Quarterly report pursuant to Section 13 or 15(d)

STOCK-BASED AWARDS AND PER SHARE INFORMATION - Assumptions Used in Estimating Fair Value of Stock Options Granted (Detail)

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STOCK-BASED AWARDS AND PER SHARE INFORMATION - Assumptions Used in Estimating Fair Value of Stock Options Granted (Detail) (USD $)
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Assumptions used in estimating the fair value of stock options granted        
Expected term 3 years 8 months 12 days 4 years 3 months 18 days 3 years 9 months 18 days 4 years 29 days
Volatility 97.00% 105.00% 101.00% 106.00%
Annual dividend per share $ 0.00 $ 0.00 $ 0.00 $ 0.00
Risk-free interest rate 0.68% 1.23% 0.81% 1.70%