Segment Information - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||||
| Revenues from customers | $ 38,753 | $ 36,960 | $ 76,325 | $ 73,252 |
| Revenue percentage from other countries other than united States and Japan to the company's total revenue | 10.00% | 10.00% | 10.00% | 10.00% |
| United States [Member] | ||||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||||
| Revenues from customers | $ 20,585 | $ 21,160 | $ 42,613 | $ 30,430 |