Discontinued Operations - Net income (loss) from discontinued operation by discontinued operation (Details) - Discontinued Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Drivetrain
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	$ 9	$ 598
Operating expenses:
Cost of revenues - inventory and other direct costs	(138)	2,208
Engineering, research, and development	0	2,989
Selling, general, and administrative expenses	0	1,297
Other	38	0
Total operating expenses	(100)	6,494
Net loss from discontinued operations	109	(5,896)
XL Grid
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	149	4,165
Operating expenses:
Cost of revenues - inventory and other direct costs	148	2,988
Loss on asset disposal	3,233	0
Selling, general, and administrative expenses	743	2,618
Total operating expenses	4,124	5,606
Net loss from discontinued operations	$ (3,975)	$ (1,441)