Taxes on Income - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Net operating loss carry-forward	$ 495,844	$ 488,603
Total deferred tax assets	114,044	112,380
Valuation allowance	(114,044)	(112,380)
Net deferred tax assets

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

+ References

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

+ References

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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