Stockholders' Deficit - Common Stock - Additional Information (Detail) - USD ($)		12 Months Ended
	Jan. 21, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Common stock, shares authorized		120,000,000	120,000,000
Common stock, par value		$ 0.001	$ 0.001
Non-convertible promissory note, principal amount	$ 1,000,000
Accrued and unpaid interest	$ 49,000
Convertible common stock, conversion price		1.75
Common Stock [Member]
Class Of Stock [Line Items]
Conversion of bridge loan from a related party to common stock, shares	599,222		599,000
Series G Preferred Stock [Member]
Class Of Stock [Line Items]
Convertible preferred stock, conversion price	$ 9.70	$ 9.70	$ 9.70	$ 9.92
Conversion ratio for each share	0.1031	0.103099	0.103099	0.1008