CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 50,750	$ 52,056
Accounts receivable, net	29,750	19,478
Unbilled receivables	16,349	37,304
Inventories	14,728	14,508
Prepaid expenses and other current assets	5,754	7,643
Total current assets	117,331	130,989
Deferred income tax asset	1,877	1,753
Property, plant, equipment and seismic rental equipment, net	50,007	52,153
Multi-client data library, net	84,433	89,300
Goodwill	25,188	24,089
Intangible assets, net	1,374	1,666
Other assets	843	1,119
Total assets	281,053	301,069
Current liabilities:
Current maturities of long-term debt	1,014	40,024
Accounts payable	22,817	24,951
Accrued expenses	26,195	38,697
Accrued multi-client data library royalties	28,324	27,035
Deferred revenue	11,330	8,910
Total current liabilities	89,680	139,617
Long-term debt, net of current maturities	116,916	116,720
Other long-term liabilities	12,938	13,926
Total liabilities	219,534	270,263
Equity:
Common stock, $0.01 par value; authorized 26,666,667 shares; outstanding 13,909,509 and 12,019,701 shares at March 31, 2018 and December 31, 2017, respectively	139	120
Additional paid-in capital	950,464	903,247
Accumulated deficit	(873,347)	(854,921)
Accumulated other comprehensive loss	(17,054)	(18,879)
Total stockholders’ equity	60,202	29,567
Noncontrolling interest	1,317	1,239
Total equity	61,519	30,806
Total liabilities and equity	$ 281,053	$ 301,069