Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Stock Options, Stock Purchase Plan and Warrants - Fair Value of Each Stock Option Award Granted (Detail)

v3.6.0.2
Stock Options, Stock Purchase Plan and Warrants - Fair Value of Each Stock Option Award Granted (Detail) - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Risk-free interest rate (%) 1.10% 1.20% 1.00%
Expected volatility (%) 54.00% 51.00% 50.00%
Dividend yield (%) 0.00% 0.00% 0.00%
Weighted average fair value/share at grant date $ 2.23 $ 1.84 $ 1.50
Minimum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term (in years) 1 year 2 years 6 months 3 years
Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term (in years) 4 years 6 months 4 years 7 months 6 days 4 years 7 months 6 days