Stockholders' Equity - Schedule of Stock-based Compensation Related to All Employee And Non-employee Stock Awards (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
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Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
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| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Total stock-based compensation expense | $ 15,201 | $ 7,998 | $ 27,470 | $ 15,013 |
| Research and development | ||||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Total stock-based compensation expense | 6,672 | 3,384 | 12,737 | 6,316 |
| General and administrative | ||||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Total stock-based compensation expense | $ 8,529 | $ 4,614 | $ 14,733 | $ 8,697 |
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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://fasb.org/us-gaap/role/ref/legacyRef
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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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