Stockholders' Equity - Additional Information (Detail) - USD ($)			3 Months Ended	9 Months Ended
	Sep. 30, 2020	Mar. 17, 2020	Sep. 30, 2020	Sep. 30, 2020	Sep. 29, 2020	Mar. 31, 2020
Class Of Stock [Line Items]
Warrant exercise price	$ 5.95		$ 5.95	$ 5.95
Warrants to purchase	19,000,000		19,000,000	19,000,000
Proceeds from issuance of common stock, gross		$ 90,439,000	$ 46,153,000
Transaction costs recorded net against allocated gross proceeds in additional paid-in-capital		$ 5,150,000
Maximum allowed aggregate gross proceeds from share issuance under ATM program				$ 20,000,000
Maximum amount of share issuance allowed per quarter				$ 6,000,000
Pre funded Warrants [Member]
Class Of Stock [Line Items]
Warrant exercise price	$ 0.0001		$ 0.0001	$ 0.0001
Class 2 Common Stock [Member]
Class Of Stock [Line Items]
Common stock issued, Shares		7,250,000	6,781,090	9,493,494
Warrant exercise price		$ 5.95
Warrants to purchase		19,000,000
Proceeds from issuance of common stock, gross			$ 46,153,000	$ 76,999,000
Transaction costs recorded net against allocated gross proceeds in additional paid-in-capital		$ 1,197,000		1,540,000
Maximum allowed aggregate gross proceeds from share issuance under ATM program				20,000,000
Maximum amount of share issuance allowed per quarter				$ 6,000,000
Common stock, shares authorized	500,000,000		500,000,000	500,000,000
Common stock, par value	$ 0.0001		$ 0.0001	$ 0.0001
Class 2 Common Stock [Member] | Pre funded Warrants [Member]
Class Of Stock [Line Items]
Warrant exercise price		$ 0.0001				$ 0.0001
Warrants to purchase		11,750,000				11,750,000
Class 1 Common Stock [Member]
Class Of Stock [Line Items]
Conversion of stock, shares converted	13,159,762
Common stock ceased to represent percentage of outstanding common stock	10.00%
Common stock, shares authorized	233,333,333		233,333,333	233,333,333	250,000,000
Common stock, shares retired	16,666,667		16,666,667	16,666,667
Common stock, par value	$ 0.0001		$ 0.0001	$ 0.0001
Common stock, shares outstanding	0		0	0