Net (Loss) Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net (loss) income attributable to BeiGene, Ltd.	$ (144,031)	$ 117,386	$ (405,514)	$ 6,218
Denominator:
Weighted average shares outstanding (shares)	739,789,269	547,546,656	703,482,491	527,329,985
Basic net (loss) income per share attributable to BeiGene, Ltd. (usd per share)	$ (0.19)	$ 0.21	$ (0.58)	$ 0.01
Denominator:
Weighted average shares outstanding (shares)	739,789,269	547,546,656	703,482,491	527,329,985
Weighted average effect of dilutive shares:
Number of shares used in per share computation (shares)	739,789,269	600,612,680	703,482,491	561,237,818
Diluted net (loss) income per share attributable to BeiGene, Ltd. (usd per share)	$ (0.19)	$ 0.20	$ (0.58)	$ 0.01
Employee share options and restricted share units
Weighted average effect of dilutive shares:
Weighted average effect of dilutive shares: (shares)	0	51,838,863	0	32,802,202
Non-employee share options
Weighted average effect of dilutive shares:
Weighted average effect of dilutive shares: (shares)	0	1,227,161	0	1,105,631

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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