Stock-based Compensation - Schedule of Recognized Stock-Based Compensation (Details) - USD ($) |
12 Months Ended | |
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Dec. 31, 2018 |
Dec. 31, 2017 |
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| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Share-based compensation expense | $ 3,833,000 | $ 3,597,000 |
| Research and Development [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Share-based compensation expense | 896,000 | 1,016,000 |
| General and Administrative [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Share-based compensation expense | $ 2,937,000 | $ 2,581,000 |
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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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