Income Taxes - Change in Valuation Allowance Account (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation Of Deferred Tax Assets, Valuation Allowance [Roll Forward]
Balance, beginning of year	$ 16,962	$ 6,511
Change in valuation allowance	642	10,451
Balance, end of year	17,604	$ 16,962
Valuation allowance for uncertain deferred tax assets attributable to U.S. federal and state NOLs	$ 17,600