v2.4.0.8

Stock Option Plans and Share-Based Compensation ESPP- Employee stock purchase plan (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	3,353,607.8	3,353,607.8
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP max percent of earnings contributable		15.00%
ESPP max annual contribution		$ 25,000
ESPP purchase price as percent of begin and-or ending fair value		85.00%
Shares, Issued	4,233,557	4,233,557
Common Stock, Capital Shares Reserved for Future Issuance	1,097,998	1,097,998
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	193,719	450,713

X

- Definition

ESPP max percent of earnings contributable - maxium percentage of employee earnings which may be contributed to the ESPP (also subject to dollar max)

+ References

No definition available.

+ Details

Name:	omcl_EsppMaxPercentOfEarningsContributable
Namespace Prefix:	omcl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

ESPP purchase price as percent of begin and-or ending fair value - employees get the benefit of discount from close price, with more favorable of begin or end of enrollment period

+ References

No definition available.

+ Details

Name:	omcl_EsppPurchasePriceAsPercentOfBeginAndOrEndingFairValue
Namespace Prefix:	omcl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

ESPP max annual contribution = maxiumum annual contribution permitted from each employee's earnings towards the ESPP

+ References

No definition available.

+ Details

Name:	omcl_EsspMaxAnnualContribution
Namespace Prefix:	omcl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Aggregate number of common shares reserved for future issuance.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 210.5-02.29)

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

+ Details

Name:	us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of share instruments newly issued under a share-based compensation plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 65

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-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.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

+ 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=d3e21463-112644

+ Details

Name:	us-gaap_SharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant