Segment and Geographical Information - Long-lived Assets (Details) - Geographic Concentration Risk - Net Assets, Geographic Area - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||
| Long-lived assets | $ 50,360 | $ 45,719 |
| Long-lived assets (as a percent) | 100.00% | 100.00% |
| Canada | ||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||
| Long-lived assets | $ 40,309 | $ 33,863 |
| Long-lived assets (as a percent) | 80.00% | 74.10% |
| United States | ||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||
| Long-lived assets | $ 9,633 | $ 11,689 |
| Long-lived assets (as a percent) | 19.20% | 25.50% |
| Rest of World | ||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||
| Long-lived assets | $ 418 | $ 167 |
| Long-lived assets (as a percent) | 0.80% | 0.40% |