Assumptions Used to Estimate Weighted Average Fair Value of Options Using Black-Scholes Option-Pricing Model (Detail)
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 25, 2011
Jun. 30, 2012
Jun. 25, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Risk-free interest rate 0.79% 0.76% 0.82% 0.76%
Expected volatility 124.41% 114.23% 114.69% 114.23%
Weighted average expected life (in years) 5 years 3 months 22 days 5 years 3 months 7 days 6 years 7 months 13 days 5 years 3 months 7 days
Expected dividends 0.00% 0.00% 0.00% 0.00%