Significant Accounting Policies Significant Accounting Policies - Depreciation and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Depreciation and Amortization [Line Items]
Depreciation and amortization	$ 6,336	$ 6,094	$ 6,578
Cost of revenue
Schedule of Depreciation and Amortization [Line Items]
Depreciation and amortization	3,942	3,610	4,019
Sales and marketing
Schedule of Depreciation and Amortization [Line Items]
Depreciation and amortization	775	884	998
Research and development
Schedule of Depreciation and Amortization [Line Items]
Depreciation and amortization	353	371	424
General and administrative
Schedule of Depreciation and Amortization [Line Items]
Depreciation and amortization	$ 1,266	$ 1,229	$ 1,137