4. Property and equipment

The following is a summary of property and equipment, at cost less accumulated depreciation and amortization:

	June 30, 2017			December 31, 2016
Leasehold improvements	$	378,194		$	358,477
Software	37,180			33,349
Construction in progress	31,998			18,859
Computer equipment	12,017			10,878
Furniture, fixtures and office equipment	1,751			1,760

Total property and equipment	461,140			423,323
Less: accumulated depreciation and amortization	(202,396		)	(172,558		)

Total property and equipment, net	$	258,744		$	250,765

Depreciation and amortization expense, which includes depreciation and amortization for property and equipment under capital leases, is allocated as follows in the accompanying condensed consolidated statements of operations:

	Three Months Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016

Network access	$	9,354	$	6,205	$	17,729	$	11,462
Network operations	4,131		3,255		8,286		6,450
Development and technology	2,270		1,689		4,465		3,291
General and administrative	259		251		519		505

Total depreciation and amortization of property and equipment	$	16,014	$	11,400	$	30,999	$	21,708

During the six months ended June 30, 2017, we recognized $164 of impairment losses primarily related to construction in progress projects that were abandoned. During the six months ended June 30, 2017, we also recognized $276 of losses on disposals of property and equipment.