v3.8.0.1

Segment and Geographic Information - Geographical Information (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Geographical Information |  |  |  |  |  |  |  |  |  |  |
Revenue | $ 86,678 | $ 70,250 | $ 64,995 | $ 64,829 | $ 57,350 | $ 51,960 | $ 49,110 | $ 47,444 | $ 286,752 | $ 205,864 | $ 150,194
Short Course Segment |  |  |  |  |  |  |  |  |  |  |
Geographical Information |  |  |  |  |  |  |  |  |  |  |
Revenue |  |  |  |  |  |  |  |  | 16,320 |  |
Short Course Segment | Non-US |  |  |  |  |  |  |  |  |  |  |
Geographical Information |  |  |  |  |  |  |  |  |  |  |
Revenue |  |  |  |  |  |  |  |  | 10,000 |  |
Long-lived assets | $ 700 |  |  |  |  |  |  |  | $ 700 |  |

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