Revenue (Tables)

12 Months Ended

Dec. 31, 2012

Revenue [Abstract]

Differentiation of revenue and cost of revenue

Revenue and cost of revenue by source are as follows (in thousands):

	Year ended December 31,
	2012		2011		2010
Revenue:
Products	$	224,777	$	181,417	$	95,021
Rentals	67,938		63,610		42,169
Services	20,113		13,758		9,792
	$	312,828	$	258,785	$	146,982
Cost of Revenue:
Products	$	135,367	$	115,875	$	60,919
Rentals	30,618		25,971		20,355
Services	8,051		4,997		3,517
Depreciation	7,173		6,122		9,221
	$	181,209	$	152,965	$	94,012