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Commitments and Contingencies (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Rent expense $ 445,000us-gaap_LeaseAndRentalExpense $ 445,000us-gaap_LeaseAndRentalExpense
Minimum future lease obligations    
2015 492,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent  
2016 82,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears  
Accrued liabilities    
Rent expense from partial abandonment of office space for remaining lease term $ 118,000isig_LeaseAndRentalExpensePartialAbandonmentExpense
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherCurrentLiabilitiesMember