Stockholders' Equity - Additional Information (Detail) - USD ($)		1 Months Ended		12 Months Ended
	Nov. 13, 2019	Jan. 31, 2020	Aug. 31, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 25, 2022	Nov. 30, 2021	Aug. 31, 2020	Jan. 29, 2020	Nov. 30, 2019
Class Of Stock [Line Items]
Proceeds from warrant exercises				$ 810,000
Changes in fair value				$ 0	$ 16,240,000	$ 20,926,000
Silicon Valley Bank [Member] | Term Loans [Member] | Warrants to Purchase Common Stock [Member]
Class Of Stock [Line Items]
Exercise price of warrants or rights			$ 74.80
Warrant expiration date			Aug. 21, 2028
Warrants issued in connection with loan			1,839
Asset Purchase Agreement Amendment [Member] | Gilead [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares		725,283
Number of securities called by warrants and rights		725,283
Exercise price of warrants or rights		$ 13.20
Warrant expiration date		Jan. 31, 2025
Series A Warrants [Member]
Class Of Stock [Line Items]
Number of securities called by warrants and rights											7,802,241
Issuance of common stock for exercise of common stock warrant, Shares				11,362
Exercise price of warrants or rights											$ 13.20
Warrant expiration date				Jan. 22, 2025
Number of Warrants exercised				11,362
Proceeds from warrant exercises				$ 100,000
Series B Warrants [Member]
Class Of Stock [Line Items]
Number of securities called by warrants and rights											2,574,727
Issuance of common stock for exercise of common stock warrant, Shares				49,995
Exercise price of warrants or rights											$ 13.20
Warrant expiration period after specified event				75 days
Number of Warrants exercised				151,500	0
Proceeds from warrant exercises				$ 700,000
Series B Warrants [Member] | Subsequent Event [Member]
Class Of Stock [Line Items]
Warrant expiration date							Apr. 10, 2022
Series A Convertible Voting Preferred Stock [Member]
Class Of Stock [Line Items]
Stock issued, shares	103,000
Share issued price per share				$ 1,000
Preferred stock conversion price per share				$ 13.20
Preferred Stock converted into of the Company's common stock										7,803,273
Convertible Preferred Stock And Warrants And Underwritten Follow On Offering [Member]
Class Of Stock [Line Items]
Share issued price per share	$ 1,000
Proceeds from issuance of convertible preferred stock and warrants net of issuance cost	$ 97,700,000
Commissions and offering expenses	$ 5,300,000
At-The-Market Offering [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares				4,316,968	732,752
Proceeds from issuance of common stock, net of offering costs				$ 78,200,000	$ 8,900,000
Authorized stock issuance value remaining capacity				$ 59,600,000
At-The-Market Offering [Member] | Maximum [Member]
Class Of Stock [Line Items]
Common stock reserved for issuance									$ 20,000,000.0
Common stock reserved for issuance								$ 130,000,000.0