Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning of period	$ 10,842	$ 11,063
Decreases related to expired carryforwards	(1,171)	(729)
Increases related to current year tax positions	439	508
Unrecognized tax benefits at end of period	$ 10,110	$ 10,842