| Accrued expenses and other current liabilities | 6 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Jun. 30, 2018 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accrued expenses and other current liabilities | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accrued expenses and other current liabilities | 
 Note 9 — Accrued expenses and other current liabilities 
 Accrued expenses and other current liabilities consisted of the following (in thousands): 
 
 
 The Company typically has a receivable for VAT. As of December 31, 2017, there was a VAT payable due to VAT arising on the milestone payments invoiced to GSK in 2017. 
 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||