Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Summary of Provision for Income Tax Expense (Benefit)

The provision for income tax (benefit) expense consisted of the following:

	(In thousands) Years Ended December 31,
	2019			2018			2017
Current tax expense
Federal	$	5,802		$	474		$	2,387
State	1,067			1,260			525
	6,869			1,734			2,912
Deferred tax (benefit) expense
Federal	(650		)	(789		)	(15,515		)
State	(917		)	291			135
	(1,567		)	(498		)	(15,380		)
Income tax expense (benefit)	$	5,302		$	1,236		$	(12,468	)

Summary of Deferred Tax Assets (Liabilities)

Deferred tax (liabilities) assets were comprised of the following:

	(In thousands) December 31,
	2019			2018
Deferred tax assets:
Accrued expenses	$	776		$	704
Allowance for doubtful accounts	314			267
Contract overrun reserves	1,004			1,263
Deferred compensation	94			302
Employment-related accruals	5,049			4,252
Environmental reserves	494			479
Federal tax credit carryforwards	84			288
Inventory reserves	2,334			1,757
Pension obligation	2,552			2,324
Federal and state net operating loss carryforwards	6,251			51
State tax credit carryforwards	8,900			9,075
Stock-based compensation	1,672			1,661
Workers’ compensation	43			51
Other	1,409			1,538
Total gross deferred tax assets	30,976			24,012
Valuation allowance	(9,375		)	(9,083		)
Total gross deferred tax assets, net of valuation allowance	21,601			14,929
Deferred tax liabilities:
Deferred revenue	(256		)	(649		)
Depreciation	(8,852		)	(7,951		)
Goodwill	(4,109		)	(3,963		)
Intangibles	(24,749		)	(19,905		)
Prepaid insurance	(346		)	(223		)
Total gross deferred tax liabilities	(38,312		)	(32,691		)
Net deferred tax liabilities	$	(16,711	)	$	(17,762	)

Principle Reasons for Variation Between Expected and Effective Tax Rate

The principal reasons for the variation between the statutory and effective tax rates were as follows:

	Years Ended December 31,
	2019	2018	2017
Statutory federal income tax rate	21.0%	21.0%	35.0%
State income taxes (net of federal benefit)	3.6	5.3	2.5
Foreign derived intangible income deduction	(1.2)	—	—
Qualified domestic production activities	—	—	(2.6)
Stock-based compensation expense	(2.1)	(1.9)	(8.2)
Research and development tax credits	(7.8)	(32.0)	(50.6)
Other tax credits	—	(1.2)	(7.5)
Changes in valuation allowance	(1.6)	0.7	10.6
Non-deductible book expenses	3.9	8.2	1.1
Changes in deferred tax assets	(2.2)	12.1	15.4
Re-measurement of deferred taxes for 2017 Tax Act	—	—	(171.3)
Changes in tax reserves	1.2	1.2	11.4
Other	(0.8)	(1.4)	0.4
Effective income tax (benefit) rate	14.0%	12.0%	(163.8)%

Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits was as follows:

	(In thousands) Years Ended December 31,
	2019			2018			2017
Balance at January 1,	$	5,283		$	5,271		$	3,036
Additions for tax positions related to the current year	408			419			422
Additions for tax positions related to prior years	—			92			1,953
Reductions for tax positions related to prior years	(28		)	(499		)	(99		)
Reductions for lapse of statute of limitations	—			—			(41		)
Balance at December 31,	$	5,663		$	5,283		$	5,271