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)

v3.7.0.1
Stock-Based Compensation - Schedule of Weighted-Average Assumptions Used for Calculating Value of Options Granted (Detail)
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
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 75.13% 75.12% 75.09% 75.12%
Expected volatility 78.89% 75.53% 78.89% 76.00%
Weighted average risk-free interest rate 187.00% 113.00% 187.00% 113.00%
Weighted average risk-free interest rate 199.00% 149.00% 216.00% 161.00%
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 5 years 8 months 12 days 5 years 8 months 12 days 5 years 8 months 12 days