v2.4.0.8
Summary of Information About Stock Options Outstanding (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Schedule Of Stock Option Activity [Line Items]    
Options outstanding, Number of Options 2,313,526 3,614,530
Options outstanding, Weighted average remaining life (years) 7 years 10 months 13 days 6 years 8 months 1 day
Options outstanding, Aggregate intrinsic value $ 2,845 $ 6,889
Options exercisable, Number of Options 808,633 1,008,031
Options exercisable, Weighted average remaining life (years) 6 years 5 months 5 days 5 years 10 months 28 days
Options exerciseable, Aggregate intrinsic value 2,471 5,082
$0.38
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price $ 0.38 $ 0.38
Options outstanding, Number of Options 57,264 145,406
Options outstanding, Weighted average remaining life (years) 8 years 26 days 9 years 26 days
Options outstanding, Aggregate intrinsic value 385 978
Options exercisable, Number of Options 57,264 145,406
Options exercisable, Weighted average remaining life (years) 8 years 26 days 9 years 26 days
Options exerciseable, Aggregate intrinsic value 385 978
$1.34
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price $ 1.34 $ 1.34
Options outstanding, Number of Options 106,777 257,680
Options outstanding, Weighted average remaining life (years) 3 years 1 month 6 days 4 years 1 month 6 days
Options outstanding, Aggregate intrinsic value 617 1,489
Options exercisable, Number of Options 106,777 257,680
Options exercisable, Weighted average remaining life (years) 3 years 1 month 6 days 4 years 1 month 6 days
Options exerciseable, Aggregate intrinsic value 617 1,489
$1.92
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price $ 1.92 $ 1.92
Options outstanding, Number of Options 23,143 23,143
Options outstanding, Weighted average remaining life (years) 4 years 3 months 5 years 3 months 4 days
Options outstanding, Aggregate intrinsic value 120 120
Options exercisable, Number of Options 23,143 23,143
Options exercisable, Weighted average remaining life (years) 4 years 3 months 5 years 3 months 4 days
Options exerciseable, Aggregate intrinsic value 120 120
$2.74
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price $ 2.74 $ 2.74
Options outstanding, Number of Options 186,286 312,572
Options outstanding, Weighted average remaining life (years) 4 years 7 months 13 days 5 years 6 months 15 days
Options outstanding, Aggregate intrinsic value 815 1,368
Options exercisable, Number of Options 186,286 307,572
Options exercisable, Weighted average remaining life (years) 4 years 7 months 13 days 5 years 6 months 15 days
Options exerciseable, Aggregate intrinsic value 815 1,346
$3.29
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price $ 3.29 $ 3.29
Options outstanding, Number of Options 183,442 564,286
Options outstanding, Weighted average remaining life (years) 6 years 9 months 7 days 7 years 6 months
Options outstanding, Aggregate intrinsic value 703 2,163
Options exercisable, Number of Options 126,014 212,929
Options exercisable, Weighted average remaining life (years) 6 years 8 months 19 days 7 years 4 months 6 days
Options exerciseable, Aggregate intrinsic value 483 816
$5.91
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price $ 5.91 $ 5.91
Options outstanding, Number of Options 169,857 363,142
Options outstanding, Weighted average remaining life (years) 7 years 7 months 21 days 8 years 4 months 28 days
Options outstanding, Aggregate intrinsic value 205 438
Options exercisable, Number of Options 42,571   
Options exercisable, Weighted average remaining life (years) 7 years 7 months 2 days  
Options exerciseable, Aggregate intrinsic value 51   
$7.12
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price $ 7.12 $ 7.12
Options outstanding, Number of Options 1,586,757 1,887,000
Options outstanding, Weighted average remaining life (years) 8 years 9 months 7 days 6 years 6 months 29 days
Options outstanding, Aggregate intrinsic value      
Options exercisable, Number of Options 266,578   
Options exercisable, Weighted average remaining life (years) 8 years 6 months 11 days  
Options exerciseable, Aggregate intrinsic value      
$1.68
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price   $ 1.68
Options outstanding, Number of Options   58,286
Options outstanding, Weighted average remaining life (years)   2 years 10 months 2 days
Options outstanding, Aggregate intrinsic value   317
Options exercisable, Number of Options   58,286
Options exercisable, Weighted average remaining life (years)   2 years 10 months 2 days
Options exerciseable, Aggregate intrinsic value   317
$1.96
   
Schedule Of Stock Option Activity [Line Items]    
Exercise price   $ 1.96
Options outstanding, Number of Options   3,015
Options outstanding, Weighted average remaining life (years)   9 years 26 days
Options outstanding, Aggregate intrinsic value   16
Options exercisable, Number of Options   3,015
Options exercisable, Weighted average remaining life (years)   9 years 26 days
Options exerciseable, Aggregate intrinsic value   $ 16