Organization and Principal Activities (Details)	12 Months Ended
	Dec. 31, 2022
Zai Lab (Hong Kong) Limited
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Lab (Shanghai) Co., Ltd.
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Lab (AUST) Pty. Ltd.
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Lab (Suzhou) Co., Ltd.
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Biopharmaceutical (Suzhou) Co., Ltd.
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Lab (US) LLC
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Lab International Trading (Shanghai) Co., Ltd.
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Auto Immune (Hong Kong) Limited
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Lab (Taiwan) Limited
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%
Zai Lab Trading (Suzhou) Co., Ltd.
Subsidiary Of Limited Liability Company Or Limited Partnership [Line Items]
Percentage of Ownership	100.00%