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Equity Incentive Plan - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Jun. 03, 2015 | Apr. 22, 2005 | Apr. 30, 2010 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2009 | Dec. 31, 2006
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Stock option exchange for new stock option granted |  |  | 4,369,000 |  |  |  |  |
Stock options exercise price |  |  | $ 1.47 |  |  |  |  |
Eligible stock options exchanged for new stock options granted |  |  | 3,785,000 |  |  |  |  |
Stock Option Granted |  |  |  | 0 | 0 | 0 |  |
Stock Option Granted Intrinsic Value |  |  |  | $ 580 | $ 3,688 | $ 1,565 |  |
Total unrecognized compensation cost related to non-vested share-based compensation |  |  |  | 0 |  |  |  |
Cash received from employee toward stock option exercise |  |  |  | 93 | 494 | 514 |  |
Tax effect for stock-based compensation benefit (expense) for option and restricted stock units exercised |  |  |  | $ 37 | 561 | (24) |  |
Minimum |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Stock option granted exercise price |  |  | $ 1.85 |  |  |  |  |
2005 Equity Incentive Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Ordinary shares for issuance upon exercise of stock options and restricted stock units |  | 10,000,000 |  |  |  |  | 15,000,000 | 15,000,000
Conversion ratio of restricted stock unit to ordinary shares |  |  |  | One-for-one |  |  |  |
2015 Equity Incentive Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Ordinary shares for issuance upon exercise of stock options and restricted stock units | 20,000,000 |  |  |  |  |  |  |
Restricted Stock Units | The 2005 Plan and The 2015 Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Total unrecognized compensation cost related to non-vested share-based compensation |  |  |  | $ 5,719 |  |  |  |
Stock Options And Restricted Stock Units Exercised |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Tax effect for stock-based compensation benefit (expense) for option and restricted stock units exercised |  |  |  | $ 1,702 | $ 1,647 | $ 1,231 |  |

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- Definition Describe the conversion features of common stock if such stock is convertible. That is, shares of common stock into which another convertible security was converted, or shares of common stock into which another class of common stock was converted. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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