Revenue (Tables)

9 Months Ended

Sep. 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 September 30,				Nine months ended September 30,
	2014		2013		2014		2013
Revenue:
Products	$	92,708	$	76,376	$	257,415	$	204,229
Rentals	16,966		15,375		45,954		46,794
Services	7,087		6,637		21,284		19,194
	$	116,761	$	98,388	$	324,653	$	270,217
Cost of revenue:
Products	$	57,315	$	50,367	$	155,048	$	131,875
Rentals	8,272		6,868		22,444		17,666
Services	3,074		1,610		9,042		7,179
Depreciation	2,022		2,041		6,051		5,771
	$	70,683	$	60,886	$	192,585	$	162,491