Annual report pursuant to Section 13 and 15(d)

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

v3.3.1.900
Stock-Based Compensation Plans - Employee Stock Purchase Plan - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized stock-based compensation expense $ 20,421,000  
Unrecognized stock-based compensation expenses recognition period 3 years 5 months 1 day  
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. The first offering period began on May 15, 2014.  
Length of purchase intervals 6 months  
ESPP discount rate 10.00%  
Expected dividend yield 0.00%  
Forfeiture rate 0.00%  
Common stock reserved and available for issuance 366,667  
Common stock shares available for issuance 307,184 341,356
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 $ 71,000  
Unrecognized stock-based compensation expenses recognition period 4 months 13 days