Common Stock Options (Narrative) (Details) (USD $)
 1 Months Ended 3 Months Ended 0 Months Ended 3 Months Ended
Mar. 31, 2012
May 04, 2013
Apr. 28, 2012
Aug. 25, 2010
2002 Equity Incentive Plan [Member]
May 04, 2013
2002 Equity Incentive Plan [Member]
Jul. 24, 2012
2002 Equity Incentive Plan [Member]
May 04, 2013
Restricted Shares [Member]
Feb. 02, 2013
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Stock options and restricted shares available for grant (shares)           7,600,000    
Stock option maximum term (years)         10 years      
Vesting period from the date of grant (years) 2 years       4 years      
Shares available for issuance (shares)         4,873,709      
Period following board of directors resolution for exercise of options outstanding (days)       20 days        
Deposit liability             $ 228,000 $ 308,000
Weighted average grant-date fair value of stock options granted (dollars per share)   $ 18.15 $ 4.36          
Unrecognized compensation costs related to non-vested share-based compensation   $ 13,300,000            
Unrecognized compensation costs related to nonvested share-based compensation, recognition period (years)   2 years