Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Weighted-Average Assumptions Used for Estimating Fair Value of ESPP Purchased Rights (Detail)

v3.6.0.2
Stock-Based Compensation - Weighted-Average Assumptions Used for Estimating Fair Value of ESPP Purchased Rights (Detail) - 2010 Employee Stock Purchase Plan [Member]
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected dividend yield of stock 0.00% 0.00% 0.00%
Minimum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Risk-free interest rate 0.41% 0.06% 0.05%
Expected life of option (in years) 6 months 6 months 6 months
Expected volatility 71.00% 0.55% 0.52%
Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Risk-free interest rate 0.80% 0.33% 0.30%
Expected life of option (in years) 2 years 2 years 2 years
Expected volatility 0.76% 0.70% 0.75%