Stock Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||
| Total stock-based compensation | $ 643,000 | $ 26,000 |
| Research and Development | ||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||
| Total stock-based compensation | 180,000 | 0 |
| General and Administrative | ||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||
| Total stock-based compensation | $ 463,000 | $ 26,000 |
| X | ||||||||||
- 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
|
| X | ||||||||||
- 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.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|