Financial Statement Components - Allowance For Doubtful Accounts (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Allowance for Doubtful Accounts Receivable [Roll Forward] | |||
Revenue | $ 162,955 | $ 152,135 | $ 137,801 |
Carrier Access Billing (CAB) | |||
Allowance for Doubtful Accounts Receivable [Roll Forward] | |||
Billings deemed not probable of collection | 10,024 | 10,494 | 7,163 |
Billed | 19,147 | 19,838 | 15,617 |
Revenue | 9,123 | 9,344 | 8,454 |
Accounts Receivable, Excluding Carrier Access Billing (CAB) | |||
Allowance for Doubtful Accounts Receivable [Roll Forward] | |||
Balance, beginning of period | 255 | 238 | |
Billings deemed not probable of collection | 176 | 238 | |
Deductions | (242) | (221) | |
Balance, end of period | 189 | 255 | 238 |
Carrier Access Billing (CAB) | |||
Allowance for Doubtful Accounts Receivable [Roll Forward] | |||
Balance, beginning of period | 22,316 | 12,317 | |
Billings deemed not probable of collection | 10,024 | 10,494 | |
Deductions | (66) | (495) | |
Balance, end of period | $ 32,274 | $ 22,316 | $ 12,317 |