Quarterly report pursuant to Section 13 or 15(d)

Weighted-Average Assumptions used to Estimate Fair Value of Stock Options and Restricted Stock Awards using Black-Scholes Valuation Model (Detail)

v2.4.0.8
Weighted-Average Assumptions used to Estimate Fair Value of Stock Options and Restricted Stock Awards using Black-Scholes Valuation Model (Detail)
3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]        
Expected volatility       100.80% 102.40%
Expected dividends       2.05% 5.07%
Expected term (in years)       6 years 7 months 6 days 8 years 2 months 12 days
Risk-free interest rate       1.06% 1.66%