International Business Machines Corporation Alliance - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Accounts Payable and Accrued Liabilities [Line Items]
Costs related to fulfillment of technical enablement milestones	$ 2,200,000	$ 317,000	$ 7,600,000
Refundable subject to achievement of future milestones		20,700,000		20,700,000
Alliance agreement liability		22,267,000		22,584,000
Alliance agreement liability, current		1,600,000		1,917,000
Alliance agreement liability, noncurrent		$ 20,667,000		$ 20,667,000