| **Consolidated Statements of Shareholders' Equity (Parentheticals) (USD $)In Thousands, unless otherwise specified** | 0 Months Ended                                               | 12 Months Ended                                                          |
|----------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------|--------------------------------------------------------------------------|
||
| Reverse stock split, conversion ratio                                                                                | 0.01us-gaap_StockholdersEquityNoteStockSplitConversionRatio1 |                                                                     | 0.01us-gaap_StockholdersEquityNoteStockSplitConversionRatio1 |
| Stock issuance costs                                                                                                 |                                                         | $ 18us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts |   |
| 2012 Issuance [Member]                                                                                               |                                                         |                                                                     |   |
| Stock issuance costs                                                                                                 |                                                         |                                                                     | 379us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts/ cob_StockIssuancePeriodAxis= cob_A2012IssuanceMember |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of decrease in additional paid in capital (APIC) resulting from direct costs associated with issuing stock. Includes, but is not limited to, legal and accounting fees and direct costs associated with stock issues under a shelf registration.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770
+ Details**Name:**us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Stock Split -URI http://asc.fasb.org/extlink&oid=6525746Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB TOPIC 4.C) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770
+ Details**Name:**us-gaap_StockholdersEquityNoteStockSplitConversionRatio1**Namespace Prefix:**us-gaap_**Data Type:**xbrli:pureItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**cob_StockIssuancePeriodAxis=cob_A2012IssuanceMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |