v2.4.0.6

Organization and Summary of Significant Accounting Policies Significant supplier disclosure (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Unusual Risk or Uncertainty [Line Items]
Purchases from significant supplier	$ 7.2	$ 6.2

X

- Definition

Purchases from significant supplier - pruchasses during period from most significant supplier mentioned in Supplier Dependence section of Note 1

+ References

No definition available.

+ Details

Name:	omcl_PurchasesFromSignificantSupplier
Namespace Prefix:	omcl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

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