Annual report pursuant to Section 13 and 15(d)

Share-based Compensation - Summary of Information under Plans (Detail)

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Share-based Compensation - Summary of Information under Plans (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Proceeds from exercise of stock options $ 2,979 $ 570 $ 288
2007 and 2013 Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Fair value of options vested   $ 184 820
Total intrinsic value of options exercised 842   432
Proceeds from exercise of stock options $ 2,979   $ 288