XML 50 R37.htm IDEA: XBRL DOCUMENT v3.10.0.1
Fair Value Measurements - Schedule of Share-Based Payment Award Warrant Liability Valuation Assumptions (Detail) - $ / shares
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Stock price (in dollars per share) $ 1.01 $ 4.01
Annual rate of quarterly dividends 0.00% 0.00%
Minimum    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Exercise price (in dollars per share) $ 3.64 $ 3
Term in years 3 months 3 months
Volatility 88.07% 71.48%
Discount rate-bond equivalent yield 0.12% 0.44%
Maximum    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Exercise price (in dollars per share) $ 24.4 $ 24.4
Term in years 2 years 7 months 5 days 3 years 7 months 5 days
Volatility 108.10% 139.58%
Discount rate-bond equivalent yield 2.48% 2.05%