Revenue (Tables)

12 Months Ended

Dec. 31, 2013

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,
	2013		2012		2011
Revenue:
Products	$	282,639	$	224,777	$	181,417
Rentals	62,042		67,938		63,610
Services	26,384		20,113		13,758
	$	371,065	$	312,828	$	258,785
Cost of Revenue:
Products	$	180,800	$	135,367	$	115,875
Rentals	24,987		30,618		25,971
Services	9,916		8,051		4,997
Depreciation	7,835		7,173		6,122
	$	223,538	$	181,209	$	152,965