Income Taxes - Reconciliation Of Income Tax Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, Amount
Statutory rate	$ 964	$ 2,936
Foreign tax rate differential	20	65
State income taxes, net of federal benefit	132	1,003
Non-deductible expenses	153	181
Tax benefits related to disposition of the Test and Inspection Services business	(2,130)	(16,282)
U.S. taxation of foreign income, net of tax credits	32	621
Income tax credits	(227)	(1,357)
Nondeductible executive compensation	17	132
Change in income tax rates	379	138
Tax on unremitted foreign earnings	(68)	174
Change in valuation allowance	1,807	731
Other	40	(183)
Total income tax expense	$ 1,119	$ (11,841)
Effective Income Tax Rate Reconciliation, Percent
Statutory rate	21.00%	21.00%
Foreign tax rate differential	0.40%	0.50%
State income taxes, net of federal benefit	2.90%	7.20%
Non-deductible expenses	3.30%	1.30%
Tax benefits related to disposition of the Test and Inspection Services business	(46.40%)	(116.40%)
U.S. taxation of foreign income, net of tax credits	0.70%	4.40%
Income tax credits	(4.90%)	(9.70%)
Nondeductible executive compensation	0.40%	0.90%
Change in income tax rates	8.30%	1.00%
Tax on unremitted foreign earnings	(1.50%)	1.20%
Change in valuation allowance	39.40%	5.20%
Other	0.90%	(1.30%)
Total income tax expense/ Effective rate	24.40%	(84.70%)