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Initial fee received from collaboration or license agreement.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Collaboration and Other Agreements, Zai Lab (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended								12 Months Ended
	Nov. 30, 2018	Oct. 31, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 29, 2020
Collaboration and Other Agreements [Line Items]
Revenues			$ 25,192	$ 18,741	$ 10,593	$ 9,662	$ 15,794	$ 20,798	$ 18,834	$ 4,695	$ 64,188	$ 60,121	$ 157,742
Deferred revenue							$ 40,722					40,722	$ 27,318
Zai Lab Agreement \| Zai Lab
Collaboration and Other Agreements [Line Items]
Non-refundable upfront payment	$ 25,000
Tax withholding	$ 2,500
Potential development and regulatory milestone payments			140,000								140,000
Revenues											16,100	$ 1,300
Deferred revenue			$ 5,000								5,000
Zai Lab Agreement \| Zai Lab \| Subsequent Event
Collaboration and Other Agreements [Line Items]
Entitled milestone payments														$ 4,000
Zai Lab Agreement, Margetuximab \| Zai Lab \| Maximum
Collaboration and Other Agreements [Line Items]
Potential proceeds from royalties percent		20.00%
Zai Lab Agreement, TRIDENT molecule \| Zai Lab
Collaboration and Other Agreements [Line Items]
Potential proceeds from royalties percent		10.00%
Zai Lab Clinical Supply Agreements \| Zai Lab
Collaboration and Other Agreements [Line Items]
Revenues											$ 2,200