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INCOME TAXES - DEFERRED TAXES (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Significant components of deferred tax assets |  |  |
Net operating loss carryforwards | $ 187,700,000 | $ 280,400,000 |
Research credits | 34,300,000 | 29,800,000 |
Capitalized research and development | 2,500,000 | 300,000 |
License fees | 100,000 | 200,000 |
Other-net | 8,200,000 | 11,500,000 |
Total deferred tax assets | 232,800,000 | 322,200,000 |
Valuation allowance for deferred tax assets | (232,800,000) | (322,200,000) |
Valuation allowance |  |  |
Increase (decrease) in valuation allowance | $ (89,400,000) | $ 9,600,000 | $ (2,300,000)

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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
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