Quarterly report pursuant to Section 13 or 15(d)

Stock Award Plans (Details 3)

v2.4.0.6
Stock Award Plans (Details 3) (Employee Stock Purchase Plan, USD $)
3 Months Ended
Mar. 31, 2013
item
Mar. 31, 2012
Employee Stock Purchase Plan
   
Weighted-average assumptions relating to options granted    
Risk-free interest rate (as a percent) 0.20% 0.10%
Expected term (in years) 1 year 4 months 24 days 6 months
Dividend yield (as a percent) 0.00% 0.00%
Expected volatility (as a percent) 58.00% 49.70%
Additional disclosures    
Shares reserved for future issuance 467,747  
Award offering period 24 months  
Number of purchase periods per award offering period 4  
Award purchase period 6 months  
Purchase price expressed as a percentage of fair market value of common stock on the first day of the offering period (as a percent) 85.00%  
Purchase price expressed as a percentage of fair market value of common stock on the purchase date (as a percent) 85.00%  
Total incremental fair value for the Purchase Plan reset $ 874,000