Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Valuation allowance	$ 256,413	$ 148,546	$ 135,046
Net operating loss carryforwards, no expiration	638,270
Net operating loss carryforwards, subject to expiration	80,528
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	718,798
Federal | Research Tax Credit Carryforward
Income Tax Contingency [Line Items]
Tax credit carryforward	0
Foreign
Income Tax Contingency [Line Items]
Net operating loss carryforwards	113,019
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	518,073
State | Research Tax Credit Carryforward
Income Tax Contingency [Line Items]
Tax credit carryforward	$ 4,230