INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2017

INCOME TAXES

Schedule of impacts of the differences between the expected U.S. federal statutory income tax to our income tax expense

	Year Ended December 31,
(In thousands)	2017			2016			2015
Expected tax at federal statutory rate	$	46,997		$	20,871		$	(6,372	)
State income tax, net of federal benefit		4			—			—
Non-deductible executive compensation		987			925			306
Other		(1,506	)		(122	)		170
Impact of tax reform rate change		124,017			—			—
Change in valuation allowance		(170,495	)		(21,579	)		5,896
Income tax expense	$	4		$	95		$	—

Schedule of significant components of the Company's deferred tax assets and deferred tax liabilities

	As of December 31,
(In thousands)	2017			2016
Deferred tax assets
Net operating loss carryforwards	$	257,000		$	417,000
Deferred revenues		—			1,000
Research and development tax credit carryforwards		57,000			53,000
Other		3,000			13,000
Total deferred tax assets before valuation allowance		317,000			484,000
Valuation allowance		(303,000	)		(484,000	)
Total deferred tax assets		14,000			—
Deferred tax liabilities
Debt issuance discount and other		(14,000	)		—
Net deferred tax assets	$	—		$	—

Summary of changes in unrecognized tax benefits

        A reconciliation of the beginning and ending balances of the total amounts of unrecognized tax benefits are as follows (in thousands):

Unrecognized tax benefits as of December 31, 2014	$	15,459
Gross increase in tax portions for 2015		29
Unrecognized tax benefits as of December 31, 2017, 2016 and 2015	$	15,488