11. Selected Quarterly Financial Information (Unaudited)

The following table sets forth selected unaudited quarterly consolidated statements of income data for each of the quarters in the years ended December 31, 2017 and 2016:



	Three Months Ended
	Dec. 31, 2017			Sep. 30, 2017			Jun. 30, 2017			Mar. 31, 2017			Dec. 31, 2016			Sep. 30, 2016			Jun. 30, 2016			Mar. 31, 2016
	(in thousands)
Revenue:
Product	$	407,195		$	380,344		$	353,904		$	291,367		$	289,008		$	254,238		$	235,616		$	212,475
Service	60,672			57,289			51,307			44,108			38,961			36,023			33,125			29,721
Total revenue	467,867			437,633			405,211			335,475			327,969			290,261			268,741			242,196
Cost of revenue:
Product	147,919			145,874			134,406			109,836			108,057			94,777			88,021			78,913
Service	12,783			11,142			11,028			11,429			9,757			9,064			9,269			8,193
Total cost of revenue	160,702			157,016			145,434			121,265			117,814			103,841			97,290			87,106
Gross profit	307,165			280,617			259,777			214,210			210,155			186,420			171,451			155,090
Operating expenses:
Research and development	107,180			79,610			81,194			81,610			71,398			70,648			69,020			62,515
Sales and marketing	38,808			40,640			38,630			37,027			38,321			33,216			31,744			27,606
General and administrative	21,789			19,535			23,319			22,155			22,941			19,535			17,529			15,234
Total operating expenses	167,777			139,785			143,143			140,792			132,660			123,399			118,293			105,355
Income from operations	139,388			140,832			116,634			73,418			77,495			63,021			53,158			49,735
Other income (expense), net:
Interest expense	(741		)	(701		)	(623		)	(715		)	(918		)	(735		)	(732		)	(751		)
Other income (expense), net	2,988			2,136			1,119			1,025			560			639			416			337
Total other income (expense), net	2,247			1,435			496			310			(358		)	(96		)	(316		)	(414		)
Income before income taxes	141,635			142,267			117,130			73,728			77,137			62,925			52,842			49,321
Provision for (benefit from) income taxes ⁽¹⁾	37,802			8,545			14,445			(9,233		)	18,354			11,668			13,938			14,076
Net income	$	103,833		$	133,722		$	102,685		$	82,961		$	58,783		$	51,257		$	38,904		$	35,245
Net income per share attributable to common stockholders:
Basic	$	1.42		$	1.84		$	1.42		$	1.16		$	0.84		$	0.74		$	0.57		$	0.52
Diluted	$	1.29		$	1.68		$	1.30		$	1.07		$	0.79		$	0.69		$	0.53		$	0.48
____________________________
(1) Provision for (benefit from) income taxes for the first, second, third and fourth quarter of 2017 included an excess tax benefits of $28.8 million, $19.1 million, $23.8 million and $38.3 million, respectively, resulting from the adoption of ASU 2016-09. In addition, provision for income taxes for the fourth quarter of 2017 included a provisional amount of $51.8 million in connection with the Tax Act enacted on December 22, 2017. See Note 8 for details.