Warrants - Schedule of Assumptions Utilized in the Valuation of Warrant (Detail)	Mar. 31, 2019 yr
Risk-free Interest Rate [Member] | June 2017 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	0.0223
Risk-free Interest Rate [Member] | February 2019 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	0.0219
Expected Life [Member] | June 2017 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	3.19
Expected Life [Member] | February 2019 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	3.86
Expected Volatility of Underlying Stock [Member] | June 2017 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	0.5947
Expected Volatility of Underlying Stock [Member] | February 2019 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	0.6000
Expected Dividend Yield [Member] | June 2017 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	0
Expected Dividend Yield [Member] | February 2019 Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value assumptions	0