| **Shareholders' Equity (Options Outstanding and Exercisable) (Details) (USD $)**                            | 12 Months Ended                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| $1.00 - $7.99 [Member]                                                                                      |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| **Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]** |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - lower range                                                                      | $ 1us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeOneMember         |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - upper range                                                                      | $ 7.99us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeOneMember      |                                                                                                                                                                                                                                                                                          |
| Options outstanding, number of shares                                                                       |                                                                                                                                                                                                                                          | 49,153us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeOneMember                                           |
| Options outstanding, weighted average remaining contractual life                                            | 8 years 2 months 19 days                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                          |
| Options outstanding, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 7.86us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeOneMember      |
| Options exercisable, number of shares                                                                       |                                                                                                                                                                                                                                          | 12,657us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeOneMember                                           |
| Options exercisable, weighted average remaining contractual life                                            | 8 years 2 months 19 days                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                          |
| Options exercisable, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 7.86us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeOneMember                      |
| $8.00 - $15.99 [Member]                                                                                     |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| **Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]** |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - lower range                                                                      | $ 8.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeTwoMember      |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - upper range                                                                      | $ 15.99us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeTwoMember     |                                                                                                                                                                                                                                                                                          |
| Options outstanding, number of shares                                                                       |                                                                                                                                                                                                                                          | 32,690us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeTwoMember                                           |
| Options outstanding, weighted average remaining contractual life                                            | 9 years 4 months 13 days                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                          |
| Options outstanding, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 9.93us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeTwoMember      |
| Options exercisable, number of shares                                                                       |                                                                                                                                                                                                                                          | 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeTwoMember                                                |
| Options exercisable, weighted average remaining contractual life                                            | 9 years 4 months 13 days                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                          |
| Options exercisable, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 0.00us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeTwoMember                      |
| $16.00 - $17.00 [Member]                                                                                    |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| **Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]** |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - lower range                                                                      | $ 16.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeThreeMember   |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - upper range                                                                      | $ 17.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeThreeMember   |                                                                                                                                                                                                                                                                                          |
| Options outstanding, number of shares                                                                       |                                                                                                                                                                                                                                          | 221,374us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeThreeMember                                        |
| Options outstanding, weighted average remaining contractual life                                            | 9 years 9 months 4 days                                                                                                                                                                                                                       |                                                                                                                                                                                                                                                                                          |
| Options outstanding, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 16.00us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeThreeMember   |
| Options exercisable, number of shares                                                                       |                                                                                                                                                                                                                                          | 0us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeThreeMember                                              |
| Options exercisable, weighted average remaining contractual life                                            | 9 years 9 months 4 days                                                                                                                                                                                                                       |                                                                                                                                                                                                                                                                                          |
| Options exercisable, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 0.00us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeThreeMember                    |
| $1,350.00 - $1,890.00 [Member]                                                                              |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| **Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]** |                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - lower range                                                                      | $ 1,350.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeFourMember |                                                                                                                                                                                                                                                                                          |
| Range of exercise prices - upper range                                                                      | $ 1,890.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeFourMember |                                                                                                                                                                                                                                                                                          |
| Options outstanding, number of shares                                                                       |                                                                                                                                                                                                                                          | 55us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeFourMember                                              |
| Options outstanding, weighted average remaining contractual life                                            | 1 year 8 months 19 days                                                                                                                                                                                                                       |                                                                                                                                                                                                                                                                                          |
| Options outstanding, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 1,662.55us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeFourMember |
| Options exercisable, number of shares                                                                       |                                                                                                                                                                                                                                          | 55us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeFourMember                                              |
| Options exercisable, weighted average remaining contractual life                                            | 1 year 8 months 19 days                                                                                                                                                                                                                       |                                                                                                                                                                                                                                                                                          |
| Options exercisable, weighted average exercise price (in usd per share)                                     |                                                                                                                                                                                                                                          | $ 1,662.55us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis= cob_ExercisePriceRangeFourMember                 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| X                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                   |
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| X                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cob_ExercisePriceRangeThreeMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                                                   |
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