Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accrued Expenses and Other Current Liabilities [Line Items]
Compensation	$ 15,450	$ 17,768
Subcontractor costs	1,915	4,635
Professional fees	544	611
Total	19,814	24,782
Facilities costs
Accrued Expenses and Other Current Liabilities [Line Items]
Accrued expense	297	189
Potential stock issue costs
Accrued Expenses and Other Current Liabilities [Line Items]
Accrued expense		411
Other
Accrued Expenses and Other Current Liabilities [Line Items]
Accrued expense	$ 1,608	$ 1,168