Stockholders' Equity - Additional Information (Detail) - USD ($)			1 Months Ended			9 Months Ended
	Nov. 05, 2021	Nov. 13, 2019	Oct. 31, 2021	Jan. 31, 2020	Aug. 31, 2018	Sep. 30, 2021	Sep. 30, 2020	May 31, 2021	Feb. 28, 2021	Aug. 31, 2020	Jan. 29, 2020	Nov. 30, 2019
Class Of Stock [Line Items]
Issuance of common stock						$ 55,364,000	$ 1,140,000
Proceeds from exercise of common stock warrants						810,000
Expense relating to the modifications to warrants						$ 0	$ 16,240,000
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 exercise of common stock warrants						$ 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 exercise of common stock warrants						$ 700,000
Convertible Preferred Stock And Warrants And Underwritten Follow On Offering [Member]
Class Of Stock [Line Items]
Share issued price per share		$ 1,000				$ 1,000
Proceeds from issuance of convertible preferred stock and warrants net of issuance cost		$ 97,700,000
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
Subsequent Event [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares	570,629
At-The-Market Offering [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares						3,257,285	100,000
Issuance of common stock			$ 12,200,000			$ 55,400,000	$ 1,100,000
Commissions and offering expenses						2,100,000
Authorized stock issuance value remaining capacity						$ 33,200,000
At-The-Market Offering [Member] | Subsequent Event [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares	570,629
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								$ 50,000,000.0	$ 30,000,000.0