CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net sales	$ 105,097	$ 115,787
Cost of sales	87,383	98,083
Gross profit	17,714	17,704
Operating expenses:
Research, development and engineering expenses	6,752	6,299
Selling, general and administrative expenses	13,890	16,060
Amortization of intangible assets	763	910
Total operating expenses	21,405	23,269
Operating loss	(3,691)	(5,565)
Other expense (income):
Interest expense	1,274	2,113
Gain from change in fair value of warrants	0	(4,400)
Other income, net	(211)	(106)
Total other expense (income)	1,063	(2,393)
Loss before income taxes	(4,754)	(3,172)
Income tax benefit	(4,042)	(586)
Net loss	$ (712)	$ (2,586)
Weighted-average common shares outstanding:
Basic (in shares)	22,858	18,639
Diluted (in shares)	22,858	22,635
Loss per common share:
Basic (in dollars per share)	$ (0.03)	$ (0.14)
Diluted (in dollars per share)	$ (0.03)	$ (0.31)