| Stock-Based Compensation - Schedule of Stock Based Compensation (Details) - USD ($) | 3 Months Ended | |
|---|---|---|
| Mar. 31, 2020 | Mar. 31, 2019 | |
| Total stock-based compensation expense | $ 1,256,000 | $ 2,103,000 | 
| Stock Option [Member] | ||
| Total stock-based compensation expense | 1,256,000 | 2,103,000 | 
| Tax benefit | ||
| Stock based compensation expense, net of tax | 1,256,000 | 2,103,000 | 
| Stock Option [Member] | Research and Development Expense [Member] | ||
| Total stock-based compensation expense | 744,000 | 1,032,000 | 
| Stock Option [Member] | General and Administrative Expenses [Member] | ||
| Total stock-based compensation expense | 512,000 | 1,071,000 | 
| Restricted Stock [Member] | ||
| Total stock-based compensation expense | 464,000 | 172,000 | 
| Tax benefit | ||
| Stock based compensation expense, net of tax | 464,000 | 172,000 | 
| Restricted Stock [Member] | Research and Development Expense [Member] | ||
| Total stock-based compensation expense | 325,000 | |
| Restricted Stock [Member] | General and Administrative Expenses [Member] | ||
| Total stock-based compensation expense | $ 139,000 | $ 172,000 | 
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