Revenue from Contracts with Customers (ASC 606) (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ 15,397				$ 4,417				$ 15,397	$ 4,417		$ 7,165
Total liabilities	88,137				90,574				88,137	90,574		102,692
Total assets	$ 187,652				196,239				$ 187,652	196,239		205,609
Amortization period of customer contract costs	5 years								5 years
Non-current deferred income tax asset	$ 226				20				$ 226	20		222
Deferred revenue and associated fulfillment costs, recognition period									5 years
Decrease in revenues									$ (170,761)	(160,088)	$ (176,122)
Net loss	(1,822)	$ (1,174)	$ (1,343)	$ (3,893)	$ (1,685)	$ (2,438)	$ (2,026)	$ (4,885)	$ (8,232)	$ (11,034)	$ (7,517)
Net loss per common share, basic and diluted (in dollars per share)									$ (0.48)
Revenue recognized									$ 4,670
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit												2,748
Total liabilities	13,430								13,430			12,118
Total assets	$ 10,677								10,677			9,370
Non-current deferred income tax asset												202
Decrease in revenues									1,311
Decrease in cost of revenues									1,257
Net loss									$ (5)
Net loss per common share, basic and diluted (in dollars per share)									$ 0
Commissions | Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit												$ 191