v2.4.0.6
Net income per share attributable to common stockholders: (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Numerator:        
Net income attributable to common stockholders, basic and diluted $ 2,777 $ 1,662 $ 5,895 $ 2,807
Denominator:        
Weighted average common shares, basic 35,080,000 33,139,000 34,618,000 20,865,000
Effect of dilutive stock options (in shares) 2,257,000 3,539,000 2,706,000 3,567,000
Effect of dilutive common stock warrants (in shares)       21,000
Weighted average common shares, dilutive 37,337,000 36,678,000 37,324,000 24,453,000
Net income per share attributable to common stockholders:        
Basic (in dollars per share) $ 0.08 $ 0.05 $ 0.17 $ 0.13
Diluted (in dollars per share) $ 0.07 $ 0.05 $ 0.16 $ 0.11
Anti-dilutive securities        
Anti-dilutive securities excluded from the computation of diluted net income per share 2,478,000 2,174,000 2,442,000 12,484,000
Convertible preferred stocks
        
Anti-dilutive securities        
Anti-dilutive securities excluded from the computation of diluted net income per share       10,293,000
Options to purchase common stock
        
Anti-dilutive securities        
Anti-dilutive securities excluded from the computation of diluted net income per share 2,478,000 2,174,000 2,442,000 2,174,000
Warrants to purchase preferred stock
        
Anti-dilutive securities        
Anti-dilutive securities excluded from the computation of diluted net income per share       17,000