13.	INCOME TAXES

The Company’s loss before provision for income taxes during the years ended December 31, 2017, 2016 and 2015, was a domestic loss of $29.4 million, $66.4 million, and $35.2 million, respectively.

The Company has incurred net operating losses since inception. The Company has not reflected any benefit of such net operating loss carryforwards in the accompanying consolidated financial statements and has established a full valuation allowance against its deferred tax assets.

The components of the provision for income taxes (benefit) during the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):

 

		December 31,
		2017				2016				2015
Current:
Federal		$	—			$	—			$	—
State			1				1				1
Foreign			—				—				—
Total current			1				1				1
Deferred:
Federal			27,228				(20,942	)			(11,080	)
State			1,703				8,936				(3,250	)
Foreign			—				—				—
Total deferred			28,931				(12,006	)			(14,330	)
Valuation allowance			(28,931	)			12,006				14,330
Total provision for income taxes		$	—			$	—			$	—

 

Deferred income taxes reflect the net tax effects of (a) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, and (b) operating losses and tax credit carryforwards.

The significant components of the Company’s deferred tax assets as of December 31, 2017 and 2016 are as follows (in thousands):

 

		December 31,
		2017				2016
Deferred tax assets:
Net operating loss carryforwards		$	31,086			$	44,909
Tax credits			4,394				4,084
Intangible assets			745				1,470
Capitalized R&D			26,661				40,297
Other			729				1,677
Total deferred tax assets			63,615				92,437
Deferred tax liabilities			—				—
Valuation allowance			(63,615	)			(92,437	)
Net deferred tax asset		$	—			$	—

Tax benefits of net operating losses, temporary differences and credit carryforwards are recorded as an asset to the extent that management assesses that realization is “more likely than not.” Realization of the future tax benefits is dependent on the Company’s ability to generate sufficient taxable income within the carryforward period. Because of the Company’s history of operating losses, management believes that the deferred tax assets arising from the above-mentioned future tax benefits are currently not likely to be realized and, accordingly, has provided a full valuation allowance. The net valuation allowance decreased by $28.9 million in 2017, increased by $12.0 million in 2016, and increased by $14.3 million in 2015.