Annual report pursuant to Section 13 and 15(d)

Equity Incentive Plans and Stock Based Compensation - Stock Options Outstanding and Exercisable by Exercise Price (Detail)

v3.3.1.900
Equity Incentive Plans and Stock Based Compensation - Stock Options Outstanding and Exercisable by Exercise Price (Detail)
 12 Months Ended
Dec. 31, 2015
$ / shares
shares
$0.42-1.38  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 0.42
Range of Exercise Prices, Upper Limit $ 1.38
Options Outstanding, Number Outstanding | shares 534,650
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 2 years 2 months 12 days
Options Outstanding, Weighted Average Exercise Price $ 1.10
Options Exercisable, Number Exercisable | shares 522,650
Options Exercisable, Weighted Average Exercise Price $ 1.11
$1.44-1.44  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 1.44
Range of Exercise Prices, Upper Limit $ 1.44
Options Outstanding, Number Outstanding | shares 1,331,064
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 4 years 4 days
Options Outstanding, Weighted Average Exercise Price $ 1.44
Options Exercisable, Number Exercisable | shares 1,331,064
Options Exercisable, Weighted Average Exercise Price $ 1.44
$1.49-3.46  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 1.49
Range of Exercise Prices, Upper Limit $ 3.46
Options Outstanding, Number Outstanding | shares 1,428,718
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 4 years 5 months 27 days
Options Outstanding, Weighted Average Exercise Price $ 1.97
Options Exercisable, Number Exercisable | shares 1,397,258
Options Exercisable, Weighted Average Exercise Price $ 1.94
$3.62-3.62  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 3.62
Range of Exercise Prices, Upper Limit $ 3.62
Options Outstanding, Number Outstanding | shares 1,164,013
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 7 years 4 months 13 days
Options Outstanding, Weighted Average Exercise Price $ 3.62
Options Exercisable, Number Exercisable | shares 641,099
Options Exercisable, Weighted Average Exercise Price $ 3.62
$3.87-5.06  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 3.87
Range of Exercise Prices, Upper Limit $ 5.06
Options Outstanding, Number Outstanding | shares 2,011,782
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 8 years 11 days
Options Outstanding, Weighted Average Exercise Price $ 4.46
Options Exercisable, Number Exercisable | shares 766,498
Options Exercisable, Weighted Average Exercise Price $ 4.52
$5.09-7.75  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 5.09
Range of Exercise Prices, Upper Limit $ 7.75
Options Outstanding, Number Outstanding | shares 2,561,909
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 5 years 6 months
Options Outstanding, Weighted Average Exercise Price $ 6.09
Options Exercisable, Number Exercisable | shares 2,225,216
Options Exercisable, Weighted Average Exercise Price $ 6.17
$0.42-7.75  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 0.42
Range of Exercise Prices, Upper Limit $ 7.75
Options Outstanding, Number Outstanding | shares 9,032,136
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 5 years 9 months 15 days
Options Outstanding, Weighted Average Exercise Price $ 3.77
Options Exercisable, Number Exercisable | shares 6,883,785
Options Exercisable, Weighted Average Exercise Price $ 3.59