|
Common Stock - Employee Stock Purchase Programs (Detail) (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | 93 Months Ended | |
|---|---|---|---|
|
Mar. 31, 2014
|
Mar. 31, 2013
|
Mar. 31, 2014
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total stock-based compensation expense | $ 1,135 | $ 1,523 | $ 14,549 |
|
Employee Awards [Member]
|
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total stock-based compensation expense | 1,122 | 972 | 9,194 |
|
Non-Employee Awards [Member]
|
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total stock-based compensation expense | 13 | 434 | 4,323 |
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Non-Employee Warrants [Member]
|
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total stock-based compensation expense | $ 0 | $ 117 | $ 1,032 |