PROPERTY AND EQUIPMENT

12 Months Ended

Dec. 31, 2014

Property, Plant and Equipment [Abstract]

PROPERTY AND EQUIPMENT

7. PROPERTY AND EQUIPMENT

Property and equipment are recorded at historical cost, net of accumulated depreciation. The following table summarizes components of property and equipment, net for each of the periods indicated:

	As of December 31,
	2014			2013
	(in thousands)
Land	$	4,158		$	—
Building		12,617			1,856
Software and computer equipment		4,415			225
Lab equipment		11,772			7,728
Office equipment		2,713			1,207
Leasehold improvements		21,640			10,058
Construction in progress		1,082			11,303
Property and equipment, gross		58,397			32,377
Less accumulated depreciation		(19,896	)		(17,328	)
Property and equipment, net	$	38,501		$	15,049

For the years ended December 31, 2014, 2013 and 2012, depreciation expenses totaled $3.2 million, $0.8 million and $1.0 million, respectively.

Andover, Massachusetts Facility

On May 22, 2014, the Company entered into a Purchase and Sales Agreement with Eisai, Inc. to acquire certain real and personal property located in Andover, Massachusetts. The aggregate purchase price, including certain fees and taxes was approximately $15.1 million, of which approximately $10.1 million was paid at closing and the remaining $5.0 million will be paid in two installments by July 15, 2015 and January 15, 2016. On July 15, 2014, the closing of the purchase of the real and personal property was completed. In connection with this transaction, as of December 31, 2014, the Company recorded $4.2 million as land and $10.8 million as building on the consolidated balance sheets.