Deferred Gross Profit (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Deferred Gross Profit [Abstract]
Sales of Medication and supply dispensing systems and packaging equipment, which have been delivered and invoiced but not yet installed	$ 39,937	$ 30,138
Cost of revenues, excluding installation costs	(12,999)	(9,366)
Deferred gross profit	$ 26,938	$ 20,772

Cost of sales, excluding installation costs for deferred gross profit - Cost of sales relieved from inventory for the products delivered, invoiced but not yet installed counted in Deferred Gross profit. This excludes the future installation cost, booked as period expense.

No definition available.

Name:	omcl_CostOfSalesExcludingInstallationCostsForDeferredGrossProfit
Namespace Prefix:	omcl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant