Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit, beginning of period	$ 1,595	$ 1,135
Gross increases — current year tax positions	595	422
Gross increases — prior year tax positions	0	38
Gross decreases — prior year tax positions	(32)	0
Unrecognized tax benefit, end of period	$ 2,158	$ 1,595