Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments - Summary of Quantitative Information with Respect to Significant Unobservable Inputs (Detail)

v3.19.1
Financial Instruments - Summary of Quantitative Information with Respect to Significant Unobservable Inputs (Detail) - April 2018 Warrant [Member]
Mar. 31, 2019
Dec. 31, 2018
Volatility [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Warrants, measurement input 70 70
Risk-free Rate [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Warrants, measurement input 2.23 2.51
Term [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Warrants term 4 years 4 years 3 months