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)

v3.19.1
Equity Incentive Plans and Stock Based Compensation - Stock Options Outstanding and Exercisable by Exercise Price (Detail)
12 Months Ended
Dec. 31, 2018
$ / shares
shares
$ 0.42-1.27  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices $ 0.42
Range of Exercise Prices $ 1.27
Number Outstanding | shares 469,797
Weighted Average Remaining Contractual Life (Years) 4 years 8 months 26 days
Weighted Average Exercise Price $ 1.05
Number Exercisable | shares 469,797
Weighted Average Exercise Price $ 1.05
$ 1.85-6.05  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices 1.85
Range of Exercise Prices $ 6.05
Number Outstanding | shares 423,710
Weighted Average Remaining Contractual Life (Years) 4 years 9 months 10 days
Weighted Average Exercise Price $ 5.22
Number Exercisable | shares 243,127
Weighted Average Exercise Price $ 5.44
$ 6.31-6.31  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices 6.31
Range of Exercise Prices $ 6.31
Number Outstanding | shares 1,389,634
Weighted Average Remaining Contractual Life (Years) 8 years 6 months 10 days
Weighted Average Exercise Price $ 6.31
Number Exercisable | shares 60,313
Weighted Average Exercise Price $ 6.31
$ 7.14-9.28  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices 7.14
Range of Exercise Prices $ 9.28
Number Outstanding | shares 459,209
Weighted Average Remaining Contractual Life (Years) 4 years 11 months 8 days
Weighted Average Exercise Price $ 7.71
Number Exercisable | shares 134,911
Weighted Average Exercise Price $ 7.67
$ 9.40-18.04  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices 9.40
Range of Exercise Prices $ 18.04
Number Outstanding | shares 947,539
Weighted Average Remaining Contractual Life (Years) 7 years 3 months 21 days
Weighted Average Exercise Price $ 10.91
Number Exercisable | shares 386,598
Weighted Average Exercise Price $ 12.37
$ 18.59-79.42  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices 18.59
Range of Exercise Prices $ 79.42
Number Outstanding | shares 313,110
Weighted Average Remaining Contractual Life (Years) 8 months 8 days
Weighted Average Exercise Price $ 52.42
Number Exercisable | shares 313,110
Weighted Average Exercise Price $ 52.42
$ 0.42-79.42  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices 0.42
Range of Exercise Prices $ 79.42
Number Outstanding | shares 4,002,999
Weighted Average Remaining Contractual Life (Years) 6 years 4 months 13 days
Weighted Average Exercise Price $ 10.43
Number Exercisable | shares 1,607,856
Weighted Average Exercise Price $ 15.19