Segment Information - Continuing Operations by Reportable Segment (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) segment	Jun. 30, 2020 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			2
Number of operating segments | segment			2
Segment Reporting Information [Line Items]
Net sales	$ 123,157	$ 78,532	$ 249,961	$ 194,745
Goodwill impairment	0	0	0	92,942
Income (loss) from operations	(1,588)	(11,177)	(610)	(115,027)
Interest expense	(3,573)	(6,356)	(5,597)	(10,163)
Other	(1,680)	1,215	(7,698)	(329)
Loss before (provision) benefit for income taxes and share of net income from joint venture	(6,841)	(16,318)	(13,905)	(125,519)
Operating Segments | Mobile Solutions
Segment Reporting Information [Line Items]
Net sales	73,886	41,037	151,662	110,921
Goodwill impairment				0
Income (loss) from operations	2,509	(4,592)	8,599	(4,328)
Operating Segments | Power Solutions
Segment Reporting Information [Line Items]
Net sales	49,271	37,491	98,346	83,892
Goodwill impairment				92,942
Income (loss) from operations	2,875	1,454	5,307	(88,880)
Corporate and Eliminations
Segment Reporting Information [Line Items]
Net sales	0	4	(47)	(68)
Goodwill impairment				0
Income (loss) from operations	$ (6,972)	$ (8,039)	$ (14,516)	$ (21,819)