Revenue (Tables)

6 Months Ended

Jun. 30, 2014

Revenue [Abstract]

Differentiation of revenue and cost of revenue

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

	Three months ended June 30,				Six months ended June 30,
	2014		2013		2014		2013
Revenue:
Products	$	82,302	$	71,523	$	164,707	$	127,853
Rentals	15,065		15,679		28,989		31,419
Services	7,951		6,384		14,197		12,557
	$	105,318	$	93,586	$	207,893	$	171,829
Cost of revenue:
Products	$	49,995	$	46,992	$	97,731	$	81,508
Rentals	7,654		4,281		14,165		10,798
Services	3,265		2,832		5,978		5,569
Depreciation	2,094		1,887		4,029		3,730
	$	63,008	$	55,992	$	121,903	$	101,605