Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans - Employee Stock Purchase Plan - Additional Information (Detail)

v3.6.0.2
Stock-Based Compensation Plans - Employee Stock Purchase Plan - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Common stock shares available for issuance 4,521,299  
Unrecognized stock-based compensation expense $ 19,340,000  
Unrecognized stock-based compensation expenses recognition period 3 years 26 days  
Employee Stock Purchase Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
ESPP offering period description The offering periods generally start on the first trading day on or after May 15 and November 15 of each year.  
Length of purchase intervals 6 months  
ESPP discount rate 10.00%  
Common stock reserved and available for issuance 366,667  
Common stock shares available for issuance 277,104 307,184
Common stock available for future issuance authorized annual share increase 366,667  
Common stock available for future issuance authorized annual percentage increase 1.00%  
Unrecognized stock-based compensation expense $ 69,000  
Unrecognized stock-based compensation expenses recognition period 4 months 13 days