Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

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Income Taxes - Additional Information (Detail) (USD $)
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Income Tax Expenses [Line Items]    
Valuation allowance $ 33,341,000 $ 33,784,000
Foreign operations 16,000 8,000
Net operating loss carryforwards federal 67,000,000  
Net operating loss carryforwards state 42,800,000  
Operating loss carryforwards, expire beginning 2013  
Cumulative unrealized excess tax deductions 6,400,000  
Unrealized tax benefits, if realized, would increase in additional paid-in-capital 1,500,000  
Valuation allowance percentage against the state deferred tax asset 100.00%  
Unrecognized tax benefits, amount that would impact effective tax rate if recognized 91,000  
Unrecognized tax benefits, penalties payable 18,000  
Unrecognized tax benefits, interest payable 29,000  
Federal
    
Income Tax Expenses [Line Items]    
Research and development tax credit carryforwards 786,000  
Research and development tax credit carryforwards expire beginning 2018  
State
    
Income Tax Expenses [Line Items]    
Research and development tax credit carryforwards $ 319,000