24. Unaudited Quarterly Financial Data

The following summarizes selected quarterly financial data for the year ended March 31, 2018.

	First Quarter		Second Quarter		Third Quarter			Fourth Quarter

Net sales	$	95,063,000	$	111,774,000	$	100,127,000		$	121,108,000
Cost of goods sold		69,224,000		84,612,000		77,583,000			90,780,000
Gross profit		25,839,000		27,162,000		22,544,000			30,328,000
Operating expenses:
General and administrative		6,187,000		8,615,000		11,915,000			8,810,000
Sales and marketing		3,394,000		3,457,000		4,048,000			4,131,000
Research and development		1,002,000		1,240,000		1,678,000			1,772,000
Total operating expenses		10,583,000		13,312,000		17,641,000			14,713,000
Operating income		15,256,000		13,850,000		4,903,000			15,615,000
Other expense:
Interest expense, net		3,314,000		3,522,000		3,953,000			4,656,000
Income before income tax expense		11,942,000		10,328,000		950,000			10,959,000
Income tax expense		4,316,000		4,027,000		7,756,000			1,764,000

Net income (loss)	$	7,626,000	$	6,301,000	$	(6,806,000	)	$	9,195,000

Basic net income (loss) per share	$	0.41	$	0.34	$	(0.36	)	$	0.48

Diluted net income (loss) per share	$	0.39	$	0.33	$	(0.36	)	$	0.47

The following summarizes selected quarterly financial data for the year ended March 31, 2017:

	First Quarter		Second Quarter		Third Quarter		Fourth Quarter

Net sales	$	85,412,000	$	108,836,000	$	112,595,000	$	114,410,000
Cost of goods sold		65,021,000		78,178,000		80,225,000		82,783,000
Gross profit		20,391,000		30,658,000		32,370,000		31,627,000
Operating expenses:
General and administrative		3,625,000		9,869,000		7,952,000		9,678,000
Sales and marketing		2,634,000		2,707,000		3,234,000		3,551,000
Research and development		869,000		905,000		1,039,000		1,011,000
Total operating expenses		7,128,000		13,481,000		12,225,000		14,240,000
Operating income		13,263,000		17,177,000		20,145,000		17,387,000
Other expense:
Interest expense, net		2,819,000		3,189,000		3,357,000		3,729,000
Income before income tax expense		10,444,000		13,988,000		16,788,000		13,658,000
Income tax expense		2,936,000		4,845,000		5,678,000		3,846,000

Net income	$	7,508,000	$	9,143,000	$	11,110,000	$	9,812,000

Basic net income per share	$	0.40	$	0.49	$	0.59	$	0.53

Diluted net income per share	$	0.39	$	0.47	$	0.57	$	0.50

Quarterly and year-to-date computations of per share amounts are made independently. Therefore, the sum of per share amounts for the quarters may not agree with per share amounts for the year shown elsewhere in the Annual Report on Form 10-K.