Income Taxes - Summary of Reconciliation of Company's Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Unrecognized tax benefit--beginning of year	$ 163	$ 163	$ 241
Decreases related to prior period positions	0	0	(78)
Unrecognized tax benefit--end of year	$ 163	$ 163	$ 163