v2.4.1.9

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014 Segment Customer Distributor	Dec. 31, 2013 Customer	Dec. 31, 2012 Customer
Significant Accounting Policies [Line Items]
Reserves for excess and obsolete inventory	$ 1,395,000crv_InventoryReserveForExcessAndObsoleteInventoryAndLifo	$ 1,454,000crv_InventoryReserveForExcessAndObsoleteInventoryAndLifo
Number of Operating Segments	1us-gaap_NumberOfOperatingSegments
Number Of Distribution Centers	17crv_NumberOfDistributionCenters
Number Of Customer Accounted For Ten Percent Or More Net Sales	0crv_NumberOfCustomerAccountedForTenPercentOrMoreNetSales	0crv_NumberOfCustomerAccountedForTenPercentOrMoreNetSales	0crv_NumberOfCustomerAccountedForTenPercentOrMoreNetSales
Level 3 assets	0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Level 3 liabilities	0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Warranty period for retail customer	24 months
Warranty reserves	$ 762,000crv_WarrantyReserves	$ 737,000crv_WarrantyReserves
Stock Option
Significant Accounting Policies [Line Items]
Anti-dilutive shares excluded from the computation of diluted loss per share	101,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount / us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis = us-gaap_StockOptionMember	279,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount / us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis = us-gaap_StockOptionMember	433,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount / us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis = us-gaap_StockOptionMember
Restricted Stock
Significant Accounting Policies [Line Items]
Anti-dilutive shares excluded from the computation of diluted loss per share	268,985us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount / us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis = us-gaap_RestrictedStockMember	318,660us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount / us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis = us-gaap_RestrictedStockMember	312,501us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount / us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis = us-gaap_RestrictedStockMember
Leasehold Improvements | Minimum
Significant Accounting Policies [Line Items]
Leasehold improvements amortization Period	5 years
Leasehold Improvements | Maximum
Significant Accounting Policies [Line Items]
Leasehold improvements amortization Period	15 years

X

- Definition

Amortization Period

+ References

No definition available.

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Balance Type:	na
Period Type:	duration

X

- Definition

Inventory Reserve For Excess And Obsolete Inventory And Lifo

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Number Of Customer Accounted For Ten Percent Or More Net Sales

+ References

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X

- Definition

Number Of Distribution Centers

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X

- Definition

Product Warranty Term

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X

- Definition

Warranty Reserves

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X

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Antidilution

-URI http://asc.fasb.org/extlink&oid=6505113



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Diluted Earnings Per Share

-URI http://asc.fasb.org/extlink&oid=6510752



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Contingent Stock Agreement

-URI http://asc.fasb.org/extlink&oid=6508534

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

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X

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