Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

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:

	Year Ended December 31,
	2016		2015		2014
Daiichi Sankyo, Inc.		29%		38%		45%
Bayer Pharma, AG and Janssen Pharmaceuticals, Inc.		27%		48%		37%
Dermavant Sciences GmbH		25%	–		–
Bristol-Myers Squibb Company and Pfizer Inc.		19%		13%		16%