Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2017

Accounting Policies [Abstract]

Percentage of Revenue from Significant Collaboration Customers

Collaboration customers who accounted for 10% or more of total collaboration and license revenues were as follows:

	Three Months Ended March 31,
	2017			2016
Daiichi Sankyo, Inc.		43	%		41	%
Bayer Pharma, AG and Janssen Pharmaceuticals, Inc.		16	%		40	%
Bristol-Myers Squibb Company and Pfizer Inc.		34	%		15	%