Income taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Income (Loss) before Income Taxes

The provision for income taxes is based upon the income (loss) before income taxes as follows (in thousands): 

	Years Ended December 31,
	2019			2018			2017
U.S. operations	$	(21,579	)	$	(43,384	)	$	(52,725	)
Non-U.S. operations	6,136			1,076			301
	$	(15,443	)	$	(42,308	)	$	(52,424	)

Components of Provision for Income Taxes

The components of the provision for income taxes consisted of the following (in thousands): 

	Years Ended December 31,
	2019			2018			2017
Current
Federal	$	(71	)	$	(49	)	$	(144	)
State	(3		)	36			3
Foreign	(1,854		)	(1,634		)	363
	(1,928		)	(1,647		)	222
Deferred
Federal	—			42			4
State	—			—			—
Foreign	295			276			(1,135		)
Total provision	$	(1,633	)	$	(1,329	)	$	(909	)

Difference in Provision for Income Taxes from Amount Obtained by Applying U.S. Federal Statutory Rate

The tax provision differs from the amount obtained by applying the U.S. federal statutory tax rate as follows (in thousands, except percentages): 

	Years Ended December 31,
	2019			2018			2017
Federal statutory rate	21		%	21		%	35		%
Tax at federal statutory rate	$	3,255		$	8,869		$	18,354
State taxes, net of federal benefit	(3		)	36			2
Mandatory repatriation/Section 956	—			—			(5,718		)
Permanent differences	1,514			(371		)	(67		)
Stock-based compensation	(1,014		)	(1,079		)	(314		)
Change in valuation allowance	(5,186		)	(10,094		)	16,273
Research and development	932			914			851
Foreign rate differences	(531		)	(697		)	(2,819		)
Foreign tax credit	(405		)	49			144
Change in prior year deferred balances	—			1,653			(28,262		)
Other	(195		)	(609		)	647
Total provision for income taxes from continuing operations	$	(1,633	)	$	(1,329	)	$	(909	)

Components of Deferred Income Tax Assets and Liabilities

Deferred income tax assets and liabilities comprise the following (in thousands): 

	December 31,
	2019			2018
Deferred Tax Assets:
Net operating loss carryforwards	$	54,339		$	56,828
Federal and state credits	30,111			28,328
Reserves, accruals and other	14,132			11,265
Fixed assets and intangibles	2,783			2,398
Total deferred tax assets	101,365			98,819
Valuation allowance	(92,149		)	(92,891		)
Total deferred tax assets, net of valuation allowance	9,216			5,928
Less deferred tax liabilities:
Acquired intangibles	(283		)	(313		)
Property, plant and equipment	(4,663		)	(4,754		)
Right-of-Use Lease Assets	(3,124		)	—
Net deferred tax assets	$	1,146		$	861
Reported as:
Long term deferred tax assets, included within other long-term assets	$	1,674		$	861
Long term deferred income tax liabilities, included within noncurrent liabilities	(528		)	—
Net deferred tax assets	$	1,146		$	861

Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): 

Balance at December 31, 2016	$	23,606
Gross increases for tax positions of current year	1,933
Balance at December 31, 2017	25,539
Gross increases for tax positions of current year	657
Balance at December 31, 2018	26,196
Net changes in tax positions in current year	(5,544		)
Balance at December 31, 2019	$	20,652