Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Schedule of Weighted-Average Assumptions Used for Calculating Value of Options Granted (Detail)

v3.5.0.2
Stock-Based Compensation - Schedule of Weighted-Average Assumptions Used for Calculating Value of Options Granted (Detail)
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options Outstanding, Weighted Average Exercise Price, and Additional Disclosures [Abstract]        
Dividend yield 0.00% 0.00% 0.00% 0.00%
Expected volatility 74.90% 72.65% 74.90% 72.65%
Expected volatility 75.12% 73.43% 76.00% 75.07%
Weighted average risk-free interest rate 1.25% 1.69% 1.13% 1.49%
Weighted average risk-free interest rate 1.35% 1.89% 1.61% 1.89%
Minimum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Options Outstanding, Weighted Average Exercise Price, and Additional Disclosures [Abstract]        
Expected term 5 years 5 years 5 years 5 years
Maximum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Options Outstanding, Weighted Average Exercise Price, and Additional Disclosures [Abstract]        
Expected term 5 years 8 months 12 days 6 years 1 month 6 days 5 years 8 months 12 days 6 years 1 month 6 days