Summary of Significant Accounting Policies - Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Payroll related	$ 10,087	$ 10,304
Interest	155	160
Current operating lease liability	85	828
Other accrued expenses	1,128	1,105
Total accrued expenses	$ 11,455	$ 12,397