Annual report pursuant to Section 13 and 15(d)

Debt - Related Party Interest Expense Concerning Bridge Loan (Detail)

v2.4.1.9
Debt - Related Party Interest Expense Concerning Bridge Loan (Detail) (Bridge Loan [Member], USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Short-term Debt [Line Items]    
Interest expense related party $ 204,110us-gaap_InterestExpenseRelatedParty $ 250,556us-gaap_InterestExpenseRelatedParty
Orbimed Private Investments III, LP [Member]
    
Short-term Debt [Line Items]    
Interest expense related party 63,955us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_OrbimedPrivateInvestmentsIiiLpMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember 		78,411us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_OrbimedPrivateInvestmentsIiiLpMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember
Global Life Science Ventures Funds [Member]
    
Short-term Debt [Line Items]    
Interest expense related party 57,709us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_GlobalLifeScienceVenturesFundMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember 		70,131us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_GlobalLifeScienceVenturesFundMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember
Gilde Europe Food & Agribusiness Fund B.V [Member]
    
Short-term Debt [Line Items]    
Interest expense related party 54,158us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_GildeEuropeFoodAgribusinessFundMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember 		67,083us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_GildeEuropeFoodAgribusinessFundMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember
Forbion B.V [Member]
    
Short-term Debt [Line Items]    
Interest expense related party $ 28,288us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_ForbionMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember 		$ 34,930us-gaap_InterestExpenseRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= pirs_ForbionMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_BridgeLoanMember