Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Federal income tax benefit			$ 0	$ 0
State income tax benefit			0	0
Provision for income taxes	$ 2	$ 0	$ 14	$ 148