Income Tax - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Taxable income	$ (443,286,000)	$ (704,471,000)	$ (268,905,000)
Provision for income taxes	0	0	0
Net operating loss carry forwards	1,483,200,000	1,089,700,000	605,200,000
Mainland China
Income Tax Disclosure [Line Items]
Taxable income	(290,056,000)	(340,865,000)	(220,813,000)
Net operating loss carry forwards	1,225,900,000
Hong Kong
Income Tax Disclosure [Line Items]
Taxable income	(53,425,000)	(243,400,000)	(20,022,000)
Net operating loss carry forwards	43,900,000
Taiwan
Income Tax Disclosure [Line Items]
Taxable income	(989,000)	(671,000)	0
Net operating loss carry forwards	1,500,000
United States
Income Tax Disclosure [Line Items]
Taxable income	(79,620,000)	(89,374,000)	(24,616,000)
Net operating loss carry forwards	208,100,000
Australia
Income Tax Disclosure [Line Items]
Taxable income	260,000	(1,758,000)	(839,000)
Net operating loss carry forwards	3,800,000
Zai Lab (AUST) Pty. Ltd.
Income Tax Disclosure [Line Items]
Taxable income	0
Provision for income taxes	0
Zai Lab (US) LLC
Income Tax Disclosure [Line Items]
Taxable income	0
Provision for income taxes	0
Zai Lab (Taiwan) Limited
Income Tax Disclosure [Line Items]
Taxable income	0
Provision for income taxes	0
Zai Lab (Hong Kong) and ZL China Holding Two and Zai Auto Immune (Hong Kong) and Zai Anti Infectives (Hong Kong) Limited
Income Tax Disclosure [Line Items]
Taxable income	0	0	0
Provision for income taxes	0	0	0
Withholding taxes on remittance of dividends	$ 0	$ 0	$ 0