Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Share-Based Compensation (Detail)

v2.4.0.8
Summary of Significant Accounting Policies - Share-Based Compensation (Detail)
6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Accounting Policies [Abstract]    
Expected term (in years) 4 years 4 years
Expected volatility 84.10% 118.11%
Risk free rate 0.60% 0.63%
Expected dividends 0.00% 0.00%