Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation - Weighted-Average Fair Value Valuation Assumptions (Detail)

v3.10.0.1
Stock Based Compensation - Weighted-Average Fair Value Valuation Assumptions (Detail) - Employee Stock Options - $ / shares
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
[1]
Jun. 30, 2018
Jun. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Risk-free interest rate 2.81% 0.00% 2.79% 1.95%
Expected term (in years) 6 years 10 days 0 years 6 years 10 days 5 years
Dividend yield 0.00% 0.00% 0.00% 0.00%
Volatility 107.00% 0.00% 107.00% 76.00%
Weighted-average fair value of stock options granted $ 5.20 $ 0 $ 5.83 $ 0.82
[1] There were no stock options granted during the three months ended June 30, 2017.