Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Earnings Per Share Basic And Diluted [Abstract] | |||||||||||
| Net income | $ 7,003 | $ 5,415 | $ 5,717 | $ 2,270 | $ 5,807 | $ 9,293 | $ 5,241 | $ 5,284 | $ 20,405 | $ 25,625 | $ 27,122 |
| Denominator: | |||||||||||
| Weighted average common shares outstanding, basic | 89,340,589 | 87,920,230 | 88,680,322 | ||||||||
| Basic earnings per share: | |||||||||||
| Net income per share, basic | $ 0.08 | $ 0.06 | $ 0.06 | $ 0.03 | $ 0.07 | $ 0.11 | $ 0.06 | $ 0.06 | $ 0.23 | $ 0.29 | $ 0.31 |
| Denominator: | |||||||||||
| Weighted average common shares outstanding, basic | 89,340,589 | 87,920,230 | 88,680,322 | ||||||||
| Dilutive securities: | |||||||||||
| Stock options | 1,373,733 | 1,815,489 | 1,856,707 | ||||||||
| Restricted stock units | 588,734 | 559,466 | 406,705 | ||||||||
| Weighted average common shares outstanding, diluted | 91,303,056 | 90,295,185 | 90,943,734 | ||||||||
| Diluted earnings per share: | |||||||||||
| Net income per share, diluted | $ 0.08 | $ 0.06 | $ 0.06 | $ 0.02 | $ 0.06 | $ 0.10 | $ 0.06 | $ 0.06 | $ 0.22 | $ 0.28 | $ 0.30 |