Accrued expenses and other current liabilities - Summary of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Employee compensation	$ 44,679	$ 28,567
Manufacturing costs	23,126	21,618
Clinical and contract research organization costs	16,799	11,891
Collaboration research costs	27,142	3,358
Property, plant, and equipment	2,354	5,451
License and milestone fees	300	7,739
Professional fees	1,827	1,830
Financing lease obligation, current portion	0	1,424
Other	25,329	17,515
Total accrued expenses and other current liabilities	$ 141,556	$ 99,393