Subsequent Event (Details) (Subsequent Event [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Subsequent Event [Member]
Subsequent Event (Textual) [Abstract]
Term agreement of senior secured credit facility	3 years
Amount of senior secured credit facility	$ 25.0
Percentage of eligible account receivable	80.00%
Percentage of domestically held raw material and finished goods inventory	35.00%
Percentage of advances against inventory	40.00%
Amount of aggregate outstanding on the revolving line of credit	10.0
Option to borrow at an interest rate of LIBOR plus	2.75%
Option to borrow at an interest rate of Wall Street Journal prime rate prime rate plus	0.50%
Liquidity rate	$ 20.0
Borrowing interest rate options	2.25%
Percentage of Unused revolving line facility fee	0.375%
Adjusted quick ratio	1.40%
Percentage of maintain operating and other deposit accounts	25.00%

Adjusted quick ratio.

No definition available.

Name:	rbcn_AdjustedQuickRatio
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility agreement period.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityAgreementPeriod
Namespace Prefix:	rbcn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility basis spread on London inter bank offered rate.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityBasisSpreadOnLondonInterBankOfferedRate
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility basis spread on prime rate.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityBasisSpreadOnPrimeRate
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility liquidity maintained basis spread on London inter bank offered rate.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityLiquidityMaintainedBasisSpreadOnLondonInterBankOfferedRate
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility maximum borrowing capacity as percentage of accounts receivable.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityMaximumBorrowingCapacityAsPercentageOfAccountsReceivable
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility maximum borrowing capacity as percentage of raw material and finished goods inventory.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityMaximumBorrowingCapacityAsPercentageOfRawMaterialAndFinishedGoodsInventory
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility outstanding maximum amount of advances against inventory.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityOutstandingMaximumAmountOfAdvancesAgainstInventory
Namespace Prefix:	rbcn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of advances against inventory.

+ References

No definition available.

+ Details

Name:	rbcn_LineOfCreditFacilityOutstandingMaximumPercentageOfAdvancesAgainstInventory
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum liquidity amount with lending institution.

+ References

No definition available.

+ Details

Name:	rbcn_MaximumLiquidityAmountWithLendingInstitution
Namespace Prefix:	rbcn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of cash securities and investments maintained for deposit accounts.

+ References

No definition available.

+ Details

Name:	rbcn_PercentageOfCashSecuritiesAndInvestmentsMaintainedForDepositAccounts
Namespace Prefix:	rbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	rbcn_SubsequentEventTextualAbstract
Namespace Prefix:	rbcn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration