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Note 16 - Subsequent Events (Details) (USD $)
12 Months Ended 0 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jan. 07, 2014
Note 16 - Subsequent Events (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 659,865us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross 3,150us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross  
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 5.94us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice      
Employee Stock Option [Member] | Subsequent Event [Member] | First Anniversary of the Vesting Commencement Date [Member] | Employees and Certain Non-employee Directors [Member]        
Note 16 - Subsequent Events (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage       25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
/ us-gaap_TitleOfIndividualAxis
= prto_EmployeesAndCertainNonEmployeeDirectorsMember
/ us-gaap_VestingAxis
= prto_FirstAnniversaryOfTheVestingCommencementDateMember
Employee Stock Option [Member] | Subsequent Event [Member] | Remainder to Vest [Member] | Employees and Certain Non-employee Directors [Member]        
Note 16 - Subsequent Events (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting, Equal Quarterly Installments       12prto_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingEqualQuarterlyInstallments
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
/ us-gaap_TitleOfIndividualAxis
= prto_EmployeesAndCertainNonEmployeeDirectorsMember
/ us-gaap_VestingAxis
= prto_RemainderToVestMember
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period       3 years
Employee Stock Option [Member] | Subsequent Event [Member] | Employees and Certain Non-employee Directors [Member]        
Note 16 - Subsequent Events (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period       10 years
Subsequent Event [Member] | Employees and Certain Non-employee Directors [Member]        
Note 16 - Subsequent Events (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross       399,929us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
/ us-gaap_TitleOfIndividualAxis
= prto_EmployeesAndCertainNonEmployeeDirectorsMember
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price       10.61us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
/ us-gaap_TitleOfIndividualAxis
= prto_EmployeesAndCertainNonEmployeeDirectorsMember