v2.4.0.8
Net Income (Loss) Per Share - Potentially Dilutive Securities Excluded from Calculation of Net Income (Loss) per Share (Detail)
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2013
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Dec. 31, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Antidilutive securities excluded from computation of earnings per share, amount   3,112,021 64,720,563 67,342,601 59,609,594
Common Shares Issuable Upon Conversion of All Series Preferred [Member]
         
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Antidilutive securities excluded from computation of earnings per share, amount     61,796,890 64,517,977 55,483,966
Options [Member]
         
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Antidilutive securities excluded from computation of earnings per share, amount 60,500 2,697,617 2,412,575 2,313,526 3,614,530
Warrant [Member]
         
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Antidilutive securities excluded from computation of earnings per share, amount   414,404 511,098 511,098 511,098