Major Customers, Partnerships and Strategic Alliances (Tables)

6 Months Ended

Jun. 30, 2012

Shire AG [Member]

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

Revenues recognized under the agreement

	Three months ended June 30,				Six months ended June 30,
	2012		2011		2012		2011
Revenue related to Sigma Collaboration:
Royalty revenues	$	306	$	139	$	607	$	431
License fee and milestone revenues		1,000		—		1,000		671
Total	$	1,306	$	139	$	1,607	$	1,102

Sigma-Aldrich Corporation [Member]

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

Revenues recognized under the agreement

	Three months ended June  30, 2012		Six months ended June 30, 2012
Revenue related to Shire Collaboration:
Amortization of upfront fee	$	542	$	903
Research services		1,517		2,072
Total	$	2,059	$	2,975