Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 76,670	$ 84,933	$ 144,438	$ 173,608
Accounts receivable, net	15,057	44,365
Unbilled receivables	17,730	19,937
Inventories	33,071	32,721
Prepaid expenses and other current assets	13,724	14,807
Total current assets	156,252	196,763
Property, plant, equipment and seismic rental equipment, net	65,785	72,027
Multi-client data library, net	123,581	132,237
Goodwill	25,595	26,274
Intangible assets, net	4,381	4,810
Other assets	3,029	2,977
Total assets	378,623	435,088
Current liabilities:
Current maturities of long-term debt	32,933	7,912
Accounts payable	20,907	29,799
Accrued expenses	29,001	34,287
Accrued multi-client data library royalties	21,790	25,045
Deferred revenue	6,021	6,560
Total current liabilities	110,652	103,603
Long-term debt, net of current maturities	148,410	175,080
Other long-term liabilities	44,215	44,365
Total liabilities	303,277	323,048
Equity:
Common stock, $0.01 par value; authorized 26,666,667 shares; outstanding 10,580,058 and 10,702,689 shares at March 31, 2016 and December 31, 2015, respectively, net of treasury stock	106	107
Additional paid-in capital	895,481	894,715
Accumulated deficit	(794,545)	(759,531)
Accumulated other comprehensive loss	(16,243)	(14,781)
Treasury stock, at cost, 508,427 and 353,124 shares at March 31, 2016 and December 31, 2015 respectively	(9,515)	(8,551)
Total stockholders' equity	75,284	111,959
Noncontrolling interest	62	81
Total equity	75,346	112,040
Total liabilities and equity	$ 378,623	$ 435,088