Segment Information (Tables)

6 Months Ended

Jun. 30, 2014

Segment Information

Summary of total revenues from customers and collaboration partners by geographic region

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2014		2013		2014		2013
	(in thousands)
United States	$	58,617	$	54,520	$	114,085	$	109,083
Outside of the United States	11,860		9,171		23,394		17,702
Total revenues	$	70,477	$	63,691	$	137,479	$	126,785