XML 43 R36.htm IDEA: XBRL DOCUMENT v2.4.1.9
Summary of Options Outstanding and Exercisable (Detail) (USD $)
 12 Months Ended
Dec. 31, 2014
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 5,427,778us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 6 years
Options Outstanding, Weighted Average Exercise Price $ 1.03us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
Options Exercisable, Number Exercisable 4,734,861us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
Options Exercisable, Weighted Average Exercise Price $ 0.99us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
Exercise Price 0.30 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 50,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice030Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 3 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price $ 0.30us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice030Member
Options Exercisable, Number Exercisable 50,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice030Member
Options Exercisable, Weighted Average Exercise Price $ 0.30us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice030Member
Exercise Price 0.33 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 100,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice033Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 6 years 6 months
Options Outstanding, Weighted Average Exercise Price $ 0.33us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice033Member
Options Exercisable, Number Exercisable 89,583us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice033Member
Options Exercisable, Weighted Average Exercise Price $ 0.33us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice033Member
Exercise Price 0.39 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 25,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice039Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 7 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 0.39us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice039Member
Options Exercisable, Number Exercisable 25,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice039Member
Options Exercisable, Weighted Average Exercise Price $ 0.39us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice039Member
Exercise Price 0.46 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 2,152,778us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice046Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 8 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price $ 0.46us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice046Member
Options Exercisable, Number Exercisable 1,756,945us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice046Member
Options Exercisable, Weighted Average Exercise Price $ 0.46us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice046Member
Exercise Price 0.53 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 20,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice053Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 6 years 1 month 6 days
Options Outstanding, Weighted Average Exercise Price $ 0.53us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice053Member
Options Exercisable, Number Exercisable 18,333us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice053Member
Options Exercisable, Weighted Average Exercise Price $ 0.53us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice053Member
Exercise Price 0.90 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 270,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice090Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 3 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 0.90us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice090Member
Options Exercisable, Number Exercisable 270,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice090Member
Options Exercisable, Weighted Average Exercise Price $ 0.90us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice090Member
Exercise Price 1.40 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 2,500,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice140Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 3 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 1.40us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice140Member
Options Exercisable, Number Exercisable 2,500,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice140Member
Options Exercisable, Weighted Average Exercise Price $ 1.40us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice140Member
Exercise Price 1.95 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 25,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice195Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 8 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 1.95us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice195Member
Options Exercisable, Number Exercisable 25,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice195Member
Options Exercisable, Weighted Average Exercise Price $ 1.95us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice195Member
Exercise Price 1.96 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 25,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice196Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 9 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 1.96us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice196Member
Options Exercisable, Number Exercisable 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice196Member
Options Exercisable, Weighted Average Exercise Price $ 0us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice196Member
Exercise Price 2.28 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 15,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice228Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 9 years 8 months 12 days
Options Outstanding, Weighted Average Exercise Price $ 2.28us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice228Member
Options Exercisable, Number Exercisable 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice228Member
Options Exercisable, Weighted Average Exercise Price $ 0us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice228Member
Exercise Price 2.37 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 15,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice237Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 9 years 8 months 12 days
Options Outstanding, Weighted Average Exercise Price $ 2.37us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice237Member
Options Exercisable, Number Exercisable 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice237Member
Options Exercisable, Weighted Average Exercise Price $ 0us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice237Member
Exercise Price 2.40 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 150,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice240Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 9 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 2.40us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice240Member
Options Exercisable, Number Exercisable 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice240Member
Options Exercisable, Weighted Average Exercise Price $ 0us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice240Member
Exercise Price 2.42 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 5,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice242Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 9 years 8 months 12 days
Options Outstanding, Weighted Average Exercise Price $ 2.42us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice242Member
Options Exercisable, Number Exercisable 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice242Member
Options Exercisable, Weighted Average Exercise Price $ 0us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice242Member
Exercise Price 2.71 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 50,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice271Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 9 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 2.71us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice271Member
Options Exercisable, Number Exercisable 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice271Member
Options Exercisable, Weighted Average Exercise Price $ 0us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice271Member
Exercise Price 4.30 [Member]  
Share Based Compensation Plans [Line Items]  
Options Outstanding, Number Outstanding 25,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice430Member
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years) 9 years 1 month 6 days
Options Outstanding, Weighted Average Exercise Price $ 4.30us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice430Member
Options Exercisable, Number Exercisable 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice430Member
Options Exercisable, Weighted Average Exercise Price $ 0us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bpth_ExercisePrice430Member