Major Customers, Partnerships and Strategic Alliances (Tables)

12 Months Ended

Dec. 31, 2015

Revenues recognized under the Biogen Agreement for the years ended December 31, 2015 and 2014 are as follows (in thousands):

	Year ended December 31,
	2015		2014
Revenue related to Biogen Collaboration:
Recognition of upfront fee	$	6,176	$	5,313
Research services		7,769		7,751
Total	$	13,945	$	13,064

Revenues recognized under the Shire Agreement for the years ended December 31, 2015, 2014 and 2013, were as follows (in thousands):

	Year ended December 31,
	2015		2014		2013
Revenue related to Shire Collaboration:
Recognition of upfront fee	$	2,167	$	2,167	$	2,167
Recognition of milestone		—		1,000		—
Research services		13,584		22,765		14,286
Total	$	15,751	$	25,932	$	16,453

Revenues recognized under the agreement with Sigma for the years ended December 31, 2015, 2014 and 2013, were as follows (in thousands):

	Year ended December 31,
	2015		2014		2013
Revenue related to Sigma Collaboration:
Royalty revenues	$	390	$	344	$	824
License fee and milestone revenues		4,463		448		1,351
Total	$	4,853	$	792	$	2,175