Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 52,652	$ 84,933	$ 173,608	$ 148,056
Accounts receivable, net	20,770	44,365
Unbilled receivables	13,415	19,937
Inventories	15,241	32,721
Prepaid expenses and other current assets	9,559	14,807
Total current assets	111,637	196,763
Property, plant, equipment and seismic rental equipment, net	67,488	72,027
Multi-client data library, net	105,935	132,237
Goodwill	22,208	26,274	27,388
Intangible assets, net	3,103	4,810
Other assets	2,845	2,977
Total assets	313,216	435,088
Current liabilities:
Current maturities of long-term debt	14,581	7,912
Accounts payable	26,889	29,799
Accrued expenses	26,240	34,287
Accrued multi-client data library royalties	23,663	25,045
Deferred revenue	3,709	6,560
Total current liabilities	95,082	103,603
Long-term debt, net of current maturities	144,209	175,080
Other long-term liabilities	20,527	44,365
Total liabilities	259,818	323,048
Stockholders' equity:
Common stock, $0.01 par value; authorized 26,666,667 shares; outstanding 11,792,447 and 10,702,689 shares at December 31, 2016 and 2015, respectively, net of treasury stock	118	107
Additional paid-in capital	899,198	894,715
Accumulated deficit	(824,679)	(759,531)
Accumulated other comprehensive loss	(21,748)	(14,781)
Treasury stock, at cost, zero and 353,124 shares at December 31, 2016 and 2015 respectively	0	(8,551)
Total stockholders’ equity	52,889	111,959
Noncontrolling interests	509	81
Total equity	53,398	112,040	$ 135,712	$ 257,885
Total liabilities and equity	$ 313,216	$ 435,088