Fair Value Measurements - Additional Information (Detail) - $ / shares		1 Months Ended	9 Months Ended
	Mar. 28, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Exercise price of issued warrants			$ 0	$ 1.23
Remeasurement of second tranche transaction liability to fair value description			This valuation at settlement was calculated as the excess of the sum of (i) the fair value of the Second Tranche Warrants and (ii) the fair value of the shares of Common Stock issued to settle the liability over the cash proceeds received by the Company for the Units.
Second Tranche Transaction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common Stock purchase price description			The purchase price for each share of Common Stock issuable in the Second Tranche Transaction was defined as the lower of (a) $1.265 (which was a 15% premium to the First Tranche Purchase Price) and (b) a 20% discount to the volume weighted average price (“VWAP”) of the shares of Common Stock on the Nasdaq Stock Market for the 20 trading days immediately prior to the closing of the Second Tranche Transaction; provided, however, that the purchase price could not be lower than $0.88, which was a 20% discount to the First Tranche Purchase Price.
Percentage discount to volume weighted average price for 20 days immediately preceding the closing of the Second Tranche Transaction	20.00%
Second Tranche Transaction [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock price per share	$ 1.265
Percentage of premium to first tranche share purchase price	15.00%
Second Tranche Transaction [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock price per share	$ 0.88
Percentage of discount to first tranche share purchase price	20.00%
Second Tranche Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage discount to volume weighted average price for 20 days immediately preceding the closing of the Second Tranche Transaction		20.00%
Warrant purchase price description			The exercise price of each Second Tranche Warrant was an amount equal to the lower of (a) $1.43 (a 30% premium to the First Tranche Purchase Price) and (b) a 20% discount to the VWAP of the shares of the Company’s Common Stock on Nasdaq for the 20 trading days immediately prior to the exercise of a Second Tranche Warrant; provided, however, that the exercise price could not be lower than $0.88, which was a 20% discount to the First Tranche Purchase Price.
Exercise price of issued warrants		$ 1.43
Second Tranche Warrants [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Exercise price of issued warrants		$ 1.43
Percentage of premium to first tranche share purchase price		30.00%
Second Tranche Warrants [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of discount to first tranche share purchase price		20.00%
Exercise price of issued warrants		$ 0.88