Accrued Expenses - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities, Current [Abstract]
Accrued compensation and related liabilities	$ 8,941	$ 11,050
Accrued contract payments	15,706	9,756
Accrued cash settled stock-based compensation	3,282	3,719
Other	10,804	14,666
Total accrued expenses	$ 38,733	$ 39,191