Leases - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 8,732	$ 8,123	$ 7,985
Selling, general and administrative
Lessee, Lease, Description [Line Items]
Operating lease expense	7,974	7,959	$ 7,985
Research and development
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 758	$ 164