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)

v3.3.1.900
Common Stock - Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Vested Options (Detail)
 12 Months Ended
Dec. 31, 2015
$ / shares
shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Vested Options | shares 846,712
Exercise Price Range, Weighted Average Vested Price $ 11.93
Exercise Price Range, Weighted Average Remaining Contractual Term 6 years 6 months 11 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 547
Exercise Price Range, Weighted Average Vested Price $ 1.17
Exercise Price Range, Weighted Average Remaining Contractual Term 9 years 11 months 5 days
Exercise Price Range, Lower Range Limit $ 1.16
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 96,695
Exercise Price Range, Weighted Average Vested Price $ 1.86
Exercise Price Range, Weighted Average Remaining Contractual Term 9 years 4 months 17 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 19,042
Exercise Price Range, Weighted Average Vested Price $ 2.44
Exercise Price Range, Weighted Average Remaining Contractual Term 9 years 18 days
Exercise Price Range, Lower Range Limit $ 1.89
Exercise Price Range, Upper Range Limit $ 3.04
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 99,764
Exercise Price Range, Weighted Average Vested Price $ 6.58
Exercise Price Range, Weighted Average Remaining Contractual Term 6 years 6 months
Exercise Price Range, Lower Range Limit $ 3.05
Exercise Price Range, Upper Range Limit $ 11.17
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 107,491
Exercise Price Range, Weighted Average Vested Price $ 11.78
Exercise Price Range, Weighted Average Remaining Contractual Term 8 years 26 days
Exercise Price Range, Lower Range Limit $ 11.18
Exercise Price Range, Upper Range Limit $ 11.84
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 113,949
Exercise Price Range, Weighted Average Vested Price $ 11.95
Exercise Price Range, Weighted Average Remaining Contractual Term 7 years 1 month 13 days
Exercise Price Range, Lower Range Limit $ 11.85
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 134,044
Exercise Price Range, Weighted Average Vested Price $ 12.87
Exercise Price Range, Weighted Average Remaining Contractual Term 6 years 3 months 4 days
Exercise Price Range, Lower Range Limit $ 12.00
Exercise Price Range, Upper Range Limit $ 13.06
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 35,284
Exercise Price Range, Weighted Average Vested Price $ 14.39
Exercise Price Range, Weighted Average Remaining Contractual Term 5 years 3 months
Exercise Price Range, Lower Range Limit $ 13.07
Exercise Price Range, Upper Range Limit $ 15.74
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 110,250
Exercise Price Range, Weighted Average Vested Price $ 15.97
Exercise Price Range, Weighted Average Remaining Contractual Term 4 years 11 months 16 days
Exercise Price Range, Lower Range Limit $ 15.75
Exercise Price Range, Upper Range Limit $ 16.40
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 129,646
Exercise Price Range, Weighted Average Vested Price $ 20.06
Exercise Price Range, Weighted Average Remaining Contractual Term 4 years 2 months 23 days
Exercise Price Range, Lower Range Limit $ 16.41
Exercise Price Range, Upper Range Limit $ 22.28