XML 46 R45.htm IDEA: XBRL DOCUMENT v2.4.1.9
Capital Stock and Warrants - Additional Information (Detail) (USD $)
 1 Months Ended 12 Months Ended
Aug. 31, 2013
Dec. 28, 2014
Dec. 29, 2013
Aug. 01, 2014
Equity [Abstract]        
Capital stock, authorized   210,000,000us-gaap_CapitalUnitsAuthorized 210,000,000us-gaap_CapitalUnitsAuthorized  
Common stock, authorized   200,000,000us-gaap_CommonStockSharesAuthorized 200,000,000us-gaap_CommonStockSharesAuthorized  
Preferred stock, authorized   10,000,000us-gaap_TemporaryEquitySharesAuthorized 10,000,000us-gaap_TemporaryEquitySharesAuthorized  
Common stock, issued   29,761,790us-gaap_CommonStockSharesIssued 29,148,029us-gaap_CommonStockSharesIssued  
Common stock, outstanding   28,934,700us-gaap_CommonStockSharesOutstanding 29,148,029us-gaap_CommonStockSharesOutstanding  
Terms of non-voting Common stock conversion basis ratio   The terms of the non-voting common stock provided that all shares of non-voting common stock would convert into voting common stock on a 1:1 basis immediately prior to the closing of an underwritten IPO or sale of the Company.    
Non-voting Common stock conversion basis ratio   1pbpb_CommonStockConversionBasisRatio    
Stock repurchase program, authorized amount       $ 35,000,000us-gaap_StockRepurchaseProgramAuthorizedAmount1
Common stock shares repurchased   827,090us-gaap_TreasuryStockSharesAcquired    
Common stock repurchased value   10,246,000us-gaap_TreasuryStockValueAcquiredCostMethod    
Remaining dollar value of authorization under the share repurchase program   24,800,000us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1    
Preferred stock dividend rate   6.00%us-gaap_PreferredStockDividendRatePercentage    
Minimum percentage of liquidation value to be paid   110.00%pbpb_DistributionOnOccurrenceOfSignificantEventAsPercentageOfSharesLiquidationValue    
Percentage of liquidation value to be paid   Dividends were cumulative, but were payable only upon their redemption or the occurrence of a significant event that would result in a distribution to their holders of less than 110% of the shares' liquidation value    
Redemption election period   12 months    
Modification of warrants issued 241,704pbpb_AdjustmentOfWarrantsDueToExtendingExpirationDate      
Expiration date of warrants   5 years    
Recognized stock compensation expense $ 100,000us-gaap_AllocatedShareBasedCompensationExpense   $ 10,000,000us-gaap_AllocatedShareBasedCompensationExpense