Balance Sheet Components - Balance Sheet Details (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Inventories:
Raw materials		$ 22,750	$ 25,103
Work in process		9,818	9,959
Finished goods		63,569	66,806
Total inventories	$ 101,868	96,137	$ 101,868
Property and equipment:
Equipment	72,122	69,550
Furniture and fixtures	6,750	6,534
Leasehold improvements	14,540	10,976
Software	38,840	37,168
Construction in progress	11,334	9,813
Property and equipment, gross	143,586	134,041
Accumulated depreciation and amortization	(95,296)	(91,446)
Total property and equipment, net	48,290	42,595
Other long term assets:
Capitalized software, net	41,146	38,599
Unbilled receivable	10,877	9,475
Other assets	1,469	1,242
Total other long term assets, net	53,492	49,316
Accrued liabilities:
Advance payments from customers	6,879	7,779
Rebates and lease buyouts	5,342	5,428
Group purchasing organization fees	3,439	3,449
Taxes payable	12,135	9,183
Other accrued liabilities	12,724	9,854
Total accrued liabilities	$ 40,519	$ 35,693

Accrued Liabilities, Rebates and Lease Buyouts, Current

No definition available.

Name:	omcl_AccruedLiabilitiesRebatesandLeaseBuyoutsCurrent
Namespace Prefix:	omcl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).