Income Taxes - Effect of Temporary Differences and Carryforwards (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 131,971	$ 100,927
Research and development tax credit carryforwards	12,028	9,513
Deferred tax assets, deferred lease liability	6,423	6,962
Stock-based compensation	6,287	5,221
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	659	648
Accruals and other	10,139	8,138
Total deferred tax assets before allowance	167,507	131,409
Less: Valuation allowance	(162,817)	(114,335)	$ (106,438)	$ (88,596)
Deferred tax assets, net	4,690	17,074
Deferred Tax Liabilities, Leasing Arrangements	(4,690)	(5,029)
DeferredTaxLiabilitiesDebtDiscount	0	(12,045)
Deferred Tax Liabilities, Gross	(4,690)	(17,074)
Deferred Tax Assets, Net	$ 0	$ 0