Property and Equipment, Net
 9 Months Ended
Sep. 30, 2016
Property, Plant and Equipment [Abstract]  
Property and Equipment, Net
Property and Equipment, net
Property and equipment, net, consisted of the following:

September 30,
2016
 
December 31, 2015
 
(In thousands)
Equipment
$
10,481

 
$
10,431

Furniture and fixtures
378

 
378

Computer software
9,932

 
9,894

Construction in progress
167

 
10

Leasehold improvements
536

 
526


21,494

 
21,239

Less: Accumulated depreciation and amortization
(19,183
)
 
(17,230
)
Property and equipment, net
$
2,311

 
$
4,009


For the three and nine months ended September 30, 2016, depreciation expense was approximately $0.6 million and $2.0 million, respectively.
For the three and nine months ended September 30, 2015, depreciation expense was approximately $0.7 million and $2.2 million, respectively.
During the three months ended September 30, 2016, the Company did not retire any property and equipment. During the nine months ended September 30, 2016, the Company retired less than $0.1 million of gross property and equipment. During the three and nine months ended September 30, 2015, the Company retired less than $0.1 million and $2.0 million of gross property equipment, respectively, all of which were nearly fully depreciated.