CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Net sales	$ 93,056	$ 138,684	$ 198,153	$ 254,471
Cost of sales	89,279	113,070	176,662	211,153
Gross profit	3,777	25,614	21,491	43,318
Operating expenses:
Research, development and engineering expenses	5,814	6,030	12,566	12,329
Selling, general and administrative expenses	12,580	13,955	26,470	30,015
Amortization of intangible assets	764	909	1,527	1,819
Total operating expenses	19,158	20,894	40,563	44,163
Operating (loss) income	(15,381)	4,720	(19,072)	(845)
Other expense:
Interest expense	1,427	2,122	2,701	4,235
Loss from change in value of warrants	0	5,752	0	1,352
Loss on extinguishment of debt	497	0	497	0
Other income, net	(44)	(395)	(255)	(501)
Total other expense	1,880	7,479	2,943	5,086
Loss before income taxes	(17,261)	(2,759)	(22,015)	(5,931)
Income tax expense (benefit)	481	239	(3,561)	(347)
Net loss	$ (17,742)	$ (2,998)	$ (18,454)	$ (5,584)
Weighted-average common shares outstanding:
Basic (in shares)	22,858	21,702	22,858	20,171
Diluted (in shares)	22,858	21,702	22,858	20,171
Loss per common share:
Basic (in dollars per share)	$ (0.78)	$ (0.14)	$ (0.81)	$ (0.28)
Diluted (in dollars per share)	$ (0.78)	$ (0.14)	$ (0.81)	$ (0.28)