Income Taxes - Net Deferred Tax Assets Balance Sheet Presentation (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Non-current net deferred tax assets	$ 30,613	$ 27,224
Non-current net deferred tax assets (liabilities)	0	(39)
Net deferred tax assets	$ 30,613	$ 27,185

Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards classified as noncurrent.

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Balance Type:	debit
Period Type:	instant