Stock Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
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Jun. 30, 2015 |
Jun. 30, 2014 |
Jun. 30, 2015 |
Jun. 30, 2014 |
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| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ||||
| Stock-based compensation expense | $ 1,895 | $ 1,468 | $ 3,316 | $ 2,734 |
| Research and Development | ||||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ||||
| Stock-based compensation expense | 1,174 | 846 | 1,991 | 1,517 |
| General and Administrative | ||||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ||||
| Stock-based compensation expense | $ 721 | $ 622 | $ 1,325 | $ 1,217 |
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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