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Organization and Summary of Significant Accounting Policies - Summary of Changes in Estimated Product Warranty Liabilities (Detail) (USD $)
9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Organization Consolidation And Presentation Of Financial Statements [Abstract]    
Balance, beginning of period $ 483,721 $ 427,459
Utilization of accrual (419,351) (312,570)
Warranty expense 643,674 265,140
Balance, end of period $ 708,044 $ 380,029