Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Constituents of Provision for Income Taxes

Income tax expense on continuing operations consisted of the following (in thousands):

	Year Ended December 31,
	2017			2016			2015
Current:
Federal	$	78,054		$	14,459		$	16,430
State	2,687			(617		)	378
Foreign	7,714			8,149			4,946
	88,455			21,991			21,754
Deferred:
Federal	1,569			(3,031		)	(2,541		)
State	(639		)	1,066			(165		)
Foreign	359			(1,058		)	250
	1,289			(3,023		)	(2,456		)
	$	89,744		$	18,968		$	19,298

Reconciliation of the United States Federal Statutory Corporate Tax Rate to the Company's Effective Tax Rate or Income Tax Provision

A reconciliation of the U.S. federal statutory corporate tax rate to the Company’s income tax expense on continuing operations, or effective tax rate, was as follows:

	Year Ended December 31,
	2017		2016		2015
Income tax provision at federal statutory corporate tax rate	35	%	35	%	35	%
State income taxes, net of federal benefit	—		1		—
Foreign tax rate differential	(27	)	(17	)	(19	)
Tax credit	(1	)	(1	)	—
Discrete tax benefit related to employee stock option exercises	(14	)	(7	)	—
Discrete tax expense related to 2017 Tax Act	36		—		—
Discrete tax expense related to write-down of deferred tax assets	5		—		—
Other discrete tax events	(1	)	—		(2	)
Other	1		—		1
Income tax provision on continuing operations	34	%	11	%	15	%

Changes in the Reserve for Income Taxes, Excluding Interest and Penalties

The changes in the reserve for income taxes, excluding gross interest and penalties, were as follows (in thousands):

Balance of reserve for income taxes as of December 31, 2015	$	5,296
Gross amounts of increases in unrecognized tax benefits as a result of tax positions taken in prior periods	11
Gross amounts of increases in unrecognized tax benefits as a result of tax positions taken in the current period	1,235
Gross amounts of decreases in unrecognized tax benefits relating to settlements with taxing authorities	—
Gross amounts of decreases in unrecognized tax benefits as a result of the expiration of the applicable statutes of limitations	(823		)
Balance of reserve for income taxes as of December 31, 2016	5,719
Gross amounts of decreases in unrecognized tax benefits as a result of tax positions taken in prior periods	(56		)
Gross amounts of increases in unrecognized tax benefits as a result of tax positions taken in the current period	1,993
Gross amounts of decreases in unrecognized tax benefits relating to settlements with taxing authorities	(116		)
Gross amounts of decreases in unrecognized tax benefits as a result of the expiration of the applicable statutes of limitations	(791		)
Balance of reserve for income taxes as of December 31, 2017	$	6,749

Constituents of Deferred Tax Assets

Deferred tax assets and liabilities consisted of the following (in thousands):

	December 31,
	2017			2016
Non-current deferred tax assets:
Stock-based compensation expense	$	11,664		$	15,365
Federal and state tax credit carryforwards	6,707			5,154
Bonuses, commissions, and other compensation	5,704			2,483
Inventory and revenue related	3,415			2,919
Depreciation	2,279			2,882
Other	3,012			3,714
Gross non-current deferred tax assets	32,781			32,517
Non-current deferred tax liabilities:
Nondeductible intangible assets	(87		)	(379		)
Gross non-current deferred tax liabilities	(87		)	(379		)
Valuation allowance	(5,309		)	(4,116		)
Net non-current deferred tax assets	$	27,385		$	28,022
Non-current deferred tax liabilities:
Other	$	(312	)	$	—
Net non-current deferred tax liabilities	$	(312	)	$	—