Income Taxes - Schedule of Aggregate Changes in Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 1,595	$ 354	$ 163
Increases for tax positions taken during current period	2,754	1,212	178
Increases for tax positions taken in prior periods	882	29	13
Balance at end of year	$ 5,231	$ 1,595	$ 354