Commitments and Contingencies - Narrative (Details) € in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 EUR (€) facility	Sep. 30, 2021 USD ($) facility	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) facility
Lessee, Lease, Description [Line Items]
Operating lease liability | $						$ 657
Non-cash lease expense | $	$ 85	$ 267		$ 252	$ 915
Los Angeles, California
Lessee, Lease, Description [Line Items]
Number of facilities			3	3
Number of facilities occupied			2			2
Boston, Massachusetts
Lessee, Lease, Description [Line Items]
Number of facilities			1	1
Dallas, Texas
Lessee, Lease, Description [Line Items]
Number of facilities			1	1
Munich, Germany
Lessee, Lease, Description [Line Items]
Contract termination fee | €			€ 125
Operating lease liability | €			316
Termination of lease			€ 191	$ 227
Minimum
Lessee, Lease, Description [Line Items]
Term of contract			1 year			1 year
Renewal term			12 months			12 months
Maximum
Lessee, Lease, Description [Line Items]
Term of contract			3 years			3 years
Renewal term			5 years			5 years