Changes in the Alliance Agreement Liability (Detail) (USD $) In Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Accounts Payable and Accrued Liabilities [Line Items]
Beginning Balance		$ 22,584
Costs related to fulfillment of technical enablement milestones	(2,200)	(317)	(7,600)
Ending Balance		$ 22,267