Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued Liabilities Current [Abstract]
Payroll and employee-related costs	$ 11,565	$ 22,402
Research costs	22,034	21,684
Licensing fees	930	1,401
Professional fees	1,874	1,670
Intellectual property costs	5,229	3,625
Accrued property and equipment	6,869	2,835
Other	1,363	165
Total	$ 49,864	$ 53,782