Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Employee Compensation (Details)

v2.4.0.8
Stock-Based Employee Compensation (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation expense $ 1,345 $ 884 $ 3,568 $ 3,175
Weighted average assumptions used in Black-Scholes valuation model [Abstract]        
Expected dividend yield (in hundredths) 0.00% 0.00% 0.00% 0.00%
Risk-free interest rate (in hundredths) 0.70% 0.40% 0.50% 0.40%
Expected volatility (in hundredths) 49.00% 49.00% 48.00% 51.00%
Expected life 3 years 6 months 3 years 8 months 12 days 3 years 7 months 6 days 3 years 8 months 12 days
Expected forfeiture rate (in hundredths) 7.00% 6.00% 6.00% 7.00%
Employee and director stock options [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation expense 904 798 2,828 2,622
Employee stock purchases [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation expense 441 86 740 553
Cost of revenues [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation expense 130 69 317 265
Sales and marketing [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation expense 260 197 678 692
Research and development [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation expense 353 204 812 726
General and administrative [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation expense $ 602 $ 414 $ 1,761 $ 1,492
Maximum [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Vesting period     5 years