Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Components of (Loss) Income before (Provision) Benefit for Income Taxes

The components of loss before benefit for income taxes from continuing operations are as follows:



	Year Ended December 31,
	2019			2018			2017
United States	$	(139,682	)	$	(133,165	)	$	(121,507	)
Foreign	(4,912		)	4,558			(1,185		)
Total	$	(144,594	)	$	(128,607	)	$	(122,692	)

Provision (Benefit) for Income Taxes

The benefit for income taxes from continuing operations consist of the following:



	Year Ended December 31,
	2019			2018			2017
Current:
Federal	$	(6,584	)	$	(1,663	)	$	(15,412	)
State	(1,166		)	(269		)	(1,298		)
Foreign	11			—			6
	$	(7,739	)	$	(1,932	)	$	(16,704	)
Deferred:
Federal	(781		)	12			(5,256		)
State	(688		)	19			19
	(1,469		)	31			(5,237		)
Total income tax benefit	$	(9,208	)	$	(1,901	)	$	(21,941	)

Income Tax Provision (Benefit) Differs from Computed Using Federal Statutory Rate Applied to Income before Taxes

The income tax benefit differs from that computed using the applicable federal statutory rate, as applied to our income before taxes in each year as follows:



	Year Ended December 31,
	2019			2018			2017
Tax provision computed at the federal statutory rate	$	(30,365	)	$	(26,854	)	$	(42,614	)
State tax, net of federal benefit	(4,126		)	(5,077		)	(2,207		)
Research and development expense tax credits	(2,526		)	(4,884		)	(1,176		)
Change in uncertain tax benefit reserve	—			—			(561		)
Change in tax credit carryforwards	81			(3,056		)	386
Officers compensation	1,506			600			(9,292		)
Stock based compensation	(230		)	(12,610		)	(2,734		)
Permanent items and other	267			(116		)	1,450
Tax differential on foreign earnings	(31		)	(32		)	33
Change in tax rate	1,126			(1,329		)	37,768
Refundable alternative minimum tax credit	—			—			(1,336		)
Change in prior year deferred taxes	1,170			6,595			(1,218		)
Valuation allowance	23,920			44,862			(440		)
Income tax benefit	$	(9,208	)	$	(1,901	)	$	(21,941	)

Components of Company's Deferred Tax Assets

Significant components of our deferred tax assets and liabilities as of December 31, 2019 and 2018 are presented below. A valuation allowance has been recognized to offset the net deferred tax assets as realization of such deferred tax assets did not meet our “more-likely-than-not” assessment threshold, as required under GAAP.



	December 31,
	2019			2018
Deferred tax assets:
Net operating loss carry forwards	$	118,163		$	103,582
Research and development expense tax credits	22,724			21,618
Stock based compensation	4,385			5,057
Lease obligation	919			—
Development costs	704			3,938
Returns and allowances	1,069			1,976
Other, net	11,861			7,185
Total deferred tax assets before valuation allowance	159,825			143,356
Valuation allowance	(152,966		)	(131,042		)
Total deferred tax assets	6,859			12,314
Deferred tax liabilities, net:
Unrealized gains	(5,607		)	(9,387		)
Depreciation and amortization differences	(389		)	(4,396		)
Right-of-use asset	(863		)	—
Net deferred tax liabilities	$	—		$	(1,469	)

Summary of Unrecognized Tax Benefits

The following tabular reconciliation summarizes the activity related to our unrecognized tax benefits:



	Year Ended December 31,
	2019			2018			2017
Balance at beginning of year	$	3,248		$	2,715		$	3,271
Adjustments related to prior year tax positions	(392		)	(551		)	(39		)
Increases related to current year tax positions	692			1,084			374
Decreases due to expiration of tax statutes	(75		)	—			(891		)
Balance at end of year	$	3,473		$	3,248		$	2,715