Share-Based Compensation - Summary of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 192	$ 156	$ 336	$ 198
Cost of Revenues
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	5	7	9	7
Selling and Marketing
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	65	43	119	56
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	87	92	142	108
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 35	$ 14	$ 66	$ 27