CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 114,450	$ 138,512	$ 312,603	$ 392,983
Cost of sales	96,281	111,640	272,943	322,793
Gross profit	18,169	26,872	39,660	70,190
Operating expenses:
Research, development and engineering expenses	6,555	6,366	19,121	18,695
Selling, general and administrative expenses	11,964	11,461	38,434	41,476
Amortization of intangible assets	763	910	2,290	2,729
Total operating expenses	19,282	18,737	59,845	62,900
Operating (loss) income	(1,113)	8,135	(20,185)	7,290
Other expense:
Interest expense	1,510	1,921	4,211	6,156
Loss from change in value of warrants	0	0	0	1,352
Loss on extinguishment of debt	0	0	497	0
Other income, net	(947)	(25)	(1,202)	(526)
Total other expense	563	1,896	3,506	6,982
(Loss) income before income taxes	(1,676)	6,239	(23,691)	308
Income tax (benefit) expense	(210)	483	(3,771)	136
Net (loss) income	$ (1,466)	$ 5,756	$ (19,920)	$ 172
Weighted-average common shares outstanding:
Basic (in shares)	22,881	22,849	22,866	21,064
Diluted (in shares)	22,881	22,876	22,866	21,088
(Loss) earnings per common share:
Basic (in dollars per share)	$ (0.06)	$ 0.25	$ (0.87)	$ 0.01
Diluted (in dollars per share)	$ (0.06)	$ 0.25	$ (0.87)	$ 0.01