Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Net sales	$ 48,277	$ 47,328
Cost of sales	35,454	34,831
Gross profit	12,823	12,497
Selling, general and administrative expenses	7,752	7,244
Gain on sale of fixed assets	(4)
Operating income	5,075	5,253
Interest expense	16	231
Other expense	327	239
Income before income tax expense	4,732	4,783
Income tax expense	841	1,049
Net income	$ 3,891	$ 3,734
Net income per share:
Basic (in dollars per share)	$ 0.52	$ 0.50
Diluted (in dollars per share)	$ 0.52	$ 0.50
Weighted average common shares outstanding:
Basic (in shares)	7,457	7,402
Diluted (in shares)	7,538	7,466

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(a),(d))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227