Preferred and Common Stock Warrants - Additional Information (Detail) - $ / shares				6 Months Ended
	Nov. 29, 2019	Nov. 26, 2019	Apr. 16, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Number of warrants, Issuance of warrants for the purchase of common stock (in shares)				0	6,035,000
Class of warrants or rights expiration period (in years)		30 days
Common stock, par value (in usd per share)				$ 0.001		$ 0.001
Class A Warrant
Class of Stock [Line Items]
Number of warrants, Issuance of warrants for the purchase of common stock (in shares)			3,900,000
Warrant exercise price (usd per share)			$ 13.20
Class B Warrants
Class of Stock [Line Items]
Number of warrants, Issuance of warrants for the purchase of common stock (in shares)	5,416,667
Warrant exercise price (usd per share)	$ 15.00
Pre Funded Warrant
Class of Stock [Line Items]
Number of warrants, Issuance of warrants for the purchase of common stock (in shares)	1,750,000		2,130,000
Warrant exercise price (usd per share)	$ 11.999		$ 10.999
Number of warrants for purchase of convertible preferred shares (in shares)			1
Common stock, par value (in usd per share)			$ 0.001