Stockholders' Equity and Employee Stock Option Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Stock-based Compensation Expense
Stock-based Compensation Expense, Total	$ 444	$ 467
Cost of Revenues [Member]
Stock-based Compensation Expense
Stock-based Compensation Expense, Total	58	29
Product development [Member]
Stock-based Compensation Expense
Stock-based Compensation Expense, Total	94	124
Sales and marketing [Member]
Stock-based Compensation Expense
Stock-based Compensation Expense, Total	88	102
General and administrative [Member]
Stock-based Compensation Expense
Stock-based Compensation Expense, Total	$ 204	$ 212