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Stockholders' Equity - Outstanding Warrants Valuation Assumption (Detail) (USD $)
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12 Months Ended | |
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Dec. 31, 2012
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Dec. 31, 2011
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August 2008 offering [Member]
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| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||
| Risk-free interest rate | 0.16% | 0.25% |
| Expected life (in years) | 7 months 28 days | 1 year 7 months 28 days |
| Dividend yield | ||
| Volatility | 118.00% | 84.00% |
| Stock price | $ 4.21 | $ 1.22 |
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October 2009 offering [Member]
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| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||
| Risk-free interest rate | 0.25% | 0.36% |
| Expected life (in years) | 1 year 9 months 4 days | 2 years 9 months 4 days |
| Dividend yield | ||
| Volatility | 98.00% | 88.00% |
| Stock price | $ 4.21 | $ 1.22 |
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March 2011 offering [Member]
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| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||
| Risk-free interest rate | 0.72% | 0.60% |
| Expected life (in years) | 3 years 2 months 16 days | 4 years 2 months 16 days |
| Dividend yield | ||
| Volatility | 94.00% | 102.00% |
| Stock price | $ 4.21 | $ 1.22 |
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- Details
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| X | ||||||||||
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- Definition
Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Risk-free interest rate assumption used in valuing an instrument. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Price of a single share of a number of saleable stocks of a company. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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