INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2019

Income tax provisions for the years ended December 31, 2019, 2018 and 2017 consisted of the following (in thousands):



	Year Ended December 31,
	2019			2018			2017
Income (loss) before provisions for income taxes	$	(19,573	)	$	54,735		$	(44,811	)
Provision for income taxes	(471		)	(392		)	(480		)
Effective tax rate	(2.4		)%	0.7		%	(1.1		)%

Schedule of pre-tax book income or loss from continuing operations

The Company reported pre-tax book income (loss) consisted of (in thousands):



	Year Ended December 31,
	2019			2018		2017
Domestic	$	(17,970	)	$	49,509	$	(23,994	)
Foreign	(1,603		)	5,226		(20,817		)
Total	$	(19,573	)	$	54,735	$	(44,811	)

Schedule of provisions for income taxes

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



	Year Ended December 31,
	2019			2018			2017
Current:
U.S. federal	—			$	—		$	—
State and local	(3		)	(3		)	(5		)
Foreign	(190		)	(331		)	(448		)
Total current	$	(193	)	$	(334	)	$	(453	)
Deferred:
U.S. federal	—			—			—
State and local	—			—			—
Foreign	(278		)	(58		)	(27		)
Total deferred	(278		)	(58		)	(27		)
Total provision for income taxes	$	(471	)	$	(392	)	$	(480	)

Details of significant components of net deferred tax assets and liabilities

Deferred tax assets and liabilities are recognized for the temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, tax losses, and credit carryforwards. Significant components of the net deferred tax assets and liabilities consisted of (in thousands):



	December 31,
	2019			2018
Deferred tax assets:
Net operating loss carryforwards	$	4,936		$	4,968
State income taxes	1			1
Deferred revenue	6,291			2,347
Research and development and other credits	8,282			9,590
Reserves and accruals recognized in different periods	1,128			3,734
Capitalized R&D expenses	3,447			3,415
Depreciation and amortization	3,636			472
Lease liability	806			—
Deferred rent	—			160
Other	—			6
Total deferred tax assets	28,527			24,693
Valuation allowance	(28,057		)	(24,398		)
Net deferred tax assets	470			295
Right of use lease assets	(466		)	—
Foreign credits	(23		)	(29		)
Other	(40		)	(17		)
Net deferred tax liabilities	(529		)	(46		)
Net deferred taxes	$	(59	)	$	249

Reconciliation between provision for income taxes at statutory rate and effective tax rate

For purposes of the reconciliation between the provision for income taxes at the statutory rate and the effective tax rate, a national U.S. 21% rate is applied for 2019 and 2018, the years in which the Tax Act took effect. For 2017, the national U.S. rate of 35%, the rate in effect prior to the Tax Act change, was applied for the reconciliation between the provision for income taxes at the statutory rate and the effective tax rate:



	Years Ended December 31,
	2019		2018		2017
Federal statutory tax rate	21.0	%	21.0	%	35.0	%
Foreign withholding	(0.3	)%	0.1	%	(0.2	)%
Stock compensation expense	(11.3	)%	(1.0	)%	(2.0	)%
Foreign rate differential	(2.6	)%	(1.5	)%	(17.0	)%
Prior year true-up items	0.2	%	—	%	(0.1	)%
Tax reserves	(2.1	)%	(1.3	)%	(0.1	)%
Loss on expiration of capital loss carryover	—	%	1.1	%	—	%
Credits	0.1	%	(0.1	)%	0.4	%
Other	(1.6	)%	0.9	%	—	%
FTC conversion true up	(5.9	)%	—	%	—	%
2017 Tax Act impact	—	%	1.1	%	(28.7	)%
Valuation allowance	0.1	%	(19.6	)%	11.6	%
Effective tax rate	(2.4	)%	0.7	%	(1.1	)%

Reconciliation of beginning and ending amount of gross unrecognized tax benefits

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



	Years Ended December 31,
	2019			2018			2017
Balance at beginning of year	$	4,611		$	4,672		$	6,232
Gross increases for tax positions of prior years	394			—			—
Gross decreases for federal tax rate change for tax positions of prior years	—			—			(1,670		)
Gross increases for tax positions of current year	34			45			110
Lapse of statute of limitations	(213		)	(106		)	—
Balance at end of year	$	4,826		$	4,611		$	4,672