| Commitment and Contingencies - Additional Information (Details) € in Thousands | Dec. 31, 2019  USD ($) | Dec. 31, 2018  USD ($) | Jun. 30, 2018  USD ($) | Jun. 30, 2018  EUR (€) | Jun. 30, 2016  USD ($) | Jun. 30, 2016  EUR (€) | Nov. 18, 2015  USD ($) | 
|---|---|---|---|---|---|---|---|
| Other Commitments [Line Items] | |||||||
| Purchase obligation | $ 0 | $ 1,604,000 | $ 2,807,000 | € 2,500 | |||
| Pfizer License Agreement | Minimum | |||||||
| Other Commitments [Line Items] | |||||||
| Potential future regulatory milestone and sales milestone payments upon achievement of net sales | $ 250,000,000 | ||||||
| Pfizer License Agreement | Maximum | |||||||
| Other Commitments [Line Items] | |||||||
| Potential future regulatory milestone and sales milestone payments upon achievement of net sales | $ 1,000,000,000 | ||||||
| Supplemental Agreement | |||||||
| Other Commitments [Line Items] | |||||||
| Purchase obligation | $ 2,301,000 | € 2,050 | 
| X | ||||||||||
| 
- Definition Potential future regulatory and sales milestone payments upon achievement of net sales. No definition available. 
 | 
| 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 | ||||||||||
| 
- Definition Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier. No definition available. 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |