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

12 Months Ended

Dec. 31, 2016

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,
	2016			2015
Laboratory equipment ⁽¹⁾	$	18,849		$	20,503
Leasehold improvements	10,395			10,369
Computer equipment and software	3,267			3,271
Office equipment and furniture	1,171			1,178
Construction in progress ⁽²⁾	124			3
Property and equipment	33,806			35,324
Less: accumulated depreciation and amortization	(31,651		)	(32,215		)
Property and equipment, net	$	2,155		$	3,109


(1)	Fully depreciated laboratory equipment with a cost of $2.3 million was retired during 2016.


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