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Employee Benefit / Incentive Award Plan - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified |
3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|---|---|---|---|---|
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Sep. 30, 2013
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Sep. 30, 2013
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Jun. 19, 2013
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Sep. 30, 2013
Research and Development Expense
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Sep. 30, 2013
Research and Development Expense
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Sep. 30, 2013
Directors Officers And Employees [Member]
|
Sep. 30, 2013
Stock Options
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Sep. 30, 2013
Non-vested shares of restricted stock
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Sep. 30, 2013
Performance Shares
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Dec. 31, 2012
Performance Shares
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||||||
| Number of shares authorized under plan | 5,938,498 | 5,938,498 | ||||||||
| Shares of common stock available for issuance | 2,900,000 | 2,900,000 | 3,100,000 | 45,000 | ||||||
| Grants in period (in shares) | 400,000 | |||||||||
| Deferred compensation expense | $ 3.2 | |||||||||
| Outstanding non vested restricted shares | 1,800,000 | |||||||||
| Stock-based compensation expense | 4.1 | 4.1 | 2.8 | 6.9 | ||||||
| Unamortized Stock Based Compensation Expense | $ 19.7 | $ 15.7 | ||||||||