Income Taxes - Narrative (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Tax Credit Carryforward [Line Items]
Valuation allowance	$ 223,367	$ 211,228
Federal
Tax Credit Carryforward [Line Items]
Operating loss carryforward	464,800
Operating loss carryforwards, not subject to expiration	211,600
Federal | Research and Development
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	21,700
State and Local Jurisdiction
Tax Credit Carryforward [Line Items]
Operating loss carryforward	620,000
Operating loss carryforwards, not subject to expiration	36,800
State and Local Jurisdiction | Research and Development
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 15,800