Stock Plans (Details 1) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Stock-based compensation expense        
Total stock-based compensation expense $ 1,166 $ 293 $ 1,834 $ 576
Cost of revenues [Member]
       
Stock-based compensation expense        
Total stock-based compensation expense 104 26 159 44
Research and development [Member]
       
Stock-based compensation expense        
Total stock-based compensation expense 260 30 387 48
Sales and marketing [Member]
       
Stock-based compensation expense        
Total stock-based compensation expense 439 85 700 143
General and administrative [Member]
       
Stock-based compensation expense        
Total stock-based compensation expense $ 363 $ 152 $ 588 $ 341