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Fair Value Measurements Fair Value of Outstanding Common Stock Warrants (Detail) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Fair Value Disclosures [Abstract]    
Stock price $ 23.21us-gaap_SharePrice $ 16.25us-gaap_SharePrice
Weighted average exercise price $ 0.10us-gaap_FairValueAssumptionsExercisePrice $ 0.10us-gaap_FairValueAssumptionsExercisePrice
Term (years) 7 years 5 months 7 years 8 months
Risk-free rate 1.74%us-gaap_FairValueAssumptionsRiskFreeInterestRate 2.01%us-gaap_FairValueAssumptionsRiskFreeInterestRate
Expected volatility 49.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate 50.20%us-gaap_FairValueAssumptionsExpectedVolatilityRate
Historical volatilities period 10 years  
Fair value of common stock warrants $ 22.89parr_WarrantsNotSettleableInCashFairValueDisclosurePerShare $ 16.17parr_WarrantsNotSettleableInCashFairValueDisclosurePerShare