INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Summary of Loss before Provision for Income Taxes by Jurisdiction

The following table summarizes the loss before the provision for income taxes by jurisdiction for the periods indicated:

	For the Year Ended December 31,
	2018			2017			2016
	(in thousands)
Domestic	$	(309,294	)	$	(45,686	)	$	(267,265	)
Foreign		(53,316	)		(2,942	)		—
Total	$	(362,610	)	$	(48,628	)	$	(267,265	)

Summary of Provision for Income Taxes

The following table summarizes provision for income taxes in the accompanying consolidated financial statements for the periods indicated:

	For the Year Ended December 31,
	2018			2017		2016
	(in thousands)
Current provision
Federal	$	(110	)	$	204	$	—
State		(653	)		1,856		—
Foreign		311			—		—
Total current provision		(452	)		2,060		—
Deferred benefit:
Federal		—			—		—
State		—			—		—
Foreign		(240	)		—		—
Total deferred benefit		(240	)		—		—
Total current provision	$	(692	)	$	2,060	$	—

Reconciliation Between Effective Tax Rate and Federal Income Tax Rate

The following table summarizes the reconciliation between the Company’s effective tax rate and the income tax rate for each of the periods indicated:

	For the Year Ended December 31,
	2018				2017				2016
Federal income tax rate		21.0		%		34.0		%		34.0		%
State taxes		12.3				(27.7	)			—
Research and development and other tax credits		3.1				8.5				1.5
Valuation allowance		(45.5	)			(93.2	)			(17.3	)
Permanent differences		6.9				6.4				(3.4	)
Sarepta International C.V. return to provision		(0.1	)			62.1				—
Impact of tax reform, net of valuation allowance		—				5.90				—
Foreign rate differential		(0.9	)			(0.6	)			(14.8	)
Other		3.4				0.40				—
Effective tax rate		0.2		%		(4.2	)	%		—		%

Analysis of Deferred Tax Assets and Liabilities

The following table summarizes the analysis of the deferred tax assets and liabilities for each of the periods indicated: 

	As of December 31,
	2018			2017
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	212,342		$	144,897
Difference in depreciation and amortization		55,162			1,210
Research and development tax credits		67,309			44,306
Stock-based compensation		15,538			14,392
Deferred rent		4,831			1,210
Deferred revenue		888			904
Capitalized inventory		22,943			22,127
Other		15,727			4,071
Total deferred tax assets		394,740			233,117
Deferred tax liabilities:
Debt discount		(25,162	)		(28,548	)
Total deferred tax liabilities		(25,162	)		(28,548	)
Valuation allowance		(369,345	)		(204,569	)
Net deferred tax assets	$	233		$	—

Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits

The follow table summarizes the reconciliation of the beginning and ending amount of total unrecognized tax benefits for each of the periods indicated:

	For the Year Ended December 31,
	2018		2017			2016
	(in thousands)
Balance at beginning of the period	$	5,134	$	4,644		$	3,706
Increase related to current year tax positions		2,164		735			801
Increase related to prior year tax positions		30,246		—			137
Decrease related to prior year tax positions		—		(245	)		—
Balance at end of the period	$	37,544	$	5,134		$	4,644