Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Feb. 29, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Aggregate lease payments	$ 15,745			$ 14,899
Short-term lease cost	157	$ 328
Cash paid for amounts included in measurement of lease liabilities	600	$ 300
Right-of-use asset obtained in exchange for new operating lease liabilities	$ 1,200
Weighted average remaining lease term	6 years 9 months 18 days
Weighted-average discount rate (percent)	6.20%
Maidenhead, United Kingdom Lease
Lessee, Lease, Description [Line Items]
Term of new lease			5 years
Aggregate lease payments			$ 1,500
Short-term Lease Terminated in March 2019
Lessee, Lease, Description [Line Items]
Short-term lease cost	$ 200