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Stockholders' Equity - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Oct. 22, 2014
Nov. 01, 2007
Equity [Abstract]          
Stock repurchase program, authorized amount         $ 50,000,000us-gaap_StockRepurchaseProgramAuthorizedAmount1
Stock repurchase program, additional authorized amount       30,000,000immr_StockRepurchaseProgramAdditionalAuthorizedRepurchaseAmount  
Repurchased shares 1,527,647us-gaap_TreasuryStockSharesAcquired 0us-gaap_TreasuryStockSharesAcquired 1,054,538us-gaap_TreasuryStockSharesAcquired    
Repurchased shares, value $ 15,000,000us-gaap_TreasuryStockValueAcquiredCostMethod   $ 5,721,000us-gaap_TreasuryStockValueAcquiredCostMethod    
Stock repurchase program, average cost $ 9.82us-gaap_TreasuryStockAcquiredAverageCostPerShare   $ 5.43us-gaap_TreasuryStockAcquiredAverageCostPerShare