Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Schedule of estimated ranges of useful lives of property and equipment

Property, equipment and leasehold improvements are stated at cost less accumulated depreciation and amortization and depreciated using the straight-line method over their estimated useful lives as follows:

Asset classification	Estimated useful life
Laboratory equipment	5 years
Computer equipment and software	3 to 5 years
Office equipment and furniture	5 years
Leasehold improvements	Lesser of useful life or lease term

Property and equipment, net consisted of the following (in thousands):

	December 31,
	2014			2013
Laboratory equipment	$	23,002		$	23,949
Leasehold improvements	9,773			9,493
Computer equipment and software	3,262			3,196
Office equipment and furniture	1,227			1,228
Construction in progress (1)	24			41
Property and equipment	37,288			37,907
Less: accumulated depreciation and amortization	(31,452		)	(29,461		)
Impairment of laboratory equipment	(1,841		)	—
Property and equipment, net	$	3,995		$	8,446

(1) Construction in progress includes equipment received but not yet placed into service pending installation.