Subsequent Events - Additional Information (Detail) - Sales Agreement [Member] - Canaccord [Member] - USD ($)			2 Months Ended	12 Months Ended
	Mar. 09, 2020	Jul. 30, 2019	Mar. 13, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Sale of common stock authorized, amount		$ 30,000,000
Number of shares issued/sold				5,486,500
Proceeds from issuance of common stock			$ 29,400,000	$ 6,700,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Sale of common stock authorized, amount	$ 65,000,000
Number of shares issued/sold			49,401,624
Proceeds from issuance of common stock			$ 29,300,000