Consolidated Financial Statement Components - Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Supplemental Balance Sheet Information [Abstract]
Accrued network costs, asset retirement obligations and other	$ 2,173	$ 2,168
Accrued outside services	2,053	1,442
Total other current liabilities	$ 4,226	$ 3,610