncomeLoss	(790,956)us-gaap_OperatingIncomeLoss	(1,393,728)us-gaap_OperatingIncomeLoss	(428,646)us-gaap_OperatingIncomeLoss	(655,910)us-gaap_OperatingIncomeLoss	(4,542,246)us-gaap_OperatingIncomeLoss	(3,269,240)us-gaap_OperatingIncomeLoss	(2,582,679)us-gaap_OperatingIncomeLoss
Other Income	5,240us-gaap_NonoperatingIncomeExpense	5,699us-gaap_NonoperatingIncomeExpense	6,024us-gaap_NonoperatingIncomeExpense	5,334us-gaap_NonoperatingIncomeExpense	1,396us-gaap_NonoperatingIncomeExpense	521us-gaap_NonoperatingIncomeExpense	1,402us-gaap_NonoperatingIncomeExpense	(92)us-gaap_NonoperatingIncomeExpense	22,297us-gaap_NonoperatingIncomeExpense	3,227us-gaap_NonoperatingIncomeExpense	142us-gaap_NonoperatingIncomeExpense
Net Loss	$ (1,597,887)us-gaap_NetIncomeLoss	$ (1,148,409)us-gaap_NetIncomeLoss	$ (1,268,777)us-gaap_NetIncomeLoss	$ (504,876)us-gaap_NetIncomeLoss	$ (789,560)us-gaap_NetIncomeLoss	$ (1,393,207)us-gaap_NetIncomeLoss	$ (427,244)us-gaap_NetIncomeLoss	$ (656,002)us-gaap_NetIncomeLoss	$ (4,519,949)us-gaap_NetIncomeLoss	$ (3,266,013)us-gaap_NetIncomeLoss	$ (2,582,537)us-gaap_NetIncomeLoss
Net Loss Per Common Share - Basic and Diluted	$ (0.02)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.01)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.01)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.01)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.01)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.02)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.01)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.01)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.05)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.05)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.04)us-gaap_EarningsPerShareBasicAndDiluted

Name:	bpth_QuarterlyFinancialInformationLineItems
Namespace Prefix:	bpth_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

No definition available.

+ Details

Name:	us-gaap_EarningsPerShareBasicAndDiluted
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Net Income

-URI http://asc.fasb.org/extlink&oid=6518256

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.19)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.18)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.22)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 19

-Article 5

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 20

-Article 9

+ Details

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

- Definition

The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 5

+ Details

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

- Definition

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

+ References

No definition available.

+ Details

Name:	us-gaap_OperatingExpenses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

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

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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