15. Segments

The following table presents the Company’s operations by reportable segment. The Company is managed through two reportable segments, Product Development and Integrated Healthcare Services. Product Development, which primarily serves biopharmaceutical clients engaged in research and development, provides clinical research and clinical trial services. Integrated Healthcare Services provides commercialization services to biopharmaceutical clients and research, analytics, real-world and late phase research, and other services to both biopharmaceutical clients and the broader healthcare market.

Certain costs are not allocated to the Company’s segments and are reported as general corporate and unallocated expenses. These costs primarily consist of share-based compensation, merger and acquisition related costs, and expenses for corporate overhead functions such as senior leadership, finance, human resources, information technology, facilities and legal. The Company does not allocate restructuring charges to its segments. Information presented below is in thousands:

	Three Months Ended June 30,						Six Months Ended June 30,
	2016			2015			2016			2015
Service revenues
Product Development	$	890,118		$	786,397		$	1,727,597		$	1,535,926
Integrated Healthcare Services		276,946			287,969			547,489			568,414
Total service revenues		1,167,064			1,074,366			2,275,086			2,104,340
Costs of revenue, service costs
Product Development		529,075			453,450			1,013,715			890,872
Integrated Healthcare Services		211,564			230,395			427,490			454,800
Total costs of revenue, service costs		740,639			683,845			1,441,205			1,345,672
Selling, general and administrative
Product Development		174,093			156,777			337,646			311,885
Integrated Healthcare Services		39,559			38,845			76,250			76,767
General corporate and unallocated		36,916			30,276			62,188			56,852
Total selling, general and administrative		250,568			225,898			476,084			445,504
Income from operations
Product Development		186,950			176,170			376,236			333,169
Integrated Healthcare Services		25,823			18,729			43,749			36,847
General corporate and unallocated		(36,916	)		(30,276	)		(62,188	)		(56,852	)
Restructuring costs		(25,114	)		(6,234	)		(28,258	)		(11,558	)
Total income from operations	$	150,743		$	158,389		$	329,539		$	301,606

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Depreciation and amortization expense
Product Development	$	26,752	$	23,553	$	52,982	$	47,429
Integrated Healthcare Services		4,272		5,171		8,529		10,379
General corporate and unallocated		1,017		1,287		2,254		2,532
Total depreciation and amortization expense	$	32,041	$	30,011	$	63,765	$	60,340