Summary of Significant Accounting Policies - Research and Development Expenditure (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Summary of Significant Accounting Policies | |||
| Acquired in-process R&D expensed | $ 210,000 | $ 1,003,000 | $ 3,000,000 |
| Grant income | 150,000 | 414,000 | |
| Reimbursement of Research and Development Tax and Expenditure Credit | $ 17,299,000 | $ 10,576,000 | $ 6,891,000 |
| X | ||||||||||
- Definition Represents the amount of reimbursement of grants. No definition available.
|
| X | ||||||||||
- Definition Reimbursement Of research and development tax and expenditure credit. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The amount of the write-off for research and development assets that were acquired in a transaction other than a business combination. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|