Income Taxes - Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 8,635	$ 6,678
Increase in valuation allowance	2,000	$ 1,000
Foreign
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 1,000