Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details)

v2.4.1.9
Stock-Based Compensation (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free Interest Rate 0.97%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate 0.69%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
Expected life (in years) 3 years 6 months 3 years 6 months
Expected volatility 52.03%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate 48.01%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate
Dividend Yield 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
Stock-based Compensation Expense $ 396us-gaap_ShareBasedCompensation $ 690us-gaap_ShareBasedCompensation
Management [Member] | Restricted Stock [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock Issued 444,364us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ManagementMember 		 
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 1.73us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ManagementMember 		 
Chief Executive Officer [Member] | Performance base shares [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures   188,165us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price   $ 5.10us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value   $ 1.87us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Expected life (in years)   5 years
Performance Shares Target Premium   50.00%pdii_PerformanceSharesTargetPremium
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Consecutive trading days   60 days
Performance Shares First Tranche [Domain] | Chief Executive Officer [Member] | Performance base shares [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Performance shares available for exercise   36,496pdii_Performancesharesavailableforexercise
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_StatementEquityComponentsAxis
= pdii_PerformanceSharesFirstTrancheDomain
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Average stock price, performance shares   $ 7.65pdii_Averagestockpriceperformanceshares
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_StatementEquityComponentsAxis
= pdii_PerformanceSharesFirstTrancheDomain
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Performance Shares Second Tranche [Domain] | Chief Executive Officer [Member] | Performance base shares [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (in years)   5 years
Performance shares available for exercise   64,460pdii_Performancesharesavailableforexercise
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_StatementEquityComponentsAxis
= pdii_PerformanceSharesSecondTrancheDomain
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Average stock price, performance shares   $ 10.20pdii_Averagestockpriceperformanceshares
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_StatementEquityComponentsAxis
= pdii_PerformanceSharesSecondTrancheDomain
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Performance Shares Final Tranche [Domain] | Chief Executive Officer [Member] | Performance base shares [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (in years)   5 years
Performance shares available for exercise   87,209pdii_Performancesharesavailableforexercise
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_StatementEquityComponentsAxis
= pdii_PerformanceSharesFinalTrancheDomain
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember
Average stock price, performance shares   $ 15.30pdii_Averagestockpriceperformanceshares
/ us-gaap_AwardTypeAxis
= pdii_PerformanceBaseSharesMember
/ us-gaap_StatementEquityComponentsAxis
= pdii_PerformanceSharesFinalTrancheDomain
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember