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Collaboration and Other Agreements, F. Hoffmann-La Roche Ltd. and Hoffmann-La Roche Inc. (Details) - USD ($) $ in Thousands	1 Months Ended
	Jan. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 7,202	$ 4,261
Deferred revenue included in long-term liabilities		13,637	$ 10,045
F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. (Roche)
Collaboration and Other Agreements [Line Items]
Potential milestone payments and royalties on future sales		$ 370,000
Expected period of development		30 months
Deferred revenue		$ 10,000
Deferred revenue included in current liabilities		4,000
Deferred revenue included in long-term liabilities		$ 6,000
F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. (Roche) \| Subsequent Event
Collaboration and Other Agreements [Line Items]
Non-refundable upfront payment	$ 10,000