Major Customers, Partnerships and Strategic Alliances (Tables)

3 Months Ended

Mar. 31, 2013

Shire AG [Member]

Research and Development Arrangement, Contract to Perform for Others [Line Items]

Revenues recognized under the agreement

Revenues recognized under the agreement with Shire for the three months ended March 31, 2013 and March 31, 2012, were as follows (in thousands):

	Three months endedMarch 31, 2013		Three months ended March 31, 2012
Revenue related to Shire collaboration:
Amortization of upfront fee	$	542	$	361
Research services		3,214		555
Total	$	3,756	$	916

Sigma-Aldrich Corporation [Member]

Research and Development Arrangement, Contract to Perform for Others [Line Items]

Revenues recognized under the agreement

Revenues recognized under the agreement with Sigma for the three months ended March 31, 2013 and March 31, 2012, were as follows (in thousands):

	Three months ended March  31,
	2013		2012
Revenue related to Sigma collaboration:
Royalty revenues	$	314	$	301
License fee and milestone revenues		—		—
Total		314		301