Percentage of stock options vested.

No definition available.

Name:	bpth_PercentageOfStockOptionsVested
Namespace Prefix:	bpth_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of stock options vested on the grant date, stock options issued.

+ References

No definition available.

+ Details

Name:	bpth_PercentageOfStockOptionsVestedOnGrantDateStockOptionsIssued
Namespace Prefix:	bpth_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

ShareBased Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Fair Value

+ References

No definition available.

+ Details

Name:	bpth_SharebasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGrantDateFairValue
Namespace Prefix:	bpth_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Share based goods and nonemployee services transaction quantity of securities issued weighted average exercise price.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

No definition available.

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average expected volatility rate of share-based compensation awards.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (f)(2)(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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

- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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

- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

No definition available.

+ Details

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

- Definition

The number of shares or units of entity securities issued in the transaction in which equity securities were issued to pay for goods or nonemployee services.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 50

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionQuantityOfSecuritiesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The noncash expense that accounts for the value of stock or unit options distributed to employees as compensation.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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

+ Details

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

Stock-Based Compensation Plans - Additional Information (Detail) (USD $)	1 Months Ended			12 Months Ended
	Oct. 31, 2013	Aug. 31, 2013	Apr. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2008
Stock Based Compensation Plans [Line Items]
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value				$ 0.47	$ 0.37	$ 0.86
Stock option expense				$ 704,480	$ 63,385
Share-based goods and nonemployee services transaction, quantity of securities issued		2,500,000	25,000
Share based goods and nonemployee services transaction quantity of securities issued weightage average excecise price			$ 0.54
Share-based compensation arrangement by share-based payment award, award vesting period	0 years	3 years	1 year
Sharebased compensation arrangement by share-based payment award, options, grants in period, grant date fair value	48,550	1,125,000	12,975
Percentage of stock options vested		50.00%
Percentage of stock options vested on the grant date, stock options issued		50.00%
Share based compensation arrangement by share based payment award average annual volitality rate	245.00%	189.00%	175.00%
Stock Option Grant
Stock Based Compensation Plans [Line Items]
Granted	25,000
Weighted - Average Exercise Price, Granted	$ 1.95	$ 0.46
Research and Development Expense
Stock Based Compensation Plans [Line Items]
Stock option expense				32,879
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized, stock options				547,691
2007 Stock Incentive Plan
Stock Based Compensation Plans [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant				8,423,787
Director Service Stock Option
Stock Based Compensation Plans [Line Items]
Stock option expense				$ 671,601