Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Effective tax rate	0.00%	0.00%
Deferred tax assets, valuation allowance	$ 55,639	$ 47,809
Change in valuation allowance	7,830
Federal net operating loss carry-forwards	191,345
State net operating loss carry-forwards	$ 122,168
Minimum maturity period for federal net operating loss carry-forward	5 years
Minimum maturity period for state net operating loss carry-forward	5 years
Federal research and experimental tax credits	$ 9,276
State research and experimental tax credits	$ 884
Minimum maturity period for federal research and experimental tax credit carry-forward	5 years
Maximum maturity period for federal research and experimental tax credit carry-forward	20 years
Minimum maturity period for state research and experimental tax credit carry-forward	5 years
Maximum maturity period for state research and experimental tax credit carry-forward	20 years
Accrued interest and penalties associated with uncertain tax positions	$ 0	$ 0