EBITDA Calculation (Detail) (USD $)	12 Months Ended
Dec. 31, 2014
EBITDA Calculation [Line Items]
Net (loss)	$ (720,000)
less: income tax benefit	(906,000)
Loss before income taxes	(1,626,000)
add: interest expense	641,000
add: depreciation and amortization	979,000
add: value of share-based payment arrangements	708,000
Add: other non-cash expense	414,000
Earnings before interest, taxes, depreciation, and amortization	$ 1,116,000

Earnings before interest taxes depreciation and amortization.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesDepreciationAndAmortization
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Earnings before interest taxes depreciation and amortization adjustments.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesDepreciationAndAmortizationAdjustments
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Earnings before interest taxes depreciation and amortization income loss before income taxes.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesDepreciationAndAmortizationIncomeLossBeforeIncomeTaxes
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Earnings before interest taxes depreciation and amortization income tax expense benefit.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesDepreciationAndAmortizationIncomeTaxExpenseBenefit
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Earnings before interest taxes depreciation and amortization interest expense.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesDepreciationAndAmortizationInterestExpense
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Earnings before interest taxes depreciation and amortization net income loss.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesDepreciationAndAmortizationNetIncomeLoss
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Earnings before interest taxes other noncash expense.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesOtherNoncashExpense
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Earnings before interest taxes share based compensation.

No definition available.

Name:	hdsn_EarningsBeforeInterestTaxesShareBasedCompensation
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	hdsn_EbitdaCalculationLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration