Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Summary of Fair Value of Option Awards (Detail)

v2.4.0.8
Common Stock - Summary of Fair Value of Option Awards (Detail)
9 Months Ended
Sep. 30, 2014
Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]    
Risk-free interest rates 1.83% 1.15%
Expected dividend yield 0.00% 0.00%
Expected life 5 years 10 months 24 days 5 years 9 months 18 days
Expected volatility 81.51% 87.02%