Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Employee compensation	$ 24,018	$ 44,679
Manufacturing costs	25,957	23,126
Clinical and contract research organization costs	21,266	16,799
Collaboration research costs	19,732	27,142
Property, plant, and equipment	730	2,354
License and milestone fees	768	300
Professional fees	2,604	1,827
Other	23,016	25,329
Total accrued expenses and other current liabilities	$ 118,091	$ 141,556