Revenue (Tables)

12 Months Ended

Dec. 31, 2014

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,
	2014		2013		2012
Revenue:
Products	$	354,356	$	282,639	$	224,777
Rentals	65,549		62,042		67,938
Services	29,252		26,384		20,113
	$	449,157	$	371,065	$	312,828
Cost of Revenue:
Products	$	214,417	$	180,800	$	135,367
Rentals	31,285		24,987		30,618
Services	12,385		9,916		8,051
Depreciation	8,111		7,835		7,173
	$	266,198	$	223,538	$	181,209