INCOME TAXES - Summary of Components of Net Deferred Tax Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Assets:
Accrued expenses	$ 3,730	$ 3,954
Depreciation	(732)ntct_DeferredTaxAssetsDepreciation	140ntct_DeferredTaxAssetsDepreciation
Deferred revenue	9,054us-gaap_DeferredTaxAssetsDeferredIncome	8,873us-gaap_DeferredTaxAssetsDeferredIncome
Reserves	1,651	1,006
Net operating loss carryforwards	19,214	23,730
Tax credit carryforwards	3,838	3,628
Share-based compensation	2,660	2,125
Transaction related costs	4,001ntct_DeferredTaxAssetsTransactionCosts	0ntct_DeferredTaxAssetsTransactionCosts
Other	808us-gaap_DeferredTaxAssetsOther	233us-gaap_DeferredTaxAssetsOther
Deferred tax assets, net	44,224us-gaap_DeferredTaxAssetsNet	43,689us-gaap_DeferredTaxAssetsNet
Liabilities:
Intangible assets	(29,202)	(25,659)
Valuation allowance	(3,906)	(4,941)
Deferred tax assets (liabilities), net	$ 11,116us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 13,089us-gaap_DeferredTaxAssetsLiabilitiesNet

Deferred Tax Assets, Depreciation

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from deferred income.

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

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

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

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed.

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The tax effect as of the balance sheet date of the amount of future tax deductions arising from all unused tax credit carryforwards which have been reduced by a valuation allowance.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from loss reserves other than estimated credit losses.

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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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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.

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