Note 1 - Summary of Significant Interim Accounting Policies - Impact of New Standard on Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net sales	$ 82,392	$ 65,604	$ 155,479	$ 126,591
Cost of goods sold	53,114	42,230	101,326	81,003
Selling and administrative expenses	23,327	$ 16,994	44,509	$ 34,423
Accounting Standards Update 2014-09 [Member]
Net sales			42,880
Cost of goods sold			27,397
Selling and administrative expenses			706
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Net sales	85,331		154,689
Cost of goods sold	55,147		100,643
Selling and administrative expenses	23,417		44,531
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Net sales	(2,939)		790
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] \| Accounting Standards Update 2014-09 [Member]
Net sales	(2,939)		790
Cost of goods sold	(2,033)		683
Selling and administrative expenses	$ (90)		$ (22)

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.

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