Annual report pursuant to Section 13 and 15(d)

Equity - Additional Information (Detail)

v2.4.0.8
Equity - Additional Information (Detail) (USD $)
 1 Months Ended 12 Months Ended 90 Months Ended 12 Months Ended 0 Months Ended 0 Months Ended 12 Months Ended
Jul. 31, 2013
Apr. 30, 2013
Oct. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2013
Sep. 30, 2013
Nov. 15, 2011
May 31, 2011
Jun. 01, 2007
Dec. 31, 2011
Additional Paid-in Capital [Member]
Sep. 30, 2013
Before Amendment [Member]
Sep. 30, 2013
After Amendment [Member]
Jun. 01, 2007
2007 Stock Incentive Plan [Member]
Jun. 01, 2007
PBS [Member]
Nov. 15, 2011
Convertible Series A Preferred Stock [Member]
Dec. 31, 2013
Convertible Series A Preferred Stock [Member]
Dec. 31, 2012
Convertible Series A Preferred Stock [Member]
Nov. 15, 2011
Series B Convertible Preferred Stock [Member]
Nov. 15, 2011
Series C Preferred Stock [Member]
Dec. 31, 2011
Series C Preferred Stock [Member]
Dec. 31, 2013
Series C Preferred Stock [Member]
Dec. 31, 2012
Series C Preferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                                                        
Convertible Preferred Stock, Authorized Number Of Shares                                           15,000,000         129,767 584,390
Preferred Stock, Par Value                                           $ 0.001         $ 0.001 $ 0.001
Preferred Stock, Shares Outstanding                                           0 0       0 0
Convertible Preferred stock number of preferred stock converted into common stock                                         4,357,885     2,525,677 4,612,624 4,612,624    
Convertible Preferred Stock, Common stock issued upon conversion                         11,496,186                              
Fully Vested Common stock issued to founders                             2,125,096                          
Fully Vested Common stock issued to founders, par value                             $ 0.001                          
Shares of restricted Common Stock were granted to certain employees                                     457,170 2,180,000                
Common Stock, par value           $ 0.001 $ 0.001       $ 0.001 $ 0.001               $ 0.001                
Fully vested Common Stock issued for compensation of past services                 23,836 5,000                                    
Fully vested Common Stock issued for compensation of past services, Fair Value                 $ 82,000                                      
Number of Shares, Options exercised           (550,157)                   138,080                        
Proceeds from Stock Options Exercised               193,000                                        
Declared a dividend for Series A Convertible Preferred Stock                           2,178,917                            
Public offering of Common Stock, shares         5,750,000 10,558,422 3,361                                          
Common Stock issued under public offer, over allotment issued to underwriters         750,000                                              
Common Stock issued during the period, price per share         $ 5.00                                              
Proceeds from issuance of Common Stock         26,400,000 92,399,000 28,855,000 193,000     121,452,000                                  
Capital Units, Authorized                                 65,000,000 115,000,000                    
Common Stock Shares Authorized           100,000,000 50,000,000       100,000,000           50,000,000 100,000,000                    
Common Stock Offering Price           70,000,000         70,000,000                                  
Stock Issuance, Maximum Amount Of Proceeds Approved $ 200,000,000 $ 45,000,000 $ 30,000,000 $ 75,000,000