| Restructuring - TCR post-acquisition senior leadership severance (Details) $ in Thousands | 12 Months Ended | 
|---|---|
| Dec. 31, 2023  USD ($) | |
| Research and development | |
| Restructuring | |
| Accelerated vesting of share-based compensation awards | $ 200 | 
| General and administrative expenses | |
| Restructuring | |
| Accelerated vesting of share-based compensation awards | 800 | 
| Employee Severance | |
| Restructuring | |
| Severance and other cash payments | 5,655 | 
| Accelerated vesting of share-based compensation awards | 1,032 | 
| Total and cumulative amount incurred | $ 6,687 | 
| 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of additional cost recognized for award under share-based payment arrangement from occurrence of event accelerating recognition of cost. No definition available. 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |