Supplemental Cash Flow Information and Non-Cash Activity (Tables)

6 Months Ended

Jun. 30, 2013

Supplemental Cash Flow Elements [Abstract]

Summary of Non-cash Items from Investing and Financing Activities

A summary of non-cash items from investing and financing activities is as follows (in thousands):

	Six Months Ended June 30,
	2013		2012
Purchases of computer equipment financed through capital leases	$	2,465	$	2,953
Leasehold improvement paid by landlord	$	1,738	$	—
Conversion of investment in a convertible note to equity	$	6,765	$	—
Transfer of inventory to seismic rental equipment	$	—	$	6,053