Summary of Significant Accounting Policies - Schedule of allowance for doubtful accounts (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Allowance for Doubtful Accounts Receivable [Roll Forward] | |||
| Beginning Balance | $ 276 | $ 711 | $ 460 |
| Additions | 828 | 581 | 460 |
| Less write-offs, net of recoveries | (374) | (1,016) | (209) |
| Ending Balance | $ 730 | $ 276 | $ 711 |