Note 12. Selected Quarterly Financial Information (Unaudited)


	Three months ended
	March 31,		June 30,		September 30,		December 31,
(in thousands, except per share amounts)	2018		2018		2018		2018
Net sales	$	40,133	$	43,161	$	43,908	$	54,076
Cost of sales		5,786		6,160		6,011		7,118
Gross profit		34,347		37,001		37,897		46,958
Operating expenses:
Selling, general and administrative		27,155		28,638		31,632		32,104
Research and development		10,906		12,611		13,202		12,957
Total operating expenses		38,061		41,249		44,834		45,061
(Loss) income from operations		(3,714)		(4,248)		(6,937)		1,897
Non-operating income (expense)		1,008		(1,139)		353		412
Provision for income taxes		5		11		37		530
Net (loss) income	$	(2,711)	$	(5,398)	$	(6,621)	$	1,779
Net (loss) income per share (1):
Basic	$	(0.08)	$	(0.15)	$	(0.19)	$	0.05
Diluted	$	(0.08)	$	(0.15)	$	(0.19)	$	0.04


	Three months ended
	March 31,		June 30,		September 30,		December 31,
(in thousands, except per share amounts)	2017		2017		2017		2017
Net sales	$	35,907	$	41,285	$	40,412	$	41,650
Cost of sales		5,180		5,522		5,718		4,630
Gross profit		30,727		35,763		34,694		37,020
Operating expenses:
Selling, general and administrative		21,481		24,675		24,141		25,963
In-process research and development		—		5,320		—		—
Research and development		8,942		9,633		9,805		10,525
Total operating expenses		30,423		39,628		33,946		36,488
Income (loss) from operations		304		(3,865)		748		532
Non-operating income		629		586		630		437
Provision for income taxes		55		22		53		(37)
Net income (loss)	$	878	$	(3,301)	$	1,325	$	1,006
Net income (loss) per share (1):
Basic	$	0.03	$	(0.10)	$	0.04	$	0.03
Diluted	$	0.02	$	(0.10)	$	0.04	$	0.03

⁽¹⁾

Net income or loss per share is computed independently for each of the quarters presented. Therefore, the sum of the quarterly per-share amounts will not necessarily equal the annual per share amount.