Income Taxes - Schedule of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance at beginning of year	$ 1,014	$ 1,521
Increase (decrease) related to prior year tax positions	(507)	(507)
Balance at end of year	$ 507	$ 1,014