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Equity - Additional Information (Detail) (USD $)
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1 Months Ended |
3 Months Ended |
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|
Jul. 31, 2014
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Mar. 31, 2015
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Mar. 31, 2014
|
Dec. 31, 2014
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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|
|
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| Shares granted during the period |
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1,271,391 |
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| Options outstanding, shares |
|
2,769,259 |
|
1,847,669 |
| Shares Issued with debt conversion |
348,535 |
|
|
|
| Stock-based compensation expense |
|
$ 5,300,000 |
$ 4,400,000 |
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| Total unrecognized compensation expense |
|
50,200,000 |
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| Employee Stock Option |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
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| Stock-based compensation expense |
|
3,000,000 |
1,600,000 |
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| Total unrecognized compensation expense |
|
23,600,000 |
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| Restricted Stock Units |
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|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
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| Stock-based compensation expense |
|
2,300,000 |
2,800,000 |
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| Total unrecognized compensation expense |
|
26,600,000 |
|
|
| Performance based stock options [Member] |
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|
|
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
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| Shares granted during the period |
|
155,500 |
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| 3.75% Convertible Notes |
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|
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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|
|
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| Principal amount of debt converted |
28,500,000 |
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