Organization - Additional Information (Details) $ / shares in Units, $ in Thousands						1 Months Ended	12 Months Ended
	Nov. 30, 2020	Jul. 10, 2020 USD ($) $ / shares shares	Oct. 10, 2019 $ / shares shares	Oct. 10, 2019 USD ($) $ / shares shares	Sep. 16, 2019	Nov. 30, 2020 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) shares	Oct. 31, 2019 shares	Oct. 11, 2019 shares	Dec. 31, 2018 shares	Sep. 30, 2016 shares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Reverse stock split, conversion ratio					0.222222222
Net proceeds after deducting underwriting discounts, commissions and offering expenses				$ 126,400
Proceeds from Issuance of Common Stock								$ 323,214	$ 126,411
Common stock price per share | $ / shares							$ 0.0001	$ 0.0001
Aggregate offering price						$ 300,000
Accumulated deficit							$ 138,600	$ 667,184
Cash, cash equivalents and investments							909,500
Cash, cash equivalents and short-term investments, excluding equity investment							$ 766,400
Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Outstanding convertible preferred stock (in shares) | shares												69,910,520
Series A-1 Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Warrant to purchase of convertible preferred stock | shares													244,444
Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of convertible preferred stock converted to shares of common stock (in shares) | shares									88,112,733
Warrant to purchase of convertible preferred stock | shares										244,444
Common Stock | Sales Agreement
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock (in shares) | shares							0
Common Stock | Sales Agreement | Maximum
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Percentage of commission rate from sale of shares	3.00%
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock (in shares) | shares			7,142,858
Common stock price per share | $ / shares			$ 20.00	$ 20.00
Outstanding convertible preferred stock (in shares) | shares			88,112,733	88,112,733							0
Net proceeds from IPO									$ 126,411
IPO | Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock (in shares) | shares									7,142,858
Net proceeds from IPO									$ 1
IPO | Common Stock | Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of convertible preferred stock converted to shares of common stock (in shares) | shares				88,112,733
IPO | Common Stock | Warrant to Purchase Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of convertible preferred stock converted to shares of common stock (in shares) | shares				244,444
Follow-on Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Net proceeds from IPO								$ 323,214
Follow-on Offering | Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock (in shares) | shares		8,214,285						8,214,285
Common stock price per share | $ / shares		$ 42.00
Net proceeds from IPO		$ 345,000						$ 1
Payments of underwriting discounts and commissions		20,700
Offering expenses		1,100
Net proceeds from issuance secondary public offering		$ 323,200