Income Taxes - Reconciliation of Unrecognized Tax Benefit (Details) - 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]
Balance at beginning of year	$ 1,459	$ 943	$ 616
Additions for tax positions taken in current year	383	441	328
Increases in balance related to prior year tax positions	0	75	0
Decreases in balances related to prior year tax position	0	0	(1)
Balance at end of year	$ 1,842	$ 1,459	$ 943