14. Segment Information

Operating segments are defined as components of an enterprise that engage in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and assess performance. The Company’s Chief Executive Officer is the Company’s chief operating decision maker. The Company reports its financial results for two operating and reportable segments which consist of Brooks Semiconductor Solutions Group segment and Brooks Life Sciences segment. Please refer to Note 18, "Segment and Geographic Information" to the Company’s consolidated financial statements included in the 2017 Annual Report on Form 10‑K for further information on the operating segments’ description and accounting policies.

The following is the summary of the financial information for the Company’s operating and reportable segments for the three months ended December 31, 2017 and 2016 (in thousands):


	Brooks
	Semiconductor		Brooks
	Solutions Group		Life Sciences		Total


Three Months Ended December 31, 2017:
Revenue
Products	$	120,203	$	21,981	$	142,184
Services		21,683		25,461		47,144
Segment revenue	$	141,886	$	47,442	$	189,328
Gross profit	$	59,453	$	15,762	$	75,215
Segment operating income (loss)		26,362		(140)		26,222
Depreciation expense		1,149		1,549		2,698

Three Months Ended December 31, 2016:
Revenue
Products	$	109,395	$	12,719	$	122,114
Services		17,221		20,620		37,841
Segment revenue	$	126,616	$	33,339	$	159,955
Gross profit	$	45,468	$	11,475	$	56,943
Segment operating income (loss)		17,371		112		17,483
Depreciation expense		1,275		1,090		2,365

Assets:
December 31, 2017	$	340,367	$	382,884	$	723,251
September 30, 2017		325,408		306,666		632,074

The following is a reconciliation of the Company’s operating and reportable segments’ operating income and segment assets to the corresponding amounts presented in the accompanying unaudited Consolidated Balance Sheets and Consolidated Statements of Operations for the three months ended December 31, 2017 and 2016 (in thousands):


	Three Months Ended
	December 31,
	2017		2016
Segment operating income	$	26,222	$	17,483
Amortization of acquired intangible assets		4,589		3,064
Restructuring charges		—		975
Other unallocated corporate expenses		793		283
Total operating income	$	20,840	$	13,161


	December 31,		September 30,
	2017		2017
Segment assets	$	723,251	$	632,074
Cash, cash equivalents and marketable securities		231,882		104,292
Deferred tax assets		1,642		1,692
Equity method investments		30,902		28,570
Total assets	$	987,677	$	766,628