Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 49,640	$ 52,652	$ 76,670	$ 84,933
Accounts receivable, net	16,173	20,770
Unbilled receivables	17,423	13,415
Inventories	15,220	15,241
Prepaid expenses and other current assets	7,262	9,559
Total current assets	105,718	111,637
Property, plant, equipment and seismic rental equipment, net	63,173	67,488
Multi-client data library, net	101,493	105,935
Goodwill	22,542	22,208
Intangible assets, net	2,745	3,103
Other assets	2,457	2,845
Total assets	298,128	313,216
Current liabilities:
Current maturities of long-term debt	12,966	14,581
Accounts payable	26,662	26,889
Accrued expenses	29,878	26,240
Accrued multi-client data library royalties	23,613	23,663
Deferred revenue	10,834	3,709
Total current liabilities	103,953	95,082
Long-term debt, net of current maturities	144,373	144,209
Other long-term liabilities	18,026	20,527
Total liabilities	266,352	259,818
Equity:
Common stock, $0.01 par value; authorized 26,666,667 shares; outstanding 11,871,647 and 11,792,447 shares at March 31, 2017 and December 31, 2016, respectively	119	118
Additional paid-in capital	900,056	899,198
Accumulated deficit	(848,021)	(824,679)
Accumulated other comprehensive loss	(21,231)	(21,748)
Total stockholders’ equity	30,923	52,889
Noncontrolling interest	853	509
Total equity	31,776	53,398
Total liabilities and equity	$ 298,128	$ 313,216