Annual report pursuant to Section 13 and 15(d)

Common Stock - Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Outstanding Options (Detail)

v3.6.0.2
Common Stock - Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Outstanding Options (Detail)
 12 Months Ended
Dec. 31, 2016
$ / shares
shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Outstanding Options | shares 1,378,805
Exercise Price Range, Weighted Average Exercise Price $ 8.62
Exercise Price Range, Weighted Average Remaining Contractual Life 6 years 3 months 18 days
Range one [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 1.00
Exercise Price Range, Upper Range Limit $ 1.54
Exercise Price Range, Number of Outstanding Options | shares 122,010
Exercise Price Range, Weighted Average Exercise Price $ 1.00
Exercise Price Range, Weighted Average Remaining Contractual Life 9 years 4 months 10 days
Range two [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 1.55
Exercise Price Range, Upper Range Limit $ 1.88
Exercise Price Range, Number of Outstanding Options | shares 337,298
Exercise Price Range, Weighted Average Exercise Price $ 1.86
Exercise Price Range, Weighted Average Remaining Contractual Life 7 years 11 months 16 days
Range three [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 1.89
Exercise Price Range, Upper Range Limit $ 3.40
Exercise Price Range, Number of Outstanding Options | shares 118,874
Exercise Price Range, Weighted Average Exercise Price $ 2.62
Exercise Price Range, Weighted Average Remaining Contractual Life 6 years 11 months 23 days
Range four [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 3.41
Exercise Price Range, Upper Range Limit $ 11.70
Exercise Price Range, Number of Outstanding Options | shares 78,447
Exercise Price Range, Weighted Average Exercise Price $ 7.70
Exercise Price Range, Weighted Average Remaining Contractual Life 5 years 8 months 19 days
Range five [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 11.71
Exercise Price Range, Upper Range Limit $ 11.86
Exercise Price Range, Number of Outstanding Options | shares 185,105
Exercise Price Range, Weighted Average Exercise Price $ 11.79
Exercise Price Range, Weighted Average Remaining Contractual Life 6 years 7 months 28 days
Range six [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 11.87
Exercise Price Range, Upper Range Limit $ 11.99
Exercise Price Range, Number of Outstanding Options | shares 144,699
Exercise Price Range, Weighted Average Exercise Price $ 11.95
Exercise Price Range, Weighted Average Remaining Contractual Life 5 years 7 months 21 days
Range seven [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 12.00
Exercise Price Range, Upper Range Limit $ 13.08
Exercise Price Range, Number of Outstanding Options | shares 132,650
Exercise Price Range, Weighted Average Exercise Price $ 12.88
Exercise Price Range, Weighted Average Remaining Contractual Life 4 years 11 months 19 days
Range eight [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 13.09
Exercise Price Range, Upper Range Limit $ 16.40
Exercise Price Range, Number of Outstanding Options | shares 135,576
Exercise Price Range, Weighted Average Exercise Price $ 15.64
Exercise Price Range, Weighted Average Remaining Contractual Life 3 years 6 months 15 days
Range nine [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 16.41
Exercise Price Range, Upper Range Limit $ 21.67
Exercise Price Range, Number of Outstanding Options | shares 63,446
Exercise Price Range, Weighted Average Exercise Price $ 17.74
Exercise Price Range, Weighted Average Remaining Contractual Life 3 years 6 months 22 days
Range ten [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 21.68
Exercise Price Range, Upper Range Limit $ 22.28
Exercise Price Range, Number of Outstanding Options | shares 60,700
Exercise Price Range, Weighted Average Exercise Price $ 22.28
Exercise Price Range, Weighted Average Remaining Contractual Life 2 years 8 months 1 day