Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	May 31, 2010
Accounts Payable And Accrued Liabilities [Line Items]
Research and development related	$ 16,110	$ 4,217
Legal and accounting fees	462	1,523
Deferred rent	879	831	3,200
Other	345	828
Total accrued liabilities	$ 17,796	$ 7,399

Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Aggregate carrying amount of current liabilities (due within one year or within the normal operating cycle if longer) not separately disclosed in the balance sheet. Includes costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered and of liabilities not separately disclosed.

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