Income Taxes (Details 2) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for doubtful accounts	$ 531	$ 559
Accrued liabilities and other	2,564	2,381
Stock-based compensation expense	296	599
Net federal, state and foreign operating loss carryforwards	1,953	1,432
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	266	0
Deferred tax assets	5,610	4,971
Valuation allowance on deferred tax assets	(1,385)	(1,502)
Deferred tax liabilities:
Other	1,181	208
Intangible assets, property and equipment, principally due to difference in depreciation and amortization	10,784	5,312
Net deferred tax liabilities	$ (7,740)	$ (2,051)