Income Taxes - Reconciliation of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Gross unrecognized tax benefits balance	$ 12,037	$ 12,406	$ 7,852
Addition for tax positions of current year	2,430	2,233	1,724
Addition for tax positions of prior years	133		6,624
Reduction of tax positions from prior years	(1,720)	(2,602)	(3,794)
Gross unrecognized tax benefits balance	$ 12,880	$ 12,037	$ 12,406