INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Reconciliation Between Effective Tax Rate and 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,
	2017				2016				2015
Federal income tax rate		34.0		%		34.0		%		34.0		%
State taxes		(27.7	)			—				—
Research and development and other tax credits		8.5				1.5				0.3
Valuation allowance		(93.2	)			(17.3	)			(19.1	)
Permanent differences		6.4				(3.4	)			(1.7	)
Sarepta International C.V. return to provision		62.1				—				—
Impact of tax reform, net of valuation allowance		5.9				—				—
Foreign rate differential		(0.6	)			(14.8	)			(13.5	)
Other		0.4				—				—
Effective tax rate		(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,
	2017			2016
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	144,897		$	174,569
Difference in depreciation and amortization		1,210			2,589
Research and development and other tax credits		44,306			37,812
Stock-based compensation		14,392			16,166
Deferred rent		1,210			2,306
Deferred revenue		904			1,315
Capitalized inventory		22,127			36,282
Other		4,071			3,047
Total deferred tax assets		233,117			274,086
Deferred tax liabilities:
Debt discount		(28,548	)		—
Total deferred tax liabilities		(28,548	)		—
Valuation allowance		(204,569	)		(274,086	)
Net deferred tax assets	$	—		$	—

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,
	2017			2016		2015
	(in thousands)
Balance at beginning of the period	$	4,644		$	3,706	$	—
Increase related to current year tax positions		735			801		613
Increase related to prior year tax positions		—			137		3,093
Decrease related to prior year tax position		(245	)		—		—
Balance at end of the period	$	5,134		$	4,644	$	3,706