v2.4.0.6
Share-based Compensation - Summary of Status of Pre-IPO Equity Rights and Changes (Detail) (Equity Rights [Member], EUR €)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Equity Rights [Member]
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares, Outstanding at January 1 444,395 472,742
Shares, Granted      
Shares, Released (381,630)   
Shares, Forfeited    (28,347)
Shares, Outstanding at December 31 62,765 444,395
Shares, Exercisable at December 31      
Weighted average grant date fair value, Outstanding at January 1 € 9.34 € 9.13
Weighted average grant date fair value, Granted      
Weighted average grant date fair value, Released € 9.10   
Weighted average grant date fair value, Forfeited    € 5.80
Weighted average grant date fair value, Outstanding at December 31 € 10.80 € 9.34
Weighted average grant date fair value, Exercisable at December 31