Revenue Accounted for 10% or More of Total Revenues (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer")
Concentration Risk [Line Items]
Percentage of major customers revenue accounted for 10% or more of total revenues	19.00%	64.00%
Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen")
Concentration Risk [Line Items]
Percentage of major customers revenue accounted for 10% or more of total revenues	38.00%	36.00%
Daiichi Sankyo, Inc ("Daiichi")
Concentration Risk [Line Items]
Percentage of major customers revenue accounted for 10% or more of total revenues	40.00%