Quarterly report pursuant to Section 13 or 15(d)

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

v2.4.0.8
Stock-Based Compensation - Employee Stock Purchase Plans - Additional Information (Detail) (USD $)
9 Months Ended
Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected dividend yield 0.00%
Unrecognized stock-based compensation expense $ 19,859,000
Unrecognized stock-based compensation expenses recognition period 4 years 2 months 5 days
Employee Stock Purchase Plan [Member]
 
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Common stock reserved and available for issuance 366,667
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
Unrecognized stock-based compensation expense $ 22,000
Unrecognized stock-based compensation expenses recognition period 1 month 13 days