The Company’s unaudited quarterly results are summarized below (in thousands, except per share data):


	First			Second			Third			Fourth
2018	Quarter			Quarter			Quarter			Quarter			Total
Net sales	$	530,670		$	596,219		$	578,021		$	715,019		$	2,419,929
Costs and operating expenses:
Cost of sales		221,421			243,135			241,139			286,869			992,564
Selling and administrative expenses		130,407			136,645			126,997			142,853			536,902
Research and development expenses		34,480			35,644			35,173			38,106			143,403
Purchased intangibles amortization		1,659			1,602			2,114			2,337			7,712
Litigation (settlement) provisions		(1,672	)		—			924			322			(426	)

Total costs and operating expenses		386,295			417,026			406,347			470,487			1,680,155

Operating income		144,375			179,193			171,674			244,532			739,774
Other income (expense)		346			(1,828	)		(811	)		(45,501	)		(47,794	)
Interest expense		(13,838	)		(11,692	)		(11,435	)		(11,676	)		(48,641	)
Interest income		9,666			8,888			9,802			10,451			38,807

Income before income taxes		140,549			174,561			169,230			197,806			682,146
Provision for income taxes		28,598			18,884			28,216			12,654			88,352

Net income	$	111,951		$	155,677		$	141,014		$	185,152		$	593,794

Net income per basic common share		1.42			2.00			1.84			2.48			7.71
Weighted-average number of basic common shares		78,883			77,833			76,575			74,802			76,992
Net income per diluted common share		1.40			1.98			1.83			2.46			7.65
Weighted-average number of diluted common shares and equivalents		79,715			78,438			77,136			75,345			77,618


	First			Second			Third			Fourth
2017	Quarter			Quarter			Quarter			Quarter			Total
Net sales	$	497,969		$	558,250		$	565,584		$	687,275		$	2,309,078
Costs and operating expenses:
Cost of sales		211,095			229,627			235,892			270,453			947,067
Selling and administrative expenses		130,673			130,093			135,206			148,391			544,363
Research and development expenses		30,752			32,937			33,782			35,122			132,593
Purchased intangibles amortization		1,729			1,693			1,682			1,639			6,743
Litigation provisions		—			10,018			—			1,096			11,114
Acquired in-process research and development		5,000			—			—			—			5,000

Total costs and operating expenses		379,249			404,368			406,562			456,701			1,646,880

Operating income		118,720			153,882			159,022			230,574			662,198
Other income (expense)		149			(97	)		12			(404	)		(340	)
Interest expense		(12,725	)		(14,083	)		(14,750	)		(15,281	)		(56,839	)
Interest income		7,343			8,370			9,516			10,849			36,078

Income before income taxes		113,487			148,072			153,800			225,738			641,097
Provision for income taxes		7,930			16,250			17,696			578,910			620,786

Net income (loss)	$	105,557		$	131,822		$	136,104		$	(353,172	)	$	20,311

Net income (loss) per basic common share		1.32			1.65			1.71			(4.44	)		0.25
Weighted-average number of basic common shares		80,073			79,979			79,712			79,454			79,793
Net income (loss) per diluted common share		1.31			1.63			1.69			(4.44	)		0.25
Weighted-average number of diluted common shares and equivalents		80,769			80,756			80,521			79,454			80,604