Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 19,163	$ 15,396
Less: Accumulated depreciation and amortization	(2,691)	(2,134)
Property and equipment, net	16,472	13,262
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	9,080	9,057
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,870	281
Computer equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,111	3,166
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,858	2,648
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 244	$ 244

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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