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 Vested Options (Detail)

v3.6.0.2
Common Stock - Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Vested 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 Vested Options | shares 1,024,529
Exercise Price Range, Weighted Average Vested Price $ 10.54
Exercise Price Range, Weighted Average Remaining Contractual Term 5 years 6 months 29 days
Range one [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 510
Exercise Price Range, Weighted Average Vested Price $ 1.21
Exercise Price Range, Weighted Average Remaining Contractual Term 5 months 1 day
Exercise Price Range, Lower Range Limit $ 1.00
Exercise Price Range, Upper Range Limit $ 1.54
Range two [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 184,008
Exercise Price Range, Weighted Average Vested Price $ 1.86
Exercise Price Range, Weighted Average Remaining Contractual Term 7 years 8 months 27 days
Exercise Price Range, Lower Range Limit $ 1.55
Exercise Price Range, Upper Range Limit $ 1.88
Range three [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 90,275
Exercise Price Range, Weighted Average Vested Price $ 2.51
Exercise Price Range, Weighted Average Remaining Contractual Term 6 years 9 months 4 days
Exercise Price Range, Lower Range Limit $ 1.89
Exercise Price Range, Upper Range Limit $ 3.40
Range four [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 75,217
Exercise Price Range, Weighted Average Vested Price $ 7.69
Exercise Price Range, Weighted Average Remaining Contractual Term 5 years 9 months 11 days
Exercise Price Range, Lower Range Limit $ 3.41
Exercise Price Range, Upper Range Limit $ 11.70
Range five [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 140,269
Exercise Price Range, Weighted Average Vested Price $ 11.79
Exercise Price Range, Weighted Average Remaining Contractual Term 6 years 6 months 29 days
Exercise Price Range, Lower Range Limit $ 11.71
Exercise Price Range, Upper Range Limit $ 11.86
Range six [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 141,951
Exercise Price Range, Weighted Average Vested Price $ 11.95
Exercise Price Range, Weighted Average Remaining Contractual Term 5 years 7 months 21 days
Exercise Price Range, Lower Range Limit $ 11.87
Exercise Price Range, Upper Range Limit $ 11.99
Range seven [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 132,650
Exercise Price Range, Weighted Average Vested Price $ 12.88
Exercise Price Range, Weighted Average Remaining Contractual Term 4 years 11 months 19 days
Exercise Price Range, Lower Range Limit $ 12.00
Exercise Price Range, Upper Range Limit $ 13.08
Range eight [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 135,503
Exercise Price Range, Weighted Average Vested Price $ 15.64
Exercise Price Range, Weighted Average Remaining Contractual Term 3 years 6 months 15 days
Exercise Price Range, Lower Range Limit $ 13.09
Exercise Price Range, Upper Range Limit $ 16.40
Range nine [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 63,446
Exercise Price Range, Weighted Average Vested Price $ 17.74
Exercise Price Range, Weighted Average Remaining Contractual Term 3 years 6 months 22 days
Exercise Price Range, Lower Range Limit $ 16.41
Exercise Price Range, Upper Range Limit $ 21.67
Range ten [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 60,700
Exercise Price Range, Weighted Average Vested Price $ 22.28
Exercise Price Range, Weighted Average Remaining Contractual Term 2 years 8 months 1 day
Exercise Price Range, Lower Range Limit $ 21.68
Exercise Price Range, Upper Range Limit $ 22.28