Segment Information - Continuing Operations by Reportable Segment (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			2
Number of operating segments | segment			2
Segment Reporting Information [Line Items]
Net sales	$ 117,244	$ 113,761	$ 367,205	$ 308,506
Goodwill impairment	0	0	0	92,942
Income (loss) from operations	(4,612)	(1,456)	(5,222)	(116,483)
Interest expense	(3,578)	(6,873)	(9,175)	(17,036)
Other	4,346	118	(3,352)	(211)
Loss before (provision) benefit for income taxes and share of net income from joint venture	(3,844)	(8,211)	(17,749)	(133,730)
Operating Segments | Mobile Solutions
Segment Reporting Information [Line Items]
Net sales	68,586	70,371	220,248	181,292
Income (loss) from operations	(257)	4,953	8,342	625
Operating Segments | Power Solutions
Segment Reporting Information [Line Items]
Net sales	48,680	43,415	147,026	127,307
Goodwill impairment				92,942
Income (loss) from operations	1,252	1,143	6,559	(87,737)
Corporate and Eliminations
Segment Reporting Information [Line Items]
Net sales	(22)		(69)
Income (loss) from operations	$ (5,607)	$ (7,552)	$ (20,123)	$ (29,371)