XML 48 R35.htm IDEA: XBRL DOCUMENT v2.4.0.8
Shared-Based Payments - Additional Information (Detail) (USD $)
 9 Months Ended 12 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Dec. 31, 2010
Dec. 31, 2008
Dec. 31, 2006
Dec. 31, 2003
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]              
Aggregate of shares             2,051,644
Increase in aggregate of shares     4,336,731 3,790,760 3,258,106 2,512,390  
Common Stock     545,970 532,654 745,716 460,746  
Shares available for issuance 8,171            
Expected life of option term 7 years 7 years          
Aggregate intrinsic value of options outstanding $ 17,400,000            
Aggregate intrinsic value of options exercisable 12,200,000            
Equity Incentive Plan 2003 [Member]
              
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]              
Expected life of option term 7 years            
Weighted-average grant-date fair value of options granted $ 2.00            
Total cash received for the options exercised 851,183            
Fair value of shares vested 402,084            
Unrecognized compensation expense recognition period 4 years            
Equity Incentive Plan 2003 [Member] | Equity Incentive Plan Two Thousand [Member]
              
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]              
Unrecognized compensation cost related to non-vested stock-based compensation arrangements $ 1,500,000            
Equity Incentive Plan 2003 [Member] | Maximum [Member]
              
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]              
Options granted, maximum term 10 years            
Stock Option Plan 2000 [Member]
              
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]              
Aggregate of shares 130,725            
Increase in aggregate of shares 150,297