Transition report pursuant to Rule 13a-10 or 15d-10

Description of the Business and Basis of Presentation (Details)

v2.4.0.8
Description of the Business and Basis of Presentation (Details) (USD $)
 1 Months Ended 11 Months Ended 12 Months Ended
Sep. 30, 2013
Jul. 31, 2011
Jun. 30, 2011
Dec. 31, 2013
item
Jan. 31, 2013
Jan. 31, 2012
Initial Public Offering            
Shares of common stock issued in initial public offering     14,684,000      
Stock price (in dollars per share) $ 25.00 $ 16.00 $ 16.00      
Number of shares of common stock issued   350,000 6,000,682      
Public offering of common stock held by selling stockholders (in shares) 5,200,000   8,683,318      
Aggregate proceeds from initial public offering   $ 94,500,000       $ 90,632,000
Offering expenses   3,900,000        
Number of common shares issued on outstanding redeemable convertible preferred stock conversion     137,542,912      
Number of shares of common stock issued on exercise of warrant     154,938      
Follow-on Public Offering            
Issuance of common stock in connection with secondary offering (in shares) 15,730,000          
Number of shares of common stock sold pursuant to the exercise by the underwriters of an option to purchase additional shares 2,730,000          
Public offering price (in dollars per share) $ 25.00 $ 16.00 $ 16.00      
Number of shares sold by selling shareholder 5,200,000   8,683,318      
Aggregate net proceeds after deducting underwriting discounts and commissions and offering expenses $ 378,700,000     $ 378,654,000    
Segments            
Number of operating segments       1    
Fiscal year            
Current fiscal year end date       --12-31    
Fourth fiscal quarter transition period       2 months    
Current fiscal year transition period       11 months    
Corresponding fiscal year period         12 months 12 months