Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Summary of Restricted Stock Unit Award Activity (Detail)

v2.4.0.8
Common Stock - Summary of Restricted Stock Unit Award Activity (Detail) (Restricted stock unit awards [Member], USD $)
9 Months Ended
Sep. 30, 2014
Restricted stock unit awards [Member]
 
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Stock Awards, Beginning Balance 356,589
Stock Awards, Granted 801,800
Stock Awards, Vested (199,849)
Stock Awards, Forfeited or expired (275,732)
Stock Awards, Ending Balance 682,808
Weighted-Average Grant Date Fair Value, Beginning Balance $ 12.06
Weighted-Average Grant Date Fair Value, Granted $ 6.55
Weighted-Average Grant Date Fair Value, Vested $ 7.00
Weighted-Average Grant Date Fair Value, Forfeited or expired $ 11.22
Weighted-Average Grant Date Fair Value, Ending Balance $ 7.41