Income Taxes (Summary of Operating Loss Carryforwards and Tax Credit Carryforwards) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Net deferred tax asset, net operating loss	$ 24,138	$ 12,812
Total net deferred tax asset	29,796	16,691
Total valuation allowance	15,459	8,520
Foreign tax authority
Operating Loss Carryforwards [Line Items]
Net deferred tax asset, net operating loss	2,109	915
Valuation allowance, net operating loss	2,109	915
State and local jurisdiction
Operating Loss Carryforwards [Line Items]
Net deferred tax asset, net operating loss	16,351	11,098
Valuation allowance, net operating loss	13,350	7,605
Net deferred tax asset, tax credit carryforwards, research	3,301	2,807
Net deferred tax asset, alternative minimum tax credit	8,035	1,871
Valuation allowance, tax credit	$ 0	$ 0