

(in thousands, except per share data)
	2018								2017
	4Q^(a)		3Q^(b)		2Q^(c)		1Q^(d)		4Q^(e)			3Q^(f)		2Q^(g)		1Q^(h)
Net sales	$	402,281	$	439,191	$	459,183	$	417,813	$	304,849		$	317,889	$	313,355	$	285,441
Gross profit	154,337		179,594		168,987		149,623		126,624			133,651		132,608		113,650
Operating income	51,628		76,228		59,622		37,571		50,780			58,609		60,270		48,852
Net income/(loss)	32,665		53,546		42,326		36,029		(10,819		)	42,808		48,638		38,891
Net income/(loss) per share
Basic	$	1.31	$	2.13	$	1.69	$	1.48	$	(0.48	)	$	1.88	$	2.13	$	1.71
Diluted	$	1.29	$	2.10	$	1.67	$	1.45	$	(0.48	)	$	1.87	$	2.11	$	1.69

(a)In the fourth quarter of 2018, the Company recorded an estimated one-time tax charge of $3.2 million related to the finalization of 2017 provisional reasonable estimate in connection with the Tax Act, partially offset by a $1.5 million benefit for previously unrecognized tax benefits in respect of which the statute of limitation has expired, $3.7 million in backlog amortization expense from the IXYS acquisition, $3.2 million in acquisition-related and integration costs and $2.4 million in restructuring, impairment and other costs.

(b)In the third quarter of 2018, the Company recorded $5.2 million in restructuring and impairment charges, $3.1 million in backlog amortization expense from the IXYS acquisition and $2.9 million in acquisition-related and integration costs.

(c)In the second quarter of 2018, the Company recorded $19.0 million for purchase accounting inventory adjustments associated with the acquisition of IXYS, $4.2 million in restructuring and impairment charges, $3.1 million in backlog amortization expense from the IXYS acquisition and $2.4 million in acquisition-related and integration costs.

(d)In the first quarter of 2018, the Company recorded $17.9 million for purchase accounting inventory adjustments associated with the acquisition of IXYS, $11.7 million in acquisition-related and integration costs, $4.5 million of stock compensation expense recognized immediately upon close for converted IXYS options related to prior services periods, $2.5 million in backlog amortization expense, $2.1 million expense related to change in control and $0.8 million in restructuring costs.

(e)In the fourth quarter of 2017, the Company recorded an estimated one-time tax charge of $49.0 million for the enactment of the Tax Act for deemed repatriation of unremitted earnings of foreign subsidiaries, $1.4 million in acquisition-related and integration costs and $0.7 million in restructuring and production costs related to the transfer of Asian operations.

(f)In the third quarter of 2017, the Company recorded $4.8 million in acquisition-related and integration costs and $1.5 million in restructuring and production costs related to the transfer of Asian operations.

(g)In the second quarter of 2017, the Company recorded $0.3 million in acquisition-related and integration costs.

(h)In the first quarter of 2017, the Company recorded $1.5 million in acquisition-related and integration costs.