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Stockholders' Equity - Estimated Fair Value of ESPP Shares (Detail) (USD $)
12 Months Ended
Dec. 27, 2014
Dec. 28, 2013
Dec. 29, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected life   6 months 6 months
Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Volatility 46.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
46.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
54.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Risk-free interest rate 0.02%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
0.10%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
0.16%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Expected life 3 months    
Estimated fair value, (in usd per share) $ 2.05infn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEstimatedFairValueOfCommonStockPerShare
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
$ 1.87infn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEstimatedFairValueOfCommonStockPerShare
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
$ 1.73infn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEstimatedFairValueOfCommonStockPerShare
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Volatility 51.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
49.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
57.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Risk-free interest rate 0.11%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
0.14%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
0.17%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Expected life 6 months    
Estimated fair value, (in usd per share) $ 2.57infn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEstimatedFairValueOfCommonStockPerShare
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
$ 3.00infn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEstimatedFairValueOfCommonStockPerShare
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
$ 2.63infn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEstimatedFairValueOfCommonStockPerShare
/ us-gaap_RangeAxis
= us-gaap_MaximumMember